Problem with servo horns detaching from Futaba 9451's

[creightoncarr]

I'm running 9451's on my T-Rex 600N using the Futaba 30mm circular wheels. Last week the screw securing the elevator arm to the servo backed out resulting in a nose in crash. I'd had about a dozen flight on its so far and I thought, "Shame on me for not checking before the day began." Well, fast forward to yesterday. After a complete rebuild (the damage from the first crash was extensive), I got a chance to fly again yesterday evening. I hand checked every screw and bolt on the heli before leaving the house and double checked the servo screws. After the first tank I eyeballed the screw on the elevator servo and it was still set. I did not, however, remove the canopy and check the screws on the other two cyclic servos (you see where this is going, and again, my bad (but it had only been one tank so far)). So, I am flying the second tank and about two minutes into flight the heli does a violent half roll to the left about ten feet off the deck, and instinctively I try to correct to the right and bring it in. It levels out and I hit TH, and just I begin to think I may save this, another violent half roll to the left and the rest is history.

So, I inspect the wreckage, and lo and behold, the servo arm has come off the aileron servo and the screw is nowhere to be found. I run the 9451 in my 600E's and Raptors and have hundreds of flights on those with never a hint of the servo arms coming loose. Now, in the course of a week, twice on the 600N on different servos :? This is the first time I've used these Futaba wheels, but have seen others using them without complaint. Anyone else have problems like this? What was the solution? Does anyone Loctite the screws in place? I am about to the point where I am going to do that and I will worry about removing them when the time comes. I appreciate any suggestions.

Thanks,

Creighton

[DavidH]

Does anyone Loctite the screws in place?

The question you ask is the solution to your problem. Either use blue loctite on teh servo screw into the metal output shaft on the servo. Or use a star lock washer on the servo screw. I use the star lock washers and don't have a problem with the screws loosening in metal output shaft servos.

David

[creightoncarr]

Thanks, Loctite it will be. I've always used the lock washers on servos and have never had a problem until these last couple of incidents with the 600N.