109 article (from www.virtualpilots.fi)

[BlauK]

Originally posted by gripen

That's exactly what I have been promoting throughout this thread; the authors should check the (unaltered) primary sources instead believing "unconfirmed internet sources" like me, Mr. Kurfürst or Mr. BlauK.

And I was not talking about publishing anything, simply talking about a constructive internet discussion, which naturally is only that... a discussion. If someone wants to use some of such info for some publication, of course they need to get the original sources. I was only refering to your decision of not talking about data in detail, which makes the discussion kind of difficult and just about pointless.

...and it is not "roughly 645 km/h" nor "640-690 km/h" nor "363kmh".

My bad.. if you did not get it, I made a typo. The speed marked in the chart on page 18 is naturally 636kmh, not 363.

I just realized that maybe you dont have Kokko's "summary" of the Malmi test, the "Tunnonmukainen ohjattavaisuusominaisuuksien arvostelu MT-koneesta." dated 9.4.43 at Tampere. I possibly failed in considering it as a part of this particular test. There on page 4 Kokko spells the top speed (todellinen nopeus) figures as 640-690kmh.


Thanks for making this personal.

Ok.. I apollogize for that remark. The way you treat knowledge in your possession simply reminds me from another person on some ww2 avation boards.

[Porta]

Originally posted by gripen
The article serie is published in the "Suomen Ilmailuhistoriallinen Lehti" (something like The Aviation history magazine of Finland) and it's written in finnish. To get it you can contact the magazine:

Suomen Ilmailuhistoriallinen Lehti
Mäkelänkatu 5 B 10
00550 Helsinki
FINLAND

I can only sum up the references I'm aware, I have merely collected data for Raunio, I don't know about other data. Anyway here is a rough summary of those I'm aware:

MT-215 test data
MTT test on G-6/Trop (several configurations)
MTT test on AS proto (contains also G-5 curve)
Erla set (13 samples)
Flugleistungen Me 109G-Baureihen (20 samples)
British tests on G-2 and G-6
Various curves from MTT
His own calculations based on Hörner, DB data and MTT data (and more)

Thank you gripen, unfortunately I don't understand a bit of Suomi.

So what does he compare (calculated stuff vs. fligh tests, flight tests of different sources,...). What are his conclusions?.

Thanks for your time, gripen.

Porta

[gripen]

Originally posted by BlauK

And I was not talking about publishing anything, simply talking about a constructive internet discussion, which naturally is only that... a discussion. If someone wants to use some of such info for some publication, of course they need to get the original sources.

I was only refering to your decision of not talking about data in detail, which makes the discussion kind of difficult and just about pointless.

Why don't you read the topic of this thread; this thread is about an article and I'm not selling them (Mr. Grendel & Co) my opinions or manipulated data (according to Mr. Kurfürst). I'm merely logical with my argument.

Originally posted by BlauK
I just realized that maybe you dont have Kokko's "summary" of the Malmi test, the "Tunnonmukainen ohjattavaisuusominaisuuksien arvostelu MT-koneesta." dated 9.4.43 at Tampere. I possibly failed in considering it as a part of this particular test. There on page 4 Kokko spells the top speed (todellinen nopeus) figures as 640-690kmh.

Maybe you should realize that report says actually:

"Suurimman nopeutensa kone saavuttaa n. 6700 m:n korkeudessa ja mittarinäyttämä tällöin 450-475km/t..."

Now just look the speed test page and read IAS value at highest speed. Generally the speed estimates are very rough if the conditions are not known, specially at winter time as in this case.

gripen

[gripen]

Originally posted by Porta

So what does he compare (calculated stuff vs. fligh tests, flight tests of different sources,...). What are his conclusions?.

He actually made his calculations on the G-6 before he got the MTT G-6 test result and the agreement between the calculations and the test data seem to be suprisingly good, the difference is just few km/h. Notable thing is that propeller efficiency charts from the MTT give lower efficiency values than efficiency charts calculated by Raunio from flight data.

He notes that there never is complete agreement between the various test data, differences between planes and conditions cause lot of variation, sometimes the data might be corrected differently etc. Factory claims seem to be in optimistic side (couple examples are claimed).

