Rusty, the rotary engine
(for what ever reason) just LOOOVVVVVEEEESSS those cooler days. I have
had fuel flow of over 20 gph on take off when OAT was 28F. That
calculates out to over 200HP, static RPM was 5800 rpm vice a nominal of 5200
on a "normal" day. I've never said anything about it because 1.
Who would believe me 2. Who would believe me? and 3. Who would believe
me? Anytime the OAT is below 65F or so my static RPM increases
about 200 rpm for ever 10F further temp drop.
Ed;
The only problems
with this is 1. I don’t believe it, 2. I don’t believe it; and 3, I find it
hard to believe J.
The air density
change is proportional to the change in absolute temp, so 10F is about
2%. Maybe 3 hp? Gee, we don’t really need to turbo because the
adiabatic temp drop with altitude will overcome the loss of power due to
altitude J. Could there be
some other effect going on here? Fuel density is also changing. How
are you measuring fuel flow.
One problem
with hp inferred from fuel burn is that we know that the rotary’s don’t burn
all that fuel to make power. Fuel is burning right on out into the
exhaust pipe, and the amount of unburned fuel varies with a lot of other
factors.
Al
See! I knew I
wouldn't be believed {:>). You are not alone. When, I first
mentioned it to Tracy, he suggested a Tach malfunction
{:<(.
First, I
abolutely agree, Al that the increased in power that would move
my static rpm from 5200 to 5800 rpm on a cold day, could of only had a small
contribution from the colder denser air. Once, I elimnated a possible
tach malfuction at high rpm, that increased power puzzle is part of what got
me started on this DIE analysis. It is now clear to me how and why
that additional power was there on cold days, but not on the warmer
days. In fact, in my presentation in October at Shady Bend, I use that
the equations to explain exactly how and why that was happening to my
engine.
I also agree that
you can crank up the mixture and fuel flow and the rotary will simply spite
out and burn in the exhaust the excess fuel. However, when the fuel
burn rate, the engine rpm and the aircraft performance all three indicate
increased power...there just might be increased power.
But, given that
the power increase was real (and despite the opinon of unbelievers {:>) I
believe it was) then the next question is how can I get it all the time, not
just on cold days. That is what I am now working on.
Ed
Anderson