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Building Tips and technical articles. => Building techniques => Topic started by: Avaiojet on January 01, 2014, 11:20:15 AM

Title: Firewall location on Electric motors?
Post by: Avaiojet on January 01, 2014, 11:20:15 AM
I'm attempting to get some drawings completed or at least gain some progress.

It would be really helpful and speed things up a bit, if I had some measurements.

What I could use, is the measurement from the back of the spinner to the front of the motor mount.

This would be for front mounted electric motors only. And the mount being the piece, wood or other type of material your motor is bolted to, actually behind.

So, front of motor mount to back of spinner.

This diagram shows a typical electric motor placed or mounted behind a .25" thick firewall.

Between those two arrows is the measurement I'm looking for.

Thanks in advance.

Charles
Title: Re: Firewall location on Electric motors?
Post by: Mark Scarborough on January 01, 2014, 03:33:04 PM
it depends on the spiner used,, the length of the shaft, the thickness of the firewall, etc etc,, do you have your motor? do you have your spinner? if so then its pretty easy to mock up and measure otherwise I think you are spitting in the wind,, to many variables,,

I could give you my dimensions, but my setup will be different than yours so its mute
Title: Re: Firewall location on Electric motors?
Post by: Avaiojet on January 01, 2014, 06:04:59 PM
Yea Mark, I guess you're right.

How foolish of me to expect someone to take a simple measurement from the forward side of their firewall to the backplate of the spinner.

I should know better.

Charles
Title: Re: Firewall location on Electric motors?
Post by: David Hoover on January 01, 2014, 07:01:06 PM
From the front of the motor mounting plate on my Cardinal to the front of the flange of the prop adapter where the prop or spinner backplate rests (I don't use a spinner) is 0.59" give or take a few thou.  I use a Bob Hunt 'hard nose' motor mounting plate which is only about 0.10" thick.  If you use something different the dimension I just gave above is meaningless.  I use a Cobra 2826/12 motor.  If you use a different motor than that, the dimension I just gave above may be meaningless.  I use an Eflite collet type prop adapter.  If you use something different than that, the dimension I just gave above may be meaningless.  I'm not using a spinner but you are so the dimension I just gave above is definitely meaningless.

There's no substitute for taking the parts, all of them, dry assembling them together and then taking the measurements that will actually be useful to you.  They may not be useful to anyone else but they will be the measurements that you need.  There's no shortcut possible around that process.
Title: Re: Firewall location on Electric motors?
Post by: 55chevr on January 01, 2014, 07:53:09 PM
The gap from the front of the fuselage ring on my Nobler to the back of the spinner is .120 measured with a vernier caliper. This appears to be what you are looking for from your drawing.

Joe
Title: Re: Firewall location on Electric motors?
Post by: Mark Scarborough on January 01, 2014, 08:45:18 PM
Yea Mark, I guess you're right.

How foolish of me to expect someone to take a simple measurement from the forward side of their firewall to the backplate of the spinner.

I should know better.

Charles
Charles,, I am legitimetly attempting to save you grief,, if you rely on someone else s measurements,, you have about a 10% chance of being right,, to many different components will yeild different distances,
why can you not accept that I am trying to save you trouble, my answer is legitimate