The stuff about having to still move all the engine components is true.
However, you are missing the point that by shutting down one cylinder you
can run the engine at a higher rpm with less fuel where the engine (per
operating cylinder) is more efficient.

Alex Madsen




-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Jack Ford
Sent: Monday, May 09, 2005 9:50 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: center rotor OFF

That entire variable cylinder configuration routine seems to me to be a lot
of (old) advertising hype. The concept seems to be that the public thinks
fewer cylinders burn less fuel, so you can have your eight cylinder cake and

eat four cylinder fuel. Purest balderdash.

The engine is still pulling eight cylinders worth of rings back and forth in

the bores even if it's not compressing any air. The cam is still trying to
lift sixteen (plus) valves and compress sixteen (plus) springs, ETC. You
can't reduce a lot of the pumping losses if the whole mechanism is still
rotating/reciprocating/wearing.

Power is proportional to the amount of air/fuel mixture going through the
pump (assuming the same combustion efficiency). The reduced air/fuel mixture

(of the variable cylinder configuration at cruise) presumably produces
increased economy. BUT, it requires exactly the same amount of power to push

the vehicle down the road at cruise using 4,6,8,10 or 24+ cylinders. The
conventional method of accomplishing this enterprise is CLOSING THE THROTTLE

so less air/fuel mixture is pumped through. Has the exact same effect with
much less complicated design.

So if you want more efficiency, just run at lower power settings. You will
accomplish the desired result.

Retracting soapbox,

Jack Ford


----- Original Message ----- From: "Ernest Christley" <echristley@nc.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Monday, May 09, 2005 3:16 PM
Subject: [FlyRotary] Re: center rotor OFF

Russell Duffy wrote:

 OK, make me look it up :-)  Apparently, they stop the valves from
opening, rather than leaving them open.  I couldn't find anything that
gave details of exactly what point in the sequence they stop the valves,
so the cylinder could either be full of air (silly and wasteful of
power), empty of air (would cause vacuum that would be as bad as the
compression force), or perhaps somewhere in between.

Other than friction losses, you'll get back everything you put into
compressing the gas in the cylinder, Rusty.  The process will be totally
elastic.

-- This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

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