Mailing List flyrotary@lancaironline.net Message #20390
From: Al Gietzen <ALVentures@cox.net>
Subject: Air filters
Date: Sun, 17 Apr 2005 22:29:42 -0700
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

 

 

Hi Leon and All,

It's clear that air filtration is required for the rotary engine to protect

the apex seals and rotors.

 

I would word it differently – in general, an air filter is a good idea –

I appreciated Leon’s post (he knows what he’s talking about, and has a use of the language that makes for enjoyable reading).  He, and others, are right that a filter is a good idea; but there are cases where one can argue it is not a “necessity”.

 

I chose to proceed without a filter for a few reasons.  To avoid the loss of the ram pressure (and small performance improvement) one would need quite a large filter, and I just didn’t have the space.  My prop is behind the intake (pusher), and the intake is toward the top of the fuselage above the strake – in “clean air”. 

 

My home airport is in coastal CA where there is little reason for much dust, I will never operate off a dirt strip, and I think it will be reasonably easy to avoid dust storms or volcanic eruptions. Once you are 1000’ AGL or so, I’m guessing it very unlikely that there would be particulates of concern.

 

I’ll likely be looking at the plugs every 25 hours or so; so I may give it a shot of oil between each set of seals and crank that around a bit to help “flush” any out any of that “abrasive paste”.

 

But, yeah; I think if my prop was in front of the intake I’d look real hard for a place to put the filter.  You have to make your own determination whether to put in the filter or not.

 

Al

 

 

Just had a few ideas that may, or may not work and could possibly work with

a ram air scoop. (1) An old idea is an oil bath where incoming air hits an

oil pan before being inducted into the engine. No use for aerobatic

aircraft. (2) Is a new idea, I'm sure you've all seen those new cyclonic

filter free vacuum cleaners, that always maintain 100% suction, or so they

say. Could an air plenum be designed on the same principle so that dust and

gravel get separated from the main airflow and get ducted out a side tube,

leaving the main air stream to go to the engine.

Just ideas guys,

Michael.

 

 

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