I have been building a Kadet LT-40 for a while now and finally am motivated to finish it up. One trip to lacal flying field is all that it took! I joined AMA and this morning I fired it up and ran a very rich tank of 10% gas through it. I wanted an easy starting engine so I bought a Thunder Tiger .40 after reading several post's on this forum. I am kind of a cheap skate (just ask my wife!) and didn't want to buy a starter. With everything ready to go, I clipped on the glo-plug igniter and with one flip of the chicken stick, she purred like a kitten! This is a great engine! I ran it rich but it idled very nice and ran good. I just have to finish up a few details and and then join one of the lacal clubs. I don't have a computer radio and a few of my servos are stalling (buzzing) at the end of there travels. Some small mechanical adjustments should take care of it. A good check out of the plane by an instructor and hopefully I will be flying soon. Bob

Very cool and congrats

Sounds like you have it well thought out and pretty much know what needs to be done. The knowledge of knowing why a servo is buzzing and what to do about it shows that.

Keep us informed and welcome to the addiction err hobby

I agree, sounds like you have things well thought out. You won't regret joining the local club and getting an instructor to help you learn either. (Especially being the cheap skate you are. It'll save you lots of money in repairs and new planes. )

Good luck, have fun, and welcome to RCU!
Dennis-

My S3004's buzz sometimes. Not all the time, though. Why is that?

Do they buzz if you take the pushrods off them?

If the buzzing goes away when you take the pushrod off, then you have friction in the linkage, and the servo is working to try to get to center.

If the buzzing is there even with out the pushrod connected to the servo, and the servo works fine, I generally wouldn't worry about it. You might try working the servo with the pushrod disconnected, and fighting it a little with your fingers. You should hear the buzzing get louder when you resist with your hands. (don't over do this, btw. A little bit won't hurt the servo, but if you over do it, you can strip gears and cause other problems).

They never buzz when centered. Only when flanked, and even then it is few and far between.

Then that is pretty normal, the servo is just working against the load of the surface.

A consistent buzzing with the servo at center or at any point in it's travel is almost always friction and most likely occurs when the pushrod is either in a tube or making a slight or even not so slight curve or bend along it's length. It is also possible that the throw is set a little bit to much on the servo and the control surface is running out of throw before the servo gets to it's end point (flanked)


Montague has a great idea on checking...

Yeah, my servos buzz sometimes just in the center position. I use the trim to stop it, but I've always wondered what it was. I'll check the pushrods.

I noticed that sometimes my batteries will jitter or buzz when the battery is fully charged. Goes away usually as soon as I turn the tramsmitter on.

If your servos buzz in the center, don't worry about it. But don't let it continue either, just move the surface with your hand till it stops (Or move the trim, whatever). because this will cause a small drain on your batteries.

Once the engine is running, the vibrations will be enough to stop the buzzing.

That 'jittering' happens to me too...
Maybe it's because I'm using eight year old batteries, transmitter, plane, field box, 12V starter, glow igniter, servos, extensions... Get the point?

You should always turn your transmitter on first, then your receiver. Some people have reported that the jittering that occurs when the transmitter is off can cause stripped servos. Don't know for sure, but I don't want to take any chances. TX on first, and off last.