450 pro dfc blade tracking

[alyon187]

The only bearing it was applied was a small amount around the top main shaft bearing and to put the tt bearing in place. Should these be changed to the right retainer?

And what bearings should it be applied to?

[alyon187]

Could the bearings on the dfc arms binding up a lil bit cause wobbles? I do recall that when I disconnected them from the swash one could fall and flip back and forth freely whole the other took a bit of force to get it to move. If I back out the screw a bit itll loosen up. Any ideas? Ive also got another ds430m that I'm really close to installing in the elevator position to see if its possibly that servo that is causing the nodding/bobbles... ideas?

[PowerDyne]

At this point it wouldn't hurt to look closer at the servos I suppose. If the DFC arm bearings are acting funny, it could cause it. Could be a bent (slightly) screw that could cause it too.

Maybe check your Mounting tape for the Robird, and all the wiring to make sure nothing is amplifying a small vibe.

Not sure what else to recommend other than everything that has been done so far.

Maybe check the servo arms as well? Sometimes the splines inside the arms can wear allowing slop under load in flight that you really can't see on the bench. Maybe the servo balls are rocking? At this point, I am just not sure what's going on.

[alyon187]

The fbl right now is a vbar, and after alot of messing around ive got it down to having clean logs w raised vibes on the start ups and spool downs... for now atleast (knock on wood). Its done this before where it has clean logs and then vibes come back. But I'm at 46 main gain from my last flight and still have a lil bit more room to try til it starts to get sloppy. So will try the gains first before switching out the servo. I do notice that the elevator will kind of tick, what it sounds like atleast, every now and then on while its on the bench. Itll like twitch/jump for no reason as well as at times I can here a sort of fast jitter coming from it that comes and goes.

[PowerDyne]

Could very well be a servo on its way out, or maybe a dirty pot in the servo.

[alyon187]

I hope not, they are new servos.


Though if thats what it sounds like to you then I think I rather be safe than sorry and go ahead and change it out

[alyon187]

What is a dirty pot?

[alyon187]

Take a look at this and lemme know what you think...

https://youtu.be/57uLEhu4Bk0

[PowerDyne]

Originally Posted by alyon187

What is a dirty pot?

Originally Posted by alyon187

Take a look at this and lemme know what you think...

Servo jitter - YouTube

That jitter is the gyro correcting an error in the servo.

If the ball links aren't too sloppy or too tight it normally will not do that. Could also be slop in the servo arm on the output shaft.

Could be a bearing, or in the gear train in the servo.

A dirty pot is the potentiometer on the output shaft of the servo that tells the circuit where the shaft is in travel.

Sometimes new servos need to be cleaned out because grease can seep into the pot causing the servo to glitch like that. The servo is having trouble centering either due to mechanical issues, or electrical issues, or a combination of both.

It could also be a connection issue with the connector pins, or perhaps just a bad potentiometer from the factory. It happens.

I would suggest contacting the shop where you purchased the servo and showing them the video. It may be that the servo can just be replaced as a warranty claim.

[alyon187]

Could this cause issues in flight? Like tracking going in and out and the occasional nodding/vertical tail bounce?

[alyon187]

It doesn't do it all the time, ive had it happen once or twice when I first plug in the battery and the gyro is calibrating but goes away as soon as I move the cyclic.

[PowerDyne]

It could definitely cause the nodding. Especially if the servo jitters a little in flight and the FBL controller tries to compensate for it.

[alyon187]

Damn, just as I'm getting it to fly better and have the vibrations all but gone, I have to take out a servo or two to get them cleaned

Guess what ill do since yesterdays flight seemed to be a quite a bit better in feel, stability, vibration and nodding/vert tail bounce is continue making small adjustments and see if it gets any better. That way mayve the issue will resolve itself. If not I guess ill go ahead and remove and the elevator servo and get it cleaned up.

[alyon187]

I think the bounce was from a tail bearing, on the output shaft, not being a close enough fit. Cuz I changed it out and installed a newer output shaft and the up and down bounce is gone. I also think that the elevator precomp was set to low causing the tail to lower and raise when I added collective to keep a stable hover. Once I changed those I dont see anymore up and down tail bounces.

[alyon187]

Powerdyne, if they still jitter like that time to time on power up and go anyway by themselves or if I move the cyclic they will stop and there is no in flight problems that I can tell do I need to worry about it? Should I still change it out and/or clean the gears? Cuz right now even though one or two of them will jitter like I said, while in flight I have no issues to note. What do you tgink?

[PowerDyne]

Originally Posted by alyon187

Powerdyne, if they still jitter like that time to time on power up and go anyway by themselves or if I move the cyclic they will stop and there is no in flight problems that I can tell do I need to worry about it? Should I still change it out and/or clean the gears? Cuz right now even though one or two of them will jitter like I said, while in flight I have no issues to note. What do you tgink?

Some of it may just be the Robird doing adjustment on the bench or at rest. If you are not noticing any in flight issues, I'd say fly it but keep an eye on it. It may get worse over time.

It may just be that the servos are having a little trouble at neutral centering, and the constant correction of the Robird while on the bench or on the ground are just amplifying a little float in the deadband.

[alyon187]

Ok then, ill jist keep an eye on them...