New Products Flash Sale
Thread Tools
Old Jul 28, 2015, 01:17 PM
gobigdave is offline
Find More Posts by gobigdave
Registered User
United States, MA, Scituate
Joined Apr 2007
286 Posts
Discussion
Outrunner play

Related to a previous post about my ESC (http://www.rcgroups.com/forums/showthread.php?t=2468352), I just noticed something in the E-Flite Power 60 that was involved in the same bad crash (nose first, high speed). I cleaned it up, and it seemed to run fine. The amps at full throttle were the same as before. After that, I went back to assembling my new Beast 60e to put this motor back in.

This afternoon, I put the plane down on the nose and heard a clunk. It turns out that I can grab the prop shaft and move it in-and-out a little bit. I also tried the same on the two other outrunners I have. The Motrofly 5325 has zero play. The E-Flite 15 has a little bit of play. I never noticed before because the motors were all new. Is a little bit of play in the bell normal, or was my motor more damaged in the crash than I thought?
gobigdave is offline Find More Posts by gobigdave
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 28, 2015, 01:51 PM
vollrathd is offline
Find More Posts by vollrathd
Registered User
vollrathd's Avatar
Joined Jan 2007
1,626 Posts
Quote:
Originally Posted by gobigdave View Post
Related to a previous post about my ESC (http://www.rcgroups.com/forums/showthread.php?t=2468352), I just noticed something in the E-Flite Power 60 that was involved in the same bad crash (nose first, high speed). I cleaned it up, and it seemed to run fine. The amps at full throttle were the same as before. After that, I went back to assembling my new Beast 60e to put this motor back in.

This afternoon, I put the plane down on the nose and heard a clunk. It turns out that I can grab the prop shaft and move it in-and-out a little bit. I also tried the same on the two other outrunners I have. The Motrofly 5325 has zero play. The E-Flite 15 has a little bit of play. I never noticed before because the motors were all new. Is a little bit of play in the bell normal, or was my motor more damaged in the crash than I thought?
The Mfg sometimes adds spacers to remove the in/out play of the motor shaft. Normally this isn't an issue.

What is an issue is the motors bearings. A hard nose in crash can ball dent them, and they won't last long if damaged in this manner. You might be able to detect dented bearings by pulling on the motor shaft and manually spinning them, then pushing on the shaft and again manually spinning it.

Sometimes you can also hear damaged bearings by running up the motor with no prop installed.
vollrathd is offline Find More Posts by vollrathd
Reply With Quote
Old Jul 28, 2015, 02:07 PM
gobigdave is offline
Find More Posts by gobigdave
Registered User
United States, MA, Scituate
Joined Apr 2007
286 Posts
By "detect" when manually spinning the motor, do you mean I will hear it? I've run the motor with and without a prop, and it sounds normal. I will try manually spinning it a few times when I can get back upstairs where the plane is. I'm lucky enough to work at home, but I'm listening in on a meeting right now.
gobigdave is offline Find More Posts by gobigdave
Reply With Quote
Old Jul 28, 2015, 03:39 PM
vollrathd is offline
Find More Posts by vollrathd
Registered User
vollrathd's Avatar
Joined Jan 2007
1,626 Posts
Quote:
Originally Posted by gobigdave View Post
By "detect" when manually spinning the motor, do you mean I will hear it? I've run the motor with and without a prop, and it sounds normal. I will try manually spinning it a few times when I can get back upstairs where the plane is. I'm lucky enough to work at home, but I'm listening in on a meeting right now.
If you have good hearing, you might be able to hear the bearings while the motor is spinning up. I did have some damaged bearings in a Hacker A40-10L awhile back when the aileron of the model it was in came completely out of the wing due to a design defect. And, with my lousy hearing, I could hear it.

Even if they might be damaged, I'd just run them until they get really noisy.
vollrathd is offline Find More Posts by vollrathd
Reply With Quote
Old Jul 28, 2015, 05:45 PM
jackerbes is offline
Find More Posts by jackerbes
Jack
USA, ME, Ellsworth
Joined May 2008
18,033 Posts
When a motor is set up right the housing is in the spot where it centers itself over the magnets. That is where the magnetic forces that push and pull the magnets will be the strongest. With the housing in that spot the Circlip on the back of the shaft should be in light contact with the inner bearing race. The magnet housing is locked to the shaft by a combinations of a pressed fit and a grub screw that bears on a flat on the shaft.

Then, when a tractor prop starts pulling on the shaft, the Circlip being in contact with the bearing race transfers the pulling forces to the airframe and the shaft and and housing are restrained from moving out of the self centering spot.

On a tractor setup the prop pushes the shaft against the bearing race and it and the housing stay where they are. And hopefully, the housing is again in the self centering spot.

With the tractor mount motor, if you can push on the shaft and the moves back a little and then rebounds back to the self centering spot, that indicated that there is a open space between the housing dome and the inner race on the front bearing. That open space would normally be filled by metal spaces that fill the open area.

At least in a perfect motor that is the way things should be. As you can imagine, not every motor is as carefully assembled as that and if you push and pull on housing it is not uncommon to find various amounts of movement. A few thousandths of an inch is an acceptable amount of movement and ensure s that the will be no binding.

If you assemble the motor yourself, let that small amount of play be located so that the movement is not in the direction of the pulling or pushing forces when the motor is in use and there will not be any movement in the housing.

I would suspect that the free play that developed in gobigdave's motor after his "one point landing" may have been caused by the shaft having moved back in the dome of the magnet housing from the impact forces. It is possible that the grub screw moved a short distance on the flat on the shaft as the flat is usually long enough to allow that.

@gobigdave,

If there is a visible gap between the Circlip on the back of end of the shaft and the inner race, that will verify that the shaft was moved back a little.

How to fix it? I would let the housing self center itself over the magnets and then measure the gap between the housing and the base plate with feeler gauges. That tells you where the "sweet spot" for the housing is and give you a measurement that will let you check for it after assembly.

Then loosen the grub screw and press shaft forward just a little less (0.001-0.002" less) thn the amount of the gap between the Circlip and the race. And then pull forward on the housing check the gap between the housing and base plate. If it is within 0.002" or so of that previous measurement you have it close enough.

Jack
jackerbes is offline Find More Posts by jackerbes
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale Extreme Flight Torque 22T/930 outrunner with a Castle Creation 25 Plug-n-Play!! Nogahyde Aircraft - Electric - Power Systems (FS/W) 0 Dec 29, 2014 05:41 PM
For Sale Altas .46 Sport Outrunner w/Atlas Black 45A ESC Plug-n-Play!! Nogahyde Aircraft - Electric - Power Systems (FS/W) 0 Dec 16, 2014 01:45 PM
Sold Plug-n-Play / Castle Creations 18 ESC & Tower Pro Outrunner!! Nogahyde Aircraft - Electric - Power Systems (FS/W) 1 Mar 02, 2011 10:32 AM
For Sale Plug-n-Play / Castle Creations 18 ESC & Tower Pro Outrunner!!! Nogahyde Aircraft - Electric - Power Systems (FS/W) 1 Feb 19, 2011 11:05 AM
Anyone played with Dymond Maxi 09 or 16 outrunners? papa38 Power Systems 5 Jun 16, 2005 12:46 PM