- Mini Bird E Building Instructions
- Ray's Practice Hi Start For Small Field Flying Instructions
- Helpful Hints for Using any CA Adhesive
- Sky Bird Construction Guide
- Sky Bird Wood Fuse Construction
- Electric Power for Sky Bird
- Challenger Assembly
- Big Bird (setup)
- (wing tip stall)
- (center of gravity)
- Lil Bird 2 (fuse)
- Lil Bird 2 (covering exposed wood)
- Lil Bird 2 (polyhedral brace)
- Assembling the Palio
- Assembling the Osprey 1 V
- Assembling the Cloud Bound 4
- 2M Lil Bird (CG & towhook location)
- 2M Lil Bird (wing)
- Sunbird (stab)
- Sunbird (fin & rudder)
- Sunbird (fuselage)
- Sunbird (wing)
- Pierce 970 - Sky Bench Modifications
- Oly II
- Oly III (Bob Leque)
- Oly III (Terry Forbes)
- Tips on adding carbon to the Oly III wing spars
- ED SLOBOD'S PARAGON KIT INSTRUCTIONS
- Legionair - tips and changes
- Legionaire - Notes from Robin Sleight
- Ray's Gulf Coaster - Building Tips (PDF)
- 3M Scooter - Ray's BUILDING TIPS
- Merlyn - Ken Bate's Building Instructions
- Push-Rod Installation Tips (separate page)
- Wing Construction Tips (separate page)
|Mini Bird E Building
by Ray Hayes
The Mini Bird E is a smaller version of the highly successful Sky Bench Lil' Bird 2 hand launch design that many builders convert to a speed 400 electric powered sailplane with great flying success. This smaller version builds exactly like all the Sky Bench Bird series, simple and quick. You will need to be careful when working with the 1/32" wing sheeting and Ca glue, the Ca will travel far and fast through the veins of the sheeting and glue your fingers to the sheeting quicker than you can blink an eye.
The following step by step instructions is the way I build, you may have a different approach and that is one of the fun things about building woodys. Please be aware that writing building instructions to a model airplane is sometimes like talking in English to a Spanish audience. The very best approach to building any woody is spend as much time as needed reviewing the construction plans to understand how and where the parts are placed. The worst thing you can do is dump all the parts out of the plastic bags at once. To review the parts, they do not need to be removed from the bags. All the parts are depicted on the plan, so why open a parts bag until it is needed ? To give you an idea of variances of building skills that can be found between the not so experienced and the experienced builders, an experienced builder like myself can build almost any kit without reading the written instructions. In my case, I consider taking time to read the building instructions is a waste of time, but I have been building woody models since I was six years old.
Start with the Wing.
Always place wax paper over the construction plan with pins in the four corners to hold the plans and wax paper flat to the building board.
Always trial fit parts before gluing them.
Place pieces of masking tape on the bottom side of the bottom sheeting where each rib will come in contact with the sheeting. The tape should be no longer than an inch on the bottom with tape protruding another inch which will be used to attach the bottom sheeting to the ribs and later the top sheeting to the ribs.
Pin the inner panel bottom front sheeting over the plan, trim if necessary. After the wing panels are joined together and the top sheeting is glued to the wing, the front edge of the top and bottom sheeting are sanded back to the front edge of the ribs prior to installing the Leading Edge pieces.
Use one of the ribs # 3 through # 7 as a guide to locate the placement of the Trailing Edge bottom sheeting. Note these ribs are shaped on the bottom to fit in between the front and rear bottom sheeting (top sheeting also). Pin the Trailing Edge down.
Using the same rib as above, use it to locate the spar location on top of the bottom front sheeting. Place the spar on the sheeting and the rib on top of the spar. The rib should fit between the front and trailing edges and over the spar. Place about 4 pins against the front side of the spar to create an alignment fence. Glue the spar to the bottom sheeting using the alignment pin fence as a guide. Never stick pins through the spar to hold it down.
Glue in the bottom 1/32" sheeting pieces at the root between the front and rear bottom sheeting. Note ribs # 1 and 2 are shaped to lay flat on the bottom and top sheeting. These ribs are shaped differently than all the remaining ribs.
Glue in ribs # 2 through # 7. Check to make sure the ribs rest on the bottom balsa sheeting, due to irregularities in spruce spar thicknesses, an oversized spar will not let the ribs rest on the bottom balsa sheeting properly. Use a file to enlarge the spar notch in the ribs as needed. Check the top spar notches at this time too. Ribs # 1 are glued in when attaching the two inner panels together to form the center dihedral joint prior to attaching the top sheeting.
For added spar strength, glue in vertical grain 1/8" wide balsa shear web pieces to the top of the bottom spar between ribs # 1 through # 4.
Glue in the top spar, be sure the vertical shear webs between rib # 1 and # 4 are flush with the bottom of the top spar. I always use weights on the top spar at this stage to insure the wing is flat and the spar is completely down in the rib spar notches.
Place weights on the ribs between the spar and trailing edge to hold the wing flat to the building board. Starting at rib # 4, use the tape previously installed to pull the bottom sheeting up tight against the bottom of the rib and glue with Ca.
Continue gluing the bottom sheeting to the ribs by alternating to rib # 3 and then rib # 5, etc.. If you start gluing the bottom sheeting at rib # 1, 2, 3, 5, 6, or 7 instead of rib #4, you will end up with a buckle in the sheeting and that will be a disaster.
Glue in the 1/32" balsa shear webs to the fronts of the top and bottom spars and the sides of the ribs and flush with the top of the spar. Use the extra 1/32" sheeting rectangle supplied in the wing sheet package to make the taller shear webs located between ribs # 8 thru # 11.
The outer tip panels are made in the same way as the inner panels. Install the 1/8" vertical balsa shear webs and the 1/32" sear webs on both sides of rib # 7 after the outer wing panel is joined to the inner panel with the plywood polyhedral brace WPB. Do not install the tip blocks until all four of the wing panels have been joined together and the top sheeting has been installed.
Join the outer tip panel to the inner panel by placing the inner panel on the work surface and use weights behind the spar to hold the wing down. The tip panel is raised 2 - 7/ 8 " at the trailing edge of rib # 13. Sand a bevel into the top and bottom tip panel spars and trial fit. Do this in small amounts so as not to sand too much off the spars. Cut rib # 7 along the back side of the spar with a zona saw and glue WPB in place. I use small bendable metal clamps available in the women's hair treatment department of most chain stores to hold the shear webs and plywood parts to the spars while gluing.
Install the 1/8" vertical shear webs on both sides of rib # 7 as shown on the plan between the spars and the remaining 1/32" shear webs to the sides of the spars.
Join the other tip panel to the remaining inner panel in the same manner.
Join the two inner panels by laying one panel on the work surface, use the weights again to hold the wing flat. The other inner panel is raised 2" at the trailing edge of rib # 7. Install both WDB parts to the sides of the spars and 1/8" vertical shear webs.
Cut to proper length and install both Ribs # 1
Install the two anti - crush blocks on each side of Ribs # 1. Sand a bevel in the top of them to match rib contour.
Use an electric drill to make the wing bolt holes as shown on the plans. Be careful not to cut the sides of WDB while drilling the hole.
After the wing panels are joined, install the top front sheeting and trailing edge to one inner panel. Use weights to insure a flat wing. The bottom trailing edge needs to be sanded with a Perma grit sander to create a nice bevel in the rear edge to accommodate the top trailing edge. See wing profile side view on fuselage plan.
Install the top front sheeting and trailing edge to the other inner panel.
Install the top sheeting and rear trailing edge to the tip panels and be sure to weight the panel down to keep the wing from being twisted. Use the masking tape to hold the top sheeting to the ribs at the front edge and weights above the spar. I use Sig wood glue for the top sheeting.
Install the leading edges and tip blocks. If you purchased a Perma Grit sander you will be able to sand out the leading edge and tip blocks in half the time of a regular sanding block and with better results. Final sanding on the leading edge should be done with spanwise strokes or you will have a wavy (changing) leading edge, which is not good. I use masking tape to hold the Leading edges on during gluing.
Any wing that is twisted will have less performance than a true wing. Place two yard sticks under each panel, site them for being parallel to each other to check on wing twist. A twisted wing means it is flying at two or more angles of incidence. A twisted wing means the plane wants to turn one way at slow speed and the opposite way at fast speed. Not good.
Next is the Fuselage.
The most important issue with the fuse sides is making sure the bottom edges of the sides are straight. This determines the wing incidence in relation to the stabilizer which in turn determines the flight performance and characteristics and the balancing point.
The second most important issue is the rear fuse sides have a left and a right side. Refer to plan where the push rods exit the fuse.
I like to make a pin fence to use as an alignment guide when gluing the front and rear fuse sides together.
To make an accurate pin fence use a straight edge ruler and be sure the pins are vertical, not slanting. This fence is also used to glue the 1/64" plywood doublers to the fuse sides.
Gluing the doublers is critical and care has to be taken to match the fuse tab holes in the 1/64" to the corresponding holes in the 1/16" balsa sides. Use a former before gluing as a guide and make sure the plywood doublers will end up on the inside of the fuse.
I use Ca to glue the 1/64" ply doubler to the fuse sides, the pin fence becomes a location guide and this is vital if you are using Thin Ca which will set up too fast to allow time to shuffle the doubler around to the proper position.
If you use wood glue on the doubler, the water based glue will cause the sides to dry with a pronounced curve. Not good.
One way to make a straight fuse (instead of a banana shaped fuse) is place a mark on the front side of the fuse formers at the bottom directly in the middle of the former. Placing a straight line on your work surface and matching the marks on the formers to the line will serve as a jig or guide to keep the fuse, front to back straight.
The fuse sides are parallel from F 1 to F 3. Glue these 3 formers at right angles to the fuse sides. At this time glue the short pieces ( 1/2" or less) of the yellow tubing in the slots provided in the formers. Doing this after you glue the formers is not good.
A nose block and tow hook is not furnished in the electric Mini Bird E, they are furnished in the Mini Bird thermal version kit.
Install the top and bottom rear longerons to both sides. Note the longerons butt against former F-3.
The longerons, as shown on the plans, are beveled at the rear to accommodate F 8. If you have a Perma Grit sander, you can create the bevel after former F 4 and 5 are installed.
Install the 1/8" sq. spruce rail.
Set the fuse side with the three formers attached upright on the straight line and glue the three formers to the other fuse side.
Install the remaining 1/8" sq spruce rail.
Install formers F 4 and 5 with the small pieces of yellow push rod tubing.
Do not install the top and bottom before installing the push rods. Although the yellow tubing is furnished in the kit, I don't use it, but you have to keep the holes in the fuse formers open during the gluing process if the tubes are not used. I install the fuse top, but not the bottom before I install the push rods. The rear bottom is installed after the stab and elevator are glued to the fuse and hooked up to the push rods and the rc/ batteries, etc are installed. The front bottom is installed after the spacers are glued to the bottom of the hatch block and the blind nut wing mounting system is installed and the servo tray is installed. If you put the front bottom on before the blind nuts and spacers, you will be hard pressed to do it later. Not good.
I install the stab and fin with the elevators and rudder installed before the wing mounting system. The stab position will then be used to align the wing horizontally. The wing can be installed before the stab and fin.
Stab - Elevator
Pin the stab to the building surface.
Place the spruce tie bar and elevators against the stab and glue the tie bar to the elevators with wood glue.
Sand the outside edges round.
You have a choice of using the hinges provided in the kit or taping the elevator to the stab. If you use the hinges, bevel the front edge of the elevator as shown on the plan. If you use a tape hinge on top of the stab and elevator, bevel the front edge of the elevator to allow the elevator to move down without hitting the back edge of the stab.
Cover the stab and elevators before assembling the elevators to the stab. Leave the portion of the stab where the fin will touch uncovered for gluing purposes.
Fin - Rudder
Glue both F 10 to each side of the rudder as shown on the plan. Note the F 10 with the slot is on the left side of the rudder.
Sand the outside edges round.
Bevel the rudder for hinging as above.
Cover the fin before gluing to the rudder. Do not cover the rudder tabs that protrude into the stab slots.
Several choices here.
I finish my Lil' Bird 2 and Mini Bird E by using oil based Polyurethane applied with a good one inch brush. Oil base is used instead of water based because you know what water does to wood and especially 1/32" thin balsa wood. Water based polyurethane is used where foam is present in the construction of some models.
The secret to a light covering with polyurethane is Bounty Paper Towels. Apply the Poly to one section of the wing at a time and wipe off with Bounty Towels immediately. Don't let the Poly run inside the wing and fuse or soak into the wood. I wipe until I can see no sign of dampness. Bounty will suck up the Poly instantly, other brands of paper towels will simply push the poly around. One coat is plenty.
The same process is used on the remaining parts of the Mini Bird E.
Cover the open bays areas of the wing with a light plastic heat shrink. I use what I sell on my web site because it is the lightest weight and is very user friendly.
Depending on what type of surface you fly from (landings) you may want to cover the front bottom of the fuse for added protection.
The entire model or parts of it can be covered in your choice of light weight heat shrink plastic without the mess of Polyurethane. But remember, the wing's trailing edge and d - tube sheeting is 1/32" balsa wood and it won't take much for the heat shrink material to warp these fragile wood surfaces.
Install fuse former F 8 if you haven't done so already. Note it protrudes behind the fuse formers..look at the construction plan.
Use an Exacto blade to cut a slot in the elevator and rudder for the plywood control horns as shown on the plans. Make sure they align with the exit slots in the fuse sides.
Use epoxy to glue in the control horns.
Use an Exacto blade to make slits for the rudder and elevator hinges unless your hinges will be tape.
Glue the rudder to the stab, make sure it is straight up 90 degrees to the stab.
Slide the wire push rods onto the plywood control horns leaving the z bend in the horns.
Install the push rods through the fuse and glue the stab to the fuse. A trial fit is called for here to check stab alignment.
Install the two laser cut plywood blind nut bases under the 1/8" sq spruce rails.
Place the wing on the fuse and check for alignment to the stab and top view.
Drill through the holes you made previously in the wing's dihedral joint and into the two plywood blind nut bases.
Place the two nylon 4-40 bolts through the wing and the plywood basses into the blind nuts. Slightly tighten the bolts and seat the blind nuts.
When your satisfied with the wing alignment, use 5 minute epoxy to secure the blind nuts to the plywood bases. Not the nylon bolts.
