The Poisson - Le Fish of the poor

The Poisson is a depron 1.20m wingspan glider. Its goal is to reach UltraBatics performance with minimum budget.

Building The Poisson
The building is inspired of the monkey swinger design, with adding some wood (balsa and thin plywood) to make the structure stronger.

The airfoils are TP42/TP29.

Wings structure is done of 2x6mm spars, decreasing with airfoil thickness, and linked at root to make a box receiving the wingjoiner (which is 6x12x250mm).

The wingjoiner takes place in the fuselage between 2 thin plywood pieces, which are also the place for 4 small servos.

All pictures of original building can be seen on this video.

Flying The Poisson


With only 320g for 1m20 wingspan, The Poisson reaches UltraBatics standards and flies realy easily in light lift.

With center of gravity at bigger thickness of airfoil, flight is sane. Like other ultrabatics, aileron deflection have to be big to provides quick response at low speed.

With big elevator rotation The Poisson allows vertical descent keeping horizontal attitude. The fuselage shape also allows knife edge vertical descent, starting from exemple at top of a hammerhead.

Improving The Poisson
Some structural improvment could be expected on The Poisson:
 * horizontal plate at center of fuselage should be of 6mm balsa with holes to enhance fuselage toughness.
 * leading edge should be protected with 1/4 carbon tube.
 * original The Poisson has push-pull system for elevator, pull-pull using ovale cam would be great.