.
Stalling
If your plane noses up, LOSES SPEED, and then falls clumsily or dives,
that is a STALL. To cure a stall, adjust the angle of the stabilizer by
changing the thickness of the incidence block under it. Lower the front
edge or raise the rear edge. See drawing. But make SMALL changes -
1/32" at a time. If a change of more than 1/16" is needed, go back and
perform the Preflight checks again. It's likely your Classic is incorrectly
balanced (tail-heavy) or the surfaces are warped.
Diving
A model that darts quickly into the ground without swooping or stalling,
is diving. The dive can be cured by adjusting the stabilizer in the
direction shown in figure 5 (in 1/32" steps). Here again, don't change the
height of the incidence block more than 1/16" without first re-checking
the Pre-flight steps. Warps or nose-heaviness may be causing the dive.
Turning
A plane that glides in a straight line takes a lot of flying space and a lot
of chasing, so it's best to adjust the glide for a slight turn. The plans for
your model will tell which direction.
The size and direction of the glide circle can be controlled by adjusting
the fin. The drawing shows adjustment for a right turn. Moving the fin
opposite, of course, gives left turn.
Small changes in fin setting can be made by bending the surface. But if more than 1/32" or so of change is required, cut the fin
loose and re-cement it at the desired angle. When the glide is smooth and steady, you are ready to go on to powered tests.
Power-On Flight
ALL ADJUSTMENTS TO THE "WOUND UP" PART OF THE FLIGHT ARE MADE BY POINTING THE PROPELLER AND
NOSEBLOCK IN THE DIRECTION YOU WANT THE PLANE TO GO. This kind of adjustment affects only the powered flight,
and will not upset the glide pattern you have developed.
Now - wind the propeller l-50 turns and launch your Classic into the wind
with the same motion you used in glide testing. The model should cruise
steadily forward, turning in the desired direction, and gaining or loosing
altitude gently.
If your ship tries to climb, but loses speed and stalls, point the propeller
downward by slipping a scrap of 1/32" balsa or a paper book match
between the top of the noseblock and the front of the fuselage. The wedge
is called a "shim" and the adjustment is called "downthrust". Downthrust is
illustrated in the drawing.
It's not likely that your plane will dive on first power flights, but if it should, put the shim at the bottom of the noseblock, tipping
the propeller upward (upthrust).
Downthrust is the "magic adjustment" that can make experts out of beginners. Learning to use it is the most important part of
your test program.
Increase or decrease the amount of downthrust (by changing the thickness of the shim behind the noseblock) until power flights
are smooth and free of stalling with 150 winds in the motor. Don't wind the motor any tighter until the lower-powered flights are
under control.