Fly Electric!

Santos Dumont "Demoiselle"

Simple slow-flying model for the smallest but still cheap RC gear currently available. It uses the 2g brushless motor, 3x2 prop, 1S 3A ESC and two 1.7g linear servos. It weighs 18.4g with a single 130mAh lipo. The only exotic part is my 0.5g DSM2 compatible receiver. Can fly in a light breeze outdoors.

The wing has a 15" span and is made with 3mm EPP. 1mm Depron would be suitable too. Tail feathers are the same. EPP is quite flexible so the wing has a pre-formed flat carbon spar. This is made separately with a length of carbon tow pulled over a depron former (two pieces of depron glued to desired dihedral angle) and then saturated in thin cyano. A shorter length of tow over the bend in the middle stiffens it up. The 3mm EPP with spar weighed 2/3 the weight of 2mm depron without a spar. There is a single rib in the middle; not sure that it serves much purpose. A 'V' is cut into the stab to make a hingless hinge.

I made the fuz from 1/32x1/16" balsa laminated to 1/16"sq to improve stiffness. Plans show outside dimensions. I've used closed loop controls. To achieve this with linear servos I added a 1mm carbon 'post' around which the cotton goes. The post was braced with 1/32 balsa. The Rx and ESC are tied to the wing with cotton. This stops them being thrashed about by prop-wash while at the same time allowing some movement in crashes. The shafts of the 2g motors are easy to bend so try first flights over grass to reduce the early risks.

The plans show a 1/32" balsa reinforcement to the fuz under the wing. Mine is the size shown on the left side with the 1/64" ply doubler on the inside of that. I glued my motor to the ply with cyano. I glued the elevator servo to the balsa under the wing. Not shown is another but narrower piece of 1/32" balsa at the top of the fuz.

Free plans below. As usual you may build the model but may not profit from the design. Check your printer settings (don't 'fit to paper') to avoid distorting the size. Let me know if you have any queries.

Free Plans PDF
A4 paper 12kb
Letter paper 12kb

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