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Servo Travel Adjustment Question
Hi Everyone,
Well, my LT40 is almost ready to fly :D. However, I have a question with regards to servo movement. I'll try to provide as much detail as possible and would appreciate any input and advice you can offer. Airplane: LT40 Engine: O.S. .46LA Radio: Futaba 9C Servos: Futaba 3004 Problem: I set up the throtle control per the SIG manual. When testing the radio controls, the carburator is fully closed before the throtle control reaches the full down position. I have adjusted the linkage attachment points (both servo arm end and throtle arm end) for minimum travel, but I am not able to reach the desired servo position to allow engine idle at the full down throtle stick position. I know the tx has end point adjustments, and it is possible to make the adjustment there. However, will that adjustment work if another radio is used in trainer mode? I hope I have provided enough details for you, if not I should be able to answer any additional questions. I would appreciate any advice you can offer. JesseV |
RE: Servo Travel Adjustment Question
Where is the throttle trim set? As I am unfamiliar with 9C, is there a separate throttle kill button or switch? What is usual method of killing engine, in other words?
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RE: Servo Travel Adjustment Question
ORIGINAL: JesseV Hi Everyone, Well, my LT40 is almost ready to fly :D. However, I have a question with regards to servo movement. I'll try to provide as much detail as possible and would appreciate any input and advice you can offer. Airplane: LT40 Engine: O.S. .46LA Radio: Futaba 9C Servos: Futaba 3004 Problem: I set up the throtle control per the SIG manual. When testing the radio controls, the carburator is fully closed before the throtle control reaches the full down position. I have adjusted the linkage attachment points (both servo arm end and throtle arm end) for minimum travel, but I am not able to reach the desired servo position to allow engine idle at the full down throtle stick position. I know the tx has end point adjustments, and it is possible to make the adjustment there. However, will that adjustment work if another radio is used in trainer mode? I hope I have provided enough details for you, if not I should be able to answer any additional questions. I would appreciate any advice you can offer. JesseV When you said you "adjusted the servo and throttle arm for minimum travel", did you use the outermost hole on the throttle arm ? You need to use the hole closest to output shaft on the servo and the most outermost (furthest away ) on the throttle arm. Doing it this way I have no problems adjusting for throttle. Another thing you can try is to use a HiTec servo for the throttle and use the "sliding arm" servo arm. Often, you can get closer to the output shaft of the servo with this arm than you can with a standard arm. The HiTec servo arms WILL NOT WORK with Futaba servos. |
RE: Servo Travel Adjustment Question
ORIGINAL: Campy ORIGINAL: JesseV Hi Everyone, Well, my LT40 is almost ready to fly :D. However, I have a question with regards to servo movement. I'll try to provide as much detail as possible and would appreciate any input and advice you can offer. Airplane: LT40 Engine: O.S. .46LA Radio: Futaba 9C Servos: Futaba 3004 Problem: I set up the throtle control per the SIG manual. When testing the radio controls, the carburator is fully closed before the throtle control reaches the full down position. I have adjusted the linkage attachment points (both servo arm end and throtle arm end) for minimum travel, but I am not able to reach the desired servo position to allow engine idle at the full down throtle stick position. I know the tx has end point adjustments, and it is possible to make the adjustment there. However, will that adjustment work if another radio is used in trainer mode? I hope I have provided enough details for you, if not I should be able to answer any additional questions. I would appreciate any advice you can offer. JesseV Make sure your EPA(s) are set for 100%. The adjustment will not work with the usual buddy box. When you said you "adjusted the servo and throttle arm for minimum travel", did you use the outermost hole on the throttle arm ? You need to use the hole closest to output shaft on the servo and the most outermost (furthest away ) on the throttle arm. Doing it this way I have no problems adjusting for throttle. Another thing you can try is to use a HiTec servo for the throttle and use the "sliding arm" servo arm. Often, you can get closer to the output shaft of the servo with this arm than you can with a standard arm. The HiTec servo arms WILL NOT WORK with Futaba servos. |
RE: Servo Travel Adjustment Question
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ORIGINAL: JesseV I have adjusted the linkage attachment points (both servo arm end and throtle arm end) for minimum travel, If that is how you are set up, the next thing to do (if you want to avoid doing it electronically with the Tx) is to rotate the servo arm to a different position See below: |
RE: Servo Travel Adjustment Question
The 9C has digital trim and it is set at 0 offset (no trim adjustment). The manual for the 9C states you need to assign a switch for throtle cut. I have not done this yet since I thought I might have a problem with the amount of servo travel and would need to resolve that first.
JesseV |
RE: Servo Travel Adjustment Question
The linkage attachemts are set at the outermost hole in the throtle end, and the innermost hole (closest to the center) on the servo arm.
Minnflyer I will try your suggestion to see it that fixes the problem. Thank you all for your fast replies. |
RE: Servo Travel Adjustment Question
I use an adjustable servo arm for the throttle, cause sometimes you'll find that the 2º servo arm hole is not enough, and the 3º is too much. In those cases an adjustable servo arm is what you need ;)
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RE: Servo Travel Adjustment Question
Hmm ... perhaps the adjustable servo arm is what I need. I tried MinnFlyers suggestion and it did not work. Well, it worked for the iddle setting, but then when I moved the throtle stick all the way up, the servo started binding before the carb was all the way open. I'll keep working on it.
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RE: Servo Travel Adjustment Question
YOu don't need an adjustable servo arm with the 9C.
You need to adjust the max and minimum throws. This can be done in the transmitter. I have the 9C and it is a very versatile remote. Look for the End point (Endpt) adjustment in the menu. Once there, select the throttle channel and reduce the high end setting until you can open the throttle all the way and it does not bind, do the same on the low end. The "throttle cut" feature is also very nice to have. It allows you to turn of the motor without using the trim button. Read the manual, it explains fairly well how to program that. |
RE: Servo Travel Adjustment Question
Actually I have read the manual. However, on an earlier reply Campy mentioned that type of adjustment would not work witha buddy box. That is the reason I am looking for an lternative method of adjusting the servo travel.
I have actually gone through all the samples in the 9C manual, I have done every possible programming option that the LT40 allowed for. I just want to make sure I'm all set before I get to the field. My club is small at this time so there are no assigned instructors. It is pretty much see who is willing to help you while you are there. So, I thought I would try and make things easier by having as much already done and set up as possible. But, if the end point adjustmets are the best way to go, I'll go for it :D JesseV |
RE: Servo Travel Adjustment Question
I think it's a good practice to always try to have all the radio gear setup the way you want it before doing it with the TX, that way you'll have a bigger available adjustment range with the TX in case you change something. It works for me ;)
Try adjusting the throttle curve using the outer hole and changing the servo arm position, if you combine it with an adjustable arm you'll get it just the way you want it good luck |
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