help flying the corsair

[Ctrl E]

a question. how best to use the superchargers for this beast?

will i go faster if i switch the supercharger to 3 - even at low levels? i might overheat quicker though? surely the more oxygen into the engine the better in an emergency? even at low levels?

and does prop pitch and magnetos really do much?

[Shrike_UK]

For the Superchargers question and most about prop pitch in flight i'll leave that for the more aviator types to explain as it still escapes me. However, Propellor Pitch is extremely useful when landing on a carrier. Whilst on your approach you can run about 40% throttle, and lower your prop pitch to adjust your airspeed. This is a big advantage as if you dont have enough speed to make the landing its faster for the mechanics of the aircraft to change prop pitch than spool up the engine revs. Therefore, control your prop pitch on landing and you can easy get power fast if you need to abort landing.

[TheGrunch]

Originally Posted by Shrike_UK

For the Superchargers question and most about prop pitch in flight i'll leave that for the more aviator types to explain as it still escapes me. However, Propellor Pitch is extremely useful when landing on a carrier. Whilst on your approach you can run about 40% throttle, and lower your prop pitch to adjust your airspeed. This is a big advantage as if you dont have enough speed to make the landing its faster for the mechanics of the aircraft to change prop pitch than spool up the engine revs. Therefore, control your prop pitch on landing and you can easy get power fast if you need to abort landing.

Isn't that the wrong way around? From what I gather, Throttle in IL-2 controls the manifold pressure and Prop Pitch controls the RPM governor on most aircraft (not some of the early war planes perhaps). You want to keep RPM high, and vary the manifold pressure, surely? Look at the RPM gauge in an aircraft as you change prop pitch and you should see that.
As for the supercharger, the best rule seems to be to see if changing the supercharger to a higher stage gives you a higher boost pressure, and if it does, leave it that way. Better than that, track down the pilot's notes or manual for the actual aircraft and see what they say.

[Blackdog_kt]

Yup, i agree with thegrunch. In fact, i think it's pretty much standard operating procedure for real airplanes to use high pitch values during landing and takeoff.

Think of pitch like your car gears. The higher the pitch, the more RPM and torque you get (useful for climbs and accelerating), but also more drag as a high pitch % means that more of the prop blades meet the air head-on. Think of 100% pitch like your 1st gear in a car, good for starting, going uphill and braking via engine resistance when going downhill.

Similarly, lower pitch % values are good for fuel economy, cruising and getting to higher speeds when you don't need a lot of "force" to pull you around. For example, in most planes you can go faster if you are high, straight and level and use 80% pitch instead of going at 100% pitch all the time. The moment you get jumped however and need to evade your speed will start dropping if you maneuver. It is then a good idea to increase pitch. Or alternatively, keep it where it is and dive to get speed, as you gain speed keep reducing pitch, something like 10% lower for every 100km/h you gain past the 500km/h mark. These are not hard and fast rules mind you, they're just empirical guidelines based on flying the Fw190A series on manual pitch. Other birds have their own best settings, i'm just using the numbers as an example.

What you need to remember is that high pitch % is like a low car gear and vice versa. The catch however is that cars have predetermined gear ratios that suit them best, but the airplanes in the sim don't have pitch presets. Which means that after a point you won't get any speed increase from lowering your pitch, in fact you might lose some, as it's like modifying your 5 gear car by adding an additional 2 gears and running it on 7th gear. These gears will be too small to drive your small engine efficiently and your car will slow down. Just like that, in most planes in the sim going below 70-80% will mean you start slowing down if you're flying straight and level. However, on a dive it pays to go as low as 50%, because the reduced resistance helps you pick up speed quicker. Just like in the previous car analogy, you know that on a downward slope running with 5th gear will mean a higher speed and acceleration than running with 4th gear. In this example, having a 6th and 7th gear wouldn't be inefficient, as these would only be used in such a case to let the car roll on its own under decreased resistance. We don't have that in cars, so you might say it's like switching to neutral and leting the car roll downhill.

