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Wrathall Mark wrote:

James Phillips wrote:

Just wondering what the opinions are on porting for aircraft use. Is
anyone using or planning on using anything other than the stock
porting. I was wondering about the suitability of street porting or
peripheral porting.       James

I posted the following question a few weeks back, but it  kinda 
disappeared in another issue.

It seems most peripheral port experience is with auto guys trying
to increase HP. For an RV-4 160-180 HP would seem ample. Is
it possible that a peripheral port on a 13B optimized for 160HP
at 5500 RPM could be smaller than the 1.75 DIA shown on the
ACRE'S site.

It is highly likely. That was the biggest hole I could get :-)
I think Everett's/Power Sport was down around 1 5/8  maybe even 1 1/2
and they are getting 210 HP at 5850 with about 24 inch
runners. Total length. I think you will be disappointed in the
performance with a 160 HP rotary. Seems to me the PSRU and 
practical cooling systems seem to result in an aircraft 
performance less than a 160 HP direct drive air cooled
engine provides. I would shoot for the 200 HP as that
seems very doable with peripheral ports. You can always
cruise at a lower number.

 Would a smaller port idle better? 

Without the butterflys... I don't think so. Probably not a 
noticeably difference. You need those butterflys right 
up there in or next to the rotor housing. 

Would it avoid
the need for an Everett Hatch style idle throttle? 

Opps I think I answered this above.

The simplicity
and weight savings over a four/six port manifold would be nice.

Paul, Is this post margins free? In outlook it is difficult to tell.

Yes its fine Mark. Thanks for getting rid of the margins.
 
Paul Lamar
 
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