17
ADVANCED FLIGHT TRIM
All the following tests should be performed at
80% power unless noted
.
C.G. Fine Tuning:
Roll inverted, neutral elevator to two clicks of
down trim, if the model descends move the C.G.
aft. If the model climbs move the C.G. forward.
C.G. movement should be no more than ¼” at a
time.
Engine Thrust Angle Right/Left:
On a low pass 50% power directly into the wind,
go to 80% power and pull to a vertical line at the
same time. As the model slows do not correct the
path with rudder. If the model yaws right add
1/16” shims under the right side motor mount
bolts at the firewall. If the model yaws left place
the shims under the left side.
Main Wing Incidence:
Roll to knife-edge flight, if down elevator is
required to maintain a straight line, shim the
back of the main wing 1/8” at a time till the
elevator is neutral. If up elevator is required
shave the rear of the wing saddle 1/8” at a time.
Engine Thrust Angle Up/Down:
On a low pass 50% power crosswind, go to 80%
power and pull vertical at the same time. As the
model slows do not correct path with elevator. If
the model tries to loop add 1/16-inch shims to
the top motor mount bolts. If the model tries to
push over to the
wheel side, add 1/16
”
shims
to the lower motor mount bolts.
Wing Tip Weight:
Level flight into the wind, roll inverted neutral
aileron. If one wing drops add weight to the
other wing tip 1/8-ounce at a time.
Elevator Surface Alignment:
Fly away from you directly into any wind, apply
full throttle and pull two consecutive loops.
Model rolls right, raise left elevator, model rolls
left, raise right elevator.
Pictures of my 50cc powered Pitts
Python
.
The 50cc version has a take-off roll out of only
about 20-30 feet. So be careful with the throttle
management.
