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Servo Problems/Failure


Old 03-25-2007, 11:04 PM
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Default Servo Problems/Failure

I have a RC Skydiving Standard Jumper; I was using Blue Bird BMS 705MG Servos; I set my servos where at Neutral the arms were full up, resting on stops, no servo buzzing; used Channel 4(Rudder) for Left arm and Channel 1(Aileron) for Right arm; to pull left arm down I would push left stick full left from neutral & to pull right arm down I would push right stick full right from neutral; this worked great for about 6-7 jumps, now the servos won't pull any more; in fact when you lift and hold the Skydiver up by the steering lanyards, the servos don't have enough torque to pull the Skydiver up when you articulate the arms, if you hold the Skydiver with no weight on the arms the servos articulate the arms witout any difficulty, put weight on them and they barely move; considering that these servos are rated for 83oz, they should easily lift the 3.5lbs(58oz) Skydiver; it would seem that servos should have enough power to lift the Skydiver up when you articulate the arms, afterall once they are dropped the weight of the skydiver would always be pulling on the arms and servos; WHY DID THEY FAIL, I saw in some pictures in other set ups that neutral or arms full up the sticks are push over all the way to the center of Transmitter and held that way with elastics; is this set up better and would prevent the Servos from failing, or should I just get Higher Torque Servos like the HiTec HS645MG with 107oz of torque or HS985MG with 133oz; the only problem is that higher torque servos come in deeper cases 1.2" vs 0.87"; would these fit in the RC Skydiving Body; Thanks Doug.
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Old 03-26-2007, 09:46 AM
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Default RE: Servo Problems/Failure

Hey Dasintex

First of all you should have set it up so full stick movement is used, instead of just half stick. I would say if you put long enough servo arms on it to work using half stick you overworked the servos. Shorten the servo arm length and use the full stick travel to accomplish the same task. Thats one thing to look at.

Second, the servos CAN NOT take 6 volt battery packs. You didn't say what you used so this is another area I would look into.

Third, the servos are not strong enough to hang the diver from and pull his own weight up like you are trying to do. The servos get mechanically disadvantaged with the arm setup (or long servo arms). The servos do have plenty of power to steer the chute even though they cannot pickup the divers weight.

With skydiving you really need to set up your skydiver as stated in the instruction manual, this will always help in the long run. I have jumped 100's of jumps with the setup shown with no faults. Hope this helps.

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