109 e4 performance

[Robo.]

Originally Posted by robtek

I still would say that the average, fresh from the factory, Bf109E should be able to reach 500km/h!

I agree, the problems is how to model this in the sim. Crumpp replied earlier, and I have no objections at all, because that sounds very reasonable, the max speed stated was reached on an Aa engine, 2500RPM 1.45ata, rads 1/4 open (or closed). That plus some variation modelled, e.g. some Emils would do slightly more and some slightly less - that would be great.

[Robo.]

Originally Posted by Kurfürst

Now the bottomline: As shown in the Baubescreibung Me 109E document, the specs for the 109E were 500 km/h at SL and 570 km/h at altitude with 1.35 ata or full power and the DB 601Aa engine, within +/- 5 % of that for each individual plane. We have exactly that aircraft modelled in the sim, so E-1, E-3 and E-4 should satisfy these specs. If they are modelled different, its wrong, end of story.

They actually satisfy these specs on the very bottom end. They should certainly be slightly faster on the deck. My point is let's get some figures that might be acceptable for the sim for both Emil engines on all ratings, ideally for all rated powers mentioned in the chart.

Interesting info about the Erla Gs, seen that one before on your website. Does not say anything about top speed being tested on the deck and I can't read the doc good enough to see the actual ata settings etc.

[Robo.]

Originally Posted by bugmenot

There's typo in the Baubeschreibung: M o t o r l e i s t u n g

I pointed out that typo already and it has been already corrected in the chart I am putting together, bugmenot.

[TomcatViP]

I don't know who put the variable s/c case frwd but the chart above posted by Bugmenot show precisely that there was none

One 1946's like hypothesis that can be thrown away

[Robo.]

Originally Posted by Kurfürst

Now the bottomline: As shown in the Baubescreibung Me 109E document, the specs for the 109E were 500 km/h at SL and 570 km/h at altitude with 1.35 ata or full power and the DB 601Aa engine, within +/- 5 % of that for each individual plane.

That's for DB 601Aa indeed. The problem is obviously the huge tolerance of 50km/h - and also, I can't seem to find anything confirming the ata used to achieve that speed. Was it Bodenleistung or did they push it on 1.45ata? Do we know? Makes quite a difference.

Originally Posted by Kurfürst

We have exactly that aircraft modelled in the sim, so E-1, E-3 and E-4 should satisfy these specs.

It's not that easy I am afraid - the Aa and A-1 were slightly different. We don't know which engine is modelled in the sim for each subvariant. That's why I am trying to get some numbers together for both.

[CaptainDoggles]

Originally Posted by Robo.

Of course they did, but did they really strain a brand new engine to verify the max speed on the deck? If you have any further information about the tests conducted by RLM / BAL in order to accept an airframe they have paid for? That would be great to know, but using logic again, would their test pilots push the new a/c to its limits? I believe they would not and if the plane performed within limits, they were happy.

It's not "straining" the engine if that's what the engine has been designed to do. The engineers say "you can run at XYZ power settings for 5 minutes." Why would the RLM pay for aircraft they aren't sure can meet the contracted obligations? They must have verified that the aircraft can deliver. It's a simple fact, and continuing to cover your ears and sing LA LA LA LA in face of this fact makes me think you are just another forum troll.

No, I never said such thing. I never stated that Mtt failed to deliver what they were legaly bound to. I said they most probably did not perform extensive tests to prove our point. The fact is, no matter what test you look at, no aiframe ever managed to reach the speed in the Mtt chart. That brings you straight back to the beginning of this discussion.

Either they tested enough to ensure the required performance was being achieved or they did not; there is no middle ground. Either the aircraft met the requirements or it didn't. There is no middle ground. You can't say "I'm not saying they didn't deliver what they were required to deliver" in one breath and then say "they didn't do extensive testing" the very next. HOW DID THEY KNOW WHAT THEY WERE DELIVERING IF THEY DIDN'T VERIFY IT WITH TESTING?

