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Date: Sun, 18 Dec 2005 17:59:33 -0600
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Prop Flange to Cowl Relationship
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The current crop of RV cowls have the Lyc prop flange about 2" back from 
the front of the cowl. Constant speed props move the prop forward around 
2" & wood props need a 2" spacer. Does that help with perspective?

Charlie
(wondering if we'll start typing right to left next)


Ed Anderson wrote:

> Bill, not certain I fully understand your question.  The prop side 
> face of the RD1-C needs to sticks out in front of the  cowl   by at 
> least 1/8-3/8" for prop clearance.   That is the front most part of 
> the cowl where the prop shaft exits. Of course, this is dependent on 
> how you design your motor mount. If you are putting the engine closer 
> to the FW (than I have) then you could need an prop extension to get 
> the prop to clear your cowl.   If you are using any sort of prop shaft 
> extender then you still need same sort of minimum clearance between 
> back of prop (face of prop hub) and cowl.
>
> Don't understand the reference to  2" you mention, I think that some 
> model Lycoming engines  may need the 2" prop extension to clear the 
> standard RV cowl.   Perhaps I did not understand your question?
>
> Ed A
>
> ----- Original Message ----- From: <bbradburry@allvantage.com>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Sunday, December 18, 2005 9:45 AM
> Subject: [FlyRotary] Prop Flange to Cowl Relationship
>
>
>> I have my motor mount jigged up and am ready to start fitting the pieces
>> together.  My question is what dimension should I set between the 
>> forward
>> face of Tracy's RD1-C and the forward face of the cowl?  I am certain 
>> that
>> the PSRU is inboard of the cowl and it appears that this distance is 
>> about
>> 2" on the several Lyco planes that I have looked at.  I assume that 
>> various
>> prop manufacturers would need different clearances and that there are
>> extensions available, but I think this distance should be somewhat 
>> standard
>> and I don't really have a clue as to what it is.
>> Thanks,
>> Bill Bradburry 
>