I Want my 4.09 Spit FM's back.........

[FC99]

Originally Posted by SEE

That video was shot in 1941 and very nice too! Has anyone else noticed that the pilot could hold the inverted pass for far longer without the engine cutting out (compared to all IL1946 variants up to 1943)? As a full switch player I would appreciate that being included.......(if my observation is correct of course!)

Hi,
our float carburetor and Shilling orifice model is primarily based on description in Pilot's Notes General AP 2095. We would welcome any better source than that.

In regard the video I think that you are wrong in your conclusion. You can take any Spitfire with SO and perform same maneuver. Biggest difference is that things are more binary in game than in RL. That is design decision because SO is tightly connected with mixture control model which is rather rudimentary in game at the moment.

Originally Posted by Nicholaiovitch

I would only add that the way the WEP is activated as KWIATEK suggests is not really very real. Better to follow all the other types and have up to 110% boost to cover the WEP and limit it's use before engine problems (realistic engine management) IMHO.

That is another deliberate decision. We know that WEP is not realistic but we see it more like immersion problem. Changing it would require careful examination of the code. Very often some changes that look simple and harmless could cause problems later when it turns out that they interfere or interact with some other parts of the code which might not be obvious at first glance.

So in terms of cost/benefit we decided that it is best and safest to leave WEP for now.

FC

[Ernst]

Originally Posted by FC99

Hi,
our float carburetor and Shilling orifice model is primarily based on description in Pilot's Notes General AP 2095. We would welcome any better source than that.

In regard the video I think that you are wrong in your conclusion. You can take any Spitfire with SO and perform same maneuver. Biggest difference is that things are more binary in game than in RL. That is design decision because SO is tightly connected with mixture control model which is rather rudimentary in game at the moment.


That is another deliberate decision. We know that WEP is not realistic but we see it more like immersion problem. Changing it would require careful examination of the code. Very often some changes that look simple and harmless could cause problems later when it turns out that they interfere or interact with some other parts of the code which might not be obvious at first glance.

So in terms of cost/benefit we decided that it is best and safest to leave WEP for now.

FC

As far as i known Mrs Shilling Orifice was a not a definitive solution. The time for engine recovery was just lesser, but the negative g effect still there. Even carburetor was not as good as fuel injection.

[Tempest123]

Fuel injection wasn't designed as solution for inverted flight, it was designed to get an even charge of fuel/air to each cylinder. Rolls Royce used carburettors deliberately in the Merlin because they gave a colder/denser fuel/air mixture, so more power was produced than with a fuel injection system. It was a trade-off at that point, and they switched to pressure carburettors later on to cope with negative G's. Kind of interesting all these small details that come out in combat.

[jameson]

BBC documentary:
Spitfire! Two seconds to kill
http://www.bbc.co.uk/archive/battleo...in/11405.shtml

Bob Stanford Tuck and Douglas Bader discussing more or less what this thread is about. From 25 mins on, pertinent remarks regarding Merlin's neg G fuel Starvation and Miss Shillings orifice by Sir Stanley Hooker of Rolls Royce.

Please post a reply to say whether it's possible to watch this if you are outside UK, thanks.

[Blackdog_kt]

Originally Posted by Triggaaar

We're talking about how good competing aircraft were, so what they're up against is very relevant. The Me 262 was revolutionairy, but late designs of the Spit, FW190, or 109 were not, so it's not the same comparison.

How good any of these fighters were is completely dependant on how good their rivals were, so we have to compare models against each other. When the FW190 came out, it was better than the Spit mkV, so the Spit mkIX was made and avialable in the summer of 42. Improvements to each side's aircraft were made specifically to counter the opponents (the spit mk IX would never have been made if it weren't for the 190).

So when we want to look at how good the D9 was, we need to look at what it was up against, and what it was up against depended on how many D9s were in the air. For example, if there weren't enough pilots or fuel for the first 190s, the RAF would have never made the Spit mk IX, and looking back the first 190s would now be compared to the Spit mk V, so we'd think of the first 190s as better than the competition.

Regardless of that I am interested in how the D9 performed against the late war Spits, so if you have any documents, let's have 'em.