Use your hand to move the push rods to make sure the controls work freely.
You can install the motor and four triangular balsa sticks surrounding the motor, the battery and controller, and rc equipment now, before installing the bottom of the fuse. The triangular sticks can be sanded to contour the nose to a prop spinner.
The battery hatch construction is self explanatory. Extra 4-40 nylon bolts are included for wing and battery hatch hold down.
Most builders today don't take the time and make the effort to read the construction plans before starting the construction. Most want to open the kit box and start building and reading the instructions simatanously. Real builders read the plans first, I hope you did.
Trimming and Flying.
Balance the model on the back edge of the spar. During first flights set the balance point on the front edge of the spar.
The up and down elevator movement is not critical. Usually, the pilot makes the difference. I like a lot of elevator and rudder travel to be able to keep the plane out of trouble when it is near the ground. If your a control stick banger, side to side, no finesse, up and down, nervous norvis type flyer than you can set the controls up to have less travel volume to smooth out your flights.
I leave the power system up to the builder. I'm using a Speed 280 direct drive with a 6 - 3 folding prop. The fuse interior has plenty of room for any type of battery configuration.
|Ray's Practice Hi Start For
Small Field Flying Instructions
by Ray Hayes
Assembly: Attach the parachute to the line and then attach the chute to the reel. Wind the line on the reel and then add the rubber to the line. Continue winding until all the rubber is on the reel. The rubber ends up exposed to light, to extend the life of the rubber, always keep the Hi Start in a box.
Launching: Drive stake, attached to the metal ring on the end of the rubber, in ground, up wind of your launch and landing site. Walk down wind until line is off the reel. Hi Start can be stretched between 20 and 30 paces, place reel on the ground from your (stretched ) launching point for easy reference.
Launching Method: Remember the rubber is only 40 foot long and therefore you do not want to waist any of the stretch by simply letting go of your sailplane. Letting go means your plane will initially travel towards the stake without gaining much altitude. Figure it out, watch how much forward and nearly horizontal the plane travels before it starts to really climb out. If the forward travel distance is 20 feet, more or less, that is the amount of stretch in the rubber you removed before the plane starts to climb by simply letting go of the plane.
Ray's Launching Technique: We learned this method when I was living in the great state of Michigan during my Hand Launch Sailplane Mini Hi Start flying events called the Great Lakes R/C Soaring League. It works great on Ray's Hi Start for 2M, Std and light weight 3M planes.
A. Place the tow hook no further forward than the CG location. I found that putting the hook behind the CG and using down trim during launching will produce the highest launch, including zooming off at the top.
B. Use 20 to 30 paces depending on wind velocity and size of sailplane. The more wind the higher the zoom. Start with 20 paces on 2 meter planes. I launch my 100" Big Bird on no wind days from 30 paces and it releases directly over the stake.
C. At time of release, do not just let go of your sailplane, you are inviting a pop off, especially on 2 Meters. Try to throw your plane as straight up as you can, this means the plane will be headed up instead of out and close to flying speed when it leaves your hand. The result is the rubber will not lose much of it's stretch and provide the power to take the plane above the stake even on windless days.
One more launching tip, my body is between the plane and the stake when I throw the plane up. I am not behind the plane, extending my arm towards the stake while holding the plane, which would mean I would just simply be releasing the plane from this stance. Enjoy and don't forget to use a landing spot or tape every time you fly, Practice, Practice, Practice.
|Helpful Hints for Using any CA
From Balsa USA
Sky Bench has been using Balsa USA and Sig Mfg. Inc. CA glues since they arrived on the market. They are both very good glues and we recommend them highly. The thin CA is the most widely used for balsa to balsa, balsa to spruce, balsa to plywood and plywood to spruce. We keep our stock in a freezer.
|SKY BIRD CONSTRUCTION GUIDE|
The Sky Bird is the largest of the Bird Series that started with the Lil bird 2 hand launch design. This Bird flies just like all my Bird Series, slow or fast with just a couple of clicks on the stab trim lever. It is capable of very tight turns to stay in small thermals without dropping a wing tip and because bigger flies better, the
Sky Bird will give you long flight times even in marginal thermal conditions. The design has produced a highly maneuverable sailplane that is extremely easy to fly and land.
I have yet to install the spoiler blades in my first Sky Bird. I usually come down from a high thermal flight by diving my planes down towards me and then burning off speed away from the landing spot. With a moderate long approach, the Sky Bird without spoilers will come in about a foot off the ground and be ready to land at the spot. My second Sky Bird will have wings with flaps with a coupling mode to the stab for precise landing control. The flaps will also open up the speed envelope and by dropping them approximately 1/16" provide increased thermaling ability in very weak lift.
Who will be the first person to build a Sky Bird full house, flaps and ailerons? The tip panels will need to be lowered and I am hoping to the first to have a full house Sky Bird. I started flying the Sky Bird with a wood fuse and now have it on a glass fuse that is truly good looking, very strong, and cuts the building time. You will not believe how quick the glass fuse Sky Bird builds up. Basically, you build the wings, and everything else is done. I know you will love flying my Sky Bird.
Watch for more new designs in the Bird Series. I am working on a 50 incher and a P-30 Class rubber free flight version of my great Lil Bird 2. Both could be used with electric power. I hope to be flying a 30" Micro Bird with electric power in my backyard soon and the free flight version at the AMA flying site this spring.
Wing: .007 Carbon spar caps are no longer included in the kite.
I stopped including the carbon a couple of years ago. I was issuing .007 x 3/8, a total waste since .007 does very little stiffening and the two spar system is very strong without carbon.
Carbon should not be considered if kit is being built for electric or just hi start launching.
About the only reason to add carbon is for hard zoom launching, but a lot thicker than .007.
|Sky Bird Wood Fuse Construction|
|The Sky Bird fuse construction is almost identical
to the Big Bird fuse, the exceptions are:
Start construction by:
Glue the 1/32 laser cut forward balsa sides to the 1/8" plywood forward fuse sides. Do not use water based glue.
Glue the forward and aft fuse side parts together, use a 36 inch ruler to make sure the bottom of the fuse is straight.
Glue the forward and aft 1/64 laser cut plywood doublers to the inside of each fuse side. apply slow cure epoxy to the 1/64 plywood.
Cut and angle the 1/8 x 3/8 spruce rails and glue to the fuse sides, use F2 as a locating guide. use slow cure epoxy.
Make a mark on the face of each fuse former at the bottom that is accurately in the center of each former.
Assemble the fuse formers to the fuse sides directly over the center line on the construction plan. line up the mark on the formers with the center line on the top view of the fuse plans.
Glue formers F 2, F3 and F4 to the fuse sides first. use slow cure epoxy and clamp. If you get this accurate, you will have a straight fuse. make sure you keep the push rod holes open in the fuse formers.
Glue formers F1 next followed by F5 and F6 and then F8 (stab mount).
Glue F9 after sanding to fit (balsa block).
Glue the nose block in place.
Cut/sand the canopy balsa block to fit and glue on the canopy block spacers to the bottom of the block by placing the spacers inside the fuse sides and placing the block on the spacers. Check spacer alignment by viewing from the bottom of the fuse.
Glue the two 1/8" rectangular plywood laser cut servo tray supports to the inside of the fuse.
Install the servo tray and the RC on and off switch.
Install an antenna tube from F 2 through F 6. I use a series of straws because they are virtually weightless.
Sky Bench Wire Control Rods: Install them after the formers are installed, but before the top is glued in. The wire push rods have pre- bent z bends, they fit in the Rudder and Elevator nylon control horns. Cut the nylon tube into small 3/8" pieces, push the rod thru the rear exit slots in the fuse sides. The rods cross at their entrance/exit in the fuse sides. Slide the nylon tubes on the wires, locate one tube at the crossing junction on the bottom wire to eliminate friction. Use balsa between the fuse sides placed under the nylon tube and use a small amount of clear Silicone to glue the tube to the balsa. Locate the other tubes between the fuse formers and glue the tubes to the fuse sides with a small dab of Silicone.
Cut the third wire to fit the distance from the end of the rear wires thru the Du Bro Servo Connectors. The wires are butted inside the couplers and soldered. Roughen the wire ends with a file for better adhesion to the solder. Use Aluminum Foil to protect the fuse sides and bottom while soldering the wire inside the couplers.
Glue the rear laser cut balsa top inside the fuse sides.
Glue the forward laser cut plywood bottom.
Install the tow hook base and hardwood mount.
When the wing is completed, install the two brass wing joiner tubes and aluminum alignment tube in the fuse, but do not glue them in until you have assembled the wings to the fuse and checked for alignment to the fuse, to the stab and equal angle of incedence of both wings. Glue the tubes in with epoxy. The alignment should happen automatically if the fuse is built properly, but we are just humans, so check your work before gluing the tubes and stab to the fuse.
I drill a few 3/16" holes in the plywood stab mount before gluing the stab to the fuse with slow cure epoxy. The holes will improve the glue joint. I also cover the stab before gluing it to the fuse as well as the fin before gluing it to the stab, be sure to leave the gluing areas uncovered.
Install the balsa blocks above the wing joiner tubes and the rear bottom of the fuse.
Sand the fuse corners, nose block area and canopy. I use a Perma Grit sander becuase they sand so much quicker than sand paper on blocks. Why are they quicker, because they don't load up.
|Electric Power for the Sky Bird|
by Bruce Ettinger
Power considerations: The final weight of the electric powered (ep) Sky Bird will be about 5 1/2 pounds. A minimum of 50 watts per pound is needed and 75 watts allows better climb and ROG (see carriage). To provide 250-300 watts, use a Phasor 30-3 or equivalent, with 12/6 folding prop (Graupner). A 3-cell lipo battery with 3400-37000mAh capacity allows lots of flying time.
Weight considerations: The power train consists of Phasor 30 (7.7oz), Jeti 40 speed controller (1.3oz), prop/spinner/adapter (1.7oz), and 3700 3-cell lipo (10.4oz). This totals 21oz. A comparable Outrunner brushless motor would be 28-12; this motor, like the Phasor, has a 32mm outside diameter. By replacing the receiver battery (3oz) and avoiding lead ballast in the nose, the overall weight is increased by about 16 ounces. Given the 9.3 square foot wing area, the added weight increases the wing loading from 7.5 to 9.2 ounces/square foot. We used one steel wing rod and one carbon fiber rod (probably one rod would do for electric power). Depending on the size of the battery, some lead will be required in the tail---about 1 or 2 ounces.
Fuselage changes: To accommodate the Phasor 30, the front of the fuselage needs to be expanded in width. Make 2 new formers (replace #1 and make new firewall). These need to measure 40mm (inside) in width, not including notch extensions. Make the hole in #1 large enough to accommodate the 3 large wires and connectors from the motor to the speed controller. The 40mm inside width will allow enough room to fit a 32mm wide motor (see thrust below for explanation). The bottom plywood sheeting also has to be replaced with a wider version to accommodate the wider front-and this should have four 3/4 inch cooling holes starting about 6 inches back from the front (leave 1/2 to 3/4 inch between holes)-these will help cool the battery. When carving the main hatch cover, create a good-sized air intake duct towards the front-this will allow air flow over the motor and back to the battery. Both 2 over-wing blocks need to be made into removable hatches to allow access to the servos as well as the wing-holding spring. Instead of installing a tow hook at the CG, set a nylon washer over the drilled hole- this will allow use of a launching hold-down pin.
Placement of battery: The lipo battery will fit nicely in front of the wing in the main hatch area. By keeping battery close to the motor and speed controller, you avoid long, heavy wires trailing through the fuselage. This means moving the 2 servos and radio to the under wing area.
Thrust: Having electrified several sailplanes, I knew that at least 4-5 degrees of down thrust was be needed---otherwise you will be applying a lot of down elevator and the transition from power to glide will not be smooth (even with channel mixing). Rather than making the firewall (engine mount) at right angles to the lower fuselage line and parallel to other formers, tilt it downward about 3/32 inch. This also avoids an unaesthetic tilting of the entire motor and prop assembly (making the spinner far away from the nose on top but close on bottom). Two or three degrees of right thrust will also be needed (accomplished by placing a washer between motor and firewall on the right upper mounting screw. The motor will be angled inside the fuse front, and this requires the extra room we have built in (40mm for 32 mm motor cylinder).
Flying: In a word, spectacular! The climb rate was fine at half-throttle. Using transparent Monocoat allows the sun to glow through the 11 foot span beautifully. The glide rate is a bit faster than "floating" and landings are possible without spoilers, although lots of space is needed. I would suggest spoilers if landing space is limited.
Congratulations: The Sky Bird is awesome in size and behavior.
This is the stab fairing block that fits inside the fin. I start by cutting the block at the same angle as the rear fin post and then making a hole from top to bottom for the block to slide down the front fin post. Mark the side of the block as shown using the plywood fairing side piece and make the necessary cut outs for the front fin post and control horn. Drill a hole for the aluminum pivot tube that the stab control horn pivots on. The front of the block has a point due to the sweep in the leading edge of the stab. After mounting the stab, use the stab's LE to finish off the front of the fairing block to match the angle of the stab's leading edge.
Notice: The stab control horn has to be installed and the push rod connected for a trial fit before gluing the block in place and putting the sheeting on the sides of the fin. Included in the trial fit is making sure the stab is straight and level with the fuse and wings. When all of the above is finished then sand the fairing block to it's final shape.
The left side sheeting added to fin frame work. Notice the 1/64 plywood rectangle at the rudder push rod exit hole. This adds durability and helps eliminate sloppiness. The metal clamps are women's hair clamps available from K- Mart, etc. They are easily shaped to fit any circumstance. Very handy.
This is my second fuse due to RC radio failure. I am trying to give it a very old look (Miss America for those that know) and have placed 1/64" plywood on the outside and inside of the fuse.
I used a top hatch in my first Challenger to have access to the spoiler servo located in the fuse between the wings and it also makes the hook up of the flap servos located in the wings convienent. Note the ballast compartment with the door removed. Nylon 4-40 bolts and blind nuts are used to secure the ballast door and top hatch. The top of the fuse and hatch lid will also have 1/64" Plywood.
|BIG BIRD SETUP
|Click here for helpful construction photos.|
|This design has several very noticeable flight characteristics
that distinguish it from all other 100" span built-up
|Sky Bench Aerotech kits designed by Ray Hayes include: Lil Bird
2, Big Bird, 1.5m Osprey, 2m Osprey, Osprey 1, and 1/2A Schtick.
