| To Test For | Test Procedure | Observations | Adjustments |
| Control Centering | Fly general circles and random maneuvers | Try for hands off straight and level flight | Readjust linkages so that Tx trims are centered |
| Control throws | Random maneuvers | A. Too sensitive, jerky controls. B. Not sufficient control |
If A. Change linkages to reduce throws.
If B. Increase throws |
| Engine Thrust Angle (1) see below |
From straight and level flight, chop the throttle quickly | A. Aircraft continues level path for short distance
B. Plane pitches nose up C. Plane pitches nose down |
If A. Trim is OK If B. Decrease downthrust If C. Increase downthrust |
| Center of gravity - Longitudinal balance | From level flight roll to 45-degree bank and neutralize controls | A. Continues in bank for moderate distance.
B. Nose pitches up C. Nose pitches down |
If A. Trim is good If B. Add nose weight If C. Remove nose weight |
| Split
Elevators.
(also Yaw and C.G.) |
Into wind, pull open loops, using only elevator.
Repeat tests doing outside loops from inverted entry. |
A. Wings are level throughout B. Plane tends toward outside when right side up and to inside when inverted. C. Plane goes in on regular loops, and out on inverted loops. D. Plane goes out on both types of loops. E. Plane goes in on both types of loops. |
If A. Trim is fine If B. Add weight to right wing. If C. Add weight to left wing. If D. Raise right half of elevator or lower left. If E. Raise left half of elevator or lower right. |
| Yaw (2) see below |
Into the wind, do open loops, using only elevator.
Repeat tests doing loops from inverted entry. |
A. Wings are level throughout B. Yaws to right in both inside and outside loops. C. Yaws to left in both inside and outside loops. D. Yaws right on insides, and left on the outside loops. E. Yaws left on insides, and right on the outside loops. |
If A. Trim is correct. If B. Add left rudder trim. If C. Add right rudder trim If D. Add left aileron trim If E. Add right aileron trim. |
| Lateral Balance | Into the wind, do tight inside loops. Or make straight up climbs into Hammerheads. Do same from inverted entry. | A. Wings are level and plane falls to either
side randomly in Hammerheads. B. Falls off to the left in both inside and outside loops. Worsens as loops tighten. C. Falls off to the right in both loops. Worsens as loops tighten. D. Falls off in opposite directions on inside and outside loops |
If A. Trim is correct.
If B. Add weight to the right wing tip.
If C. Add weight to the left wing tip.
If D. Change the aileron trim. |
| Aileron Rigging (3) see below |
With wings level, pull to a vertical climb and neutralize controls. | A. Climb continues along the same path.
B. Nose tends to go to inside loop. C. Nose tends to go to outside loop. |
If A. Trim is correct. If B. Raise both ailerons very slightly. If C. Lower both ailerons very slightly. |
| Wing Incidence | Knife edge flight | A. Model tends to veer in nose up direction.
B. Model tends to veer in nose down direction |
If A. Reduce wing incidence If B. Increase wing incidence |
(1) Engine thrust angle and C.G. interact, check both.
(2) Yaw and lateral balance produce similar symptoms, note the fin may be
crooked. Right and left references are from the plane's
vantage
point.
(3) Ailerons cannot always be trimmed without sealing the hinge gap.