Mailing List flyrotary@lancaironline.net Message #21190
From: Charlie England <ceengland@bellsouth.net>
Subject: Re: [FlyRotary] Re: Inserts
Date: Sat, 30 Apr 2005 22:06:39 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Tracy Crook wrote:

I did say that I found no significant difference BUT, that was based on two different engines with two different intake configurations.  The splitters were in a 6 port engine (normal) and the turbo ports were in a 4 port.  This was also with an  -A drive (2.176 : 1)   where the rpm was held lower.  I agree with Ed that the turbo ports may make a bigger difference at higher rpm.  In summary, there were too many variables involved to make any hard declarations about the effect of exhaust ports alone.   But the effect on noise was obvious  - The turbos are MUCH louder.   If I had it to do over, I would have put splitters in my 20B.  I really like quiet flying  (quiet being a relative word).
 
Tracy  (doing dreaded fiberglass stuff on the RV-8)


Not directly applicable here except in the sense that we should make no untested assumptions, but here goes:

Kent Paser of 'Speed with Economy' fame played with 'reversion cones' on his Lyc. They are cones smaller in diameter than the exhaust ports & mounted directly in the ports. Obviously this should interfere with exhaust flow but he found that they can improve breathing in a Lyc.

The NA splitters look suspiciously like flattened cones....

To invert Bob's tag line: when things change, things change.

Charlie
(just stirring the pot a little)
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