Aircraft peformances, is this joke ?

[FS~looksharp]

also... are you switching to rich mixture at sea level ????

i can get 290 mph out of the spit 2a at sea level with boost cut off enabled and rich mixture just as it should be

[Redroach]

Originally Posted by skouras

personally i doubt if there going to make them exactly the same
for example
the manual of the BF-109E says that the plane is a heavy tail so during take off you have to push your stick fully forward and to the right....do that in COD and soon you will be dead very soon
the plane it seems very unstable
and the rudder it sucks

Shiver me timbers! I'm a staunch and obsessive "do-it-like-the-real-thing" guy, but if this were EVER implemented, we'd probably not be able to stem the wave of complaints rushing in. It scares me to death right now!

[ATAG_Snapper]

Originally Posted by looksharp

also... are you switching to rich mixture at sea level ????

i can get 290 mph out of the spit 2a at sea level with boost cut off enabled and rich mixture just as it should be

Yep. And when you do that, pull your mixture lever back to Full Lean and see what happens.

[Redroach]

oh, and: Isn't Lean <==> Rich in the current (latest) beta incarnation? At least on the SpitMkIa?

(I mean that I am of the opinion that the lever works the wrong way around)

[ATAG_Snapper]

Originally Posted by Redroach

oh, and: Isn't Lean <==> Rich in the current (latest) beta incarnation? At least on the SpitMkIa?

(I mean that I am of the opinion that the lever works the wrong way around)

Hi Redroach,

Yeah, that's been so since Cliffs of Dover was first launched and never corrected:

http://www.il2bugtracker.com/issues/18

But that's not what I'm referring to in my reply to Looksharp.

[jf1981]

Originally Posted by looksharp

also... are you switching to rich mixture at sea level ????

i can get 290 mph out of the spit 2a at sea level with boost cut off enabled and rich mixture just as it should be

No I don't think it was this way, the engine is rated with its full boost of 6,25 psi, going over that should give you an extra margin on top of the normal performance.

That's what I have understood from the sources I could cross.

Also if you note that the military power was only to be used for short time, I don't think it was the meaning to level the aircraft and apply more than its rated power in order to determine its maximum speed. You have to take into account that it was leveling up for a relatively long time before a stable reading could be obtained, say between 5 and 10 minutes most probably.

If you find informations supporting that it shall have its performance with the boost cutout open and applying the full available boost, I think it'd be worth to share.

In my opinion, we should have the right performance without use of bost cutout, up to my understanding. Octane grade 100 was probably also not available in 1938 for the Mk I prototype. The prototype itself fit with a wooden fixed pitch propeller reached 349 mph TAS at 17'000 ft.

I'll try to get more accurate datas from one of the big books I have related to Spitfire, a very good and complete one indeed. Those are interesting lecture.

Edit
I find no information supporting that the max speed of Mk I & II were measured with more than the rated power at 6 psi of boost.
Apparently the Mk I had 1030 bhp at altitude (either 16,250 or 17,000 ft ?) and Mk II 1150 bhp at 14'500 ft, source "The story of the spitfire" book.

[Blackdog_kt]

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.

[jf1981]

Originally Posted by Blackdog_kt

Generally speaking, all piston aircraft checklists that i've seen specify rich mixture for high power settings.
[...]

Leannig purpose to keep air fuel mixture to 1/15, when climbing, the less dense air means it comes to 1 of fuel for less than 15 of air in ratio, in other words, too rich of fuel, so less efficiency, some fuel is burnt meanlessly.

However as explained there's a temperature issue, generally, when the leaning is done manually, full power with rich mixture expect at very high altitude where some leaning may be needed.

When cruising one can lean further.

Except if the sim has a sort of bug, no full power should be done with lean but if one wants to shorten an engine's life. Maybe they'll model an engine failure due to incorrect leaning.

Obiously, a lot of fuel consumption reduction achieved at altitude in lean mixture, could be 20% less. I seem to remember the spit was giving 40 gph rich and 35 gph lean by 15'000 ft.

[ATAG_Snapper]

Per Redroach's post above, the Spitfires have the mixture control incorrectly reversed in Cliffs of Dover. The Hurricanes have the mixture control modelled correctly: Pull backwards for Rich, push forward (toward the instrument panel) for Lean. When CoD was first released last year, a lot of Merlins got destroyed over this confusion until it got sorted out. Surprisingly, this seemingly easy fix was never rectified so newcomers are still frying Merlins as a result.

To confuse the issue further, when flying a Spitfire IIa at low level you go "through the gate" with your throttle and hit 12 lbs of boost at 3000 rpm with your lever in Rich position your aircraft begins to shake, throwing your aim off. Pull the mixture lever back to lean and your aircraft smooths right out -- until it blows a head gasket after about 2 minutes (on a good day).

So, you have a choice at 12 lbs boost, 3000 rpm low level in a IIa: strong shaking (rich mixture) for 2 minutes before you kill your engine, or silky smooth (lean mixture) for two minutes before you kill your engine. Or push your WEP button for 1.33 ata repeatedly with no ill effects at all for a whole tankful of gas. Oops - sorry, the Spits and Hurries don't have that feature.....

[tintifaxl]

Originally Posted by ATAG_Snapper

Or push your WEP button for 1.33 ata repeatedly with no ill effects at all for a whole tankful of gas.

I would call that glitching. Should be instant kick on a server.