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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-1580539@logan.com>
Subject: Re: [FlyRotary] Re: Spark Plugs
Date: Sat, 18 Nov 2006 23:00:36 -0500
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I agree that the "idea" auto spark plug for the flying rotary is still 
waiting in the wings.  I am currently using a special lead scavenging 
formula to see if it can extend the useful life of lead fouled spark plugs 
(don't ask I don't know what's in it {:>)). Well, see whether it does 
anything for the problem.

 I normally get approx 25 hours on a set before SAG sets in using 100LL.  I 
speculate that one reason that such things as TCP do not appear to do much 
for the rotary engine is that the chemical reaction apparently (according to 
reports) requires the high cylinder head temperatures of air cooled 
cylinders (like 375F +).  I believe that with our plugs buried within the 
housing (as opposed to protruding into the combustion chamber (and they had 
better not or you will clip your apex seals), that the plugs do not reach a 
sufficiently high temperature to deter fouling or to activate the TCP 
chemical reaction.  So perhaps a "hotter" plug might help - on the other 
hand, since we are running WOT for longer periods that many rotary racers - 
I'm not certain I want a hotter plug.

I have tried fine wire and the stock plugs - but both seemed to have the 
same problem of lead fouling the ceramic cone and "bleeding" off spark 
causing misfiring.

My $0.02

Ed


----- Original Message ----- 
From: "John Overman" <mooneydryver@yahoo.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, November 18, 2006 10:39 PM
Subject: [FlyRotary] Re: Spark Plugs


> The most troublesome aspect of rotary engines in
> airplanes has to be the spark plugs. Everyone uses the
> BUR7 of BUR9 or the finewire plugs. When you look at
> the business end of these plugs your first thought has
> to be this is a fouled plug waiting to happen. Even
> when not using Avgas fliers like Tracy are only
> getting 200 hours on them. With Avgas they last like
> 25 hours.
> These plugs may work ok in a car with a generally
> lighter load but they seem ill advised for aircraft.
> There a lot of "standard" design spark plugs with the
> same thread diameter and thread depth out there. I
> wounder has anyone tried a more standard type of plug
> to see how they may hold up?
>                     John Overman
>                     Velocity N711VE (reserved)
>
> --- Dennis Haverlah <clouduster@austin.rr.com> wrote:
>
>> Thanks everyone for the spark plug cleaning
>> recommendations.  I tried
>> brake cleaner and oven cleaner.  The oven cleaner
>> appeared to work much
>> better.  I had been running the fine wire RE7A L and
>> RE9B T plugs that
>> came with my Renesis.  After cleaning they still had
>> s slight miss at
>> full throttle.  I cleaned an old set of plugs that
>> came with a 1987
>> engine BUR7EQ L and BUR9EQ T and tried them.   The
>> engine ran better and
>> had no miss at full throttle.   I believe these are
>> the same plugs Tracy
>> has been running in his Renesis.  All the plugs are
>> manufactured by NGK.
>>
>> Dennis H.
>>
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:
>> http://mail.lancaironline.net/lists/flyrotary/
>>
>
>
>
>
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> --
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