Mailing List flyrotary@lancaironline.net Message #47238
From: <wrjjrs@aol.com>
Subject: Re: [FlyRotary] Intake velocity stack lengths
Date: Wed, 15 Jul 2009 13:09:24 -0400
To: <flyrotary@lancaironline.net>
 Message Header

Undecoded Message
Ben,
There is no reason not to make intake tubes of carbon fiber. The variable length stacks on Mazda's 4 rotor Le Mans engine used composite stacks. Be sure you select a high temp resin. The inlet bell is a well defined technology the best results are achieved using a radius approximately 1/4 of the tube diameter. Improvements are measureable running up to a full 180° turn on the intake bell. The small radius at the end of the tube actually turns back in the opposite direction. Tapering the tube along it's length isn't really needed. You could only tell if it helped on a flow bench.
 The overall length makes a BIG difference. The length determines the RPM that the tube will provide the best flow. Generally the longer the tube the lower RPM the engine will make peak power. The shortest length suggested on a peripheral port engine is about 14 inches. (That will tune the inlet for around 9000 RPM +  for peak power) The longest I have seen used around 22-24 inches. with best power around 7000 RPM. the longer stacks are better for aircraft RPMs.
Bill Jepson


-----Original Message-----
From: Ben Schneider <plumberben@yahoo.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Tue, Jul 14, 2009 6:33 pm
Subject: [FlyRotary] Intake velocity stack lengths


Fellows,

  I have been thinking up this crazy idea of trying to make intake runner tubes 
out of carbon fiber. My question is regarding length of the velocity stack. Does 
the length make a difference? Could a velocity stack be more or less the entire 
length of the tube? Meaning, if I have a 12" intake tube, could the entire 
length of the tube be a gradual taper to the diameter of the block opening? 
Would that mess with the speed the air is traveling in the tube? Aerodynamics is 
not something I have a very good handle on, and am hoping someone out there in 
Fly Rotary land can shed some light.

Toughts???

BTW,  Any reasons why carbon fiber should not be used for intake tubes? May make 
the velocity tubes a mute point.

Thanks for any thoughts.

Ben Schneider

P.S. Any Fly Rotary fellows going to OSH??? Perhaps a lunch one day or 
something.




--
Homepage:  http://www.flyrotary.com/
Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster