Servo buzzing
 

I've got this bugger of a problem with my aileron servos. The plane is a p-51 mustang arf with the jr 600 receiver and the jr sx6000 transmitter. While doing a pre-startup this morn. the servo started buzzing. I swapped the leads around and it still buzzes. If I turn the tansmitter off, it quits.(radio still on). I double-checked the receiver leads and all looks good. I'm going to check the mounts tonite but is there anything else I should be looking for. I'm hoping to put in my first flight (With an instructor) on Monday Thanks [8D]

RE: Servo buzzing
 

With analog servos this USUALLY means your linkages are binding somewhere slightly and the servo is fighting to get back to neutral. Disconnect the linkages to verify. Then reconnect one side at a time and you should be able to decide WHICH (if not both) side is binding. Find the cause of the bind and remove it and the buzz should go away. Linkage could also be improperly bent too. Do the ailerons move freely when the linkage is NOT attached? I mean with NO drag at all near neutral?

RE: Servo buzzing
 

Are these digital servos? If they are buzzing is normal for them. If not, read on.

Ok, here's what you need to do to narrow down the problem.

Turn the radio on and disconnect the pushrod from the servo. If the buzzing continues then you have a bad servo. If the buzzing stop you have something wrong with the control surface/connecting rods. Something is pushing/pulling against the servo and the servo is having to push/pull back to maintain its position, and this is were the buzzing is coming from. You need to troubleshoot this and see what's causing this. Your instructor can probably go a lot further in helping you diagnose this problem than we can, simply because he can look and see the problem first hand.

Is this the Hanger 9 P-51 PTS plane you are going to learn on?

Ken

RE: Servo buzzing
 

OK, I've just re-read your post. You appear to have a version of Hangar 9 P-51 trainer with dual aileron servos. Most of what I said still applies but naturally you know which side the problem is on.:D Carefully flex the aileron joint and see if you can loosen it up some.

Ken - probably not digitals. I think they'd all be buzzing if they were. I doubt he would have just one digital in the plane, but could.

RE: Servo buzzing
 

Bruce,
Just trying to cover all bases. :D

Ken

RE: Servo buzzing
 

Sent ya an email with more bases in it Ken.:D

RE: Servo buzzing
 

Hmmm, me thinkst that I must givest somebody a good thunk on the skull!!!!!! :D:D:D:D

Ken

RE: Servo buzzing
 

Thanks Ken and Bruce. Will check for binding tonite and yes it is the pts. Learned the hard way about needing an instructor, but there's a good group of guys at the field who'll be teaching me Mon. Again Thanks for the advice;)

RE: Servo buzzing
 

You two geniuses overlooked the most obvious thing... :eek:

my05monte, try this:

While the servo is buzzing, lightly move the aileron - just tap it up and down and see if the buzzing quits. If it does, don't worry about it (The engine vibration will do the same thing once the engine is running)

RE: Servo buzzing
 

That was supposed to be one of Ken's bases.:D

RE: Servo buzzing
 

:eek:

:D

Ken

RE: Servo buzzing
 

:D

RE: Servo buzzing
 

Also if tapping it works ( which it will ) you may want to adjust the linkages so that the control rod is connected to the INNER hole on the servo control horn. Then connect the clevis on the other side to either the middle or outer hole.

This gives the servo more leverage to move the control surfaces and give you finer control, but it will reduce travel a bit.

Since you are starting off, this will not be an issue at all, and you'll prefer the finer grain control.

BTW: My PTS planes also did the same think and as Miniflyer said, once the engine is running it stops.

As the hinges wear a little it will also stop.

RE: Servo buzzing
 

It happened with my P51 Mustang PTS of Hangar 9 not Hanger lol:) but once engine started it went away. I found that extented wire with connector connected to Y-harness was not properly attached. Well, You all people are very senior and respectable flyers, but what if that problem persists? like I had the experience, left aileron was not responding and couple of times I experienced left aileron didnt respond during flying, and its dangerous and it may cause a crash, as mine crashed. Aileron did give a problem but my Rx's IF was burned during flight, and it was JR's R700 slimline.

It should be properly checked, and servos are standard with it. I hope this glitch would get over otherwise I hope not for any bad incident.

Mody

RE: Servo buzzing
 

If the "IF" circuit (Intermediate Frequency) is acting up in the RX it should be expected that ALL of the servos would be acting up equally. For just one servo to mis-behave is not logical for that diagnosis. The IF portion of the circuit is also a very low current part of the RX.

RE: Servo buzzing
 

bruce,

Im not talking about all servos. The crash of my Mustang was due to IF burned of Rx. One of my servo was acting up, yes, but the cause of my plane's crash was IF not the servo. What I experienced couple of times during flying, that left aileron stopped responding, one of the senior flyer who is also commercial jet airliner pilot he flew it too, and told me the same thing, but somehow as it was flying and engine was running on and off it would respond and not, but he landed her safely and told me don't fly it until you resolve this glitch. When my plane crashed it took a left turn, it moved right aileron it didnt respond, as it took a deep nose left dive and crashed, finally I gave it to a friend of mine most senior flyer and electronics experts, he showed me it was burned. That would have been the major cause of crash not one servo. But one servo playing up may cause severe problems.

Mody