Members’ Projects

The Colibri aircraft in this article was built and designed by club memebr Mike Benwell and featured in a recent issue of RCM&E magazine.  The following text is by Mike:

This model is a 1/5 th scale replica of the full size Max Brugger Colibri I built from drawings
between 1981 and 1988; subsequently flying it for twenty five years to rallies all over northern
Europe with a back packer’s tent on the rear shelf, and a sleeping bag replacing the seat cushion.
Low wing models with one piece wings have an inherent weakness where the fuselage is cut out to
receive the wing. A two piece wing with an aluminium dowel through the fuselage permits a full
depth fuselage making it significantly stronger.
On the Colibri, the fuselage sides are curved out either side of the seat, providing a generous 22” of
shoulder width for the pilot!

FLYING
Weight with 2200 Mah lipo 4 lb (1.82 Kg)
On it’s first flight, the elevator proved to be very sensitive and more aileron movement was
required.
Subsequent flights and adjustments suggested the optimum movements are:
Ailerons; full +/-20mm , fine +/-15mm
Elevator full +/-15mm , fine +/- 10mm
Rudder full +/-25mm , fine +/- 20mm
The optimum c.g. position was 75mm back from the leading edge. These settings can be re-
evaluated once you are familiar with the handling. As shown, the model is docile on fine rates, and
aerobatic on full rates.

The colibri is a small single seat aircraft which is quite cute in appearance. Flying the model is
generally straight forward, although I would say just beware that the pitch control can be sensitive,
so set up your elevator carefully. Tight turns can be happiest when flying at a reasonable speed, and
it generally handles well.With the correct radio set up, this model will be quite aerobatic. Inverted is
easy, as are rolls, loops and spins. It is not as neutral as an all out aerobat, but makes for a compact
sports model which is different from the crowd. My experience when landing is to keep the power
on all the way down, as it is prone to stalling if slowed too much. With the current set up this model
shouldn’t cause any problems for club pilots.