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Scott, my take on this is since we don't have to
worry about possibly burning exhaust valves by running too lean, reducing
pumping losses by having the throttle wide open may have merit. I do
it.
I personally fly with my Throttle wide open at cruise and
using my mixture control to regulator the amount of power I want to
produce. In theory that reduces pumping losses by keeping the manifold
pressure as high (or nearly) as ambient pressure. I'm not certain what
heating the air would do but further reduce the air density which would
theoretically mean you would need less fuel to maintain the same air/fuel ratio
- so that might reduce the risk (to a piston engine) of running tool lean - but
would still cut down the fuel consumption by permitting less fuel and yet
maintain the same air/fuel ratio.
The only down side I have notice in flying WOT
(at cruise altitudes) with reduced air/fuel ratio is that the engine
occasionally will miss - not enough to worry about (unless you worry about
things like that {:>), generally just enriched the fuel mixture a bit stops
it.
Having said that - I have never compared operating at
reduced throttle setting to WOT so can't say how much (if any) difference it
makes - theoretically, it should make some difference.
FWIW that's my $0.02
Ed
Sent: Saturday, January 22, 2011 11:30 AM
Subject: [FlyRotary] Charge Air Pre-Heat
I was just over on the VAN's Airforce forum. Paul Lipps (Elippse props)
was talking about using carb air heat @ wide open throttle to reduce power in
cruise instead of patial closing of the throttle.
This Rotary group talks of reducing power and increasing efficiency by
leaning @ WOT, which rotary engines tolerate better than piston recips.
Question for the group?
Would Charge Air Pre Heating be an additional benefit for the rotary?
Paul was idenifying carb air heat @ WOT as a way to increase
cruise efficiency for aircraft with fixed pitch propellers. I simply extended
the idea to this group.
Scott
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