What should be apparent from this discussion is that it makes sense to use 100% pitch during takeoff and landing. Just like your 1st car gear, it's the "strongest" pitch setting even if it's the slowest. Well, on take-off you need this force to start you on your way and during landing you won't mind the slowing-down effect it has. The biggest advantage of using 100% pitch though is that, just like your 1st car gear, it's also the most responsive setting. This simply means that throttle changes take effect much faster when you run at high pitch, which is only a good thing during take off and landing. If you need to abort the landing and go around, an engine that runs 35% throttle and 100% pitch during the descent will be much better in accelerating the plane above a safe speed than an engine that runs 60% throttle and 30% pitch.

As another example, it was often stated that the wingmen burned more fuel than the leader did. This isn't only because they have to throttle up and down to keep formation when the leader flies on a pretty much constant setting. It's also because they needed their throttle input to be responsive and hence, used higher pitch settings than the leader. It's like racing cars (again) and your goal is not to overtake the opponent, but stay glued to his rear bumper. He might be doing 200kmh on his 6th gear and his engine running at 5500RPM, but if you want to follow him and have good control over your throttle inputs to manage your distance you would be wise to drive one gear lower than him, for example 5th and run your engine at 6500RPM as a result. As you can see, this means burning more fuel in exchange for a more responsive throttle.

Hope it makes sense

[dflion]

Last year I drew up a 'prop pitch' diagam to help my son better understand the principles of manual prop pitch as it applies to aircraft in IL2 - 'a picture is a thousand words'.

The percentages I have used in this diagram may not suite every aircraft using manual pitch in IL2 - you will have to experiment with the Corsair. I used the excellent Tempest as the basis for these percentages.

You can type in to your aircraft controls in the game the 'Shift values' I have shown. 'Fine pitch' (higher rpm) is used for takeoff and landing. 'Course pitch' (lower rpm) is used for fast cruise and air combat. You will need to experiment with various aircraft to really understand how varying pitch will help through the whole range of flight - stationary, taxying, take-off, climbing, air combat, descent and landing.

I have also included real pilot notes on prop pitch for the Spitfire II. Later Mk's of Spitfires had their throttles linked to the prop pitch mechanism, which could be overided.

Anyway I hope this diagram helps you understand how it all works.

DFLion

[Shrike_UK]

Yes very good examples of the propeller pitch guys ^^, i particularily like the part about thinking of it as gears in a car 100% like 1st. However, my point was just about landing, and i still beleive its best to run a low prop pitch with higher throttle. Think about this, and even test it...

Which is fastest to gain speed if you are too low and about to hit the back of a carrier:
Landing @ 40% Throttle with 20% prop pitch
Landing @ 20% Throttle with 100% prop pitch

Time for Throttle to reach 100-110% will be less if the throttle is already at 40%, and the prop pitch takes less time to adjust to 100% than the engine spool up. This means your acceleration will be faster for an emergency abort. It also allows for fine tuning of your speed on landing using prop pitch rather than throttle.

I maybe wrong and feel free to correct me, but in either case above that you guys have talked about, general flight and takeoff. Is there any particular reason why you would want 100% prop pitch on landing? As far as i can think of the only result would be increased drag, (as your descending) and increased engine labour as you throttle from 20% to 110%.

@dflion, the picture you've given, thanks for that, is interesting as is shows 50% prop pitch as being a good setting for takeoff. however would this be incorrect for carrier takeoffs where you need maximum acceleration or you end up in the sea?. Thanks and i really fancy trying out your values in your diagram now and see if its better. I hope im surprised!

[TheGrunch]

My knowledge is restricted to aircraft with constant speed propellers, but as far as I know it's the other way around. Engine RPMs take far longer to respond than manifold pressure - try flying the Spitfire IX, set to manual pitch (Shift+0). Set prop pitch to 0%, then to 100%, and watch how long it takes for engine RPM to change. Then change the throttle setting, and watch the boost gauge. It should move almost instantaneously. When you say it takes longer for the engine to 'spool up', you're right, because the engine revolutions do take longer to change, but given for that the majority of the aircraft in the game, prop pitch controls the governed RPM, not the actual propellor pitch, this means that it takes longer for 'Prop Pitch' to change the engine's functioning than 'Throttle'. So for landing, better to have Prop Pitch set to 100% and vary the throttle since you'll already be operating at max revs if you need to go around.