All use the same airfoil. The airfoil performs in a way that allows
my designs to be built without washout in the wing tip panels,
regardless if it is a powered or sailplane design. None of my
designs have tip stall tendencies.
There are two benefits received from building model airplanes without washout in the wings.
Washout in wing panels is used to delay tip stall, and therefore make the model easier to fly, but at a lower flight performance.
Please do not build the above
designs with washout in the wings.
|Locating the balance point is critical to flight performance
of any model.
Most beginners to r/c models are advised by someone to be sure and have the c.g. (center of gravity), or balance point, set forward so the airplane won't be squirrelly. I have heard this on flying fields since 1968. Because of this poor advice, most r/c sailplane pilots' skill levels at finding thermals remains mediocre.
The results of a forward balance are:
Remember, the thermal is being pushed downwind by the wind, so
let the glider go downwind with the thermal to gain more height.
All my designs penetrate at light wing loadings and therefore, even
the Lil Bird 2 will fly safely in 15-20 mph. winds without adding
|There are two ways to attach former f-6.
Why narrow the fuse?
|Put just one coat, instead of two coats of oil-based
Polyurethane on balsa according to kit instructions. This provides
adequate water-proofing at less weight.
Please do not cover any parts of LB2, other than the open
sections of the wing. Do not wrap covering around the wings'
|The plans show this polyhedral brace (wpb) installed on the
front side of the wing spars, but it will be easier to install and
just as strong on the back side of the spars. The wpb brace must be
epoxied to the spars rather than a balsa shear web for proper
strength. A completed, in the air, LB2 should weigh 10 oz. or less.
In winds above 20 mph. I add 4 to 8 oz. of ballast just behind my
normal C.G. location.
|The pre drilled wing and stabilizer joiner holes in the
fuselage are absolutely dead on accurate and so are the joiner
tubes in the wing and stab. Therefore, the alignment of the stab to
the fin and wing is also accurate. All that is required to assemble
the stab to the fuse is slide the stab wires through the fuse and
slide both stab panels on.
To install the brass wing joiner tube, first roughen it up with a file to improve epoxy adhesion. Slide the tube over the wing joiner rod and then install in the fuse. Slide both wing panels on to the joiner rod, check alignment, and apply small amounts of 5 minute epoxy around the tube inside where it touches the fuse. Just enough to secure it. Let the epoxy set up fully before sliding the wing panels off the joiner rod. Apply additional epoxy to one end of the brass tube at a time inside the fuse for additional strength. To prevent the sides of the fuse from becoming scratched while filing off the protruding ends of the brass tube, cut a hole in masking tape and slip over the brass tube and apply to the fuse sides.
The plywood R/C and electric motor battery tray is shaped perfectly, and so are the two formers. To remove the die cut parts, simply sand the back side of the plywood until the part is easily removed.
If you install an electric motor, two plywood motor mounts are furnished. Use only one to clear prop connector.
The plywood R/C tray sits low in the fuse, so the servos are best mounted by using a cross rail on top of the tray. The ACE 8107 servos ($17.95 from Sky Bench Aerotech) get lost in the huge, but strong , servo tray. I am using a 500 motor, ACE six cell 1800 Mah battery and a 10 - 6 Graupner folding prop. The Graupner 8 - 6 spinner/folding prop combination fits the fuse profile perfectly, but I altered the 10 - 6 prop to fit the smaller spinner to increase the thrust performance.
The control cables have pre-installed, threaded, connectors for the clevises to attach to at the control horn junction, and the screw-down type connectors quickly anchor the cables to the servos.
The Palio can be assembled in a long evening or in one day
for sure. Therefore, the first step in assembly is to put the
batteries on charge.
Photo #1: Vertical grain balsa blocks between the spars at
ribs # 1 have been added to strengthen the dihedral joint. The
blocks are also necessary because of the hole that will be drilled
for the 4-40 one inch nylon wing hold down bolt. A 1/32 plywood
dihedral brace will be added to the rear of the spar. Add similar
blocks to the polyhedral joints. I have found using a Teflon tube
in the CA glue bottle is very helpful. Apply rubber cement or
contact glue around the tube where it exits the bottle to stop
Photo #4: The black line in the leading edge is .007 laminated carbon fiber. If you want to have a very strong , but light weight leading edge to help avoid dents and brakes here is how I build my LE. First glue on a 1/16" balsa stick to the sheeting and ribs as pictured in photo #3 and when the Sig Bond glue has dried sand the strips to the contour of the sheeting. Then use thin CA glue to apply the .007 laminated carbon to the face of the 1/16" thick balsa strip. Next glue on another 1/16" balsa stick to the carbon with CA and sand the edges to the contour of the sheeting and the first 1/16 strip. Glue on a 1/16" spruce stick to the 1/16" balsa strip and sand to the contour of the LE shown in the plan side view of the wing mounted to the fuse. A blunt leading edge is better than a to sharp leading edge.
Photo #5: Thanks to an accurately CAD drawn plan, the holes in the fuse formers to mount the boom are dead on accurate and coupled with the tab/slot fuse construction means the wing / stab incidence will be automatically attained. Experience has taught me that a kit with a nose block butt glued to the front former and/or the ends of the front fuse sides is a nose block that will break off easily. All my wood kit designs have the nose block sandwiched between the fuse sides for maximum strength and durability. Also note, that I have tapered the nose block, use the width of the flight battery pack as a guide.
Photo #6: This is how I glued my v-tail together. First cut it in half, then sand the proper angle and glue with short cure epoxy. The very tips of the stab are raised 4 ¾" from the work board. Make sure your blocks are parallel to each other and the v-joint is located centrally between the blocks. Apply 3/4oz. fiberglass tape to the v joint top and bottom with CA glue.
Photo #7: The construction plan shows a simple way to attach the v-tail to the bottom of the fuse. This photo shows how to make a completely drag free attachment. The next step is using CA to glue down ¾ oz. fiberglass tape over the glue joint top and bottom and then bevel a 1/16" thick spruce stick to fit inside the v joint and glue with slow cure epoxy. Drill two holes as shown to exit the yellow control cable housings. Drill them at an angle to prevent the cables or wire push rods from binding. Check for binding before you attach this assembly to the boom. Install the yellow cable housings in the holes and use slow cure epoxy to glue the stab to the inside of the stab notch in the boom. Use the glue sparingly. Drill undersized holes through the bottom of the stab and 1/16" spruce using the boom stab mounting holes as a guide and screw in the white 4-40 nylon bolts. Trim off the bolts as necessary.
The initial frame was extended a couple of inches to lengthen the tail moment. The kit has 1/64 plywood doublers located on the inside of the fuse frame and 1/4" sheet is used to fill the frame members starting just behind the wings trailing edge location. A piece of 3/32 plywood doubler is located inside the fuse on both sides approximately 2" outside the two wing joiner holes that extend from the top of the fuse to the bottom longeron. 3/32 plywood formers were made and glued in-between the 3.32 doublers. This will make the fuse in the wing joiner area adequately strong for modern day winch launching.
1/8 x 1/2 plywood strips are glued inside the fuse 1/8" below the hatch longeron and a 1/8 plywood servo tray is glued on top of the plywood strips. The strips extend from nose block to 2" behind the rear hatch opening. Additional 1/4 sq spruce longerons were glued inside the fuse on the bottom from nose block rearward past the hatch opening.
1/16" balsa was glued cross grain to the top and bottom longerons from front to rear except the bottom of the fuse from nose block to behind the rear wing joiner received 1/8" plywood. An additional balsa block will be glued to the bottom plywood and contoured sanded to make a rounded shape to the front of the fuse.
1/8 plywood piece not shown on plans. Attach to the bottom of the fuse after the fuse is framed up and the nose block is installed. The part is shaped to extend below the nose block for added strength.
2M LIL BIRD CG AND
|Many persons ask how I set my sailplanes up for CG and tow hook
location. I have learned over years of experience how to recognize
when a sailplane is set for maximum performance. The 2M Lil Bird,
because of the large inner panel wing spars, plywood dihedral
braces and D-tube construction (balsa sheeting on top and bottom of
wing from spar to leading edge) allows for a very aggressive launch
Consequently, I have my 2m Lil Bird set up with the tow hook behind the CG, just like my Big Bird and 2M Osprey. This location requires a bit of down trim on the elevator when launching to produce a fast launch speed and end with an impressive zoom. My 2M Lil Bird weighs 22.5 oz. ( wing loading is 5 oz. per sq. ft.) and balances with out nose weight with micro servos and Hitec micro 555 Rx and a 700 mah flight battery. An alternative is a 270 mah battery with large servos and large RX. I did not install spoilers on this one piece wing version.
My set up specifications: Cg: 5 1/4" forward of trailing edge,
Tow hook: 5 3/16" forward of trailing edge, Rudder throw: 2 1/2"
L-R, Stab throw: 1/2" up/down.
2M LIL BIRD WING
|Laser cut wing parts and tip block. Notice the wing ribs are
notched to receive the top and bottom 1/16" sheeting. This is D
Tube construction and is superior to an open frame wing because it
creates a more accurate airfoil than wings construction that causes
the covering material to sag between each wing rib. Also notice,
the sheeting is far behind the spars, this provides a very rigid
and strong wing structure. Open framed wings usually rely on the
plastic heat shrink covering for torsional stiffness and have a
tendency to flutter during launching or in a dive.
2 piece wing; brass tubes are located in each inner wing panel as shown. To install the tubes, cut the front (longest) 1/16" plywood spar braces, WDBF, in half and glue to front edges of spars and vertical 3/8" balsa shear webs, prop up each inner panel at rib 7A (dihedral joint) 1 1/2", place the tubes with the joiner rod in place in the panels, space the root of each inner panel 1/4" apart and make sure the panels are straight and not tilted forward or rearward, make sure the joiner system is level and flush against WDBF, tack glue with 5 minute epoxy. Do the same with a 1/16" wire and aluminum tubes to make a rear alignment pin system. The brass and aluminum tubes must protrude through the furnished 1/16" plywood root caps for necessary strength. The cavity surrounding the brass tube is filled with a mixture of epoxy and micro balloons before the 1/16 Plywood brace, WDBR, is glued to the rear of the spars.
The polyhedral joint plywood brace part is glued to the inner panel before gluing the tip panel. Sand the bevel in the trailing edges before gluing the panels together. You can save a lot of time when sanding if you use a Perma Grit sander, see "Sanders" catalog for a photo of the sanders.
Join the tip panels before joining the inner panels. After the plywood polyhedral brace is glued on and dried, install 1/4" wide vertical balsa shear webs between the tip panel spars as shown on the plans. At the same time, glue on the vertical shear web to the outside of the tip panel spars and clamp. This produces a light-weight and strong polyhedral joint
Why is a Sky Bench wing so strong? I use
1/8x3/8" spruce spars in the inner panel and most important are the
3/8" wide vertical grain balsa shear webs between the top and
bottom spar. The next photo will show the remaining step to make
the center dihedral super strong. Note the vertical grain
shear web at the end of the inner panel, a corresponding shear web
is located in the outer tip panel after the tip is glued to the
Another view of joining the inner
panels. Notice the wings are weighted down to insure the
wings are built flat instead of with a twist. Nothing turns a great
sailplane into a dog quicker than a wing that is twisted at the
center dihedral joint. A twisted wing requires the rudder to
be offset during flight. During slow flight the twisted wing
will cause the sailplane to turn one direction and during fast
flight it will turn the opposite direction. Take your time,
check the alignments before gluing.
Just below the stab is a 1/8 lite ply part that has the tab/slot feature. This functions as a fuse alignment jig and insures the glue joint between the fuse and stab is very strong.
The kit was revised to include pre laser cut holes for the nylon
control horn bolts in the rudder and elevator. The fuse is
extremely easy to build and build straight.
SUNBIRD STAB CONSTRUCTION
Construction of the SUNBIRD is simple.
This is a photo of the proto-type kit laser-cut stab and elevator.
The rear slot location in the stab has been moved forward in the
kit version. Also, one extra stick rib has been added to each side
of the stab in this photo. Sand the leading edge to a 1/8" radius
and taper the elevator to 1/32" at the trailing edge. If you use
tape for the elevator hinge, bevel the front edge of the elevator
as shown on the plans for clearance. The laser cut hole in the
elevator accommodates the pushrod control linkage. Cover with heat
shrink Mylar and double check for twists.
SUNBIRD FIN & RUDDER CONSTRUCTION
The fin has four laser cut balsa wood parts plus the front fairing. One fin side has not been installed in this photo for clarity. Note the two tabs at the top of the fin. They correspond with the slots in the stab to help create a stronger joint. The very top of the yellow push-rod housing is not glued to the fin to allow some movement during activating the elevator.
After the fin is completely assembled, glue the
furnished spruce sticks to the leading and trailing edge of the fin
for strength. The front edge of the rudder is beveled when using
tape for a hinge. The 1/64" plywood doublers are glued to the
rudder to support the rudder horn which is attached to the left
side of the rudder . After the doublers are attached, remove the
balsa wood to make a slot for the rudder horn and use 5 minute
epoxy sparingly to glue in the rudder horn. Sand the rudder's edge
to a 1/8" radius.
All the fuse parts except the four longerons, two spruce rails, hatch and nose block are laser cut. The bottom front piece is rectangular in the kit rather than narrowed at the front as shown here. Not shown in this photo are two carbon laminate strips glued to the fuse sides to reinforce the rear of the fuse at the fin mounting location.
The kit's LEFT rear fuse side has a slot for the rudder push wire exit. The longerons, 1'64 plywood doubler, fuse side halves, one of two spruce rails and F-2 and F-3 formers have been glued together in this photo. The formers have tabs that correspond to the slots in the fuse sides, this system provides building speed, strength and accuracy.
NOTE: the two wing mounting plates (F4 and F5) are
not identical and must be located correctly to match the wing bolt
locations. A plywood servo and switch tray is provide for the
builder's convenience and added fuse strength. REMEMBER TO INSTALL
the wire rudder push rod, glue the spacers to the hatch, and
install the wing mounting blind nuts in F4 and F5 BEFORE gluing in
the two bottom pieces.
SUNBIRD WING CONSTRUCTION
The first stage of wing construction. The bottom front sheeting has not been glued to the bottom of the ribs from the spar forward. Note rib 1 (center dihedral rib) has not been installed. It is glued in when joining the wing halves. The clamps are holding the spar shear webs while the glue is curing.
