News:



  • June 17, 2024, 02:06:45 AM

Login with username, password and session length

« previous next »
Pages: [1]   Go Down

Author Topic: OS 3525-750  (Read 641 times)

Offline Darkstar1

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 326
OS 3525-750
« on: October 22, 2011, 07:25:31 AM »
This is just a heads up for those trying the new OS motors, This one had about 20 flights going when soon after I noticed a slight rub on something. So I put it aside to look into it later. Took it apart this morning, Its really simple just loosen the two set screws, pull the collar off and just remove the outer housing comes right off. So what was discovered?
I hope the picture will show it clearly. There is a tie wrap that wasn't quite tucked out of the way and it just found its way on to the stator just enough to drive me nuts. So I just simply pushed it out of the way put it back together and spun the prop and poof the rub went away! Run the motor on the test stand and all is well with the world again. Going
to put it on the plane to really check it out. So far I still think Its a good motor for practice.
Logged
Later,
Evolve or get left behind!

Offline John Rist

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2956
Re: OS 3525-750
« Reply #1 on: October 22, 2011, 11:04:12 AM »
I have a OS 3525-750 (test run no flights yet).  They are supposedly a 3 ball-bearing motor.  Looking at your pictures I am not sure where the three barrings are located.  Having looked inside could you enlighten me on how this works?

 :P
Logged
John Rist
AMA 56277

Offline Darkstar1

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 326
Re: OS 3525-750
« Reply #2 on: October 22, 2011, 12:23:40 PM »
Sorry John,
The OS is just a two bearing motor If I knew that before hand I probably would not have bought them.
Logged
Later,
Evolve or get left behind!

Offline Dean Pappas

  • Moderator
  • Trade Count: (0)
  • Admiral
  • *****
  • Posts: 1195
  • Welcome to the Stunt Hanger.
Re: OS 3525-750
« Reply #3 on: October 22, 2011, 12:35:31 PM »
Okay ...
So what we see is a production QC issue. At least OS put a ty-rap(tm) on the wires just befor they leave the motor. Some don't and that's where they wiggle and break.
Bummer that this is not a true 3-bearing motor. On the plus side, the center tube/pylon looks like it has fairly thick walls. Some are terribly thin for weight savings.
Now that you've found this and remedied it (dot of CA?) I look forward to hearing how well the motor holds up. Please keep us informed. I did expect better from OS, though.
Regards,
  Dean P.
Logged
Dean Pappas

Offline John Rist

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2956
Re: OS 3525-750
« Reply #4 on: October 22, 2011, 01:17:28 PM »
That sucks.  Per OS web page:

Copied from OS

"Other performance features of O.S. brushless motors include:
A thick can design that resists distortion;
Three high-quality bearings;
Rigid and secure rear mounting design;
Shortened motor length for easy installation in short cowls;
A stainless steel prop shaft;
Supplied backplate, prop shaft, and gold-plated female plugs."

So the OS web page is flat out wrong!!!

 n~
Logged
John Rist
AMA 56277

Offline William DeMauro

  • 21 supporter
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 796
Re: OS 3525-750
« Reply #5 on: October 22, 2011, 02:47:50 PM »
Are you sure there are not 2 bearings stacked at the front end of the motor? On some of the better motors that I have taken apart, I have found 2 bearings stacked in the front. If you look at the third picture (pa220025.jpeg) it looks like there may be a second bearing there. Sometimes you can't see it until you press them out.
Logged
AMA 98010

Offline John Rist

  • 24 supporter
  • Trade Count: (0)
  • Admiral
  • *
  • Posts: 2956
Re: OS 3525-750
« Reply #6 on: October 22, 2011, 04:53:47 PM »
Quote from: William DeMauro on October 22, 2011, 02:47:50 PM
Are you sure there are not 2 bearings stacked at the front end of the motor? On some of the better motors that I have taken apart, I have found 2 bearings stacked in the front. If you look at the third picture (pa220025.jpeg) it looks like there may be a second bearing there. Sometimes you can't see it until you press them out.

You are correct.  I see two bearings.  The test runs of my OS it has been stiff, strong and smooth.  It's definately head and sholders above the Trunigy it is replacing.
Logged
John Rist
AMA 56277

Offline Darkstar1

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 326
Re: OS 3525-750
« Reply #7 on: October 22, 2011, 07:00:57 PM »
I'm looking at the picture again. There may be a bearing right behind the first but I don't see a benefit in that. But I have another one I'll take it apart and have a closer look.
Logged
Later,
Evolve or get left behind!

Offline Darkstar1

  • Trade Count: (0)
  • Commander
  • ****
  • Posts: 326
Re: OS 3525-750
« Reply #8 on: October 22, 2011, 10:14:42 PM »
Just took the other one apart to turn around the other tie wrap anyway. There seems to be a third bearing pressed behind the other one. But I don't think there is a benefit to that. Any opinions ?
Logged
Later,
Evolve or get left behind!

Offline Russell Bond

  • Bandolero
  • AMA Member
  • Trade Count: (0)
  • Captain
  • *
  • Posts: 450
Re: OS 3525-750
« Reply #9 on: October 23, 2011, 12:47:15 AM »
That 3rd bearing might be good for supporting the shaft, but our problem with rear mounted motors is the can flexing and the magnets hitting the stator. .... (I think I used the correct words to describe the motor "bits".. ???   ;D)

The Plettenburg's 3rd bearing is a large diameter one that supports the can, preventing this problem. (Much better!)
Logged
Bandolero

Offline Dean Pappas

  • Moderator
  • Trade Count: (0)
  • Admiral
  • *****
  • Posts: 1195
  • Welcome to the Stunt Hanger.
Re: OS 3525-750
« Reply #10 on: October 23, 2011, 09:32:30 PM »
Quote from: darkstar1 on October 22, 2011, 10:14:42 PM
Just took the other one apart to turn around the other tie wrap anyway. There seems to be a third bearing pressed behind the other one. But I don't think there is a benefit to that. Any opinions ?
The doubled-up bearing is better than not having it.

Regards,
  Dean
Logged
Dean Pappas

Advertise Here
Pages: [1]   Go Up
« previous next »
Tags:
 


Advertise Here