Construction demonstration of a super simple Science Olympiad "Flight" event airplane. Half an hour to build an airplane capable of over two minute flights in a typical gym. Construction cost is only $7.00 if building multiple copies to keep shipping cost to a reasonable share of total cost.

Here is the airplane flying over two minutes at only 20 ft climb height in a gym:    • Simple Science Olympiad Airplane Flyi...  

Construction Details:
Wing: 16" span 3.75" chord - all spars and ribs are 1/16"x1/8" sticks, 12-14 lb cu ft wood (36" stick weight = 0.87g-1.05g) plus a 5" 1/8"x1/8" stick of 16-18 lb cu ft wood as a wing mount (36" stick weight = 2.3g-2.65g); completed wing weight = 1.8g
Stabilizer: 9"span 2.75" chord (40% of wing); same wood dimensions as wing, 8-10 lb cu ft wood (36" stick weight = 0.58g-0.75g); completed stabilizer weight = 0.6g
Fuselage: Motor stick: 12" of 1/8"x1/4" 16-18 lb cu ft (36" stick weight = 4.66g-5.31g) plus a small 1/2"x 3/32" square stick to mount the nosebearing ring; completed fuselage weight (with rear hook and front nosebearing ring = 1.85g
Tailboom: 8.5" of 1/8" square 8-10 lb cu ft w/ 1/2" overlap joint to motor stick (36" stick weight = 1.15g-1.5g); tailboom weight = 0.38g
Fin: 2" height, 2.5" base, 1.5" tip; same wood as stabilizer; completed fin weight = 0.18g
Propeller: 24 cm Ikara symmetrical; propeller weight =2.3g

Completed airplane weight = 7.15 grams with tape attached wing to fuselage. Add 0.90 grams of modeling clay ballast to the side of the fuselage near the CG point to bring total weight to 8.05 grams to meet minimum weight requirement for Science Olympiad "Flight" event. Note the airplane built in the video is 6.88 grams. The wing spars were actually a little on the light side at about 10 lb cu ft and it is not necessary to use wood this light for this part.

All wood purchased from Specialized Balsa or other good sources to get correct density. When ordering from Specialized select "medium" density 10-14 lb cu ft wood for wing, stabilizer, fin and tailboom and use the lighter 10 lb cu ft sticks for the ribs, stabilizer, fin and tailboom and the heavier 12-14 lb cu ft for wing spars. Motor stick wood should be ordered as "heavy" density 16-18 lb cu ft to prevent stick bending from rubber tension.

Trim Details:
1. Center of gravity (CG) location 1.0" forward of wing trailing edge with the 2.0 gram motor installed and wing mounted with the leading edge 2.5" from the nose of the motor stick.
2. Left wing washin - 0.25"
3. Stabilizer tilt: 3.0 degrees (left stabilizer tip 0.5" higher than the right)
4. Tailboom left turn offset: 3.58 degrees (0.5" offset)
5. Tailboom negative incidence: 1.8 degrees (0.25" negative incidence)(2.5 degrees mentioned in video, but actual measure of 0.25" offset over 7.875" tailboom is 1.8 degrees)
5. Wing incidence shim: 1/16"

This airplane can also be built with the 5.5" red plastic slip on prop and with this prop will still fly about 1:30. This smaller prop sometimes weighs as much as 2.8 grams and might require the wing to be mounted .025" - 0.5" further forward (if all other parts are the weights noted above). See a 60 second flight video with the 5.5" red plastic prop here:    • Science Olympiad Wright Stuff 2021-22...   This is a slightly different version of the same basic airplane flying with a too thick rubber motor at a climb height of only 18 ft. With a thinner rubber motor and climbing to 22-24 ft. 1:30+ flights are possible.

The CG location and all other trim/turn settings are important. It's simple to slightly crack a joint, or heat (with breath) or slightly wet a spar to correct wing warps and washin. Do not try to fly till all settings are correct. CG can be adjusted by mounting the wing 025"-0.5" forward (to move CG back) or 0.25"-0.5" back (to move CG forward).

Other trim and dimension details are mentioned in the video

Brian T
National Free Flight Society Education Committee