Trimming Your Plane

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CONTENTS $Math Formulas$	Please read first Trimming is a constant procedure throughout the life of your aircraft. If a trim condition changes noticeably inspect all airframe and control components carefully to determine what caused the change! If any changes are made to your model go back over previous steps and verify or readjust as necessary.				FORUM CONTENTS
	WARNING!! Static balance the model prior to flying it. Set your control surface movement according to the manufactures instructions before making your first flight. If you do not have instructions for your model use the following suggested settings. Set the CG to between 34% and 38% of the MAC. Ailerons 12 Degrees up and down Elevator between 11 and 12 Degrees up and down Rudder TEST PROCEDURES (All vertical dives are power off) Trimming must be done in calm conditions. Make multiple tests before making adjustments.
	OBSERVATIONS	ACTION	ADJUSTMENTS	SOLUTION
	Neutral Controls	Fly the model straight and level	Use Transmitter trims for hands-off straight and level flight	Adjust clevises to center Transmitter trims make mechanical adjustments to push rods and repeat this test till you have straight and level flight with trims centered or zeroed.
	Surface Control Throws	Fly model and apply full deflection of each control in turn	Check response of each control	Aileron Hi-rate 3 rolls in 3 to 4 seconds. Lo-rate 3 rolls in 6 seconds Elevator Hi-rate to give a smooth square corner Lo-rate to give a loop of approximately 130 feet diameter Rudder Hi-rate approximately 30-35 degrees for stall turns Lo-rate to maintain knife edge flight
	3. Center of Gravity (Method 1)	Roll model into a near vertical banked turn	A. Nose drops B. Tail drops	A. Add weight to tail B. Add weight to nose
	3a. Center of Gravity (Method = 2)	Roll model inverted	A. Lots of down elevator required to maintain level flight B. No down elevator required to maintain level flight or model climbs	A. Add weight to tail B. Add weight to nose
	4. Decalage	Power off vertical dive cross wind (if any). Release controls when model is vertical, (elevator neutral)	A. Model continues straight down B. Model starts to pull out (nose up). C. Model starts to tuck (nose down).	A. No adjustment required B. Reduce incidence C. Increase incidence
	5. Tip Weight	Fly the model straight and level upright. Checking for wing drop Roll the model inverted, wings level. Release aileron stick and check again for wing drop.	A. Model does not drop a wing B. The left wing drops C. The right wing drops	A. No adjustment required B. Add weight to right tip C. Add weight to left tip
	Independent rudder control surface test.	Fly model away from you and into any wind. Pull it into an inside loop or vertical climb Roll it inverted and push it into an outside loop or vertical climb	A. No rolling tendency when elevator applied B. Model rolls in same direction in both tests C. Model rolls in opposite directions in both tests	A. Elevators in correct alignment B. Elevator halves misaligned. Either raise one half or lower the other C. One elevator half has more throw than the other (the model rolls to the side with the most throw) Reduce throw on side with the most throw or increase throw on the other side
	1. Tip Weight (Final adjustment)	Fly the model high into the wind either coming towards you or going away from you, smoothly push the model into a vertical dive pull out sharply and watch for a wing to drop.	A. Neither wing drops on pulling out. B. The right wing drops on pulling out. C. The left wing drops on pulling out	A. No adjustment required B. Add weight to the left wing tip. C. Add weight to the right wing tip
	2. Dihedral	Fly the model straight and level into the wind, apply rudder and watch for any tendency for the model to roll. a. Test in both directions. b. Make changes in increments of no more than 1/8" at a time c. Don't worry about the nose pitching up or down	A. The model does not roll. B. The model rolls in the direction of the applied rudder. (Proverse roll) C. The model rolls in the opposite direction to the applied rudder (Adverse roll)	A. No adjustment required B. Reduce dihedral C. Increase Dihedral
	3. Engine Side Thrust During tests re-trim the rudder until a straight vertical is achieved then add side thrust to the value of half the rudder trim that was needed. Zero the rudder trim Go back and re-test after adjusting	Fly the model away from you into any wind. Pull it smoothly into a vertical climb going at least to normal maneuver height (watch for deviations to the left or right as it slows down)	A. Model continues straight up B. Model veers left C. Model veers right	A. No adjustment required B. Add right thrust C. Reduce right thrust
	4. Engine Up/Down Thrust	Pull it into a vertical climb. (watch for any deviations up or down as it slows down)	A. Model continues straight up B. Model pitches up, (goes towards the top of the model) C. Model pitches down, (goes toward the bottom of the model)	A. No adjustment required B. Add down thrust C. Reduce down thrust
	5. Aileron Differential Set the model up with 12 Degrees up and 11 to 12 Degrees down as a starting point	Fly the model level going away from you. Pull it up into a 45 degree climb and roll to the right. (After adjusting, try again in both directions)	A. The model does not veer sideways. B. The model's path veers to the right. C. The model's path veers to the left.	A. No adjustment required B. Increase the up throw on both ailerons C. Increase the down throw on both ailerons.
	6a. Pitching in knife-edge flight (Method 1)	Roll into a knife-edge and maintain height with rudder, (do this test in both left and right knife-edge flight)	A. There is no pitch up or down B. The nose pitches up, C. The nose pitches down (the model dives laterally)	A. No adjustment required B. Alternative cures: 1. Move the C of G aft 2. Increase wing incidence 3. Add down trim to ailerons C. Reverse the above
	6b. Knife-edge tracking (Method 2)	Roll into a knife-edge maintain height with top (do this test in both left and right knife-edge.	A. The model does not pitch up or down B. The model pitches to the canopy in both knife-edges. C. The model pitches to it's bottom in both knife-edges D. The model pitches in opposite directions in each knife-edges	A. No adjustment required B. Lower both Ailerons 2 turns and try again. C. Raise both Ailerons 2 turns and try again. D. Use mixing from rudder to elevator to fix the problem.
	7a. Power off Tracking (Test #1)	Fly the model level into the wind. Pull the power off and watch for any roll off to either side	A. No roll to either side B. The model rolls left C. The model rolls right	A. No adjustment required B. Mix 2% to 3% right aileron to low throttle, enough to neutralize the roll. C. Mix 2% to 3% left aileron to low throttle enough to neutralize the roll.
	7b. Power off Tracking Test = #2	Fly the model at a safe height and push it into a power off vertical dive. Watch for any tendency to roll while in the dive.	A. The model shows no tendency to roll B. The model rolls to its left C. The model rolls to its right	A. No adjustment required B. Mix some right aileron with low throttle, C. Mix some left aileron with low throttle,
	7c. Power off Tracking Test #3	Fly the model at a safe height sideways to yourself and push it into power off vertical dive and watch for any tendency to pitch up or down while in the dive.	A. The model continues straight down B. The model pitches up C. The model pitches down	A. No adjustment required B. Mix 2% to 3% down elevator with low throttle C. Mix 2% to 3% up elevator