Overall nothing revolutionary but a well made article serie. In the coming parts there will be tested data on roll rates and other interesting stuff.

gripen

[Kurfürst]

Originally posted by gripen

I can only sum up the references I'm aware, I have merely collected data for Raunio, I don't know about other data. Anyway here is a rough summary of those I'm aware:

MT-215 test data
MTT test on G-6/Trop (several configurations)
MTT test on AS proto (contains also G-5 curve)
Erla set (13 samples)
Flugleistungen Me 109G-Baureihen (20 samples)
British tests on G-2 and G-6
Various curves from MTT
His own calculations based on Hörner, DB data and MTT data (and more)

gripen

Hmmm.... quite an interesting dataset, I can`t comment on the multi-plane test for I haven`t seen those. As for the others, it appears to be picked from the most poor performing examples, a similiar attitude what M Williams is using for his agenda.

Ie. the MT-215 was a well used plane with the tailwheel fixed down. Then, G-6/trop, a funny choosing, considering it`s the most draggy 109 one can find, not only fixed tailwheel, MG bulges are present, but it was topped with the tropical filter for additional -10 kph loss. Using the British tests is also funny, ie. the G-2 was a /trop version again, and from the details of the report, the plane was captured damaged and malfunctioning, the propeller being holed by schrapnel and the radiotors sticking in open position. Other British tests, G-6 with gondolas, nice pick again.

As for Horner`s article, I`ve read it, it`s about completely useless for the 109, for which he couldn`t get the  weight,  speed, or power data correct, using 100% (!!!!!!!) powerplant/thrust effiency in all cases overestimating the power requirements thus arriving at a surreal drag coefficient of .036, LOL.  Mtt docs I have state, err .023.. Horner also assumes some things that are strictly fiction, ie. drag from 'rivet heads', whereas the Bf 109 had used flush rivets, that`s quite commonly known.

Using such dataset to start with, I`d be not surprised if Raunio`s claimed performance are WAY below for what was actually achieved on test examples he simply doesn`t know of or ignores... err, reminds me of a notorious spit-fan site..

But I`d rather not put Raunio in such bad company without seeing his article first. It might as well be an honest research, and perhaps some are just qouting the parts they like from it. This happens far too often, so it`s nothing new or a reason to be blamed on the Finnish gent.

[Porta]

Originally posted by gripen
He actually made his calculations on the G-6 before he got the MTT G-6 test result and the agreement between the calculations and the test data seem to be suprisingly good, the difference is just few km/h. Notable thing is that propeller efficiency charts from the MTT give lower efficiency values than efficiency charts calculated by Raunio from flight data.

He notes that there never is complete agreement between the various test data, differences between planes and conditions cause lot of variation, sometimes the data might be corrected differently etc. Factory claims seem to be in optimistic side (couple examples are claimed).

Overall nothing revolutionary but a well made article serie. In the coming parts there will be tested data on roll rates and other interesting stuff.

gripen

Thank you again, gripen.

Usually Mtt calculated prop efficiency charts from physical data of propellers supplied by VDM, instead doing flight tests.

In general, I find Mtt claims on production planes to be OK (you have to take in account the tolerances too, e.g. ± 3% in horizontal speed).

Does the article contain any calculations or graphs?. If yes, it might be interesting to get even if I don't speak finnish.

Porta

[MiloMorai]

Originally posted by Kurfürst
Hmmm.... quite an interesting dataset, I can`t comment on the multi-plane test for I haven`t seen those. As for the others, it appears to be picked from the most poor performing examples, a similiar attitude what M Williams is using for his agenda.

Ie. the MT-215 was a well used plane with the tailwheel fixed down. Then, G-6/trop, a funny choosing, considering it`s the most draggy 109 one can find, not only fixed tailwheel, MG bulges are present, but it was topped with the tropical filter for additional -10 kph loss. Using the British tests is also funny, ie. the G-2 was a /trop version again, and from the details of the report, the plane was captured damaged and malfunctioning, the propeller being holed by schrapnel and the radiotors sticking in open position. Other British tests, G-6 with gondolas, nice pick again.