Pierce 970 Sky Bench Modifications
Changes from original kit plan. March, 2004
Laser cut parts: Fuse
Non Laser cut parts furnished that are not on the plan.
This is how I placed the fuse longerons. The top longeron stops 2 7/8" and the bottom longeron 1 1/4" from end of fuse sides. This allows the interior stab control horn to move freely and the fin post to be sandwiched between the fuse sides for greater strength. The forward ends of the longerons are beveled to allow the balsa block to fit on top of them. Mark the location of the rear fuse formers before installing the uprights. Bevel the ends of the longerons to allow the fin post to fit flush against the fuse sides.
The stab ribs are scaled so the root is approximately 1/16 larger than the plans, do not sand the ribs or jigs to match the plan. Use the spar line on the plan as a guide. All the ribs will need to be beveled to compensate for the angle of the leading and trailing edge for a good glue joint.
The all flying stab has a symmetrical airfoil. Construction is aided by three ribs actually designed as construction jigs. The trailing edge has been cut to perfectly fit flush against the ribs while laying in the jigs, so no sanding is needed. The jigs are designed to allow wax paper to be slipped under the front and rear ends of the ribs to eliminate the LE and TE sticking to the jigs.
Trial fit the spar notches in the ribs to be sure the spars will be flush with the top of the ribs before assembly. The spar stock size tolerances can vary, I had to use a file to deepen the notches just a tad. The ribs can be glued in before the spars, use a straight edge across the top of the three rib jigs to align the ribs top surfaces or your stab will be wavy. I prefer to place the spar in the three jig ribs first and then the remainder of the ribs, using the straight edge between the LE and the spar to assure alignment. I used wood glue and the weights to make sure the top spar is flush with the tops of the ribs.
The root rib is blocked up above the building board to compensate for the jigs. Install the aluminum tubes with the joiner wires in them in both panels for perfect alignment before removing the three jigs from each panel. Install the plywood root caps after the aluminum tubes are installed, be sure the tubes protrude through the plywood caps.
It doesn't show on the plans, but I will taper the LE as it approaches the tip before sanding it round to eliminate a sharp leading edge at the tip.
After the horizontal plywood shear webs are installed (do not cut the plywood up into pieces that fit between the ribs, cut the ribs away from the spar instead) Install the brass and aluminum joiner tubes.
Make sure the brass tubes are flush against the plywood and the 1/16" rear alignment wire is horizontal to the wing joiner rod and both the wire and joiner rod are parallel to the building board. The root edges of the wing panels have to be resting flat on the building board. Spot glue 5 minute epoxy to the joiner tubes and then fill cavity around brass tube with a mixture of epoxy and micro balloons. See the next pic for this procedure.
Mods not part of the kit: The stab horn is on the inside of the fin instead of the outside as shown on the construction plan. I have filled the stab spars 4 bays with vertical balsa, capped the stab root and stab fairing block with 1/64 plywood, capped the angled trailing edge with 1/16 balsa and filled the first rib where it meets the trailing edge with balsa. The aluminum pivot tube will be supported by the 1/64 ply on the stab fairing blocks.
The fin leading edge was rounded and streamlined a bit and the stab blocks faired to the fin's streamlined shape contour. The aluminum tubes will be partially filled with balsa to position the shortened piano wire stab connectors in the center of the joiner tube assembly. I have the option of covering the fin assembly with heat shrink plastic or glassing and painting it. I probably will go with glassing it so the fairing block junction with the fin will have a smooth and contoured fit.
The stab with out the wire connector rods weighs one ounce.
Sky Bench Aerotech
This design has been the accepted beginners kit by the R/C Soaring enthusiast for years and is still flown successfully in RES and Nostalgia competition today. It is strong and durable and has taught thousands of R/C pilots to fly sailplanes. See our Sky Bench web site for info on the RES (rudder, elevator and spoilers only) and the Nostalgia classes of flying categories. Also, be sure to review the Wood Crafters page too. The Wood Crafters is an annual event that takes place in Muncie, Indiana at the renowned AMA flying site.
This is a Fun Fly that includes the opportunity to fly in competition events if you so choose. The event is restricted to wood constructed sailplanes only and includes scale aero towing and electrics.
The Sky Bench OLY ll kit has been modified to strengthen the wing and uses a 5/16" diameter wing joiner rod and much longer plywood shear webs (W11). All balsa shear webs that fit between the spars have been changed to vertical grain types as opposed to some of the shear webs shown on the plan that have horizontal grain. The small part in each wing that fits against rib number 1 and is used to retain the rear wing alignment wire has been changed from hard wood to balsa wood. The laser cut plywood root cap has holes cut for the rear alignment wire and will be more than sufficient to retain the wire. All wing ribs, plywood shear webs and poly joint braces are now laser cut for dead on accuracy. The wing plan shows a wire on each wing tip block, this has been eliminated since most builders do not put the upward curve in the tips and makes the wing tips weigh less.
The wing ribs are packaged and stacked in the sequence they are placed on the construction plan.
The fin has been changed from a built up structure to a single laser cut part to increase strength and reduce building time. The rudder has laser cut top and bottom balsa wood block parts and the stab has laser cut tip blocks and center joint brace to reduce building time.
The fuselage now has one piece top and bottom parts to eliminate the time consuming installation of the gross grain fuse top parts. Included in the Sky Bench kit is a laser cut plywood servo and on/off switch tray.
A laser cut plywood fuse former, approximately 7 ¾'' long, has been created to be installed at the top of the rear fuse sides. The rear fuse sides are notched to receive the corresponding tabs on the new part.
An electric motor mount laser cut plywood fuse former is included in the kit for optional electric powered conversion. Notch the fuse sides to match the tabs on the former.
Six rubber bands are included in the kit, crisscross four of them and place two of them straight across the wing.
Refer to the Sky Bench web site "Assembly Tips" page for current up dates on all our kits.
OLY II Wing Construction Tips
Notice: Start the wing construction by placing the trailing edge on the plan first, this way the ribs serve as a guide to locate the spars and then the leading edge. The parts are more accurate than any plan due to the plan 's moisture content and copy machine tolerances.
Notice: Ribs W - 1 (one in each wing panel) are different than the two W - 1A ribs and the three W - 1 B ribs. Before installing ribs W - 1 and the first W-1A, glue in the 1/16 pre cut wing sheeting rectangles located beneath Rib W-1 and the first W-1A ribs. Look at side view of wing panel on the lower left hand side of the plan, notice the bottom spar and 1/4" sq rear spar are placed on the plan and the sheeting butts to them.
Notice: Ribs W - 1A and W - 1B have wider spar notches, This serves as a cutting guide when cutting the ribs away from the spar sides to place the Plywood W - 11 shear webs next to the sides of the spars.
Be sure the spars are in the middle of these wider spar notches.
W -11. 1/16 plywood laser cut spar webs, 2 required per wing panel, one on each side of the inboard wing panel spars. Note one end of W-11 are angled to butt against rib W-1. Use the angled end of W-11 to set the angle of the root rib, W-1.
Do Not Cut W-11 To Fit Between The Ribs.
Install the front W-11 first by cutting the ribs away from the spars, after the brass wing joiner tubes are installed, install the rear W-11.
After the 3/8" vertical balsa shear webs and top spar have been glued in, cut ribs W-1A thru W-1B between the spar and leading edge away from the side of the spar and glue in the front W -11 using slow cure epoxy.
Do not cut rib W-1 away from the side of the spar. W-11 butts to rib W-1.
OLY II Fuse Construction Tips
Sky Bench is continually improving all of our kits and designs with two things in mind, faster building and stronger airframes. Below are some of the updates to the great OLY ll, originally designed by Lee Renaud.
The kit now includes a complete package of DuBro Laser push rods and hardware. This will simplify the push rod installation. Directions are on the DuBro package.
Long 1/64" plywood fuse doublers and 1/8" plywood front fuse sides are used for greater fuse strength. The kit is now also supplied with 1/32" balsa sides to be glued to the outside of the metric size 1/8" ply fuse sides. This will cover the fuse former tabs and make up for the difference in thickness of the ply to create a smooth fuse side. A laser cut 1/8" ply part was created to fit between the fuse sides for the stab to be glued to for greater strength. The new part goes forward several inches to add strength and make alignment easier. I don't want your fuse to look like a banana.
Assemble the right side front plywood, 1/32" balsawood and 1/64" plywood doubler and rear balsawood fuse side first over the plan. The 1/32 balsa covers the fuse tab slots, the 1/64 strengthens the fuse. Use a very thin application of slow cure epoxy sparingly. Glue the rear 1/64 ply doublers to the inside of the fuse sides, use weights over entire surface of 1/64 doubles to eliminate warping. Place a metal yardstick on the bottom edge of the fuse sides to insure the bottom is perfectly straight. Use of Wood glue is OK for the rear 1/64 ply doublers if weighted during curing.
If you use wood glue between the 1/64 and 1/8 the sides will curl due to water content in the wood glue unless you weight the sides down until they are completely dry. And then they might curl a bit if you don't assemble the fuse right away.
Make sure the fuse former tab slots are lined up. Use the tabs on formers one and three to align the tab slots when gluing the 1/64" ply to the 1/8" ply sides.
The triangle sticks located on the front sides/bottom have been eliminated, the two front formers are no longer beveled to accommodate the triangles. The 1/64 ply doublers are much stronger than the triangle sticks.
Some parts may not fit the original OLY ll plan, the parts are accurate.
INSTRUCTIONS FOR COMPLETING THE OLY lll
Proudly written by Bob Legue
Items needed to complete your OLY lll
Tools required to complete the OLY lll
General notes for construction
Horizontal stabilizer and elevator assembly:
Fin and Rudder assembly:
* I converted the fuse to have this piece removable, only used cut off and scrap wood out of the kit to do it-no added wood.
** I used HS85MG.
THOSE BIG BEAUTIFUL WINGS!!
Congratulations you are ready to fly your new Oly lll !
Building a woody kit can be accomplished in many different sequences, techniques and methods. Doing things your way and making modification is one of the joys of building a woody. So have it and don't stop building till the OLY lll is flying.
WATCH FOR TIPS, CHANGES AND MORE PHOTOS TO THIS SET OF INSTRUCTIONS.
Thank you Bob Legue for volunteering to build, photograph and write these OLY lll instructions.
OLY III CONSTRUCTION
From notes by Terry Forbes
The OLY III represents a refinement of an R/C sailplane, the OLY II, a sailplane has been around for a long, long time. Many pilots built the OLY II as their first kit and found it to be not only an excellent trainer but a good competition sailplane as well. It is hoped that these instructions will help you complete your sailplane. If you're relatively new to hobby, years ago all R/C sailplanes were built this way. If you've been around the hobby for awhile, welcome back to the joy and satisfaction that only comes from both building and flying.
The first thing that should always be done with any kit is to get familiar with the parts and their location with respect to each other. The fuselage parts in this kit come out of the box rubber banded together so this is very easy. Locate the balsa side pieces. Lay out the sides next to each other with one right and one left. This has been stressed in every kit that I have ever built. It is very easy to build two right or two left sides. Mark everything so you won't make this common mistake. Be sure and make the marks on the inside surfaces so they won't show when construction is complete.
The lines offer a reference for the application of the epoxy, and to help in aligning the parts. Use blue painters tape to hold the parts in position and then cover them with wax-paper and weight them down for curing.
Most modelers use too much epoxy when laminating parts. Only a small amount of epoxy is needed to permanently bond the pieces. Use a slow cure epoxy of 30 min. or longer. Use an artist's knife for mixing and application of the epoxy. Then use an old credit card or one that you get in the mail for offers of a new card to spread the epoxy out. You will be able to work the epoxy into the wood. Balsa will soak up the epoxy very fast and the ply will also but not as fast. Squeegee the epoxy back and forth over the piece only leaving a very thin coating. You can move the excess epoxy from piece to piece. Once the contact sides are coated, you can align and tape them in place. Align the edges and the holes for the fuse former tabs. Tape the fuselage every few inches and then place on wax-paper and cover with wax-paper as to prevent bonding to your work bench. Push out from the middle of each part prior to applying the hold-down weight to get rid of any air trapped in the middle of the lamination. The parts to be bonded should have only a slight sheen on the sides to be mated. You don't want any excess epoxy oozing out anywhere. If there is any excess epoxy, clean it up with a paper towel and some 90% isopropyl Alcohol if it has started to set up. Pay special attention to the tab holes and the fuse fore and aft joiner edges. This will result in a more attractive fuselage and save much sanding later.
Bond the two aft fuselage balsa sides and the two nose fuselage sides first. Then bond the fore and aft fuselage sides together with the ply doubler. Use a metal straight edge and butt the fuse side bottoms up tight to keep the side assembles perfectly straight. Hint: candle wax rubbed on the straight edge's edges will prevent any bonding. After bonding, clean up any edges for a nice tight joining of the fore and aft fuselage sides.
Follow these steps:
1. Locate and mark the locations of the inner ply doublers on the outside balsa fuse sides. Make and mark a left and right side fore and aft. Balsa is to be on the outside of the fuselage sides.
2. Laminate the rear ply doubler's to the inside of the rear balsa fuselage sides. Mark the location of this ply-doubler on both aft balsa sides.
3. Laminate the nose ply doublers to the inside of the nose balsa fuse sides. Align edges and tape to hold correct alignment. Weight both fore and aft fuselage assembles and let cure. Remember to use wax paper under the weights.
4. Once both fore and aft fuselage side pieces are bonded, check fit prior to bonding fore and aft sides together. Apply epoxy carefully and bond the fore and aft side pieces together. The bottom of both sides are flat. Use a straight edge to ensure that sides are bonded with correct alignment.
Fuselage Construction Cont'd
Once the fuselage sides have been assembled with all of the lamination's and sub assemblies together, begin to assemble the sides with the bulkheads. It is always good to check the sides for alignment by stacking them next to one another. Several large Gym-Clips or similar clamps can hold the sides together. Then transfer any marks from one side to another and also lightly sand the bottom and top of the sides for a true matching set. Only "light" sanding should be required.
Number each bulkhead from nose to tail and also mark the bottom of the front side with a center mark. These marks are used as guides when joining the sides together. A straight line should then be marked on the building board. You will set the fuse sides with the bulk heads over this center line and use it and the center marks to align the bulkheads. Cover the building surface with wax-paper to prevent bonding the fuselage to the surface.