And again you're trying to make it sound as if every single test ever conducted on the 109E shows it not meeting proper speeds. Guess what? We don't have the data from every test ever. Stop trying to re-frame the issue based on your agenda.

----

I'm done engaging with you on this subject. You next post is going to be another one saying that the contractual obligations were actually just imaginary, theoretical numbers and blah blah. I don't have the patience to repeat the same facts over and over and have somebody just ignore it and say "but I think it's this way" so I will leave you to it.

?
I dunno how you conclude from bugemots chart that there had been no variation in speed from one plane to another. Actually Kurfürst's chart clearly provides proof that there had been significant scattering in speed. Indeed this chart is highly interesting as one might be able to transpose the scattering in speed to that one for the Emils.

However it also prooves that the manufacturer's spec were likely spot on. So I now tend to think that there were 109E could indeed reach 500 kph or more. However it also shows that the real obtained mean value would probably be below the 500 kph because only three of the 13 managed to surpase the theoretical mean value of the spec.

[CaptainDoggles]

Originally Posted by 41Sqn_Stormcrow

?
I dunno how you conclude from bugemots chart that there had been no variation in speed from one plane to another. Actually Kurfürst's chart clearly provides proof that there had been significant scattering in speed. Indeed this chart is highly interesting as one might be able to transpose the scattering in speed to that one for the Emils.

However it also prooves that the manufacturer's spec were likely spot on. So I now tend to think that there were 109E could indeed reach 500 kph or more. However it also shows that the real obtained mean value would probably be below the 500 kph because only three of the 13 managed to surpase the theoretical mean value of the spec.

If you're familiar with statistics, you'll know that 13 aircraft of the 33000+ that were produced is not a representative sample.

The mean certainly could have been lower than 500, but it just as easily could have been higher. This is why I think it's silly to use anything other than this figure.

At least Microsoft was satisfied with testing only 13 aircraft. So why should we be less.

Oh, and I am very familiar with statistics. But I tend to adopt a pragmatic approach to problems. We do not have more than these 13 figures and we have to work with what we got. Anything else is just pure guessing around.

[Robo.]

Originally Posted by CaptainDoggles

It's not "straining" the engine if that's what the engine has been designed to do. The engineers say "you can run at XYZ power settings for 5 minutes." Why would the RLM pay for aircraft they aren't sure can meet the contracted obligations? They must have verified that the aircraft can deliver. It's a simple fact, and continuing to cover your ears and sing LA LA LA LA in face of this fact makes me think you are just another forum troll.

No, I am not another forum troll, just because I don't happen to have the same opinion like you. Please keep this unpersonal.

I am asking a simple question(s): Did they try to fly the airplane at full power at the deck as a part of the test? Did they verify the performance by attempting to achieve the top speed at any other altitude? They obviously did - and seeing the aircraft producing MFP / RPM expected, they simply assumed the curve as such was met within limits. We don't know, unfortunately, what ata they have been using. Other inspections (instruments, equipment etc.) were more important and if they were happy, they did not send the a/c back to get any issue fixed.

How do you think the Emils in CoD should be modelled?

Originally Posted by CaptainDoggles

And again you're trying to make it sound as if every single test ever conducted on the 109E shows it not meeting proper speeds.

No, I am not. Please read my posts again if you care. I am just asking what the 'proper' speed should be.

Originally Posted by CaptainDoggles

I'm done engaging with you on this subject. You next post is going to be another one saying that the contractual obligations were actually just imaginary, theoretical numbers and blah blah. I don't have the patience to repeat the same facts over and over and have somebody just ignore it and say "but I think it's this way" so I will leave you to it.

That's OK with me dude. I am not saying any of the above, I simply don't see it as black and white as you. No need to get emotionally involved , if you can't answer my questions by providing some facts, that's fine. I respect your opinion and I don't ignore it at all, but I keep mine until I get enough facts to adjust it. We are not about change anything anyway so please take it easy.