Gordon,
You lose the weight of the gearbox but gain the weight of the
SUPERCHARGER and all it's plumbing and mounting hardware. I'd bet it
would be close to a wash on weight, and the wear aspect would be MUCH
higher. Paul hammers on this all the time but I'll take over this time.
The rotary is NOT a piston engine! There is no reciprocating motion, and
higher e-shaft RPMs are NOT a wear problem. As has been said many times
Mazda instrumented the engine and found that bearing load at 6000 RPM
was NIL, ZERO, NADA, NOTHING. The compression and power loads balanced
out. I plan to cruise at or slightly below that figure using a 2.85:1 PSRU.
Secondary item: Paul the figures on the screw Lysholm supercharger are
true. The efficiency improvement lead to the NHRA banning them at one
time. I don't know it that is still true or not.
Bill Jepson

Hi Bill,
Regarding the 'no bearing load at 6000 rpm' means that the inertia force of the
pistons equals the force generated by the combustion pressure. The pressure curve
at combustion has a very sharp, short duration peak and falls off quite rapidly
at both sides of the curve. Also keep in mind that at the other side, when the
eccentric is at the 'bottom' meaning at the side of the ports, the full inertia
load of the piston is loading the bearings, similarly to an RPE at BDC or rather
at TDC during open valves.

There are always bearing loads, no matter at what speed the engine runs. Of
course, running near 6000 rpm reduces the bearing load near TDC, again, similar
to an RPE. (Just don't want to get the wrong impression out there.)

Rolf


The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.