Transfer the location of the last two bulkheads (#5 and #6) from the plans to the inside of the fuselage sides. Trial fit the other bulkheads with the tabs in one side of the fuselage, one side at a time. Lightly sand the tabs to ensure a correct fit " As hard as I tried, I still managed to get some epoxy in the corners of the tab holes. I had to use my hobby knife and sanding tool to slightly round them off for a nice tight fit". Make sure that the fuse bulkheads correctly aligned with the large holes on the same side. Also make sure that the bulkheads are flush with the bottom of the fuselage sides. Do NOT bond the bulkhead to the sides at this time.
Locate the two 1/8" Ply servo tray supports. These fit between bulkheads #1 and #2. They are flush with the bottom of the fuselage sides. Use #1 and #2 bulkheads to correctly align these supports and bond them to the fuselage sides. Use thick CA or 5 minute epoxy and use weights to them hold in place until the adhesive of choice is set. Do both sides.
Next, find the two spruce fuselage doublers that fit flush with the top of the canopy opening. These extend from the rear of bulkhead #1, pass through #2 and butt up to the front of #3. Trial fit these doublers "dry" first (No Glue). Bevel the ends, if necessary, to get a nice tight fit. It may be necessary to relieve the pass through in #2 for proper clearance. Once you have them fitting correctly, bond in place, using the bulkheads to correctly position. (Do not bond the bulkheads)
Next, bond the fuse bulkheads #2, #3, and #4 to one of the fuselage sides. Use a 90 angle piece to ensure these bulkheads are at a true right angle. 5 min. epoxy is sufficient to bond the bulkheads to the fuselage sides. These three bulkheads make a box when aligned correctly. Positioning and bonding these bulkheads correctly are a good start for a perfectly aligned fuselage. Use clamps to ensure good bonds .The Stab support can now be bonded (thick CA or 5 minute epoxy) to one of the fuselage sides.
Once the bulkheads and stab support are bonded, pull the tail section together keeping the center marks on the bulkheads lined up with your center line bench mark. View the fuselage from above to ensure proper alignment -- the sides should come together exactly over the centerline on the work surface. Install the bulkheads #5 and #6, aligning these to the marks that you made in the fuse sides. Also, install the tail block. Use tape and pins to hold everything in place without adhesive. When the alignment is satisfactory, use 30 minute epoxy as it gives plenty of time for tweaking the alignment. Use tape, weights, model clamps and rubber bands to hold all in place. T-Pins can be used to hold bulkhead #5 in position. Make sure that the fuselage bottom is flat to the work surface and that the center marks on the bulkheads are lined up nice and straight while the adhesive sets.
When the adhesive is completely set, pull the nose section together and epoxy the nose block in place using tape, clamps and weights to hold it in alignment while the epoxy cures. It is best to do this stage at the end of a build period. For a strong fuselage, let it cure completely while the fuselage is down flat to the building surface (Remember waxed paper).
[Note for experienced builders]
The benefits of a well-constructed fuselage
The fuselage is the base or foundation of the sailplane that ties the wings and tail group together. The aircraft designer has set the proper angle of attack for the wings and tail group. At true fuselage maintains these and eases the task of subsequent flight trimming. The many laminations in the fuselage sides help maintain the sailplanes integrity under high loads during launch, high speed runs, or unplanned "rough" or spot landings. They prevent the fuselage from twisting and flexing under these loads. Therefore, the builder that does not rush the assembly of the fuselage and pays attention to alignment will get two rewards: a strong fuselage and a nice flying sailplane requiring little trim adjustments if any. Remember, reducing the trim needed to keep the sailplane flying straight will eliminate trim-induced drag.
Ray Hayes Note:
The most important tip of all that covers all my kits.......... the wing joiner brass tubes have to extend through the 1/16&qout; plywood root caps and the brass tube in the fuse has to extend through the 1/16 root caps that are glued to the outside of the fuse sides.
The control rods should be installed prior to covering the fuselage top and bottom. The kit contains music wire rods with "Z" bends in the ends. The "Z" bends used to connect to the stabilizer and rudder control horns. The rods will need to be extended to reach the servos. To extend the rods, cut the extra piece in half and then use the included couplers and solder these together. Clean the rods and coupler then place them inside the fuselage. Then, assemble them with solder flux and solder them together while they are inside the fuse. Use some cardboard under the solder joints to prevent scorching the wood underneath. This is an easy task, just take time and it will come out correctly.
Suggested tip: Prior to installing the rear fuselage top, put a light coat of oil on the metal control rods. Use a high-silicon based oil and make sure that the rods slide freely. This provides protection against rust and ensures smooth control surface operation even in the most humid conditions.
Nose Block modification.
The following modifications to the hardwood nose block are suggested to provide a cavity for nose weight. Locate the center of the block with respect to the end facing toward the rear of the fuselage. Find the center of the rear surface of the block. If you have the proper bits, start with a 3/4" bit and drill to a depth of 1/2". Then, using smaller diameter bits, continue to drill until the cavity is 1 1/2" deep. If proper drill bits are not available, use a Dremel tool or sharp blade to create the cavity. In all cases, do not make the cavity too deep as the outside of the block will require shaping.
When bonding the nose block in place, use the top canopy block for a reference as to how far back to mount the nose block in between the fuselage sides. Then, mark the nose block for proper location. Sand a slight angle into the canopy block where it meets the front of former #2. This provides a nice tight joint in this area.
Next, locate the bottom fuselage parts. These consist of a rear laser-cut balsa and forward plywood piece. Use a sanding tool and true up the bottom of the fuselage to knock off any excess epoxy and take off any high spots there. Only a slight sanding should be required the objective here is to maintain the flat bottom.
Using the rear balsa fuselage bottom piece as a guide, make a mark where this piece ends on the fuse bottom. Use this mark to know where to stop the application of epoxy. Then use tape and weights to hold this piece in place while the epoxy cures. Repeat this process with the ply nose section. Let the epoxy cure completely making sure to keep the fuselage in alignment and true.
The fuselage is now ready for the addition of the top sections. Note that the canopy block and the block just behind former #2 should be removable as access to this section provides for ballast, getting to the wing securing hooks, and any servo leads.
Removable hatch construction:
Find the brass tube and music wire for the lock down fixture. Cut the brass tube into two separate 1/2" lengths. Clean up the ends of the tubing pieces with a file and make sure that the music wire passes through with ease.
Then, cut the rear part of the catch and epoxy this in place as shown on the plans. This part of the catch should butt up to the rear wing alignment tube to be installed later.
Next measure and trim the remaining balsa block for the forward hatch cover. Use care and take time to ensure a nice tight fit. It is best to cut to the outside of the line and sand to get the final close fit. Next, notch the bottom of the hatch cover so that it will fit over former #3 and the large brass wing joiner tube.
When the hatch block fits nicely, install the hatch hold down latch using the brass tubes previously cut to length and the music wire. Use some scrap balsa blocks under the holes in former #2 and #3 to provide added support for the small brass tubes. (Note: the balsa blocks are optional but ensure the latch will not come loose later.) Assemble the wire and the two 1/2" brass tubes on the ends. Side the assembly into the holes in the formers. Make sure that the 1/2" tubes do not extend past former #3 and obstruct the placement of the large brass wing joiner tube later. Rough up the outside of the brass tubes for good adhesion. Use 5 minute epoxy and place small amounts on the 1/2" end pieces. Be careful and ensure that the music wire is not bonded to the tubes.
Once this has set up, trial fit the hatch cover in place. The underside of the hatch block may need to be notched slightly for a nice tight fit. ( Option: Two music wire guides can be added to the rear edge of the hatch for additional security. These guides are not shown on the plans but can produce a nice tight fitting hatch cover. Use a small drill and place short pieces of music wire with about 1/8" extending and use thick CA to hold them in place. Then push the hatch up to the rear block to make slight marks or indents. Using these marks, drill two holes to accept the guide pins. Trial fit the hatch cover in place. Work slowly and produce a hatch that fits well and is secure.)
Make sure not to get too much epoxy on at this time. Now re-install the hatch cover and hold in place with weight or tape until the epoxy has set. Once it is cured, pull out the wire and the hatch cover can be lifted off. Measure the hold down wire and place a 90 bend in the end.
When the sanding and shaping is completed, hooks for rubber bands or an optional canopy latch will be installed.
After the fuselage is shaped to satisfaction, check the fit of the brass tube that the wing rod slides through (remember that the tube goes through the fuselage sides and the plywood ribs to be fastened to the fuselage sides). With the tube in place and the fuselage flat on the workbench, ensure that the wing rod is perpendicular to the centerline of the fuselage and parallel to the workbench surface. Tack glue the tube in place. Do not enclose the fuselage top at this time. Optional Canopy Latch
While hooks and rubber bands can be used to hold down the canopy, this latch system, not shown on the plans and requiring parts not included in the kit, provides a nice looking, trouble free latch.
Install a small 1 1/2" piece of music wire in the nose edge of the canopy to hold nose in place on fuse. Drill and fit the wire in the center of the forward edge of canopy block, leaving 1/4" to 1/2" protruding forward. Cement the wire in place in the canopy block and, when set, use it to mark the location for the hole in the fuselage nose block. Carefully drill a hole in the fuselage nose block to accept this pin.
You will need some inner Nyrod or the outer yellow tube that golden-cable comes with. You can also use brass or alloy tubing if you have that on hand.
You will also need some music wire of a diameter that slide fits the tubing that you are using.
You will need a plastic bead, the kind that are found in the fishing departments of major discount stores. They are used for making up fishing rigs. They come in a small bag of 25 or so. They are a bright red and catch the light really well. One of these beads will slip fit the wire that fits in the tubing used. Actually, any bead that you might find can be used but may require drilling to fit the wire. This bead will be glued on the end of the wire that protrudes through the canopy to provide protection from the sharp end.
Measure about 1 1/2" from the rear end of the canopy block on the centerline and mark the location on a slot that is 1" long. Then drill a hole in both ends of the marked slot location. Now, using a sharp knife cut between the holes to produce the slot. An old hack saw blade may be used to cut out the slot as well. An emery board is a useful tool to final sand the slot for a nice close fit. The wire should slide snugly in the slot.
Now bend the wire at 2". This will be the slide or locking part of the latch. You want the other end of the wire to go just past the top of the canopy leaving room for the bead handle. Place the wire in the tubing (this is now the "latch") and trial fit the tubing to the bottom of the canopy. The ends of the tubing should be flush with the rear of the canopy and the rear end of the slot. ,
When the wire is pulled forward, it should not extend past the rear of the canopy. Tape the tubing to the canopy bottom and trial fit the canopy to the fuselage. Once satisfied with the fit, epoxy the tubing in place. When the epoxy has cured, slide the bead down the wire so it is close but not touching the canopy top. A small drop of CA will bond the bead to the wire. Cut off excess wire. Be sure to file the wire on both ends to a nice edge with no burrs.
Now fit the canopy in place and gently but firmly push the latch to the rear to mark the location for the hole in fuselage former #2. Make sure that the canopy is aligned correctly.
Using this mark, drill and make the hole. Now try to latch the canopy -- if needed, enlarge the hole in the former slightly. Using this latch system helps ensure no "shed parts" on a flight.
Tail Group (fin/rudder & stabilizer/elevator).
Place waxed paper or Saran wrap over the fin/rudder and elevator/stabilizer plans on a flat surface. Lay out the pieces of the tail group over the plans and trial fit the pieces together prior to bonding.
If necessary, lightly sand the edges of the pieces to ensure a good fit and bond. Thick CA can be used for bonding. If CA is used, apply pressure while holding the pieces together while the CA Sets up. If using white glue, carefully use pins to provide pressure. After the parts are bonded, give the assemblies a few swipes with a sanding block. Sandpaper with a grit of 220 is useful for this step. Note, prior to sanding, examine the assemblies for gaps. If gaps he occurred, a drop of CA in the gap right after sanding can fill the gap. Touch up the filled gaps with the sanding block after the CA has set.
The rudder has two light ply stiffeners. Bevel the outside edge of these prior to bonding with thick CA. Use care and mark the locations with a pen or sharp pencil while lining up the holes. Marking during the dry fit will make this an easy task. Pre-sanding the edges will help the covering transition later.
Prepare the tail group parts for final shaping. Mark the center line of the leading and trailing edges of the rudder, fin, stab, and elevator. These lines help determine how much material has to come off the trailing edge to get proper taper.
The leading edges of the rudder and elevator need to be beveled at a 45 degree angle to the center line for proper movement of these surfaces. Carefully use a razor plane or sanding bar for this. The leading edges of the fin and stab should be rounded. Hint: A short piece of PVC pipe, cut in half length-wise, with sandpaper glued inside the curve makes a useful tool for the task of shaping leading edges. Take your time and you will produce a good aerodynamic tail group. Weight removed from the tail group results in less nose weight for proper balance. This, in turn, leads to a lower all-up weight for the sailplane.
Set these parts aside as they will be covered and added to the fuselage later.
Remember that the wings are the "heart" of a sailplane. The objective is to produce a set of wings that are both true and strong. If your OLY III is to be winch launched, consider the following optional modification.
Optional carbon fiber reinforcement
The four spars of the inner panel wings can be reinforced with carbon fiber. The material to do this is not included in the kit. A commercial product from "Dave Brown Products" (CFS-5230) provides carbon fiber suitable for the task. Each package of the product contains 5.5 feet of fiber. Two packs will provide plenty of carbon to do both inside spar sets.
First, check the spar material for warps or bends. Now the spars must be sanded to remove enough material so that the spar with carbon fiber applied is the same size as the original spar. The four spars can clamped to the work bench, side-by-side, and sanded to the proper thickness. The thickness of the carbon fiber is approximately that of three sheets of notebook paper. Sand the spars carefully to produce a flat, clean surface. When the sanding is completed, wipe the sanded surface with a tack cloth. Trim the spars to length, but leave some extra for cutting to the final length once the wing section is completed. Now, bond the carbon to the spars with slow epoxy. Use a thin application on the wood first and then almost dry brush the carbon strips with the excess. Caution should be taken when handling the carbon fiber strips as carbon fiber can and does have splinters. Use some painters tape to hold the carbon to the spars every 8 to 10 inches. Ensure that each carbon fiber strip is thoroughly bonded.
