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Incidence and Lateral balance

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Old 12-20-2006, 03:57 PM
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racanicchi
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Default Incidence and Lateral balance

Hi Don, I'm Tiago from Brazil and i have a question about How to adjust wing, stab and engine incidence to fly the Fuselage without AOA, and hot to adjust lateral balance in Giant airplanes.

Thank's for Help
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Old 12-22-2006, 08:34 PM
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Don Szczur
 
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Default RE: Incidence and Lateral balance

CG first, according to plans. Next aileron trim and elevator trim. Hands off from one side of field to other. Fly JR, you change trim rate to 1% rate. Do not fly low quality servos, otherwise this experiment is fruitless. Fly JR 8411 or JR 8611A servos or other high quality servos. The best you can especially on ailerons, then elevators.

After plane flies perfect level left to right and right to left you are done. If the tail drags (nose up) during level cruise (all above trimming is at 60% to 75% throttle fixed position). Positive incidence in stabilizor brings the tail up. You will need corresponding up elevator trim. This is ok. Again, any changes to tail incidence be sure to re-trim level flight as above.

With all straight and level trim set, trim for hands off uplines. Adjust thrust then throttle to rudder if it needs just a little more right rudder on upline. Next is downline. You trim for staight uplines and downlines. These are the most important. Taught to me by a TOC champion and legend. Mostly left rudder trim with low throttle. Double check central trim by doing hoizontal figure 8's and watch the nose and tail.

Now, before I changed wing incidence, I mixed in some right aileron with low throttle. This kept the wings (and plane) tracking straight in a spin entry (particularly inverted spin entries, since at the time it was tough putting in left rudder when approaching the spin entry). The issue with the idle-to-aileron mix- I found that the wings would (very slowly, like 5 degrees to the right) drift at/during the bottom of a pull out. Example would be at the bottom of a square loop, as the plane pulls out of a vertical down line to horizontal, (going fast) the plane would roll slightly right as its going fast... So put in left wing neg incidence so it will require right aileron trim for straight and level cruise speed flight, and as the plane slows down that right aileron trim takes over, resulting in a nice straight, stable spin entry (either inverted or upright). This works the same way as trim tabs on full scale cessna's.

Just started aggressively cranking in the adjusters on the left wing and the plane flew like magic. This is what you do if you trim for straight and level, cut throttle and the plane drifts to the left. If it drifts tot he right when throttle is reduced to idle during a spin entry, do the opposite.
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Old 12-23-2006, 01:58 PM
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Default RE: Incidence and Lateral balance


Quote:
ORIGINAL: Don Szczur

Double check central trim by doing hoizontal figure 8's and watch the nose and tail.
Interesting Don, could you please expleain in detail that step?

By central trim you mean with half throttle? How the figure 8 should be performed? Rudder?



I wish you my best Merry Christmas, thanks for all your help, it is very very appreciated.
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Old 12-23-2006, 11:39 PM
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Default RE: Incidence and Lateral balance

Mid throttle with these turns, will give you mid-throttle rudder trim. See if nose is higher/lower each way. THe plane will need some "top ruddder" or fall off one turn more than the other.

All the best

Don
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Old 12-26-2006, 01:50 PM
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Default RE: Incidence and Lateral balance

Hi Don
Thank you very much for the tips.
Happy New Year for you end your family.
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Old 12-27-2006, 08:13 AM
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Default RE: Incidence and Lateral balance


Quote:
ORIGINAL: Don Szczur

CG first, according to plans. Next aileron trim and elevator trim. Hands off from one side of field to other. Fly JR, you change trim rate to 1% rate. Do not fly low quality servos, otherwise this experiment is fruitless. Fly JR 8411 or JR 8611A servos or other high quality servos. The best you can especially on ailerons, then elevators.

After plane flies perfect level left to right and right to left you are done. If the tail drags (nose up) during level cruise (all above trimming is at 60% to 75% throttle fixed position). Positive incidence in stabilizor brings the tail up. You will need corresponding up elevator trim. This is ok. Again, any changes to tail incidence be sure to re-trim level flight as above.
Don, if I can ask you another question...

You suggest to do the trimming at 60% - 75% throttle.Two questions:

1) 60% or 75% of what? With throttle curve and expo, it is not clear where we have the 60% of power, or do you mean 60% of stick travel?

2) So you fly your sequence passes at 60% to 75% throttle? I thought that a cruise speed should be setup at about mid throttle. If we trim with 60% - 75% throttle then at mid throttle the up trim could be not enough to get a level flight...

Thanks for your unique willingness.
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Old 12-27-2006, 11:11 PM
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Default RE: Incidence and Lateral balance

Throttle curve is set to provide a linear power curve on the stick, vs throttle barrel or servo position. The cruise position depends on your thrust-to-weight ratio and also the wind. On a windy day I'm at three quarters to 7/8 even full on many horizontal lines. However the trim during relative calm is near 60% throttle for me. Basically I fly at a throttle position on the horizontals that approximates the down-line and upline speeds. My trim on the elevator/thrust, whatever (CG) provides basically level flight around cruise speed. Even at full throttle there is not any noticeable/ significant climb or dive, but I trim for a set 60% on my current plane. Sequence actually varies up to +/- 10% airspeed, since it is the ground speed I try to maintain constant throughout the flight.

Hope this helps,

Don
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Old 12-28-2006, 04:41 AM
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Default RE: Incidence and Lateral balance

It helps a lot Don!!!!!!

My best Happy New Year to you and your family!!!!
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Old 07-13-2011, 04:51 PM
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Default RE: Incidence and Lateral balance

Wow that was alot! I'll need to read that a few times.
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