Mailing List flyrotary@lancaironline.net Message #1854
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: air filters?
Date: Thu, 5 Jun 2003 07:44:44 -0500
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
RE: [FlyRotary] air filters?

        I'm using a K&N air filter. I considered going without, but since I expect to operate out of allot of dirt strips and I really don't think it would be too healthy for the turbo compressor, I decided to incorporate one.

 

Hi Todd,

 

I’m curious, what size is your filter?  I have a K&N cylindrical style filter, that’s 6” long, and 3.5” diameter, and is made to fit over a 2.5” diameter flange.  They claim it will flow 900 cfm, and I can only hope that they mean at a reasonable pressure differential.  Spruce sells preformed aluminum flanges in several sizes, so I plan to rivet a couple of those back to back on the side of a simple air box.  Since the right cheek is empty, I’ll probably go ahead and install the filter over there.  I’ll use the same size tubing for the inlet and outlet of the filter box, so I can bypass it for tests.  Actually, while thinking about the issue of gyro loads on the turbo bearings, I wish I had some sort of filter or screen between the turbo and intake.  A broken compressor blade would ruin your day. 

 

Another factor to consider is the turbo boost.  Unrestricting the intake has the same effect as unrestricting the exhaust, and doing both will get you in real trouble with a 3rd gen RX-7.   If boost creep is a serious problem, maybe I can borrow Mark’s oil soaked filter :-) 

 

Cheers,

Rusty (eternally two months from flying)

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