Then, place the four spars, carbon fiber side down, on a flat surface covered with waxed paper or Saran Wrap prior to placing weight on them. A long board and weights is useful for this step -- don't forget a layer of waxed paper between the board and the spars so that the spars are not glued to the board. Allow plenty of time for the epoxy to set. When the epoxy has set, lightly sand the edges of the spars. NOTE: Gloves and a dust mask should be used as the dust produced by carbon fiber IS dangerous to your health. This optional step has produced very strong spars for the inner panels of the wings.
Wing Construction Cont'd
Now, proceed with the wing construction. Cover the plans with waxed paper or Saran Wrap and pin them to a flat surface. Note: a cork board or plain ceiling tile make an excellent building board that takes pins well.
First, pin the trailing edge to the plan. Then, using two of the #5 ribs, align the edge of the forward sheeting. Trim the center sheeting at the wing root. This piece fits between the front and rear sheeting. Bond with thin CA. Use the #5 ribs to place the spar in position. Note: if the carbon fiber is on the spar, the spar surface with the fiber goes down on the bottom spar. Use slow epoxy to glue the spar to the bottom sheeting as it bonds well to the carbon spar caps. Before setting in the ribs and shear web blocks, Check each rib at each rib location to be sure the bottom spar notch of the rib is deep enough to allow the rib to fit down on the spar with the bottom of the rib fully resting on the bottom sheeting. Why? Well it isn't because the rib notches are incorrect or erratic; the spruce spar is the culprit. The thickness and width of each spar can vary, if this check is not performed, the bottom sheeting (airfoil) will be distorted and look poorly constructed after the covering is put on. The ribs may now be glued in place on the spar while the epoxy was curing. Do not bond the ribs to the bottom sheeting as it must contour to the bottom of the ribs. Glue the bottom sheeting after the spar and shear webs are in place. This can be done more readily once the wing is off the building board.
Now bond the balsa shear webs in place. Carpenters glue or slow cure epoxy can be used. If epoxy is used, mix in some micro-balloons to enhance gap filling. For maximum strength, good contact with both spars is essential. Excess glue or epoxy will not add strength -- only weight. When the all of the ribs and shear webs are bonded in place, glue in the top spar. If the spar is reinforced with carbon fiber, the carbon fiber side should be on top.
While the center wing sections are curing, construct the wing tips. The construction steps for the tips are the same as the center section. Start by finding all the correct stock for the tips. The trailing edge bottom is pinned down to the covered plans and the tip and root ribs are used for location of the leading edge sheeting and spruce bottom spar. Bond the spar down first on top of the leading edge sheeting. Then bond the trailing edged and spar pockets as the ribs are set in place.
Do not bond the root rib at this time. Start at the tip and the rib that is next to the root rib and bond rib #17 through rib #28. Remember to use a 90 angle and carefully reference the plans to insure proper placement. Once these are bonded in place, dry fit the solid balsa shear webs between the spars. These will need to be sanded to follow the taper of the wing tip. Once the fit is satisfactory, bond them in place with slow cure epoxy. Use a metal ruler placed on top of the shear webs following the spar notch to check for proper height. Install the top spar at this time also and use slow cure epoxy for this bonding also. Place weights on top of the spar and make sure that the wing tips are flat during this process. Now bond the bottom leading edge sheeting to the ribs with CA by placing a yard stick under the sheeting and holding the ribs down while the CA cures.
Once the spars and inner shear webs have cured, place a 1/8" piece of stock under the trailing edge tip in order to give the wing tips a slight measure wash-out. Washout prevents tip stalls and makes flying easier.
Next, bond the balsa shear webs to the front and rear of the spars. The root section will get the polyhedral brace when the tips are attached to the center sections of the wing. Cut and/or sand these to fit the taper of the wing as it gets to the tip. Bond these several at a time with slow cure epoxy and clamp them in place. (Clip clothes pins are good clamps for this step.) Apply the epoxy to the inside of the shear webs and spread it out thin with an old credit card. The epoxy soaks into the wood and helps give added strength to the webs. Also hit the edges of the spars with epoxy also. Do not get carried away with epoxy as only a small amount is needed. Excess epoxy will not add to the strength of the bond it will only add weight. Both wing tip sections are built this manner. They will be mated to the center sections once the wing rod tubes are bonded in the root sections of the wing.
Now, bond the bottom sheeting to the front of the ribs. Use CA or your favorite glue. Apply a bead to the bottom of all of the ribs then use a yard stick or something similar underneath the bottom sheeting and pin or press down the wing section while the adhesive sets. Be sure to put waxed paper between the bottom sheeting and the shim so that the shim is not bonded to the bottom sheeting.
Locate the laser-cut light-ply shear webs W-11 and W-11A. There should be four of the W-11 and two each of W-11A and W-11B. Fit the W-11 into a slot cut in the front side of the spars and shear webs as shown on the plans. W-11 has an inboard angle to it for proper dihedral at the root. Mark these root ends and the locations within the wing with a pen for ease of part placement.
A razor saw and an emery board make this task quick, easy work and ensure the parts fit well. W-11A is bonded to the front of W-11. This can be done all in one step once satisfied with the part fit. Make sure that the ply shear webs are flush with the top and face of the spars. Use Slow-Cure 30min epoxy for bonding. Clamp and make sure that the wing section remains flat to the building board. Repeat this process for the other wing center panel.
The Brass wing rod tubes will be installed once the inner wing sections are complete. At this time, slot the rear wing ribs and dry fit the parts. These will be bonded to the rear section of the wing panels once the wing rod tubes are tack glued in place.
Refer to the plans for proper placement of W-11B. These parts contribute significantly to wing strength in areas are where wing failure often takes place under hi-load conditions. Remember to use slow cure epoxy and take your time in fitting the parts.
It is time to install the brass wing joiner tubes. Before starting, realize that there are three phases in installing these tubes in the wings: 1) Cutting holes in the ribs and tack gluing the tubes in place. 2) Placing the wings on the rods and checking the alignment with the fuselage. 3) Encapsulating the rods in epoxy in the innermost spar bays.
First prepare the tubes by using a reamer or the blade of a hobby knife and clean up the ends of the brass tubes. As this step is accomplished, ensure that the wing rods fit easily through the brass tubes. Make a sharp edge on one end of each brass tube and use this sharp edge to cut hole for the tubes in the ribs and a balsa plug for that end of the tube. To properly cut the holes in the ribs, block a wing center section on the workbench surface so that the tip end is 1 3/4 inches above the workbench surface. Pin the wing section to the surface to secure it and carefully cut holes for the tubing in each balsa rib. The tube should be perpendicular to the root rib (balsa rib #1 which should be perpendicular to the work surface) and parallel to the work bench surface as each hole is cut. While the section is pinned down, use the hole in root rib #1 to mark the hole in the plywood root rib. This is good time to also mark and drill the hole for the wing locator wire in the plywood root rib. Remember that the tube must extend the thickness of the plywood root rib (not yet installed) toward the fuselage.
that you are going to seal. Use the sharpened edge to cut a balsa sheet plug for the end that will be in the spar bay. Thin CA, carefully wicked, will seal the plug. Make sure that no CA runs down the tube and trial fit the wing rods to be sure that none did. Now, using coarse sandpaper or a file, rough up the outside of the tube to ensure a good bond with the epoxy. Insert the tube in each wing panel and using minimal amounts of 5 minute epoxy, tack glue the tubes in place. Install the rear wing alignment wire and tubes. Be sure that the rear alignment tubes are parallel to the trailing edge and that the pins will be perpendicular to the root ribs.
These next steps ensure correct alignment of the wings. Correct alignment will mean a better flying finished sailplane. Before installing the fuselage top above the wing joiner tubes and plywood root caps that fit on the outside of the fuselage, set the inner panels on blocks placed on each side of the fuselage with the rod in the wing and the tubes inside the fuse. These blocks should be high enough to raise the fuselage off the building board. Place the inner wing panels on the rod. Check the alignment by measuring from tip of inner wing panels to the end of fuselage. Use a large pin with a thread attached placed in the rear of the fuselage. Use this thread - pin system to make the distance equal from the pin to the rear outer edge of the wing inner panels. Correct misalignment by re-positioning the tack-glued tubes the wing panel. While the fuselage is set up this way, place a ruler or straight edge on the plywood stab mount to make sure the stabilizer will be horizontal when mounted. The fuselage former tab lock system will ensure the wing incidence is correct and, if a straight edge was used to make sure the bottom of the fuselage was a straight line, the stabilizer will be set at the correct incidence. Once the alignment is satisfactory, the brass tubes inside the inner wing panels will be permanently secured.
Find the two rear ply shear webs W-11 and W-11B. These will be epoxied to the spars and close in the brass wing tubes. Use a razor saw to cut the notches in the ribs required for these. Dry fit the parts and check for proper fit. Make sure that the angle cut end is at the root of the wing. Once the fit of the ply shear webs is satisfactory, it is time to bond it all together.
Use some Plasticine clay to seal up the ends of the brass tubes and make a seal at the root part of the wing to prevent leakage. Make up a slurry of slow cure epoxy and micro balloons. This will be placed into spaces between the spars and the brass tubes. Block up the wing panels on the leading edge so the epoxy will flow into place.
Once you get the epoxy mixture in place, use the ply shear webs to cap over this area. Make sure that you have a thin coat of epoxy on the bonding side of the ply shear web. Once the epoxy is poured in place, put the shear webs in the slot and clamp in place. One tip here, when filling the brass tubing area use small amounts of epoxy at first and fill the large areas first. This will let the epoxy flow and let the air out. Watch for bubbles as the epoxy flows in place as voids in the epoxy filler are weak points. Then, lay the panels on the wax paper covered building board and make sure that the wing section is flat. Clean up any excess epoxy with paper towel and solvent. Allow the epoxy to cure.
Now that you have finished the wing panels basic construction it is time to decide to add either spoilers, flaps or both. Spoilers are strongly suggested. Not only will they be useful in strong lift, but also are a good aid to precision landings. Flaps can be installed as well and will be an aid to performance. However, please note that flaps are not allowed in RES competition. Some (note that's some) contest directors may allow flapped ships if the flaps are disabled (Disconnected and taped)
Optional flap installation
About flaps - they will help with launching, landing, and thermal soaring. If you are new to soaring you can install the flaps and lock them in place for later use. Installation at this point of construction is relatively easy. If flaps are not desired, skip over this section and move on to spoiler installation.
The inner wing panel now should be complete except for the top sheeting and the installation of the spoilers and the flaps.
First, transfer the flap location from the plans to the inner wing panel. The flaps start at the third rib from the root of the wing panel and go to the very end of the inner panel.
Use two 1/8" X 1/4" balsa strips for the new trailing edge of the wing and the new leading edge of the flap. Mark 1/4" slots on the flap ribs. Start the slot 1/16" behind the notch for the trailing edge sheeting. Mark these with a ball tip pen and then cut the slots with a razor saw. Carefully cut three ribs at a time. (Let the saw do the work and lightly drag the blade over the marks making sure to be at a 90 angle to the bottom sheeting.) Don't cut through the bottom sheeting, only the ribs.
Use a sanding tool to lightly clean up the edges and then dry fit the first piece in place. Bond the 1/8" X 1/4" balsa wing trailing edge in place with thick CA. Use some pins and weights to hold the wing flat and the new trailing edge in place while the glue sets.
Cut the new leading edge from 1/8" sheet stock as the rib/wing section tapers slightly to the tip. Fit the new leading edge in place and check for proper fit. This should be tight to the trailing edge just installed. Bond this in place with thick CA. (Be sure not to bond this to the new wing trailing edge. ) Once the top sheeting is installed and the final sanding is done, the flap will be cut loose from the wing section. Make two rib sections for the flaps using one of the ribs that are yet to be installed at the polyhedral joint for a template. Bond these in place with thick CA.
Now that the new leading and trailing edges of the flap are in place, mark the location of the cut to separate the flap from the inner panel once the top sheeting is installed. Use a thick or heavy T pin to mark this location. Take the T Pin and push it between the newly installed leading and trailing edges to mark the bottom of the sheeting with a series of holes. Turn the wing section over and find the holes and lightly mark them with a pen. Later, when the top sheeting is installed, again use the T pin again to push through the bottom holes and make holes on the top for the top cut line. When making the cut to release the flaps, use a sharp Xacto knife and guide the cut with a straight edge.
Do both wing panels in this manner making sure to keep the wing sections flat.
Find the parts for the two spoilers. The spoilers are made from trailing edge stock that has been pre-shaped. Transfer the location of the spoiler bay from the plans to each inner wing panel. When completed, each center panel will contain a boxed section for the spoiler blade to rest in with about a 1/16" clearance around the blade on all sides to allow for covering and some space for unrestricted blade movement. Notice that the spoiler leading edge is butted up to the end of the top leading edge sheeting. Start the boxed spoiler bay here. Tape the two spoiler bay fore and aft pieces to the spoiler blade and use this to help mark the ribs for the spoiler bay cut out. Then use a steel ruler to mark the bottom of the cut outs on the ribs. Use a razor saw to cut to the marks and then use a hobby knife to cut the notch into each rib. Cut to the inside of the marks as this leaves some wood for final sanding to the correct measurement. Now tape the spoiler blade in place and turn the wing panel over. Then use two 1" pieces of scrap balsa to make rests for the spoiler blade to sit on. These are bonded to the side of the ribs on the two ends of the spoiler bay. Repeat this procedure on the other inner wing panel.
The wing components are now nearly finished. Add a small block of pine about 1/2" X 3/4" to serve a an anchor for the screw-eye for the wing retainer system. This is epoxied to the inside of the root rib just ahead of the spar. A pilot hole will be drilled and an opened screw-eye will be placed here. A slit will be cut into the fuse sides to allow the hooks to be joined by a zip-tie via the hatch. This is a good time to ensure your servo wire(s) pass through holes in the ribs. Also, drill the necessary holes in the plywood ribs which will be bonded to the fuselage. The holes in these ribs will serve as guides to bore holes in the fuselage once the ribs are bonded.
Joining the tip and center panels
Locate the wing polyhedral joiners (numbers #14 and #17). The ends are tapered, one for the inner panel and one for the outer tapered tip panel, the numbers correspond to the rib numbers.
Take a razor saw and cut the ribs at the outer tip of each center wing panel. Then, sand the slot to allow the wing joiners to slip on both sides of the spar. Dry fit these first and set up the tip panels prior to bonding with slow cure epoxy. The inner wing panels should be held flat on the building surface and be sure to cover the joint area with wax paper. The wing tip should be 5 3/4" from the flat building surface. Use a piece of scrap balsa with the measurement on it and pin it to the tip rib. Use a wood block to slide under the tip panel to get the proper height. Also make sure that the tip leading edge and trailing edge meet the inner panel with out any twists.
