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Old 07-23-2012, 11:05 AM
Blackdog_kt Blackdog_kt is offline
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Generally speaking, all piston aircraft checklists that i've seen specify rich mixture for high power settings.

The engine runs a bit more powerful on auto-lean but it also runs quite hotter, so for all high power regimes of flight auto-rich is used. Lean is just for cruising at reduced fuel consumption.

In short, going flat out and switching from rich to lean might cook the engine in short order.

I was lucky enough to have access to a friend's PC with a quite a few FSX add-ons that do extensive engine management and that's where i practiced before CoD was released.

At some point we were flying a Catalina add-on by Aerosoft that is modeled after the one they have restored in the Lelystad airfield museum in the Netherlands. We even did a 10-hour flight in it across the Caribbean, taking turns at the controls.
What we noticed right away was that flying at economy settings on auto-lean would result at the same cylinder head temperatures as when flying at higher power on auto-rich. The lower demands on the engines were completely offset by the leaner mixture.

The main gain was that we were burning less fuel because of running the engines at lower manifold pressure/RPM. Going to maximum continuous power resulted in the exact same cruising speed (an abysmal 100 knot IAS, that's slower than many cars ), but we had to go to auto-rich mixture instead. Then, after 2-3 minutes we also had to open the cowl flaps fully and the result was that at max continuous power we had to compromise so much in drag that our speed was lower and our fuel consumption much worse.

So why don't people fly like that (on lean/economy) all day long? Because higher power means better acceleration and climb. The difference here is that we were just cruising, but in a combat scenario it's different.

You can also see this in CoD to an extent. There are times when i am cruising at 1.1 Ata and the 109 does 380km/h IAS, there are other times when i'm pushing emergency power and it barely does 350km/h because i just exited a maneuver.

What we need is someone who can extract the data files to tell us which way for the in-game controls and levers corresponds to lean and which to rich for all of the flyable RAF aircraft, so that we can deduce with some accuracy if and what is wrong.
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