Brushless shaft too short

I am trying to install a brushless motor into the nose of a glider that was not originally designed for a motor. The plane's fuse is
quite narrow at the front, so it is difficult to get the motor to fit. I already have the motor, so I'd prefer to not buy a new one.
If the motor shaft was a little longer, I could get it to work. I have a small metal lathe, so I could easily either make new, longer shaft for the motor out of piano wire, or I could make an extension that clamps onto the existing shaft. Making a new shaft seems easier, lighter and more reliable.
As an alternative to making something, are there any commercially available methods to solve this problem?
How far can the shaft be extended before I have to add a support bearing close to the propeller?
--
RoRo

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On Sat, 07 Jul 2012 13:22:21 +0200, Robert Roland wrote:

Music wire is often too soft to use as a motor shaft. Maybe contact the maker of the motor and see if they have a shaft that is longer that would work with your motor?
--
to reply via email: vhoward1122 at gmail dot com

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On Sat, 7 Jul 2012 14:19:45 +0000 (UTC), Vance Howard
I have noticed the shafts are glass hard, but I have never been able to figure out why they have to be so hard. I have made two shafts from piano wire myself earlier, and they are still flying just fine.
Why are the shafts so hard?

This is a cheapo Chinese motor, so that's probably not even worth checking.
--
RoRo

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On 7/7/2012 4:22 AM, Robert Roland wrote:

A creative motor mount might be a better choice than extending the shaft. I have snapped motor shafts that were not extended, in very minor bungled hand-launches. Extending the shaft would add leverage to make that problem worse.
Good Luck, BobH
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On Sat, 07 Jul 2012 07:35:04 -0700, BobH

The motor diameter is just about the same as the spinner, and the fuselage is a rounded rectangle balsa construction, so I cannot see any way to make this look even remotely decent. Getting a bigger spinner might be an option, though, but those folding prop hubs are not exactly cheap.

Yes, they are incredibly brittle. I snapped two of them in one crash into water (on a Catalina seaplane).

I understand that. I'd be willing to risk the compromise, at least as an experiment. If it turns out I damage them too often, I'd have to try another solution.
--
RoRo

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Just out of curiosity, define "not exactly cheap."
I had a Multiplex Easyglider that I learned on a few years back. When I got tired of burning up the standard brush motors, I upgraded the system to brushless. I used the spinner hub from a Parkzone Radian.
http://www.parkzone.com/Products/Default.aspx?ProdID=PKZ1018
Only $7.
To modify the plane, I chopped the nose off and made a bulkhead to attach the brushless. I made sure to chop off so the overall length remained the same (thus keep the CG pretty much the same).
Then, using spare foam, I carved up a new cowling to make it all streamlined. Admitedly, this wasn't meant as a showpiece. Currently, the bird is in pieces awaiting the budget to let me fly again, so I can finish it's conversion to a twin. It's been rebuilt so many times it's not much of a 'glider' anymore.
Brian
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On Sat, 07 Jul 2012 13:22:21 +0200, Robert Roland wrote:

* Get the right size ground shaft material from McMaster-Carr or Enco or something -- music wire is hard to machine, and not accurate.
* If you use ground shaft material you should be able to get an off-the- shelf bearing that'll fit. Set the motor back as far as you need and just press the bearing into a hole in a plywood bulkhead.
* Make an extended prop driver -- that should be easier than installing a longer shaft, and if you're lucky you'll be able to bolt it to the motor bell.
* Make that custom motor mount that was suggested (although we can't see the nose you're putting it in, so maybe that's just not in the cards).
--
Tim Wescott
Control system and signal processing consulting
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On 7/7/2012 9:22 AM, Tim Wescott wrote:

Also, make sure you have good airflow over the motor, especially if it is set back in the fuselage.
BobH
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