Paul--regarding your note on Powersport tuning specs, all I know about the
version of the current engines is what I read. On the early aluminum
Superlight prototypes we first built a dual side port engine that made
over
200 hp @ 7,000 but wanted more power at lower rpm and went to peripheral
ports with 1 9/16" runners from the plenum and moved the throttles plates
to
inside the peripheral port in the rotor housings ala Mercedes C-111.
These
engines were rated at 160 hp, then 180 h.p.@ 5500.
The Mazda "conversion"
prototype with the internal spur gear on which the current Powersport
engine
is based used all of those systems but we increased induction tube
diameter,
ports and throttles (also in the rotor housings) to 1 11/16". This
engine
was rated at 200 horsepower at 6,000 rpm. When we moved the throttles
from
the plenum to the rotor housings, the idle dropped down to 1,000 rpm.
Worked great with the torsional stiff internal spur reduction gear which
had
minimal gear lash. And had great response at off-idle, making it nice for
approaches with a fixed pitch prop. In that regard we started off using an
84" diameter x 96" pitch prop on the RV-4. When we started making more
power with later engines we had to run the pitch up to a goofy level. I
think the last one was 74 x 120+". Recently I saw you guys were talking
about props for rotary engines and at one point we had a prop maker supply
us a 74" diamether wood prop he provided for 200 H.P Lycoming powered
GlasAirs and we had to take it back because the Mazda conversion engine
needed more pitch in it for cruise.
Steve Beckham
The NSU RO 80 also had the throttles in the p-port housing. It too idled
well and pulled from low RPM as I drove one in Germany. It had intake
pipes about 30 inches long or more.
Paul Lamar
Steve,
How long were your 43mm (1 11/16") intake tubes?
George ( down under)
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