You're correct in what you say, but maybe i misunderstood why you were saying it.
What i was trying to convey is that the FM is the FM and it's not dependent on the competition's FM.
In that sense, when you are talking about how good the D9 was you obviously refer to how good it was in comparison to other aircraft, while i was talking specifically about what it can do in its own right. In any case, i'm glad you cleared it up for me

Originally Posted by JG4_Helofly

Hmmm... FM discussions. Have you ever noticed that most times it's only about turning performance or speed? As if these were the only variables that mattered.
That's the result of IL2 playing: It's the only reality we know

Let's hope that COD will introduce other things we will have to worry about in combat. Complex engine management for exemple. At the moment you can hit the W-key leave everything on 100% and you are ready to go. There is no advantage having the Kommandogerät or other automatic devices.
Should be interesting to see how COD will increase the workload in the cockpit. This should slightly change things. For exemple:Having a slight advantage in speed or turn will not make your plane supperior, because maybe the other guy can handle prop pitch etc. better then you.
Or more engine failures due to improper engine management.

I am looking forward to all this (if it's in the game)

That's exactly why i've been advocating improved subsystems modeling over IL2. Currently in IL2 the situation is completely reversed sometimes, for example a P47 can use most settings with near impunity while in reality it had 4 different engine controls to monitor (prop pitch, semi-auto mixture, throttle and turbo-supecharger), while the FW-190 which was completely automatic performs better when used in manual mode (at least the stock ones, the modded ones work fine on auto).

It's not only historically correct to model these intricacies, it also happens to balance the game out between higher and lower performing aircraft without resorting to gimmicks but by copying what each aircraft actually did in real life.

What's more, this doesn't only benefit the blue team's planes, since the situation was reversed early in the war due to the different choice of propellers used as Kwiatek correctly points out:

Originally Posted by Kwiatek

JG4_Helofly Spits or Hurricanes from BOB era have not too much engine workload. You opearated mostly throttle level beacuse you got CSP ( constant speed propeller unit) which mean that you just set only wanted RPM ( in fight maximum possible, in cruise depend of economy of fuel) and mixture level was also only for economical flying ( auto - reach - lean). Much more work load have planes with variable prop pitch like early 109s and early russian planes.

With a constant speed prop you move the lever until you reach the desired RPM and the prop governor keeps it there no matter what you do with the throttle or if you climb or dive (within certain limits due to the prop blade's gimbal stops/rotation limits, it's still possible to have increased RPM in a long dive or low RPM when idling on the ground even when the prop lever is at maximum, but it's easy to manage), but with a variable pitch prop you have to manually do the work that the prop governor does in constant speed props.

Essentially, with a CSP you select your RPM and the governor keeps it there by automatically adjusting the blade angle, but with a variable pitch prop you directly change the blade angle yourself. Since the same blade angle produces different RPM for different airspeeds and throttle settings, you have to constantly be on your toes and juggle between inadequate RPM and overspeed.
For example, if CoD can save separate control configurations for each aircraft, it's most likely that i will map the in-game throttle to my keyboard and use my joystick throttle for prop pitch when flying an early 109E, just to be able to manage this.

Once again, the better performing plane (the 109) has the increased workload, which balances things out in a historical manner.

P.S. Jameson, it's not possible to get the clip you posted about the negative G issues outside the UK, but the other interview works fine.

[Seeker]

Originally Posted by jameson

BBC documentary:
Spitfire! Two seconds to kill
http://www.bbc.co.uk/archive/battleo...in/11405.shtml

Bob Stanford Tuck and Douglas Bader discussing more or less what this thread is about. From 25 mins on, pertinent remarks regarding Merlin's neg G fuel Starvation and Miss Shillings orifice by Sir Stanley Hooker of Rolls Royce.

Please post a reply to say whether it's possible to watch this if you are outside UK, thanks.

Not from Denmark

[WTE_Galway]

Originally Posted by Ernst

As far as i known Mrs Shilling Orifice was a not a definitive solution. The time for engine recovery was just lesser, but the negative g effect still there. Even carburetor was not as good as fuel injection.

All the Tilly Orifice did was restrict the maximum rate of fuel flow to the float chamber and hence reduce the rate of flooding and resultant over rich mixture cut-out in the SU carbs fitted to early Merlins. (The needle valve was also modified.)

It absolutely did NOT eliminate the problem just made it more manageable.

Eliminating the problem completely was impossible without using a totally different type of carb or going to fuel injection ... the neg G issue was "built in" to the float chamber based SU carb design.

The onset of neg G flooding and cut out was much later in a Tilly/Shilling Orifice equipped Merlin than with a standard SU but the problem remained and sustained inverted flight was still impossible.

