Spit/109 sea level speed comparisons in 1.08 beta patch

[Kurfürst]

Originally Posted by Holtzauge

There are a number of issues with the outlyer 109E 500 km/h sea level top speed:

First of all the Baubeschribung 500/570 Km/h speed curve does not map any known engine power/alt curve: These either have the characteristic bulge associated with the hydralic clutch or the notch type with two speed superchargers where as the curve showing 500 Km/h at SL and 570 Km/h at altitude in the Baubeschribung has a straight line between these points.

The Baubeschribung curves are obviously simplified, drawing a straight line between low level and FTH performance. Again, nothing uncommon in that, Rechlin did the same thing for a tested G-1 chart:

So which DB601 in a series Me109E had this power/altitude characteristic? None that I have seen published.

All, in fact:

In addition, it looks like estimate for the "guaranteed" engine data coming close to 500 Km/h for the V15 prototype is for 1,35 not 1,3 ata.

Unsurprising, since both the V15a flight tests results and guaranteed specs in the Baubeschreibung are for 1.35ata.

The sillyness lies in that some people want to compare these 1.35 ata results to 1.3ata, uncorrected figures, and the fact that uncorrected results achieved with the less powerful DB 601A-1 at 1.3ata / 990 PS are irrelevant when modelling our 1.35 ata / 1045 PS Bf 109E equipped with the DB 601Aa.

The rest of your post is irrelevant.

BTW it's worth comparing the V15a (WNr. 1774) results with the speed results with a Swiss export Bf 109E-3a. The reports show remarkable similarity in the top speed achived at altitude with the original VDM propellor of J-347 (572 vs. 564 km/h at rated altitude), especially when taking into account that J-347 already saw considerably use. However the low level speeds diverge greatly (498 vs 464 km/h at 0m altitutude). Note that the low-level performance of V15a with the Höhenlader (high altitude supercharger speed, or 'F.S gear' in British terms) shows good agreement with J-347 at both high- and low altitudes.

This would suggest that J-347`s level speed results were achived with the Höhenlader in operation and agree well with the results of Bf 109E-1 / V15a WNr. 1774.

Also note that the Baubeschreibung agrees well with the V15a results, but the curves are bit more simplified (mean avarage results).

[TomcatViP]

Originally Posted by Kurfürst

BTW it's worth comparing the V15a (WNr. 1774) results with the speed results with a Swiss export Bf 109E-3a. The reports show remarkable similarity in the top speed achived at altitude with the original VDM propellor of J-347 (572 vs. 564 km/h at rated altitude), especially when taking into account that J-347 already saw considerably use. However the low level speeds diverge greatly (498 vs 464 km/h at 0m altitutude). Note that the low-level performance of V15a with the Höhenlader (high altitude supercharger speed, or 'F.S gear' in British terms) shows good agreement with J-347 at both high- and low altitudes.

There was some diff btw the 109 exported in Switzerland and the original E. Notably in aerodynamics.
I don't think you can make a comparison without taking this fact into account.

[Kurfürst]

Originally Posted by TomcatViP

There was some diff btw the 109 exported in Switzerland and the original E. Notably in aerodynamics.
I don't think you can make a comparison without taking this fact into account.

What kind of difference do you have in mind?

[TomcatViP]

Originally Posted by Kurfürst

What kind of difference do you have in mind?

I hve in mind the guns (barrel for sure). I think the rad were different. But I need to check this. There is also a good article on the net (in French probably) if you browse around "bf109" and switzerland ("Suisse"). Will try to have a look.

EDIT:
Guns for sure and prop

[Kurfürst]

Originally Posted by TomcatViP

I hve in mind the gun barrel for sure. I think the rad were different. But I need to check this. There is also a good article on the net (in French probably) if you browse around "bf109" and switzerland ("Suisse"). Will try to have a look.

Yes I will check that, I had a good (IIRC German language) book about Swiss 109s, which helped me to ID J-347's WNr. and service record.

As for the gun barrels, I am not sure - one of the tests being waved about is explicitely about measuring the speed diff. between guns present/not present, and it's about 1 km/h.. I'd imagine different gun barrels amount to even less.

Rads look interesting though, this might account for something, but again, looking the Swiss test results, the difference is only about 8 kph at VDH, which from my experience, is an extremely good match for a serial production plane compared to the guaranteed specs!

Originally Posted by Holtzauge

Seeing you seem to be such an expert perhaps you would be so kind to point out what is wrong in my Me109E speed/alt chart and how it really should look like?

Well for one it probably has wrong data.. guessworked drag, guessworked wing effiencies, guessworked propeller effiency, manipulated until it fits one's agenda.

As Tagert said, garbage in... garbage out.

BTW, care to tell why you disappeared from allaboutwarafe forums? I am sure it's hell of a story.

[Holtzauge]

Originally Posted by Kurfürst

Well for one it probably has wrong data.. guessworked drag, guessworked wing effiencies, guessworked propeller effiency, manipulated until it fits one's agenda.

As Tagert said, garbage in... garbage out.

BTW, care to tell why you disappeared from allaboutwarafe forums? I am sure it's hell of a story.

I think people are aware by your modus operandi by now: If you don't like the message then discredit the messenger.

Me "disappering" is for no more sinister reason than for working on a book project. Believe me it's much more satisfying than arguing about your doctored data or sparring with your mathematically challenged pal Crumpp!

So if my Me109E data is so totally wrong then I guess this means that HoHun's charts are off the wall as well because we get the same results, i.e. around 475 Km/h on the deck. Garbage in and garbage out in both cases huh?

BTW: Concerning disappering, in your case we know the answer don't we? Permanently banned from a number of forums and as editor in Wikipedia. That sure is one hell of a story!

[Kurfürst]

Originally Posted by Holtzauge

I think people are aware by your modus operandi by now: If you don't like the message then discredit the messenger.

Nobody needs to discredit you.

Me "disappering" is for no more sinister reason than for working on a book project. Believe me it's much more satisfying than arguing about your doctored data or sparring with your mathematically challenged pal Crumpp!

.. but you seem to need to discredit others.

So if my Me109E data is so totally wrong

It is. It doesn't match tested results, does it?