>
>   > Paul,
>   >
>   > I recently viewed Mistral's website and learned that
> they are
>   > offering two-
>   > 3 rotor engines. One is a 300 hp, 3 rotor engine, and
> the other
>   > is a 360 hp,
>   > turbocharged, 3 rotor engine.
>   >
>   > My question:
>   >
>   > Are they using the 20B? Will this lead to scarcity of
> the 20B
>   > engines? One
>   > caveat. I AM A ROTARY NEWBIE. Therefore; is a 3 rotor simply
>   > "more" of a 2
>   > rotor? I realize the bolts and eccentric shaft are
> unique. I am
>   > asking, as
>   > to the urgency of securing a 3 rotor engine for myself.
> Will the
>   > source for
>   > 20B's dry up anytime soon? Or, with all the 2 rotors
> out there,
>   > can I build
>   > a 3 rotor from 2 rotor parts, and with parts from a
> "trick" shop?
>   >
>   > Thank you,
>   >
>   > Perry- IL.
>   > N801YZ
>   >
>   > Basically yes a three rotor is one more 13B rotor however
>   > there are some unique parts.
>   >
>   > Mistral are building their own engines and parts
> loosely based
>   > on the
>   > Mazda. You need to contact them for details.
>   >
>   > The source of three rotor parts from Mazda could dry up
> any day.
>   > There are other sources for 3 rotor shafts and perhaps
> Mistral  > is the only alternate source for the special
> three rotor intermediate
>   > end housings right at the moment.
>   >
>   > Rumor has it Mazda is about to announce a larger two rotor
>   > 16B any day. Mazda needs a higher torque rotary for the RX8.
>   > The 3 rotor is deemed too expensive to make by Mazda.
>   >
>   > Paul Lamar ...No rotor no motor.
>
> Hi Paul
>
> Would a greater torque engine be preferred over the renesis in a
> aircraft conversion.
>
> Marc Montreal Canada
>
> No! Only if the greater torque engine also had more HP.
>
> Geared aircraft engines only care about HP. The simple fact of
> the matter is drag times speed IS HP! One HP IS ten pounds of drag
> moving at 55 feet per second or 550 pound feet per second.
>
> An aircraft powered by a 200 HP engine (net out of the prop) going
> 200 MPH or 293 feet per second has 200HP X 550 / 293FPS or 375
> pounds of drag.
>
> At 7500 RPM the 16B (assuming the same volumetric efficiency I.E.
> "porting".) will generate 16/13 more HP at 7500 RPM. Lets say your
> 13B P-port engine is now making 250 HP at 7500 RPM. A 16B P-port
> will make 307 HP at the same 7500 RPM.
>
> What counts in cars (given the same set of gears) is torque at
> 1000 to 3000 RPM. In theory if you lower the gears with a given HP
> you get more acceleration. This gives diminishing returns due to
> the rotating inertia of the engine itself. When you slam open
> the throttle on an engine not connected to anything it takes
> time for it to reach red line RPM. This is the problem with
> the small displacement rotary in cars. People don't like to shift
> a lot of gears. They like to drive around in high gear at 2000 RPM
> (good MPG) and slam open the throttle and expect instantaneous
> high acceleration. In this case there is no replacement for
> displacement (torque). That is why 500 cubic inch V8's are so
> popular.
>
> Paul Lamar ...No rotor no motor.

Ok Paul so if I understand you correctly.  When fine tuning an aircraft
conversion engine, one would willingly sacrifice torque in order to
increase HP.  For ex. exhaust restriction reduced diminish torque and
increase HP.

Marc Montreal Canada

Let me rephrases that slightly.

"When fine tuning an aircraft conversion engine, one would willingly
sacrifice torque [at any RPM below 5000 RPM] in order to increase HP."

The ideal aircraft engine has peak torque at cruise RPM with no
sacrifice above that RPM. You want as much torque as you can get
from 5000 RPM to 7500 RPM given a 2.85:1 gear ratio. The lowest
amount of fuel burned per HP generated is always at the torque peak.

As far as exhaust restriction is you want the least amount of restriction
you can get all the way through 7500 RPM. Read big pipes. In fact
what you want to do is organ tune the pipes so they are best at cruise
RPM (5000) for minimum fuel burn. Same goes for the intake pipes. This
usually results in a slight loss of HP at 7500 RPM.

HP is torque X RPM / 5252.


Paul Lamar ...No rotor no motor.

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