Spit/109 sea level speed comparisons in 1.08 beta patch

[Glider]

Originally Posted by JtD

Like with that Gripen, most accidents happen due to pilot error, not erroneous design calculations. It's rather an argument against the reliability of pilot accounts, than an argument against reliability of maths and physics - so I'm not quite sure why you posted the video.

What is more likely to go wrong, A prototype on its sixth flight or a test pilot of many years experience. The problem was traced to issues with the avionics and delayed responses to control input, not pilot error.
These had been calculated and tested in simlators but it was only when they flew that the problem was idnetified.
So the calculations and theory was flawed resulting in a serious accident the pilot was lucky to get away with. People who rely on theory are banking the farm on a theory and thats why I posted the video.

I notice that no one has come up with any examples of an F4, F105 or 262 taking on a slower aircraft in a turning fight. The F4 and F105 people say that they had the advantage in a turning fight at over 0.9. If this is the case then why didn't the US pilots use that advantage?
Its a simple question, in reality they didn't, they used their speed to go vertical or gain a tactical advantage.

This is the core of the difference. In Vietman I can find examples of US pilots going vertical or using speed to gain a tactical advantage. No one has (so far) show that US pilot wanted to go into a turning fight.
I believe from what I have read that the 262 pilots did exactly the same thing.

PS the main target for the 262 were the bombers, not fighters

As far as the game goes, do you want it to reflect what could happen, or did happen.

Going back to the subject. I do get a little frustrated when people pick and choose which part of the offical test reports they agree with.

Can I ask you if you agree with what the German test establishment said about the 109 and Spitfire? I do in its entirety good and bad from all points.

[TomcatViP]

Originally Posted by Glider

Its a simple question, in reality they didn't, they used their speed to go vertical or gain a tactical advantage.

This is the core of the difference. In Vietman I can find examples of US pilots going vertical or using speed to gain a tactical advantage. No one has (so far) show that US pilot wanted to go into a turning fight.
I believe from what I have read that the 262 pilots did exactly the same thing.

Tht's what I am saying here, Glider. Changing direction is not about drawing circles like a compass with your plane but to point your nose faster in the intended direction that your opponent.

Again, if your plane fly at the limit of his envelope you have no chance in term of manoeuvrability. A faster plane will fight at a higher speed were he is more efficient in term of E. This what hve ruined Il2 with a Spit that never depleted his E (and again in CoD) turning basic BFM useless (YoYo for example).

[pstyle]

Originally Posted by TomcatViP

This what hve ruined Il2 with a Spit that never depleted his E (and again in CoD) .

Are you suggesting that the CLoD spit does not loose energy in the turn?

[Al Schlageter]

Originally Posted by JtD

Yes, 109E prototype.

Then why is prototype data being used and not data from a production Bf109E?

[ACE-OF-ACES]

Originally Posted by Al Schlageter

Then why is prototype data being used and not data from a production Bf109E?

Based on past experience with Kurfürst.. My guess would be the prototype data has better results than the production data.. That is to say Kurfürst tends to go with the best of the best data for 109s and the worst of the worst data for anything allied.. Also known as cherry picking!

[NZtyphoon]

Originally Posted by Al Schlageter

Then why is prototype data being used and not data from a production Bf109E?

Awww, why so serious? Anyway, Check out http://www.wwiiaircraftperformance.o...09/me109e.html

[JtD]

Originally Posted by Glider

What is more likely to go wrong, A prototype on its sixth flight or a test pilot of many years experience. The problem was traced to issues with the avionics and delayed responses to control input, not pilot error.
These had been calculated and tested in simlators but it was only when they flew that the problem was idnetified.
So the calculations and theory was flawed resulting in a serious accident the pilot was lucky to get away with. People who rely on theory are banking the farm on a theory and thats why I posted the video.

OK, so they did employ maths and physics improperly. I'm fairly certain that they came up with proper calculations after the accident and managed to simulate the problem. Just like we can calculate turn performance nowadays, the calculation is sound and all you can do wrong is input data.

