bacosa

My Feedback: (6)

Hey everyone. I am new into electric pattern flying and had an issue yesterday that I thought I would ask about. I just purchased a pattern plane that was equipped with a Neu FAI gear drive motor. It is being controlled by a Jeti Spin 99 Opti Pro. I flew it for the first time yesterday in preparation for a contest at the end of this month and the first 5 flights were awesome. Motor ran smooth and had outstanding power and throttle response. When getting ready for my 6[SUP]th[/SUP] flight I turned the motor by hand and it sounded really bad. Not the usual ratcheting sound that you get but this was more a gravel type sound and not smooth. I decided to not fly and take the plane home for some triage. I removed the motor and took the gear box off thinking that it might just need to be lubed. I found that the gear box turned smooth and there was lube but not very much. I added some additional lube with a Q tip. The lube I used I got from F3A Unlimited. I added just enough to make sure that the gears were coated. I then reattached the gear box and reinstalled in the airframe. When turning over by hand it didn’t as rough this time. I then hooked everything back and ran up the motor. At around 50% throttle it motor vibrated violently. I immediately reduced throttle and it smoothed out. I tried it again with the same result but it vibrated so bad that it broke the rear soft mount off. I removed the motor and re-glued the mount. With the motor removed I again removed the gearbox and aside from a little more grease in the planetary pocket everything looked good. I did notice that the flat washer that rides behind the planetary did not look flat and in fact looked distorted. I tapped it flat with a small hammer and reinstalled with the gearbox. I re-balanced the propeller (PT 20.5 x14) and made sure all the mounts were still solid and not torn. Everything checked out. I hooked every back up and tried again with the same result. Heavy violent vibration approaching 50% throttle. I am at a loss on what is causing this. I used a known set up from a programming perspective for the Jeti 99 and this motor that I found online from a Team Futaba pattern flier. I am using 4 degrees timing, 20% initial brake and 46% final break, .1 second delay, linear throttle.... I am at loss as to what happened or what is causing this. The mounts are all in good shape, prop and spinner balanced. Has anyone run into this type of situation before. I called and e-mailed Neu but haven't heard back from them yet.

Thanks,
Michael

bacosa

My Feedback: (6)

Just talked with Jeff and Neu. He is not sure and has not heard of this before. I have it packed up to ship to him overnight so they can check it out. I will keep you guys posted if they find anything.

MAVROS

My advice to you is get a GP motor...


sorry I couldn't help it...he he he ,,

bacosa

My Feedback: (6)

Ya... I need one those like I need a hole in my head....

Anthony-RCU

My Feedback: (2)

You may have slipped the rotor but the techs will tell you for sure. I believe they are a press fit onto the main shaft and can shift. Mine have been replaced a few times they can be a little temperamental.

bacosa

My Feedback: (6)

Thanks Anthony. As much I would like them to say everything is ok it would also be nice if they found the smoking gun and get it fixed. Jeff at Neu was great on the phone and they received my motor yesterday morning. Hopefully I will have news soon.

bacosa

My Feedback: (6)

So I got the motor back from Neu. No issues found but the bearings were replaced as a pre-caution. I reinstalled the motor and it is still doing the same thing. Bad shaking at near 50% throttle. I have a new prop that arrived today (Carbon APC) I am going to balance and install and see if the problem is still there. The only thing left would be the mount itself. It has a Hyde mount. The front is the rubber isolator disk arrangment that bolts to the motor and then the other half bolts to the fuse. The rear of the motor is supported by a ring. The rear ring fits snug. With the motor installed you can grab the prop and flex the motor about 1/8 inch in all the directions which seems normal but I am not sure.I am super frustrated!

tggilkey

I fly a couple of instances of the Neu motor with the Castle ESC's and am by no means an expert on pattern electric stuff -- starting 4th electric season. Having said that have you looked at the motor/gear shaft when it is turning to see if there is any run out? The same for the spinner backplate relative to the nose ring; and the nose/cone of the spinner? Might look at the tracking of the prop tips, also.

It's not prop flutter is it? Frustrating for sure. Post the findings please for the rest of us! and good luck with it!

bacosa

My Feedback: (6)

Those are good tips. I got my new prop today so I will try it out when I get home. I think I'll do what you said and check the run out on the motor shaft and adapter when I get home. The tracking on the prop tips is a good idea too. Thanks for the advice. I'll post my findings later. I'm taking it out the field tomorrow as well to let the "brain trust" review it as well. I am really new into this electric stuff as well... 3 weeks so I'm learning as I go.

tggilkey

It might be a pain to do but it might be interesting to run your motor with a different ESC to see if that is introducing something weird into the equation.

We're all learning as we go!!

bacosa

My Feedback: (6)

I can see if I can borrow one from someone to try it. Initially I thought it might be a timing issue but I was told that would not cause this issue. I had the programmer plugged in to see all the data and there is nothing odd abnormal with the ESC (that I can see) but I will try to leave no stone unturned.

f3a05

Could you perhaps run the prop,motor, and esc up together without the Hyde mount? Maybe replace the mount temporarily with solid spacers of some kind in the model, or even outside the model, solid mounted on a test bench?
That would eliminate the mount as a possible cause?

nonstoprc

My Feedback: (90)

Some possible causes of the vibrations to check.

Is the prob balanced?

Is it possible that the three screws holding the front hyde mount to the firewall not tighten enough?

The condition of the firewall should be checked as well. It should not bend easily and glue solidly to the fuze on all contacting sides.

Lastly, check the mount itself and make sure the rubber glues well to the rings.

bacosa

My Feedback: (6)

So it appears that the problem has been found. It appears that the Hyde soft mount (which is 5 plus years old with an unknown number of flights is bad). I made a temporary solid mount to try it without the soft mount and the problem was gone. I did inspect the "firewall" mounting and everything is stiff and still glued solidly to the fuse sides. The rear support is also solid and fits very snug around the aft end of the motor assembly. I am just going to make another mount for it and move one. This was pretty frustrating but at least I know the motor and gear box are good to go!