RC SCALE EXPERIMENTAL McDONALD DOUGLAS MD500 NOTAR CONVERSION TO MD520 HELICOPTER DON CARDY - 2015

Описание: DON CARDY BROUGHT HIS SCALE MD500 HELI CONVERSION TO THE NOTAR MD520 WITH ROTATING DUCTED FAN TAIL NOZZLE (INSTEAD OF ROTOR) DOWN TO THE PATCH AND ASKED ME TO DO A PROMOTIONAL VID OF HIS WORK SO FAR, DON SENT THIS INFO OVER -
The model is an experimental conversion of the
Align Hughes / Macdonald Douglas MD500 Scale model, based
on TREX 500 mechanics, to the NOTAR version known as the MD
520. The five bladed main rotor uses SPIN slim asymmetrical
blades which lift the model weighing nearly 7 lbs at just
1400 rpm although it normally flies at 1500 rpm. The tail
boom, made from thin 3-ply, is powered by a 50mm EDF
running at 42,000 rpm using the same 4 cell battery as the
main motor and the BEC. Duration is about 7 mins. The air
under pressure in the main boom escapes through two slots
down one side of the boom which, using the Coanda effect,
generate a "sidewards" lift on the boom in the downwash
from the main rotor. However, most of the air produces
sideways thrusts at the end of the boom, to both left or
right, using nozzles with a rotating control cone. This
rotating control cone is controlled using a micro servo
connected to the normal tail-rotor output of the SAS gyro.
On the full size helicopter the Coanda effect balances 60%
of the torque reaction from the main rotor, the remaining
40% coming from the rear nozzles. On the model the Coanda
effect is at present much less significant. Experiments
continue.