[JonM]

I took my new e-Flite Extra for its maiden flight yesterday and ran into a bit of a problem that I cant recreate and am still scratching my head about...

The plane has a new CC Pheonix Ice Lite 75A ESC flashed to the latest firmware and a new Power 32 motor. Battery was brand new and holding charge well. It was a perfect morning for the maiden flight so I did a couple test run ups at the field and a range test and everything was looking good.

Lined her up on the runway and slowly applied power. It left the ground at about half throttle and climbed like a champ at 60% throttle needing only a couple clicks of trim to fly straight and level. Everything was looking great and I was just about to take it up and test the stall characteristics and try a roll or two. Was heading down field parallel to the flight line at about 100' up when I heard the engine power wind down. I assumed it was the battery, so I closed the throttle to reset and slowly applied power again. It started to come up but then I heard a clunk come from the engine and it powered down again. Closed the throttle and brought it in for a dead stick landing. The prop was windmilling on landing so I tried to give it a bit of power to taxi in and I heard the clunk and loss of power again. When I got to the plane, the ESC was signalling 4 beeps which according to the manual is:

Motor Anomaly: Controller encountered
abnormal motor behavior such as a prop
strike or other physical interference.
May also indicate lost synchronization or
magnetic overload within the motor.

Tested the battery and it was fine so I ran it up to 75% again and had no troubles at all on the bench.... The motor worked and sounded perfect. Am really scratching my head on this... despite the good bench test, I don't want to fly it until Im sure the problem is eliminated.

The windmilling prop has me thinking it may be creating a timing issue between the motor and the ESC, or it could simply be a faulty motor. I could enable the brake setting and try again, but still don't want to experiment in the air until I know the problem is fixed.

Anyone seen this before or have some suggestions on the best approach here?

EDIT: Correction, ESC is CC Pheonix IceLite 75A

Thanks.... Jon

[Cougar429]

I would check a couple of things first. With the prop removed spin it up again and see if there is any unusual vibrations coming from the motor once at full RPM. This can show a mechanical imbalance, bearing or magnet issues and possible timing problems between the ESC and motor. I would expect timing problems would show up even with no load.

The only other possibility could be a problem between the motor housing and shaft. I have frequently seen pinion problems on helis where there is no flat filed into the shaft for the set screw to lock into. Under flight loads the pinion can swell, (this is especially true with brass pinions) and rotate on the shaft. Unfortunately it can happen in flight, but by the time you can check it has cooled enough to lock tightly again. Without the flat I have seen this happen even Loctited as heat softens the material.

This can occur at the drive and driven ends of the shaft between the housing, shaft and prop flange, although unless axially prevented from moving you would expect thrust loads causing the prop to go have a party on its own.

Is there adequate airflow through the motor? Check motor heating at the end of a full power run. Although not familiar with yours, I've seen a few of the HK offerings bury their motors inside a housing and blank it off with a spinner. Minimal entry airflow options with nowhere for it to exit. That stagnant air is a good recipe for short motor life.

I would expect the last error on your list would be from excessive current. Do you have a wattmeter or onboard recorder to check amp draw under flight loads?

[davidz58]

Are you running a seperate BEC?

[JonM]

No, using the CC's integrated BEC set to default of 5V. Didnt see any control issue with the servos at all in this config.

[astrofler]

the only time I've ever heard a clunk with an e-plane was when the motor threw a magnet. probably not your problem as the prop was windmilling, but something you might check.

also is the speed controller set for inrunner or outrunner. some castle controllers can be set for either. my son's pylon racer was having motor problems and his controller was set for outrunner, when his motor was actually an inrunner.

timing can give a clunking sound and you usually see it when first spooling up. check the timing and try high timing on the controller.

[ogopogo]

my eflite power 46 gave multiple klunks under load but was fine on pre-flight. It was timing - set to high and no more klunks. Was an exceed 60a which fried shortly after
john

[JonM]

OK, I think I found the problem. After buying a new motor yesterday, swapping it out and trying a number of settings I was still having problems. Decided to take the new motor off and have a closer look and when I disconnected it one of the bullet connectors from the ESC came with it...

Poor connection seems to be the root of this one. It was likely stable on the bench but the vibration from flight and landing rool caused it to cut out and mess up the motor timing.

Resoldered the connection and reset all the ESC settings back to default and now it tests fine on the bench. A few more run-up test before flight but Im hoping I have it fixed.

Looks like I bought a new motor for nothing... Anyone need a NIB eFlite Power 32?

Jon

[Max]

Originally Posted by JonM

Looks like I bought a new motor for nothing... Anyone need a NIB eFlite Power 32?

Jon

I'll give you 5 bucks for it... LOL\

I'm glad you figured that out. It's amazing how little things like that can bugger up your entire power system. Catching stuff like that is difficult, unless you learn to do the "pull test" on all your connections. Judging from what I have learned here on RCC, bad connections are a common problem, and the "Pull test" is on my personal checklist when troubleshooting problems that come my way via my students.

[JonM]

Yup... After so many successful run up tests on the bench, shrink wrap around the connectors, and tieing off loose wires to the frame that kind of thing never crossed my mind... you can bet I'll be adding the pull test to my checklist too from now on.

As for the motor... maybe Ill hang on to it for my next plane

[ogopogo]

Glad you found it - on the ground
Hopefully, your LHS will take the 32 back. I have a couple of planes waiting for a 25 and one with a 32 that probably should be a 25 ...