Friday 2010-10-22 Dev. update and Discussion

[Blackdog_kt]

Originally Posted by Skoshi Tiger

AFAIK the position of the mixture control will be set to get the most efficiency. I've never flown a plane with a CSU or super charging, but I think once your plane is set up at a given RPM/throttle you would alter the mixture to get the correct Exhaust Gas Temperature.

In emergency/combat with full throttle and high RPM's to avoid the possiblity of pre-ignition and detonation, I think you'ld be using full rich mixture most of the time. (less efficient but safer - of course when we're up at 20,000 feet that may be different).

In a light plane it's easy, once you've settled into your cruise you reduce your mixture from rich until you you obtain the highest RMP (indicating the most efficient Fuel/Air mixture) then bump the mixture in a bit so your not running to lean.

[EDIT]
Those throttle quadrants didn't have RPM leavers- Hmmm early fixed pich props maybe????????
[\EDIT



Did you mean shooting down a plane with a Bazooka? or was there another equally impressive scene I missed?

Actually i think they are wondering if the mixture lever operated "backwards". In most planes lever forward=rich. However, i've seen a freeware FSX tiger moth add-on and it too had it backwards (lever back=full rich, while in most cases the full back position is the fuel cut-off). Even more so, if you pulled the throttle back in the Moth it would pull the mixture lever back along with it.

Essentially, it was a crude "auto-mixture" method to ensure that the engine was running rich when at low throttle settings.

As for how mixture is set, it's just like you said. If you have a fixed pitch prop you can do it by leaning for maximum RPM at the given throttle setting. If you have a constant speed prop however the RPMs will be constant. In some cases you can still observe a small jump in the RPM needles until the governor system stabilizes under the new forces.

When this is not possible leaning in general aviation aircraft is done with the help of cokcpit instruments, either a fuel flow/power gauge or an exhaust gas temperature (EGT) gauge. It usually involves leaning for magimum EGT, then enriching just a touch to make sure the engine doesn't run too hot (too lean a mixture can cause somewhat of an overheat).

However, i have absolutely no idea how they did it back then in planes with constant speed props (that don't exhibit enough of an RPM difference to indicate the proper leaning point) but no EGT gauges. It's ok doing it in a civilian aircraft, but when people are shooting at you i guess it's a bit harmful keeping your head inside the cockpit for long periods of time, looking to catch a glimpse of a tiny jump of the RPM needle before it stabilizes again due to the pitch governor. I guess it's one of the reasons that mixture was automated to a large extent early on in many designs, either completely in the German ones, or partially like in the US designs (cut off, full rich, plus two automatic settings, one for auto lean for economy during cruise and one for auto rich to keep temps a bit cooler during climb out and combat).

Maybe it was also done "by ear", listening for changes in the engine's sound? Would be interesting to know.

As for running full rich without taking altitude into account, it won't kill the engine (in fact engines run cooler with richer mixture) but it's generally not advisable if you want to develop any kind of serious power. Restored warbirds run richer than specified in the manuals to preserve their old engines, but back in the day they were more concerned with delivering peak power during combat.
I doubt they would ever go to full rich over 8000 feet or so, unless the engine was starved of fuel/stalling due to battle damage and they tried to keep it running no matter what, at the cost of optimum power.

Originally Posted by Flanker35M

S!

I remember the Whaa-Whaa when discussing the option of it being clickable. Oleg stated it would be and discussion faded. Now the bandwagon is oohh aaah..Go figure Oleg for sure has put thought to this and not made an half arsed implementation as you can see.

Yeah, i remember that too, almost nobody wanted it
Just as i was saying at the time, it might not the best interface but it's the easiest one if you want to do in-depth modelling of aircraft systems as we'd be out of available shortcuts (or don't remember them) if we had to map everything to keyboard and HOTAS.
So, it was a question between optionally using the mouse for some controls (i doubt people will be clicking the gun triggers or other vital stuff, things like that will stay on the joystick) in exchange for extra realism, or not using the mouse and not modelling the extra stuff because we lack the controllers for it. The correct answer is of course obvious