Mailing List flyrotary@lancaironline.net Message #17359
From: Tracy Crook <lors01@msn.com>
Subject: Re: [FlyRotary] Re: I found the power
Date: Thu, 17 Feb 2005 00:51:08 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
4 feet of 2.75" dia. SCAT running to a naca scoop on bottom of cowl was enough to ruin the power on my installation.  The difference between this and my current short ram air scoop was dramatic.   The power loss was due to both pressure loss and heat rise but I don't know which was predominate.
 
Keep air inlet plumbing clean, short and cool.  It really does matter. 
 
Tracy

Paul C wrote:

 I was thinking of installing two small NACA ducts on the bottom of my cowling with two hoses coming up to feed air to my TWM throttlebody.  The NACA ducts I purchased from Van's RV (made for cowling ventilation) already have a male outlet already molded in the assembly, so you just slide a hose over it and secure with a clamp

---------------------------------------------

Paul, you will have to make sure the NACA ducts are mounted on a pressure surface and not a suction surface or you may be very disappointed in their recovery. How far do you have to route the air to the T/B plenum. Tracy picked up a lot of heat when he used SCAT tube for intake ducts and lost power. He was not sure whether it was pressure loss of heat rise causing the problem. What do you say Tracy?

I would be very tempted to copy Tracy's periscope and put hard smooth pipe to the plenum to extract all the power possible.

Bernie, DAR coming next Tuesday, still waiting my new injector

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