One Sheet Swappable Trainer

I challenged myself to make a great first plane out of a single sheet of Dollar Tree foam board. After a few designs and tweaks, this is what I came up with.

Quick flight video:

Stats of plane in video:

- 1300kv Hobby King 2824 motor

- 8 x 4 GWS (style) propeller

- 25 amp Hobby King ESC

- 2200mah 3S battery

- Weight of plane without the battery: 272grams or 9.6ounces

- Flying weight: 460grams or 16.3ounces

- Estimated wing area: 175 square inches

- Estimated wing cube loading: 12.2 oz./sq.ft.

note: I am flying this plane rather heavy. A wing cube loading of 12 is in the Sport category. A trainer should be at least under 10 if not closer to 7. But I used a 2200mah battery, which is heavy (185grams).

note: My power plant set up has an estimated static thrust of 1000grams or 36ounces. I was definitely flying over powered and over weight. If you're going to be overweight, you have to be over powered.

recommendations for beginners: Use a smaller/lighter battery. Possibly a similar motor with a 2S battery but I still think a 3S is best.

Photos:

Completed plane.

I mounted the servos on top of the wing, but feel free to do whatever.

For control linkages, I use coffee stirrer straws and MIG welding wire. I taped on the straws because it's faster and easier than using hot glue.

The underside. Note that even though this is a swappable, I glued the power pod in place and then mounted all of the electronics externally. But feel free to do whatever.

The wing tips are undercambered.

Note how the tail edges of the top and bottom of the wing line up. It appears to not line up, but if you hold the bottom on a flat surface, both touch the flat surface.

I don't have a specific height to the airfoil, but when gluing the triangle airfoil together, aim for a total height of 1 inch. It doesn't have to be perfect, just make it "look about right".

When gluing the wing tips to the triangle airfoil, simply tape it on and then use lots of glue and glue it flush. The angle cut into the wing tip will create the polyhedral for you.

Note that the leading edge of the wing is two sheets thick. You do not have to cut any bevels (for the wings) with this design. Simply fold the wing back, not onto it's self. I laid a bead of hot glue onto the leading edge and smeared it into the foam similar to a hot glue hinge (as invented by Chad).

This photo is misleading. The back notch for the rudder is actually cut 2 inches back, the rudder just sticks out past another inch.

I glued the wings onto the fuselage 4 inches back. With my servos near the CG, this made the plane balance out so the battery is put directly onto the CG.

Random picture of the tail.

Plans:

Printable plans (PNG photo) and plans in Sketchup: OSST Plans

Photo of layout/measurements. note: "A" is 1 and 5/16 inches. The small gap between "A" and 2" is 3/16 inches.

If you already have the plans for the FT Flyer printed off, you can use parts from that for this plane. The rudder, elevator, and power pod are all identical to the FT Flyer. It just makes life easier. However the FT Rudder actually needs to be modded a little bit. The fuselage on this plane is about 1/8" taller than the FT Flyer fuselage. So there will be a gap in the build.

The fuselage is basically a 5" by 20" piece with strips scored and removed that are identical to those on the Power Pod. The fuselage is going to be a "B" fold, where as the power pod is an "A" fold. This allows the Power Pod to fit directly into the fuselage. You can use the Power Pod to measure out the slots for the Power Pod tabs.

The wings are basically a 11" by 20" piece with two score cuts.

The wing tips are basically two 6" by 5" pieces with one score cut. And then a small piece is cut out 1/4" from the side as shown in the plans.

I hope the plans are rather self explanatory along with the photos of the completed plane. I do not plan on doing any sort of build log or build video.