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From: Bulent Aliev <atlasyts@bellsouth.net>
Subject: Re: [FlyRotary] Re: Static runup
Date: Thu, 17 Aug 2006 08:22:10 -0400
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>


On Aug 17, 2006, at 7:27 AM, Lehanover@aol.com wrote:

> In a message dated 8/17/2006 6:09:26 A.M. Eastern Daylight Time,  
> atlasyts@bellsouth.net writes:
> Rusty, I did not play with the mixture too much, but I could see
> changes as I was turning the knob up and down. I'll do that with the
> timing also, but later. I have to fabricate the heat shields, but
> working with stainless sheet is a bitch if you don't have the right
> forming tools. Keeps springing back, unlike aluminum.
> Buly
> Remember that the timing is reported as crankshaft degrees. The  
> rotor is going one third as fast, and it is the position of the  
> rotor that is our interest. A total advance of 20-22 degrees (at  
> the crank) is plenty for up to 9,000 RPM. The object of the advance  
> point is to generate the highest cylinder pressure between 40 and  
> 50 degrees (crankshaft) after top dead center.
>
> More than 22 degrees would be needed for RPM over 9,000 RPM to keep  
> maximum cylinder pressure below 50 degrees after top dead center.  
> You can run some very poor quality fuel and very low octane fuel at  
> 22 degrees of advance. If you are stuck with 100 or 110  then 25  
> degrees is plenty. When the timing is anywhere around this point,  
> the rotor is by any observation, at TDC. So for 21 degrees of   
> advance the rotor is 7 degrees BTDC. At 24 degrees it is at 8  
> degrees BTDC.
>
> In street cars some timings were near zero with the trailing firing  
> after TDC.
>
>
> Mixture to rich enough to cost a few RPM off of peak, for take off  
> and climb to help with temperature control. Once at speed, then  
> lean to well lean of peak EGT as quickly as possible. In the 150  
> degrees lean of peak area. The airplane is a dyno and you can see  
> the result of any timing or mixture changes. Best power is near  
> ideal timing, and is just rich of peak EGT. And peak EGT can be  
> real high as in 1800 degrees and that is bad for apex seals.  A/F  
> can be below 12 to 1. EGT can be in the high 1400s, like 1490 or  
> so. Not far off of a piston engine.
>
> A strong running 12A can do 173 HP at 6,500 with 12.3 A/F and 25  
> degrees of advance,
> ( for the ideal power above 9,000 RPM shifting at 9,600 RPM) BSFC  
> is .666 so it is using plenty of fuel. Front EGT is 1515, rear EGT  
> is 1491.
>
> The engine is not used below 7,000 RPM we just pass through that  
> 6,500 RPM on a dyno pass.
>
> Lynn E. Hanover

Thanks Lynn. My advance is still set for the turbo installation. I'll  
have to go back and adjust it again after I spend some time trying to  
understand the whole logic. All these numbers are slowing down my  
brain :)
Buly