[dflion]

Thanks Shrike_UK, its all about experimenting with each IL2 aircraft, they are all different in weight and power values. You will find a 'happy medium' in the prop pitch percentages for each aircraft.

Just a note about your reply 'TheGrunch' - you are right about prop pitch governing RPM. For the Tempest, I use a 'finer pitch' of 50% and this gives me a slower initial take-off speed yet a higher RPM which gives me more control of the aircraft. The same situation applys for landing. Fine pitch was used by most WWII aircraft for take-off and landing - higher RPM - more control. You can use a courser pitch of 100% or 90% for take-off and landing, though theroretically you have less RPM and less control.

For Ctrl E on the subject of Superchargers for the F4U - quote straight from IL2 1946 aircraft pilot notes " Switch supercharger speeds at 2,600m (8,500ft) and 8,200m(26,900ft)". I have also attached real pilot notes from the Spitfire IX explaining supercharger operation. I would also recommend Googling Wikipedia under 'aircraft superchargers' for a very comprehensive explanation on how superchargers and 'turbo' supercharges work on WWII aircraft.

[TheGrunch]

Originally Posted by dflion

Just a note about your reply 'TheGrunch' - you are right about prop pitch governing RPM. For the Tempest, I use a 'finer pitch' of 50% and this gives me a slower initial take-off speed yet a higher RPM which gives me more control of the aircraft. The same situation applys for landing. Fine pitch was used by most WWII aircraft for take-off and landing - higher RPM - more control. You can use a courser pitch of 100% or 90% for take-off and landing, though theroretically you have less RPM and less control.

100% Prop Pitch in the game = Max RPM, so I don't see what you mean. The reasons I can see for dabbling with prop pitch in an aircraft with a CSU are to gain more speed in a dive, prevent the prop overspeeding in an abrupt powerdive or for fuel economy and oil/radiator coolant temperature reasons, although for some reason I HAVE always felt more comfortable flying the with prop pitch on manual. You CAN get an extra jot of speed by reducing pitch slightly when you're fast and level, but other than that, 100% in combat most of the time, and definitely for takeoff, landing and maximum climb rate.

[dflion]

Originally Posted by TheGrunch

100% Prop Pitch in the game = Max RPM, so I don't see what you mean. The reasons I can see for dabbling with prop pitch in an aircraft with a CSU are to gain more speed in a dive, prevent the prop overspeeding in an abrupt powerdive or for fuel economy and oil/radiator coolant temperature reasons, although for some reason I HAVE always felt more comfortable flying the with prop pitch on manual. You CAN get an extra jot of speed by reducing pitch slightly when you're fast and level, but other than that, 100% in combat most of the time, and definitely for takeoff, landing and maximum climb rate.

I have just had a test fly of the Tempest and explored the prop pitch situation in the game. The diagram that I originally posted was taken from an English 'Aeroplane Mag' - I know that the finer the prop pitch is, (see diagram) the higher the RPM. And if you set a courser pitch the lower the RPM (real WWII aircraft situation).
What I have noticed, in the take-off situation, Oleg and Co. may have reversed this situation in IL2 (he may have resolved the situation in BOB) - if you set the pitch to 100%(course) in the game the higher the RPM.
Once the aircraft gets to altitude in IL2, the courser the propellor pitch (100%), the aircraft travels at higher speed - good for combat. It appears that Oleg may have compromised the situation for the sake of gameplay?
I have a friend that flys a real Kittyhawk and Spitfire at Temora NSW Australia - I will try and contact him to further discuss this situation.
Anyway we have a real discussion point in this thread. Suggest you 'test fly' the Tempest and see what you think?

DFLion