Tracy Skyliners R/C Club

Trim Chart for Model Aircraft

To Test For Test Procedure Observations Y/N Adjustments
Control Neutrals Fly model straight and level Use transmitter trims to achieve hands-off straight and level flight.   Adjust clevises to center transmitter trims.
Control throws Fly model and apply full deflection of each control Check the response rate for each control.   Aileron Hi Rate:  3 rolls in 4 seconds
Aileron Lo Rate:  3 rolls in 6 seconds
Elevator Hi Rate:  For smooth square corners
Elevator Lo Rate:  For loop of approx. 130' diameter
Rudder Hi Rate:  For Stall Turns
Rudder Lo Rate:  to maintain knife-edge
Center of Gravity Method 1: Roll into near vertical banked turn 1-A: Nose Drops   1-A:  Add tail weight
1-B:  Tails Drops   1-B:  Add nose weight
  Method 2:  Roll inverted 2-A:  Requires lots of down elevator to maintain level flight.   2-A:  Add tail weight
2-B:  Requires no down or model climbs.   2-B:  Add nose weight
Incidence Method 1:  Power-off vertical dive, cross wind (if any).
Release controls when model is vertical.
1-A:  Model continues if straight down.   1-A:  No adjustment
1-B:  Model starts to pull up (to top).   1-B:  Reduce incidence
1-C:  Model starts to tuck under (to bottom).   1-C:  Increase incidence
  Method 2:  Remove power and then suddenly apply power. 2-A:  Model maintains level flight.   2-A:  No adjustment
2-B:  Model tends to climb when power is applied.   2-B:  Reduce incidence
2-C:  Model tends to dive when power is applied.   2-C:  Increase incidence
Side Thrust Fly away from yourself into any wind.  Pull into vertical climb.  Watch for deviations as model slows. A.  Model continues straight up.   A.  No adjustment
B.  Model veers left.   B.  Increase right thrust.
C.  Model veers right.   C.  Decrease right thrust/add left thrust.
Up/Down Thrust Method 1:  Fly into wind, parallel to strip at around 300 ft. out.  At center, pull into vertical climb and release elevator. 1-A:  Model continues to straight up.   1-A:  No adjustment
1-B:  Model pitches up (towards top).    1-B:  Increase down thrust.
1-C:  Model pitches down (towards bottom).   1-C:  Decrease down thrust.
  Method 2:  Maintain level flight and suddenly cut power 2-A:  Model maintains level glide slope.   2-A:  No adjustment
2-B:  Model dives when power is cut.   2-B:  Increase down thrust.
2-C:  Model climbs when power is cut.   2-C:  Decrease down thrust.
Aileron Differential Method 1:  Fly towards yourself, pull into vertical climb, neutralize controls then half-roll model. 1-A:  No heading change   1-A:  No adjustment
1-B:  Heading changes opposite roll direction (i.e. heading veers to left after right half-roll).   1-B:  Increase differential
1-C:  Heading changes in same direction as roll command.   1-C:  Decrease differential
  Method 2:  Fly model on normal pass and perform 3 or more rolls. 2-A:  Roll axis on model centerline.   2-A:  No adjustment
    2-B:  Roll axis off to same side of model as roll direction (i.e. right roll, roll axis off right wing tip).   2-B:  Increase differential
    2-C:  Roll axis off to opposite side of model as roll command   2-C:  Decrease differential
Dihedral Fly knife-edge pass; maintain altitude with top rudder (NOT full rudder unless needed).  Perform test in both left and right knife-edge flight. A.  Model has no rolling tendency in knife-edge flight.   A.  Dihedral ok.
B.  Model rolls in direction of applied rudder.   B.  Decrease dihedral
C.  Rolls in opposite directions (both tests).   C.  Increase dihedral
Elevator Alignment (for models with independent elevator halves). Fly away form yourself wings level, pull into inside loop; Roll inverted and repeat as above pushing into outside loop. A.  No rolling tendency with elevator.   A.  Elevator alignment is correct.
B.  Model rolls in same direction in both inside and outside loops.   B.  Elevator halves not aligned at neutral.  Raise one half and/or lower other.
C.  Model rolls in opposite direction in inside and outside loops.   C.  One elevator half has more throw than the other (Model rolls to the side with more throw).  Reduce/Increase throw on one side.
Tip Weight (Course adjustment) Fly straight & level upright, check aileron trim for wings-level.  Roll inverted, level wings, release aileron A.  Wings remain level.   A.  No adjustment
B.  Left wing drops.   B.  Add weight to right tip.
C.  Right wing drops.   C.  Add weight to left tip.
Tip Weight (Fine adjustment) Method 1:  Fly away from yourself into any wind.  Pull into fairly small inside loop. (1 loop only). 1-A:  Model exits wings level.   1-A:  No adjustment
1-B:  Model exits w/right wing low.   1-B:  Add weight to left tip/subtract from right.
1-C:  Model exits w/left wing low.   1-C:  Add weight to right tip/subtract from left.
  Method 2:  Fly away from yourself into any wind.  Push into a fairly small outside loop.  (1 loop only). 2-A:  Model exits wing level.   2-A:  No adjustment
2-B:  Model exits w/right wing low.   2-B:  Add weight to left tip/subtract from right.
2-C:  Model exits w/left wing low.   2-C:  Add weight to right tip/subtract from left.