Also a 2.85 gear box over a 2.17 gear box will add as much as 20% to
you HP numbers depending on how well the engine is ported and by
running the engine up to 8000 RPM for takeoff and climb. Ian reports
around 200 HP with his side port & 2.85 gear box and he must have
close to 300 hours so far. Ian, how many hours now?
I have 210 hrs now, still going strong. I recently dropped the vaccum pump
speed from 1/2 engine speed to about 0.3 . The Lyc. vac. pump is driven from
the camshaft and geared up by 20%.
What is the official redline for the 13B turbo, and how much margin is there
in
that number? I've found numbers between 7000 and 8500 rpm, and differences by
engine type. I'm specifically interested in the 3rd gen U.S. 13B.
I'm definitely interested in the combination you describe above
(a modest amount of porting and a 2.85:1 gearbox) but don't want to
sacrifice engine life to get there.
Regards,
Chad
You will never destroy a Mazda rotary engine in an airplane due to over
revving.
The prop load will see to that by limiting the RPM. Just about any Mazda
rotary will rev to 9,000 or 10,000 without damage.
The red line varied from year to year. It is mainly a function of the rotor
weight and consequently the pressure in the rotor bearing. The lighter the
rotor and the higher the oil pressure the higher the RPM can be.
Paul Lamar
Paul, you should remind people from time to time that rotor speed is not the
same as the shaft speed (RPM)
Bulent
Very true. It is one third shaft speed. At 9000 shaft the rotor is
turning on its rotor bearing 3000 RPM. This in and of itself would
never be a problem but what is happening is the rotor is also rotating
around the center of the e-shaft on a one or two inch radius. Just like
the earth turns and rotates around the sun at the same time. That is
why the wankel is occasionally referred to as a planetary engine. And
that is what causes the high rotor bearing loads.
Paul Lamar
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