List of changes to Merlyn by Sky Bench

Revised 2-24-12

Original airfoil: Trailing edge sheeting is 3", eliminates need for all those vertical grain shears between the T.E. sheeting. The plan shows a 1/4" wide leading edge, but has a call out of 3/8 sq leading edge. The plan's leading edge schools be drawn to the 3/8 dimension. D-tube sheetings, 6" wide. Spar is 1/4 x 1/2 spruce with long multi-laminated 1/16 plywood horizontal shears on the sides of the spars and vertical grain blocks between the spars. Plywood root caps to anchor the wing rod tubes. Leading edge is pre shaped spruce that fits between top and bottom sheeting. The 1/8 sheet is not included for the Miller Mod. No rib caps required. All these changes will make the wing stronger, easier and much quicker to construct.

Note ... match the spar notch in the ribs to the spar location on the plan.

S 3014 Airfoil: This is the same airfoil used on the Sky Bench Bird Series, Oly ll S, Oly lll, WF-XL and other kits to come. The S 3014 is a great all weather airfoil that allows high performance flying in calm or windy conditions. Another feature the airfoil has is the tip stall is very gentle, no wash out in the wing tips is required or recommended . Consider building the S 3014 wing with flaps that also can be raised for increased speed.

2100 sq. in. of wing area with a S 3014 airfoil, WOW, I can't wait!!!

Fuse and Fin: Front and rear 1/64 ply interior fuse side doublers. Full sized basswood nose block eliminates balsa nose block. No plastic tow hook or pushrods are furnished. A 1/8 plywood ( B 4 ) fin base will be created to secure the fins leading and make this junction much stronger. The rear fin post will extend down thru the fuse sides and 1/4 balsa dorsal fin to create a stronger dorsal fin joint and will be spruce instead of balsa. The bellcrank will be laminated plywood.

Wing rod: Kit available with two 5/16" ( ejector pin, not piano wire ) rods and brass tubes. The root rib has been changed to accommodate the two wing rod system. The top spar needs to be beveled to allow for the top wing brass tube.

REMEMBER .. the brass wing rod tubes must pass through the plywood root caps on the wings. Place a plywood root cap on the out sides of the ruse for the brass tubes to pass thru. File the tubes flush.

Positioning the S3014 airfoil on the fuse side ... The side view plan shows a center line for the stab, assuming the stab is built according to the center line. Using the fuse plan, continue the stab's center line to the wing. The flat bottom portion of the S3014 airfoil is parallel with the stab's center line. This does not create a zero degree setting.

Notice .. The fuse sides are cut with one wing rod hole, as shown on the plan, modifications to the fuse sides will be necessary to build the Merlyn with the two wing rod system. See Ray's build pages 1-2, page 3, page 4 for photo clarification. More pages will be added to the web site.

Start the wing construction by pinning the bottom trailing edge to the plan and use a rib to locate the bottom front sheeting and spar.

1/16th plywood horizontal shear strips.. cut to fit: Front, from root to the 7th rib, Rear, from root to the 6th rib.

The wing ribs do not have notches for the false spar shown on the plan.

Build the canopy before gluing the front ply bottom on. You may need access to the bottom of the canopy. The nose blocks also need to be installed prior to the canopy construction.

Plans call for a balsa canopy block, the kit is furnished with balsa sheet pieces. Use one of the 1/4" laser cut fuse canopy shoulder's ( for lack of a better description ) that sets on the fuse below the rear of the canopy to mark the outline on the curvy canopy sides. Before assembling the canopy block pieces, cut the rear sides to match the curves of the 1/4 laser cut pieces.

One of the appealing interests to building your own plane is building a kit your way, with your ideas and modifications. There are many different ways to build a kit. The most important is building it with straight, not twisted wings and stab and a straight fin and rudder. That being accomplished, setting the balance point and learning to ballast is key to a high performance RC Sailplane.

This list and suggestions are subject to change and additions.




Sky Bench Aerotech 

Ft. Wayne, Indiana 46804