Mike:

My intake tubes are 43 inches measured from rotor face of rotor # 1 to rotor face of rotor #2.  Design RPM was 6200.

Someone asked about my static RPM.  Today I checked - with engine just warm enough to open the throttle fully, I got 5870 RPM with my new intake.  With the engine completley warmed up I got 5700 RPM.  This demonstrates what Lynn Hanover has stated several times - more air/fuel enter the combustion chamber at lower oil temps!   I believe with my original intake I only got about 5300 RPM static. 

Mike Wills wrote:

Dennis,

 

So for that RPM, how long did your intake runners end up being?

 

For what its worth, I tried to emulate Tracy's dynamically tuned intake as well. But cowl constraints probably compromised the intake at the point where the TB is mounted. This is something I want to modify anyway. As it is things are tight enough that I cant even run any sort of air filter, so I do need to make some changes here - may as well try to do it right.

 

I know I had a picture of your intake - saw it just recently. But cant find it now. Could you re-post it?

 

Mike

From: Dennis Haverlah

Sent: Friday, February 12, 2010 11:19 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: N.A. Renesis to turbo

I used the same 65 mm Mustang throttle body on both my original and new intakes.  If  I remember correctly, I believe I had a longer  unused throttle travel with the original intake but I never measured it.  I don't know the static rpm increase with the new intake - probably have that in my notes some where but my max. rpm at high altitude (8,000 - 10,000) increased 400-500 rpm.  I estimated I went from 165 -170 HP with the old intake to about 185 HP with the new intake.  This in in line with Ed Anderson's recent note that Mazda got about a 16% power increase at 6000 rpm with the DIE effect.  I felt much improved acceleration the first time I took off with the new intake.

The new intake is based on dynamic intake effect  (DIE) where the closing of an intake valve caused the moving intake air to bounce off the valve creating a pressure wave.  The wave travels at the speed of sound to the other intake valve and arrives there just before that valve closes.  This increases the amount of air and fuel that enters the combustion chamber.  (As we know the rotary has no valves but uses the sides of the rotor for opening and closing the intakes.)  I designed my intake to give max. performance at 6300 rpm.

If I had cut down my prop to 74" it would give me more clearance for the prop on my RV-7A and increase my top end rpm.   Max rpm is about 6400 rpm with the new intake and the 76" prop.  I'm really not needing higher RPM now.

Dennis Haverlah

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