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From: "George Lendich" <lendich@aanet.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-4431448@logan.com>
Subject: Re: [FlyRotary] Re: Turbo Questions
Date: Mon, 16 Aug 2010 07:18:54 +1000
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John,
I visited Leon in Sydney to get a first hand experience of his expertise. He 
does have experience with the rotary, the people he refers the more complex 
issue to, from questions which come from this group, have more experience. 
To regard him to as an expert is a stretch, he certainly isn't an expert in 
Turbos, however his contacts are experts in Turbo for car application - 
only. As this is the closest thing to 'best advice' without the aviation 
experience it's what others have had to work with.
My suggestion would be to follow those in aviation who have had some modicum 
of success. From what I read I don't think anyone can say that they have the 
problems associated with Turbo application completely beaten. It appears to 
me that the problem are more to do with  constant high speed use in the 
thinner altitude air i.e. high constant heat and overspinning.
George (down under)


> Ed, this sentence summarizes the advice I received from the Aussie rotary 
> expert, Leon Promet (anyone know what became of him?) and others. The way 
> he put it, using the non-turbo (9.7:1) rotors in a turbo installation gets 
> you an extra 30 HP "for free" because this part of the increased pressure 
> doesn't involve heating the air via the turbo. You still have to deal with 
> the potential detonation either way if mixture and timing are wrong.
>
> My experience with detonation (or pre-detonation) was much less severe 
> than yours. I heard 'popping' at high rpm during run-up at around 44MAP. 
> Reduce the throttle a hair and the popping ceased. This was with a big 
> fixed pitch prop that I could only turn at around 4900 rpm. I had the 
> feeling that it was rather like flooring a car in top gear on a hill. 
> (remember in the old days before ECUs and knock sensors when that would 
> get you a popping sound?). I was able to fly my first 40 hours with no 
> issues from detonation by keeping the throttle away from the area that 
> caused it during runup. I never experienced (or at least heard) any 
> popping once airborne, even during a high-speed run at 44 MAP and 6300 
> rpm. I once tried hooking up a knock sensor to the intercom without 
> success. I never had any damage to the plugs.
>
> When I installed the adjustable IVO prop my static rpm when from 4900 to 
> 5600rpm and the popping sound disappeared (analogous to changing gear on 
> the hill?). I haven't experienced any popping since. I think Tracy's ECU 
> does a good job of providing a rich mixture at high rpm to keep you away 
> from detonation.
>
> Regards,
> John Slade
> Cozy IV, N96PM
>
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