From 42/43 onwards Bendix and later Rolls Royce pressure carburettors were fitted and these actually DID eliminate the problem altogether.

[JtD]

Originally Posted by WTE_Galway

All the Tilly Orifice did was restrict the maximum rate of fuel flow to the float chamber and hence reduce the rate of flooding and resultant over rich mixture cut-out in the SU carbs fitted to early Merlins.
...
but the problem remained and sustained inverted flight was still impossible.

The Tilly Orifice reduced the fuel flow to the amount of fuel needed at maximum power - 12/16 lb of boost and 3000 rpm. At that power setting, the engine would not cut out in sustained inverted flight due to flooding.

[Friendly_flyer]

Originally Posted by FC99

Hi,
our float carburetor and Shilling orifice model is primarily based on description in Pilot's Notes General AP 2095. We would welcome any better source than that.

I am primarily an off-line flyer, and don't really care about one side having an edge over another. I fly almost exclusively "red", preferring Hurricanes rather than Spitfires. I am extremely pleased with the "new" 'Tilly orifice'! Thank you TD for making the game more immersive!

From a purely game enjoyment-POW, I think neutral trim for all planes (not just Spitfires) should be set to combat speed. When you are cruising around at economy setting, you have all the time in the world to fiddle with the trim-knob. When in a fight you have more than enough with keeping an eye on temperatures, superchargers and stalls, not to mention trying not to get shot down. Going straight and level for a few seconds to adjust your trim is fairly low on the priority-list.

I have no idea how trim was adjusted in real life. I suppose a pilot could always ask the mechanics to adjust it to his personal liking. I would therefore like to ask TD if they would consider changing the trim setting so that "neutral" trim is close to maximal cruise speed rather than to maximal fuel economy cruise speed in the upcoming 4.11 patch. Would that be possible without upsetting some other aspect of the game code?

[Blackdog_kt]

Originally Posted by Friendly_flyer

I am primarily an off-line flyer, and don't really care about one side having an edge over another. I fly almost exclusively "red", preferring Hurricanes rather than Spitfires. I am extremely pleased with the "new" 'Tilly orifice'! Thank you TD for making the game more immersive!

From a purely game enjoyment-POW, I think neutral trim for all planes (not just Spitfires) should be set to combat speed. When you are cruising around at economy setting, you have all the time in the world to fiddle with the trim-knob. When in a fight you have more than enough with keeping an eye on temperatures, superchargers and stalls, not to mention trying not to get shot down. Going straight and level for a few seconds to adjust your trim is fairly low on the priority-list.

I have no idea how trim was adjusted in real life. I suppose a pilot could always ask the mechanics to adjust it to his personal liking. I would therefore like to ask TD if they would consider changing the trim setting so that "neutral" trim is close to maximal cruise speed rather than to maximal fuel economy cruise speed in the upcoming 4.11 patch. Would that be possible without upsetting some other aspect of the game code?

If the trim was adjustable in flight there was no reason to do anything.
If you mean presets for the ground adjustable trims (for example, rudder in a 109 or aileron in a hurricane), then i guess it does have some merit.
For pilot-adjustable trim tabs it's a non-issue since the pilot will be fiddling with it soon enough. For example if my mechanic sets my elevator trim in the Spit and i climb in the cockpit, i'll see the trim indicator needle showing an off-center position and i'll have the same amount of remaining trim towards either direction as if i had done it myself, it's not like i somehow have a "surplus" of trim tab tab travel because the mechanic did it.

In any case, the main problem with what you describe is that real life combat speeds are not IL2 combat speeds. First of all, what is combat speed? I guess we could define it as the airspeed reached with maximum continuous power and in level flight.

Well, if trims were set to real life combat speeds, people would still complain and the reason is simple: both us and the AI fly way faster than was possible in reality, due to the simplified engine management model.

For example, there would be no reason whatsoever to trim a Spitfire's ailerons for +16lbs or something like that which could be held for less than a minute, they would probably trim it for something like +8/+9 lbs of boost which was actually what the engine could do indefinitely without overheating or damage. In IL2 we all fly higher than those limits because the only penalty is a resettable overheat timer that must reach 5 minutes before any damage occurs, the AI doesn't have any penalty whatsoever, so we have to choose between unrealistic trim presets or more manual control inputs at the unrealistic high speeds we attain. Actually, it's not the speeds per se that are unrealistic, it's how long we can keep going that fast that is the problem