When the fit is satisfactory, mix up some slow cure epoxy and bond the sections together. Make sure to give everything a thin, even coat of epoxy to avoid dry joints. Put the clamps in place making sure that everything stays in proper alignment. Clean up excess epoxy and let cure. Follow this procedure for both wings.
Once the epoxy has set, install the rib #16. This will be cut and fit next to rib #15. The wings are now ready for the top sheeting.
Sand the trailing edge to a taper. If you don't have a sanding bar you can make one that will work with a 1" X 2" X 12" piece of wood. The piece needs to be straight with no twists. Give it a light sanding to knock off the sharp corners and make sure that the flat sides have no bumps or lumps. Take some 60 grit and some 120 grit no load sandpaper and glue it on each side of the board. Use yellow Elmer's Glue or a similar product thinned slightly. Apply it to both the sandpaper and the wood and then place it over wax paper and place some weights on it to hold it flat while drying. Both sides can be done at the same time if you place a suitable weight on top of the piece. Tip: A selection of various length sanding bars using various grades will save time and provide a useful set of sanding tools for this and future projects.
Make sure that the wing is supported at the tip and that the main inner panel is flat. Gently sand the trailing edge as shown on the plans. Make sure that you do not sand into the ribs. The ribs have been laser cut so some dark ash or scorching is seen on the edges. Use this as a sanding indicator. Check for and eliminate any high spots in the area of the spoilers or the new leading and trailing edges of the flaps if installed. Take time, sand carefully, and the material will come off quickly. When the inner panel is done, move the wing over and prop up the inner panel and sand its trailing edge with the same manner. This sanding could have been performed prior to joining, but it may be easier to work with the trailing edges after the parts are joined. Prop the inner panel on foam blocks while sanding the outer panel. These foam blocks are also useful to avoid dings during covering.
Now sand the leading edge area to make sure that there are no ribs or glue spots that will interfere with the sheeting. Do not sand the notch that is cut into the rib, as no cap strips are used in this wing.
Start with the inner panel of the wing at the root and apply the leading sheeting using thick CA. Used some tape and pins and many weights to hold the sheeting in place. T-pins could be used to hold the sheeting down but the resulting holes will have to filled.
Make sure that a nice tight joint occurs at the polyhedral joint with the tip section. The root section of the wing can be trimmed and sanded later. Also, make sure that the sheeting comes up to the step in the ribs just behind the spar.
Now, sheet the trailing edge. Make sure to keep the trailing edge flat and make a good joint at the polyhedral joint just as you did with the leading edge D-Tube section. The root section and the trailing edge can be sanded later.
Move on to the outer tip section in the same manner. Prop up the inner wing panel and make a good joint at the polyhedral joint with the sheeting and trim the tip later. REMEMBER: The tip panel has 1/4" Wash out. Prop up the trailing edge at the tip rib by 1/4".
At this point, wings, fuse, stab, rudder, and elevator are completed. Flaps (if flaps are not desired, skip to next section)
The pin-hole and pen marking of the flap leading edges still be visible as final sanding of the wings has not yet occurred. Take a T-Pin again and push it thought to the other side of the trailing edge. Now mark these holes as well. Now use a straight edge to help guide the hobby knife and cut through the sheeting only one side at a time. The flap should only be held now by the ends. Cut these with a razor saw keeping the cuts perpendicular to the flap leading edge and the flaps should separate at the hinge line. Eliminate any spots that are still bonded along the hinge line using a hobby knife and gently separate the flap from the wing. A light sanding with the sanding tool should true up the edges. Check for any loose or separated sheeting and bond it with thin CA.
Now set up the flaps and spoilers with the servos. Use blue painters or masking tape to hold the flaps and spoilers in position while setting up the control horns and linkages. Install the flap servos into the wing with the control horn coming out of the bottom of the mounting plate. Mount the control horn on the flap directly behind the control horn in the wing. Attach a clevis to the control rod half way in the middle of the threads, this will provide adjustment in both directions of the rod. Now attach the clevis to the flap's control horn and let the control rod lay next to the servo's control horn. Mark the location of the 90 bend in the control rod. Use a Z-Bend tool to make the bend with the mark at the 90 bend point. The flaps should function and allow for adjustments. The flaps will be hinged from the bottom of the wing with clear packing tape once the wings are covered. This is the time to ensure that you have proper throws for the flaps.
The spoilers may be connected to the servo by a wire made out from a heavy duty paper clip. The paper clip is easy to shape and has a nice plated surface. Use a trial and error method here and eye-ball the measurement. The servo should be in its closed position. The servo and its mount may be removed from the bottom of the wing to allow installation of the spoiler blade by sliding the blade on and off the paper clip wire. Use a 1/2" piece of yellow golden cable outer plastic tube for the attachment point. Mount the tube in the middle of the spoiler blade's bottom just to the side of the control output horn on the servo. Use the tape to hold the spoiler blade in position and check the movement. Once the desired movement is obtained, make a copy of this wire for the other side. Note: music wire may also be used to drive the spoiler.
Note: Materials for the skid are not included in the kit.
The advantages of the skid are:
Materials needed are:
Round the front or nose section of the skid and cut some nerf cuts into the bottom of the skid. These cuts go about half way through the wood and allow the skid strip to bend around the contour of the bottom of the nose block. The rear end of the skid stops 3/8" in front of the tow hook location allowing some room for tow hook adjustment. After marking the skid location on the fuselage bottom, dry fit the skid for proper alignment with marks that locate the center of the fuse. Then use some thick CA and bond the skid starting at the rear and working toward the nose section. Use some rubber-bands to hold the nose section down while bonding.
Once the CA has set, mix the epoxy and micro-balloons to make a thick slurry. Use an artist knife or equivalent and a wetted finger to make a nice fillet one each side of the skid. Do one side at a time and set the fuselage on its side so that the epoxy will flow into the joint making a nice smooth fillet. Small adjustments to the fillet can be made while the epoxy cures using a finger wetted with solvent. When both sides are completed and the epoxy has cured, give the skid a nice sanding and taper the skid into the nose section.
Covering Choose a color scheme that ensures good visibility at a distance.
The sailplane is now ready to final sand and cover. Final sand carefully and wipe down with a tack cloth before applying any covering. Cover the tail group prior to bonding to the fuselage. Drill some small holes in the mounting pad on the rear of the fuselage as this lets the slow cure epoxy into the wood and rivets the tail in place. (Note: Measure the distance from the stabs tips to a spot on the fuse top or the nose of the fuse. This will insure that the tail group is correctly aligned. Also, step away from the fuse and sight down the fuse from the nose to tail to check for alignment. Before bonding, dry fit and mark the tail for easy placement.
Install the servos and wire up the wings prior to covering. A piece of music wire may be used to feed the servo and flap wires through the wings and then any servo extensions may attached and pulled through the wing. Cover the wing starting with the bottom. Cover the servo mount/covers at this time also. Now cover the top of the wing.
Once the wings and the fuse and tail are covered and mounted, it is time to check the balance.
See the plans for the correct location of the CG. Use some scrap covering or trim tape to mark this range of balance on the sides of the fuse under the wing root laminates. (Once initial flight testing is done, the CG may be shifted within this range.) The initial correct CG should be the one on the plans. Attach the wings, and, with the radio gear and receiver battery installed in the nose, check for the CG by balancing the ship at the CG points by holding the ship up under the wings just out from the side of the fuse.
A balance stand can be easily made with a piece of wood that is wide enough to hold the sailplane's fuselage and allow you to drill a series of holes with 1/4" between the edge of the holes. This will allow future to use of the stand for other models. To complete the stand, obtain some new #12 round pencils and some blade-shaped eraser tops from an office supply store. Do not sharpen the pencils and place an eraser tip on each pencil. This provides non-invasive balance points far more accurate than fingers. Balancing is best done indoors. Place the sailplane on the rubber points and see how it balances. More than likely, some additional nose weight will be required.
Small pieces of lead, fishing sinkers (Best smashed flat via vise or hammer into a small wafer), or lead shot may used to achieve the correct balance point. Once the correct balance is achieved, Remove the battery pack and, if necessary, the receiver. Set aside a small amount of the lead, then pack the remaining lead into the hole in the nose block and pour slow-cure epoxy into the hole to hold the lead in place. Tip the fuselage up on its nose and let the epoxy cure. Once the epoxy has set up, re-install the battery and/or receiver and check for proper balance. Use some of the lead set aside to "fine tune" the balance point. Be sure to secure any weight used in this step. The sailplane should now be checked for lateral balance. This is easily done by placing the assembled ship on a flat table and letting the tow hook act as the point of balance. Suspend the inverted sailplane from the tow hook and check to see if the wings are level. If not, small amounts of weight must be added to the tip of the higher wing. This is very critical for proper flight characteristics. Tape small weights to that tip until balance is achieved. Take the light wing tip and make a small slice in the wing tip's covering. Make a hole just large enough to accommodate the weight, glue the weight in and recover the spot. As a final workshop step, check all of the control movements to ensure the surfaces are moving in the right direction. After a fresh charge of transmitter and receiver batteries, it is time for the first test flight.
Definitely seek some help here if this is your first flight with an R/C glider or Aircraft. At the field, try a gentle hand toss or two to check the controls. Toss the sailplane into the wind with a slight downward angle and let the sailplane do the rest. If it was built right and these instructions were followed it will fly straight away. Some slight elevator and rudder trim may be required to get it to fly straight away. Use the trim levers to correct for any nose down or nose up conditions and rudder trims for left or right. Once it is flying hands off straight away from you, it is a good idea to mechanically re-adjust the controls to allow the trim levers to be set to their neutral positions. Your new OLY III is now ready for a good clean winch or hi-start launch. Good luck and good lift.
Replacing the inner wing panel's spruce spars with carbon
This is how I build the inner panel spars in my kits to enable them to zoom launch, a combination of carbon and plywood in place of the spruce spars.
The simplest way to add carbon to my kits is use .060 carbon strips, 3/8" wide for top and bottom the full length of the inner panels. Cut 1/16 plywood to 3/8" wide strips the length of the inner panels, this combination is 1/8" thick. Same thickness as the spar, means no sanding the vertical balsa shear blocks or rib notches required .
Source for carbon strips:
Starting with the bottom spar, use a rib to locate the plywood strip on top of the bottom sheeting, apply wood glue sparingly to one side of the plywood, make sure it is spared over entire ply surface, glue down to sheeting and use lots of weights to press the ply to the sheeting. After glue drys, add the carbon strip using 30 or 60 minute epoxy spread sparingly one one side, use weights as above.
Add the ribs and vertical shear blocks, use epoxy between the bottom carbon and shear blocks and weights on the blocks. Clean up any epoxy squeezed out before it cures.
Top spar has carbon on top of the shear blocks and ply on top of the carbon. I apply epoxy to the carbon, place on top of the shear blocks and epoxy to the ply and place on top of the carbon, then add the weights to the top of the plywood. The rib notches become a jig to hold the carbon and ply. Clean up the squeezed epoxy now, a lot easier than after it has cured and your trying to cut the ribs to install the laser cut plywood shears.
Ray Hayes LSF 803
Legionair building tips and parts change notification
The fin is laser cut one piece instead of built up. Stab and Rudder gussets and tips are laser cut.
Some of the parts have been changed and therefore will not match the plan or the original kit instructions.
Fuse Pod and Boom:
Original kit had a two piece pod and aluminum boom. If you fly this Legionair at the AMA LSF NATS YOU WILL HAVE TO PAINT THE BOOM WITH SILVER PAINT TO SIMULATE THE ORIGINAL KITS ALUMINUM BOOM ACCORDING TO Jack Iafret. If you are going to fly in your local Nos contest, check with the CD about the silver paint, he may decide the carbon looks like aluminum when the light is on it just right. The carbon wing spars are NOS legal.
Supplemental Legionaire Building Notes
These reflect what I found when building my Legionnaire 132, May 2005
1) I could see no good reason for making the 132 rudder hinge line vertical (as the new kit items clearly intend) rather than the slight sweepback of the original plan. (Note the 140 plan shows no sweepback on this hinge line, so the supplied items may well be correct for the 140). A vertical hinge line avoids a twist in the rudder linkage actuation action but the small twist is easily accommodated by a ball/socket fitted on the end of the snake to the rudder horn. As such, to keep the sweepback as per plan on the 132, I modified the shape of the bit of wood provided for the "fixed" portion of the fin and built the fin and rudder to the original shape. This means cutting one new "tongue" at the rear of the fixed fin balsa and re-shaping the front one slightly. Also it requires some (non kit provisioned) ¼" by ¼" (hard). However I did change from the plan by continuing the hinge line all the way up, as is done on (say) the Eliminators, and not incorporate an aerodynamic forward balance portion on the fin, I would suggest doing the same for the 140. Note also the bit of obechi which provides the tailplane mount by acting as a saddle on the boom also (for the 132) then needs it's leading & trailing edges sweep changed to suit the original swept back fin & rudder for the 132.
Because of the bigger diameter boom (relative to the original plan) I felt the rudder would look a little better by being extended by ½" at it's base with an upsweep to join the original outline by its trailing edge. That avoids a visual "step" discontinuity at the boom to rudder junction. Finally in gluing the fixed fin to it's base mounting plate, I added a couple of bits of ¼" triangular stock at each side rather than the "substantial epoxy fillet" suggested - more weight effective and equally strong.
2) On my 132 tailplane I had to cut down (in span) the pre-cut elevators supplied, I suspect they are standard items (from a laser cutting viewpoint) between the 132 and the 140, the latter probably has a somewhat bigger tailplane span to match it's wings. I found using the kit items means that the elevator hinge line is ¼" further aft than the original plan shows i.e. the rear spar for the built up portion of the tailplane is ¼" by ½" and the elevators are thus ¼" narrower in chord - no bad thing. I also had to trim about 1/16th off the rear of the centre piece supplied into it such that with the rear spar in place, the front of that item lined up with the overall tailplane leading edge. Could be, of course, that the 30 year old (hand drawn) plan is less accurate than the laser cut bits! All the above relative to the tail feathers almost takes longer to describe than it does to build; building is quite simple and rapid.
