Great Planes PT-40 Kit (original) - Manual (Page 38)

FLIGHT PROBLEMS
TROUBLE SHOOTING GUIDE
FLIGHT PROBLEM PROBABLE CAUSE RECOMMENDED SOLUTIONS
Does not automatically pull out of a
dive after elevator stick is released 1 If dive continues straight ahead, the
cause may be incorrect elevator trim (a)
or improper balance (b).
2. If dive results in a right or left
turning spiral, the cause may be
incorrect elevator and/or rudder
trim.
1 (a) Re-trim the elevator for level flight
at 1/2 throttle.
1 (b).Carefully balance the airplane, front
to back at the balance point shown on the
plan, 5/8" behind the center of the main
spar.
2. Re-trim the rudder and elevator for
straight and level flight at 1/2 throttle.
If this does not correct the problem, see
below.
Does not automatically return to
straight flight after a right or a left
bank after rudder stick is released 1. Incorrect rudder trim.
2. If rudder trim varies as speed is
changed, the cause may be incorrectly
aligned or warped vertical fin.
3. The airplane may not be laterally
(side-to-side)) balanced.
4. The wing may be crooked in the
saddle.
5. Unequal or insufficient washout
(twist) in the wing panels.
2. Insufficient or weak wing hold down
rubber bands may allow the wing to lift
when making a tight turn or when
pulling out of a dive.
3. If the model is balanced more than
1/4" behind the recommended location, it
will be too pitch sensitive and "squirrely".
Operating elevator and rudder control
stick results in jerky and erratic flight. 1. Improper control surface throws.
1. Re-trim the rudder for straight flight
at all speeds.
2. Check alignment of vertical fin. If
warped, twist while heating. If not
aligned with fuselage centerline, cut off
and re-install.
3. Check lateral balance by lifting the
airplane at the propeller shaft and at the
aft end of the fuselage If one side drops,
add weight to the opposite wing tip to
balance.
4. Check wing alignment by
measuring from both wing tips to
the top of the rudder hinge line
These measurements must be the same,
within 1/16" If not, re-position the
wing in the saddle.
5. With the wing on a flat surface, check
the amount of washout at each tip. The
washout must be the same at both tips
(7/8").
1. Set up the elevator and rudder to move
the recommended amounts with full
deflection of the transmitter stick.
2. Attach wing to fuselage with at least
10 or 12 good #64 rubber bands.
3. Carefully balance the airplane,
front-to-back, at the balance point shown
on the plan, 5/8" behind the center of
the main spar.
38