jwmachon

Hi,

I have just fitted my servo into my new model plane its one servo for two ailerons the movement and power is fine however when i trim there is not much movement on the ailerons very minimal i have tried 2 servos and all my other models trims work fine using same equipment so i must be doing something wrong on the linkages any suggestions would be fantastic the arms from the aileron horn to servo arm are straight should i move these out on a longer horn? Please help me.

Thanks,

Jonny

Campgems

As a general rule, if you have end point adjustments, the arm length on the servo should be near the horn to hinge length. You can then adjust the endpoints to get the maximum throw you want

If your TX doesn't have endpoint adjustment, then you need to mechanically adjust the throws. Again, a 1 to 1 ratio of servo arm to horn is a starting point. THis will usually be to much throw on an aileron as the servo normally has a 60 degree rotation. If you wnat 15 degrees up and down, the you would want a 2 to 1 ratio. IE a servo arm 1/2" long to a 1" horn on the aileron. YOu would get half the movement and a bit more torque.

Get a servo with nothing attached rotating correctly first. If it will not rotate 60 degrees or more full throw, then you TX is not providing enought throw.

I just re-read your post and have a question. Are you saying that the stick movement of the ailerons is OK, that it is just the trim you are worried about?

Don

jwmachon

Hi mate.

The travel is full way but the trim hardly moves the aileron I have tried a few servos and the same it works ok on all my other models the radio a rd6000

Thanks

A.T.

E.P.A - A.T.V - Dual Rates differences, cautions and arming ESC may asist.
Also check that the ailerons can move past the point of full aileron stick deflection and full trim so as to ensure there is no binding from surplus glue on the hinges or insufficient gap along the hinge line.
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links

RJConnet

Jonny,

I can't say about the RD6000 but several of my transmitters allow you to change the trim authority of the trim switches or trim levers. My new RDS 8000 Tx is that way. The amount of trim produced by the lever or switch can be reduced all the way to zero or all the way up to maximum. Check your manual for STEP or TRIM STEP and see what it says..........RJ

Smacka

RJ is correct. This feature is available, as I have it with my JR X9303...however...the way it works is that it changes the iterations the flight surface moves at null for each click of trim change. my radio's trim step is set to "4". The higher the number, the coarser the adjustment per click. Meaning, set at "10", this is the setting used to make drastic trim adjustment to a plane that is on its maiden flight, and is way out of wack (sins of the builder). Settings of 1 to 3 is for fine tune adjustments. If you set the number to 1, you severely limit the amount of trim movement per click.

Now, be aware that this in no way changes the total trim stroke available EXCEPT if you set the trim step to "0", the trim becomes inactive and will not work at all for that particular flight surface. Setting it at "1" gives you the full stroke available BUT it takes much longer to get to the trim stops because you are at the least itierations per click of the trim lever.

The part that puzzles me is that this gentleman states that if he swaps servos, all is well and it works correctly. So why does he have trim issues with just the one servo? That does not even leave room for the possibility that he programmed the incorrect "wing type" into his radio for the model OR that he forgot to inhibit the flap system while trying to use a multiple aileron servo setup. If you do not inhibit the flap system in the setup software portion of the programming, you turn your ailerons into flaps and it screws up the proper aileron servo strokes and you will not have any trim control.

Mysteries...
Smacka

BuschBarber

My Feedback: (2)

Smacka - It appears that he said he tried two servos and they both behaved the same. yet all of his other trims were fine.

I don't know if he specifically mentioned how much travel his ATV was set to, but I know that if the ATV is set to a low percentage, the Trim will not have much authority. When I set up Throttle, I always try to keep the Low Throttle ATV at 100%. If it is set to less than 50%, the Throttle Trim has very little affect.


[quote]ORIGINAL: Smacka

Smacka

[quote]ORIGINAL: BuschBarber

Smacka - It appears that he said he tried two servos and they both behaved the same. yet all of his other trims were fine.

I don't know if he specifically mentioned how much travel his ATV was set to, but I know that if the ATV is set to a low percentage, the Trim will not have much authority. When I set up Throttle, I always try to keep the Low Throttle ATV at 100%. If it is set to less than 50%, the Throttle Trim has very little affect.


Hi Busch!
Yep, you are exactly correct for the throttle. Anything less than 100% for the throttle trim step will reduce the available trim travel. Even the manuals state that if you adjust the throttle trim step you do lose full stroke in a linear fashion. However, the trim step for my JR radios for the rudder, elevator and ailerons do not lose full stroke capability, just how long it takes to achieve full stroke due to a decrease in movement per "click" (per beep on your radio) change at the lower trim step settings, as with settings 1 thru 3. Please note, I am talking only about the trim tabs and not the actual stick positions and movement. The stick position/movement stroke is handled with the "travel adjust" portion of the programming.

I focused on other than the throttle because his issue is with the aileron servo(s).

I would like to be able to see a video of what his issue is, and the radio settings. It appears the programming may not be quite right (?)

Okay, in re-reading his post, I see what you mean with respect to the other servos he tried had the same outcome. That leads me to believe he has his radio programmed for "flaparon" wing type BUT he has his flap system set to active. This will cause fits with the aileron servos. The strokes will be way off, and the trim tab inactive because the radio thinks his ailerons are flaps. I had this same issue with my 1/4 scale Piper Cub until I set the flap system to inactive. Then the ailerons behaved themselves. I had to re-establish mechanical null, then all was well with minor adjustments from there.