Backyard Flyer (oz15899)

About this Plan

Backyard Flyer. Simple rubber sport model. Wingspan 20 in.

Direct submission to Outerzone.

Update 13/3/2025: Added article, thanks to Pit.

Quote: "When he was 12 years old, the author designed this easy-to-build rubber job. It will out-perform most small kit models. Backyard Flyer, by Gary Heeb.

AFTER returning home from the 1966 Chicago Nationals, I decided to build a small rubber-powered model to fly around the backyard. Since my rubber-powered Wakefield Stratowake (oz8763) won second at the Nats I scaled down, modified and simplified this basic design. The result is a small easily built rubber-powered model which Richard Anderson named the Backyard Flyer.

This model was designed to be flown for fun in a small area. It is not a contest model but is a plane a beginner can learn and have fun with. And the model is not complicated with prop-carving and making a prop-hinge fold mechanism. But the main thing I had in mind when designing and building the Backyard Flyer was a model which I could fly in my backyard.

The first step is to build the wing and stab so that by the time the model is completed, any warps will be developed. Then they can be removed before first flight.

Select only choice straight-grained balsa wood: try to get the strongest wood possible. If you want a really strong model, use the next size larger wood. The extra weight will decrease the flight performance, but the model will survive many more crashes and rough landings. For the wing. I strongly recommend that you use spruce for the leading and trailing edges and the spar. Spruce has a little extra weight but will make a strong warp-free wing. Use Sig balsa and spruce for the best results.

Make a hardwood or aluminum template of the wing rib including the spar notch and two pin holes. The pin holes assure that the template will stay in place when cutting out the ribs. It is very important to cut out all the ribs accurately; this will keep the same airfoil throughout the wing. Cut out ten ribs from very hard 1/32 balsa sheet, using the template: make sure to notch the ribs carefully for the 3/32 spar. Pin a 1/8 sq spruce leading and a 1/16 x 3/16 sprucee trailing edge to the plan. Pin the wood down to the plan at the exact location. Do not stick pins through the wood but to edges, and use small weights to hold down the wood. Glue in the ribs, leaving out the ones at the dihedral joints. Glue small triangles to the tip ribs as shown in plan; add 3/32 tip sheets to the outsides of the tip ribs.

Cut the wing at the dihedral joints. bevel the leading and trailing edges to the proper dihedral angle. Prop the wing up to the correct dihedral measurement and cement: it is best to double cement before gluing the wing together. After the wing is throughly dry, glue in the remaining ribs. Next, cement a 3/32 spruce spar in place. making sure that you have a good fitting glue joint at the dihedral break. Glue large gussets to the ribs at the dihedral joints. These gussets will greatly increase the strength of the wing and could be added to every rib if desired. Sand the leading edge to the proper airfoil shape; next sand the tips to the correct contour. Finish sanding the wing, making sure to smooth out any bumps or rough spots. Reglue all joints!

Use the wing rib template to make the stab ribs. Take the wing rib template and lay it on top of the stab rib shown on the drawing. After finding the same contour. mark the leading and trailing edge location on the template. Cut a sheet of 1/16 balsa (with the grain running chord-wise) to the exact length of the stab rib. Use the marked template and cut around the top edge, slide the template down the required distance and again slice around the top edge. After cutting out the ten required stab ribs, pin down the leading and trailing edges to the plan and glue the ribs in place. Go over the wing and stab frameworks lightly with sandpaper, smoothing out all the bumps and rough spots..."

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