3) In respect of the wings, I built the tip panels first. The trailing edge 1/16th sheet supplied is actually wider than shown on the plan (not narrower as in the supplemental building notes supplied). I chamfered the rear ½" of both the top and bottom TE sheets and re-enforced the final trailing edge with a ¼" wide strip of very thin "iron on" carbon. This can be conveniently glued to the TE sheet using thin cyano. I matched the LE sheet (also significantly wider than shown on the plan) to match the plan leading edge anticipating trimming about ¼" off before butt joining the actual LE strip. I pinned the TE & LE sheets to the plan, filled in the entire bay next to the dihedral join with a 1/16" sheet base with a 1" wide strip of 1/16" ply let into the LE sheet beneath the position where the wing carry though will be. I also added ¼" wide bottom cap strips at this stage before attempting to position the "lower spar cap". I found the laser cut ribs supplied anticipate NO cap strips on the tip panel ribs outboard of the sheeted inner bays however I felt cap strips were a good idea so I trimmed 1/16" off the top and bottom of these offending tip panel ribs - easily done at the bottom and, by using the next inboard rib as a template fairly easily done at the top given care. After the above rib trimming, the lower spar cap was glued in place (using the dry fitted ribs to get it correctly positioned) followed by gluing (glue only from the spar cap cut out rearwards - not in front of the spar cap) all the ribs in place. Of course you can save significant time and effort by omitting the cap strips and using the ribs just as they come out of the kit but I think the cap strips look better, are a little stronger, and add negligible weight.
I then fitted all the 1/16" web shears centrally on top of the bottom spar cap. To further stiffen the wing in torsion (for negligible weight impact) I fitted 1/8" square balsa strip diagonally between the shear webs and the TE. I used a length of carbon tube (which was an exact fit into the centre section tube) to act as the wing joiner spigot tube for detachable tips. (Detachable tips are probably needed even more on the 140 model to ease transportation). NOTE: The centre section carbon spar tube (on my 132) was joined 7/8th of the way along. Placing the short joined on section outboard (which is clearly the way to use it) means the spigot tubes on the wing tips which plug into this tube spar need to be about ¼" shorter than is shown on the plan. Ideally this carry through spar material to provide the spigot should be cranked but, as it comes as straight stock, I chamfered one end to slightly less than half the original diameter and tapered the chamfer to run out over a two inch length. This can then be fitted at the correct angle into the wing tip and tacked in place with cyano. I placed a web shear panel on each side of the carbon carry through tube with about 1/32" clearance on each side. This allows a thin epoxy, mixed to a thick slurry with Kevlar pulp, to be packed into the "well" so created and, while wet, the top spar cap needs to be fitted in place. The incidence peg can also be fitted. Obviously it too needs to exit the tip panel at 90 deg (as per the main carry though) and be parallel in dihedral to the main carry through carbon tube. I used 1/8" dia carbon rod cut to 1 ½" lengths for this and it only needs to project from the tip by ½" or so. The LE strip excess conveniently can be used on each side of this rod in the tip panel to provide some foundation to cyano it to.
Following this the top TE can be added (I mixed some thin epoxy, I used some to coat the carbon strip at the back of the bottom TE before adding the Kevlar pulp to fill the carry through spar well) and whitewood glue was used for all wood to wood joints.
After this, let it all dry overnight, then lift from the board, cyano the bottom LE sheet to bottom of all the ribs then cut the LE sheet to be flush with the front of all the ribs, butt joint on the balsa strip LE then re-pin to the board. To finish it off, the top LE sheet can now be added - I find thick cyano on top of the ribs gives adequate glueing time, use whitewood for the LE & spar cap - add the rib caps, root panel sheeting. It is easier to roughly plane the LE strip at this stage then add the root rib and the tip block.
4) On the centre panels, again note the carbon tube supplied has a joint in it - the joint should be positioned towards the outboard end. Having opted to use rib cap strips on the outer panels, I was duty bound to repeat that on the centre panels. As such a number of the ribs need trimmed - much easier than for the outboard ribs because the 1/16th ply rib can be used as a cutting master. Note too the spar caps for the inner panels are about 1/32" wider than for the outers - that means the notches in all the ribs need to be widened slightly to accept these spar caps (applies both top & bottom). The spar caps for the outer panels fitted exactly to the laser cut ribs supplied. While rib trimming check the carbon spar tube fits OK to the ribs - all my balsa ribs were fine but the ply ribs needed a bit of light filing to enlarge the laser cut circular holes a fraction.
Again I laid down the trailing edge, the 4" wide leading edge sheet, the fill in sheeting for the panel outer bays (each end), the rib cap strips and finally the lower spar cap strip and let it all dry. I dry fitted all balsa ribs in their required positions on the spar, applied white wood glue to all of the laid down sheet/cap strips (again, as per the outer panels not gluing ahead of the spar cap at this stage), then I placed the spar/balsa rib assembly on top pinning down each rib to lie in the exact position required. Once happy everything was in the correct place I applied a little thick cyano to the top of the carbon spar tube at the junction with each rib and let it run down the joint. I also placed a strip of 1/8th square balsa on top of the spar cap cut to length to fit exactly between each rib to form a "dam" for the epoxy slurry to be applied soon.
Once all dry this can be lifted from the board, further cyano applied as needed to the carbon spar rib junctions, the leading edge sheet attached with cyano to the rib bottoms and the leading edge fitted as per the notes on the outer panels. Check carefully that the 1/8th strip has blocked off any gap below the carbon tube - if not run a fillet of white wood glue in to ensure the gap is fully sealed. Again let it all dry. Now mix about 20ml of wing skin type thin epoxy, stiffen to a slurry with micro balloons then, wing the wing on edge - leading edge down - add the slurry to the top and bottom of the carbon spar to fill the section between the spar tube and the spar caps. This is quite an easy operation - sounds more hairy than it is, and wipe off any surplus to ensure the slurry does not extend beyond the high centre radius of the tube and the rear edges of the top and bottom spar caps. Just before adding all this slurry to the rear of the spar tube, I cut a piece of 1/16th carbon sheet (not supplied in the kit) to fit exactly between the two ribs which are on each side of the carbon spar joint. This bit of carbon sheet extended from bottom of the lower spar cap to the top of the upper one. The gaps on the leading edge side of the carbon spar in this joint bay were then filled with the epoxy slurry and the carbon sheet fitted in place (again on the LE side of the spar tube) and pinned to keep it there while the wing is turned LE downwards for the main application of the slurry to all bays including this joint bay. After the epoxy hardens it is then a good time to ensure the tip panel fits the inner panel and the inner panel fits the fuselage with relevant holes/incidence dowel pegs added as appropriate.
The wing can then be pinned back to the board, the spars on each side of the spoiler bay added, the spoiler pull tube added, the 1/8th sq stiffeners - on the open bays - as per the tip panels, all top cap strips, the LE sheeting and the root area sheeting. When dry the root and tip panel ribs can be added, the whole assembly sanded down and all final touches like the spoilers and their bottom stops added.
5) To fit the boom to the fuselage fit it in backwards from the nose direction. Opening the hole at the rear of the pod moulding is easily done with a rotary sanding drum on a Dremel. I could not see anywhere on the plan just how long the boom is supposed to be however, scaling the little rigging drawing on the 132 plan, gives an overall fuselage length: tip of pod nose to rear of the boom of 48 inches - the 140 might well be longer. This means, for the 132, cutting about an inch off the length of the boom. I cut at a taper so the end of the boom matched the sweepback rudder hinge line (of the 132) - probably not relevant for the 140.
6) The snakes supplied with the kit are well suited to the carbon boom, however it is essential that the snakes are well anchored down the length of the boom. A good way of doing this is to cut white foam or balsa discs to match the inner diameter of the boom with a couple of small circles to fit the snake outers at opposite sides on the periphery of these discs (they need to be at least ½" thick), coat their circumference & snake cut outs with epoxy and push them down the boom with a pushrod of some sort so they are located about every 10" from the snake exit from the boom to the pod end of the boom. Note the snakes supplied with the kit are marginal on length (if the fuselage is made 48" long). This, especially, applies to the inners so it is probably better to buy a pair of 48" snakes as replacements and keep the 36" ones supplied for a smaller model. Before fitting the snakes, I worked out which direction of rotation applied for the specific servos I would be fitting (this model will take "standard" sized servos) and which exit I wanted from the boom to the control horns to use a pre-existing "standard" program on my transmitter. In short I figured out where all the servos and control runs would go.
I found this fitting of the snakes was best done after the tailplane mounting block was epoxied to the top of the end of the boom but before the boom was fitted to the pod.
I found I had to trim the former which helps anchor the forward end of the boom a little and also open out the hole somewhat. This former then needed a temporary holding stick glued on it at right angles to allow it to be positioned back in the pod. I dry fitted the boom to the pod, dry fitted the anchor former in place then after I was happy the overall length was correct and that the tailplane platform was exactly square to the wing seatings, I thin cyano tacked the boom to pod junction. The dry fitted forward former was then removed, and some thin epoxy poured in to run down to the rear of the pod and re-inforce the pod/boom attachment. I the re-fitted the forward former and spread an expoy/ Kevlar pulp slurry on the former to fuselage and former to boom junctions. Once all epoxy has cured the "former holding stick" needs twisting off and removed.
7) I was somewhat concerned that the alloy carry through spar supplied in the kit might bend a little under towing loads and I felt that a carbon spar would be stiffer. However having done so I felt it was a lot of nugatory work and only saved ½ ounce in weight. I have added relevant notes as an appendix but I suggest simply using the metal carry though rod as supplied. The carry through spar is fitted, check the inner wing panels fit square to the fuselage to get the rotation of this carry through spar absolutely correct, and cyano tack the spar to the fuselage. Add a ¼" by ¾" balsa cross piece fitted immediately aft of it. Another ¼ by ¾ balsa cross piece is added in front and the whole lot re-enforced with thin epoxy thickened to a sludge with Kevlar pulp.
8) Drill matching holes in the root rib moulding to match where the spoiler cables exit from the inner panels and fit guide tubes with a 90 deg bend to allow the pull cords from the spoilers to exit about the same position as the rudder & elevator snakes finish. The tow hook block can now be fitted and move on to the servo installation. I found it was convenient to make a 1/8" light ply tray using the bottom edge of the canopy as a template. This fitted exactly into the space required. Cut outs for the servos and bearers for the hold down screws can be added to the tray and I found the whole assembly (servos and all) could be fitted in place as a single assembly. I used three standard sized servos (legacies from some earlier model) plus a mini receiver, however some mini servos plus a standard size Rx would also fit the space available OK. In my layout I positioned the rudder & elevator servos side by side with the spoiler servo in front of the elevator servo and the Rx in front of the rudder servo. I put a switch behind the servos and a 600mah NiCd fitted readily in front leaving enough space for nose weight.
9) I found canopy completion quite tricky to get the good fit required both for looks and minimum drag. I think the 1/16th thick soft ply supplied for the canopy base raises the canopy too high. Rather than re-trim the canopy I used two laminations of 1/64th ply (main grain going in the spanwise direction) glued together and the canopy epoxied to this lamination. Two laminations, rather than one of 1/32nd because the thinner wood bends to the required contour much better. It all fitted once the ply base was nearer 1/32 thick rather than the 1/16th supplied although even that double lamination to 1/32nd was, if anything, fractionally too thick.
Cut the 1/64th layers to the same size as the item supplied with the kit - that is about 1/8th oversize all round but it is easier to trim the excess off once the canopy is epoxied to its ply base. I found that plastic insulating tape was good for holding down the ply to the fuselage to allow the laminating glue to dry (and the lamination to hold to the required shape). I then, with little tacks of whitewood glue, glued the ply base to the fuselage and, when dry, epoxied the canopy onto the base and again held the canopy onto the base and thus onto the fuselage with insulating tape. Once the epoxy is dry, the whitewood glue tacks come off the fuselage moulding easily and the excess ply on the canopy base can be trimmed and sanded back to fit. A peg at the front and a proper spring loaded canopy catch finishes it off much more positively than the suggested rubber band hold down. To minimise drag I think a positive "hold down" fit is better than a rubber band.
10) I finished my model with transparent film. This was also applied to the stub mounting for the tail feathers. I meditated about painting the fuselage and settled for painting the pod black - matched the boom which was left as was, to avoid adding un-needed tail end weight. Lead was added to the extreme nose to bring the cg to about 5/8" aft of the main carry through spar and that completed the activity - hook up the spoilers, check all the controls and go flying!
Appendix - A Carbon Carry through Spar
I made up such a spar using carbon tubing where the O/D just fitted inside the carbon wing spar tubes and cut it as shown below to match the required dihedral angle. The two cut halves were then fitted and cyano tacked together. Over these tubes, two short lengths of carbon tube (diameters as per the wing spars) were fitted with their joint on the model (dihedral kink) centre line. Some Dremel sanding was needed to get the sleeving tubes to fit over the joints. These sleeves were then attached with thin cyano and the inside of the carry through spar tubes filled with thin epoxy thickened to a sludge with Kevlar pulp.
Once dry and cleaned up this carry through spar was fitted and cyano tacked to the fuselage with a ¼" by ¾" (not ¼" by 5/8" as shown on the sketch below) balsa cross piece pre-fitted immediately aft of it. A length of ½" Graupner strip was (slow) epoxied to the front of the spar to help beef up the join at the centre line, another ¼ by ¾ balsa cross piece added and the whole lot re-inforced with thin epoxy thickened to sludge with Kevlar pulp.
This all saves just over 1 oz relative to the metal spar supplied but, having done it, I frankly doubt if it is worth the trouble -maybe it will be, if it proves to be stiffer and stronger than the original metal spar.
- Ray's BUILDING TIPS
Nose block changed to have a straight, vertical back side.
I'll build the Hatch block in two pieces and not use the plywood hinges:
Cut block length to fit between the back side of the wing rod tube and the front edge of fuse former # F 2. This part is glued to the fuse sides, top of F 2, then drilled to install brass tube.
The large remaining block fits between the nose block and the above block.
The thinner 6-1/2" long block is glued to the fuse sides and fits between the forward block and top fuse sheeting.
The top fuse sheeting will have .014 carbon or tow epoxied to the under side from front to rear. I do this to all my builds.
I'll drill a hole in F 2 for a ballast holding tube. The hole may catch some small amount of the top balsa block to create the necessary tube angle.
Ken Bate's Merlyn Building Instructions