Mailing List flyrotary@lancaironline.net Message #25261
From: Mark R Steitle <mark.steitle@austin.utexas.edu>
Subject: RE: [FlyRotary] Re: 13b crankshaft
Date: Thu, 21 Jul 2005 16:02:01 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

Ralph,

I don’t know the physical dimensions of the 20B shaft.  Maybe someone else can answer your questions on dimensions (my engine is assembled). 

 

Yes, there is more space between 1 & 2 than 2 & 3 due to the extra bearing.  The side housing is visibly much thicker.  You can easily see the bearing in the attached jpg.  This side-housing is one of the pieces unique to the 20B.  The other side and rotor housings are interchangeable with the 13B.  The split shaft is held with a long woodruff key.  No, I have never heard of a one-piece 20B eccentric shaft.  The issue is how to get the 3rd bearing in there.  In my opinion it is plenty strong for our purposes.  There’s at least one 20B putting out 900hp. 

 

Mark S.

 

 

 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ralph Reed
Sent: Thursday, July 21, 2005 3:34 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: 13b crankshaft

 

Does that mean that rotors 1 and 2 are farther apart than 2 and 3?

 

What fixes the two together?  Are there no 20B cranks that are all one piece? Why?

 

What is the smallest diameter of the shaft on either one and how much over built is it?

 

Could the 13B  be hollow and strong enough?

 

Thanks, Ralph

----- Original Message -----

Sent: Thursday, July 21, 2005 3:20 PM

Subject: [FlyRotary] Re: 13b crankshaft

 

Ralph,

The 20B utilizes a split shaft design.  The #1 stub-shaft slips over the snout of the 2-3 journal.  There is a 3rd main bearing between the #1 & #2 rotor. 

 

Mark

 


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