This what hve ruined Il2 with a Spit that never depleted his E

You're wrong, Spits always flew to the same physics that applied to all other planes. The reason it could sustain a 17s turn is because it's one of the aircraft's design features. Just like high speed was a design feature of the Fw 190, which had no problem whatsoever to outrun Spitfires. Take a ton off a 190, give 200 extra hp at altitude and add 20% drag, and you got yourself a Spitfire.

[MiG-3U]

Originally Posted by Kurfürst

Nope, this is just your opinion and has nothing to do with any test report's contents.

The facts:
1. Prototype aircraft V15a, tested well before production started
2. Tested speed 493kmh at altitude of 440m, gives 485kmh at 0m
3. The supercharger has two fixed speeds:
- boden- and hohenlader are claimed and the optimal change altitude is determined
- manifold pressure drops above the FTH of the bodenlader, until hohenlader is set on
- the speed test confirms that the supercharger has two fixed speeds
- according to Flugmotoren und Strahltriebwerke by Kyrill von Gersdorff, Kurt Grasmann, Helmut Schubert the first order of the DB601 was the pre-series of 150 motors, A-0 ie Baureihe A (carburator engine with fixed speed supercharger), so based on engine number of 140, the V15a had one of these instead a A-1. The hydralic clutch came later with the Baureihe B along with fuel injection.

Originally Posted by Kurfürst

Unfortunately it is test data and it is relevant. Unless you want to dream up specifications.

It's not a test, just a piece of paper, no test data nor kenblats of production planes support 500km/h at sealevel. Everything else is around 460-470km/h including swiss planes with the 601Aa.

Originally Posted by Kurfürst

Oh but an 500+ kph Spitfire I as fast as the 109F *IS* logical, riiiiight?

Calculating the speed of the the Spitfire I at +12lbs the same way as done in the V15A report:

Density at sealevel: 1.225 kg/cubic meter
Power at sealevel at +6.25lbs: 880hp
Power at sealevel at +12lbs: 1180hp
Speed at sealevel at +6.25lbs: 280mph

r = ((1180/880)*(1.225/1.225))^(1/3) = 1.103

V0 = 280mph * 1.103 = 309mph = 497kmh

However, that is a crude, unaccurate and partially wrong way to calculate it.

Originally Posted by Kurfürst

Thank you for admitting that your remark about supposed two speed superchargers was just speculation.

The only speculative but logically correct part in my post is the size of the oil cooler, and it was there only because you asked it. The rest are facts.

Originally Posted by JtD

Regarding level speed performance of the 109, a question raised by I think MiG-3U puzzled me, maybe you have a good explanation, I'm at a loss for now: How come the 109E is faster than the 109F at less power, if you accept the 498 km/h for the 109E at 990ish hp from the V15 test and the 495 km/h for the 109F at 1065ish hp from the 109F Kennblatt?

Thanks for correcting the power of the 601N.

We do have several datapoints for production 109E giving 460-470kmh at 1.3ata and 990hp.
Calculating again the speeds of the 109E same crude way using 470kmh as base line:
601Aa 1045hp = 479kmh
601N 1060hp = 481kmh

Then we have the 109F doing 495kmh ie about 15kmh faster than the 109E at same power, that difference is roughly same as found at FTH. These values match very well while 500kmh is clearly an outlier and not supported by any test or kenbalt of the production planes.

[Osprey]

Would you mind, TomcatVIP, not slandering me by implying that I am some sort of Spitfire fanboy. I don't appreciate it because it's just not true. You constantly insult people with your replies, it's all in the tone you apply, and then you often go on to make ludicrous statements afterward (such as the one about no energy loss for the Spitfire in COD).

If you reply to me again in this manner then I'll report it. The mods here are hot on infractions.

[Robo.]

Originally Posted by MiG-3U

It's not a test, just a piece of paper, no test data nor kenblats of production planes support 500km/h at sealevel. Everything else is around 460-470km/h including swiss planes with the 601Aa.

I am completely with you here (although I am a huge Bf 109 fan), the Mtt 500kph +-5% guarantee debate has been here before and I was saying pretty much what you're saying now.