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Message-ID: <49E532B7.3080900@gmail.com>
Date: Tue, 14 Apr 2009 20:04:55 -0500
From: Dave <david.staten@gmail.com>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Catalyst in an aircraft application
References: <list-3581001@logan.com>
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Cat converters convert Carbon monoxide, a product of incomplete 
combustion, to Carbon Dioxide.

If you have your mixture at peak or lean of peak as determined by an 
EGT, or have an oxygen sensor connected to your ECM, you should have 
complete combustion and no carbon monoxide. The vast majority of your 
operations are steady state/cruise and there is very little aircraft 
engine operation with widely varying engine power settings, such as a 
car would have in stop and go traffic.

A cat converter adds weight, complexity and a HUGE heat source that has 
to be shielded/cooled/wrapped to prevent heat damage or fire within the 
cowl... and in a properly operated engine, not a lot of benefit.

Leaded avgas will destroy/contaminate the platinum catalyst agent in a 
cat converter so you would be restricted to unleaded fuel PERIOD if you 
desired the converter to work. One tankful of lead could do the damage. 
One inattentive or "helpful" line guy who tops your tank off with 100LL..

You get the picture.
Dave

Ernest Christley wrote:
> Christopher Owens wrote:
>> Good afternoon all,
>>
>> In this day and age of EPA, pollution control, green earth, etc., I 
>> wondered about the viability of an exhaust catalyst in an aircraft 
>> application.  Are there any reasons not to use a catalytic converter 
>> in this capacity?  Weight?  Exhaust restrictions?  Other?
>>
> Weight and exhaust restriction are the start of it.  I believe the 
> rest is that there is not much payoff.  The cat gets the most payoff 
> during hard accelerations, which you do a lot of in a car.  Not so 
> much in a plane.
>
>