View Full Version : Finnish Brewster

05-25-2005, 10:01 AM
Flying a Brewster in the Winter War campaign and wondering at what altitude I should be switching fuel mixture to 80 percent. Maybe around 3000 metres?


05-25-2005, 10:08 AM
You mean fuel mix? Rule of thumb is to reduce the fuel mix as far as it will go before you start to lose RPM.

05-25-2005, 10:13 AM
Not quite true. The idea is like a supercharger--at the proper altitude, you drop it just enough to counter the performance loss.

Just wish I could be more helpful by remembering at what altitude that is. :\

05-25-2005, 05:46 PM
I'd hazard a guess at about 3000 metres.

Not exact, but it's approximately the same age (in the sim) as a few of the russian planes, which were 'set' to lose RPM at 3500m due to over-rich mixture. Pulling it back to 80 at 3000m ensures that you'll stay steady.

There's a fair bit of leeway for less rich mixture (Some planes will manage back to 40% without losing RPMs at 3500m...not that that's a good idea, though), but not a lot for over-rich.


05-25-2005, 07:15 PM
reduce mixture from 100% to 80% at 9300m (!).
at 9400m you will have already black smoke out of the engine.
shift the supercharger from lowblower to highblower at 3000m

05-26-2005, 06:16 AM
Thanks for the replies. Sorry should have said fuel mixture and not air - corrected in my original post.

I noticed an improvement to RPM switching my superchargers as low as 2000-2100 metres.

As for my question the mixture has always remained a bit of a mystery to me with this plane. My guess is 3000 metres but maybe 9000+ mate? That seems way too high but maybe you are correct.

Again thanks for the comments.


05-26-2005, 12:07 PM
well, in the game , so far you dont have black smoke trails coming out of your engine, you havent to reduce the mixture.
and the B-239 is beginning to do so between 9300m and 9400m

remember, its a game, not the reality.

05-26-2005, 12:58 PM
Exactly mate. Will keep in mind as I play through the campaign. As I don't fly that high for this theatre it means one less thing to worry about.

05-26-2005, 02:17 PM
A 1943 Wright Cyclone manual says that switching from stage 1 to stage 2 should not be done at too low an altitude and suggests a band in which to do so- I usually switch at 3,000 m which is approx. 10,000 ft and is in the band suggested by Wright.
As for mixture strength, when cruising at approximately 65% power, I lean it to 80% and switch back to 100% when going into combat and increasing power output. This increases the aeroplane's range, as it would in real life.
Running stage 2 at low altitude will excessively increase cylinder pressures- in real life this would lead to detonation, overheating and eventual engine failure. IN FB/PF, the Cyclone mimics this behaviour quite well as the engine will lose power and eventually fail if stage 2 is run at low altitude for too long.