LOL Kurfie. It would have been nice if the Germans had suppled factory fresh a/c straight from the assembly line for the British to test.

[Charge]

"Niklas has some maximum Cl values for the 109E on his site, unfurtunately I havent seen any specific for w./wo slats for the 109. Some general slats/flaps data yes, but these would be inconclusive, since the properties of each airplane can lead to very different results. So we are left with the common sense of LES increasing max. AoA and Cl above the avarage, unless someone comes up with something specific.."

TY for your answer Kurfürst.

I'm a bit disturbed by general lack of interest from people when it comes to aerodynamical performance of 109. The 190 got a thorough treatment in thread where Crumpp and Gripen measured their manhood against eachother (No offence guys..t'was interesting read :-))) and I am wondering why such a debated airframe as 109 has not received the same interest.

What I understand from different sources is that 109's max AoA is somewhere around 16 degrees for its wing profile at certain speed (if it is even near the same as that of 190). However Crumpp(?) posted a NACA flap/slat comparison chart where HP slat is presented as having a rather small Cl capability itself but it enables a theoretical max of 28 degrees of AoA. What that does to wing performance in terms of maximum attainable lift I don't know. In comparison Fowler flap has a greated Cl potential but its limits the AoA lower than would be otherwise possible for certain wing profiles (thinking about the P38 here). I find this rather interesting and it would be nice to see this matter debated, too.



-C+

[gripen]

Originally posted by Kurfürst
the MT-215 was a well used plane with the tailwheel fixed down.

The MT-215 was a factory overhauled airframe (like most FAF G-2s) ie condition was like a new.

The tail wheel was fixed down sooner or later in all FAF G-2s once these got bigger tail wheel (like in pretty much all G-1s and G-2s in LW service too). BTW most FAF G-2s had bigger tail wheel allready when delivered.

Shortly the MT-215 was a very typical FAF Bf 109G-2.

Originally posted by Kurfürst

Then, G-6/trop, a funny choosing, considering it`s the most draggy 109 one can find, not only fixed tailwheel, MG bulges are present, but it was topped with the tropical filter for additional -10 kph loss.

The MTT tested this plane in 7 different configurations and of these 4 were without tropical filter and I have been talking about values without filter. Besides filter was very commonly used by FAF due to sandy airfields.

The G-6 was by far most important Bf 109 variant produced; there were more G-6s (and practically same G-14s) produced than entire production of F and K models together. And it was also main variant in FAF service.

The G-6 is a very rational choosing infact.

Originally posted by Kurfürst
Using the British tests is also funny, ie. the G-2 was a /trop version again, and from the details of the report, the plane was captured damaged and malfunctioning, the propeller being holed by schrapnel and the radiotors sticking in open position. Other British tests, G-6 with gondolas, nice pick again.

Raunio notes condition of the tested G-2/trop and also notes the estimated speed for the plane in normal condition (which is actually well within MTT 3% tolerances).

The G-6 tested by the brits seem to be actually faster than G-6 tested by MTT in the same condition.

Originally posted by Kurfürst
As for Horner`s article, I`ve read it, it`s about completely useless for the 109, for which he couldn`t get the  weight,  speed, or power data correct, using 100% (!!!!!!!) powerplant/thrust effiency in all cases overestimating the power requirements thus arriving at a surreal drag coefficient of .036, LOL.  Mtt docs I have state, err .023.. Horner also assumes some things that are strictly fiction, ie. drag from 'rivet heads', whereas the Bf 109 had used flush rivets, that`s quite commonly known.

Apparently Mr. Kurfürst has not even seen the Hörner's study or understood it.

It's somewhat simplified and more like theoretical example but all values are realistic. As an example propeller efficiency is estimated to be 85% unlike Mr. Kurfürst announces above. Besides used values result suprisingly good agreement with flight tested data. Hörner did work in MTT and he actually studied the drag of the Bf 109. After war he (really) wrote the book on fluid dynamics.

Originally posted by Porta
Usually Mtt calculated prop efficiency charts from physical data of propellers supplied by VDM, instead doing flight tests.

I don't know how Mtt created their prop charts but the efficiency at FTH seem to be too low for flight tested values (according to my own calculations, not Raunio's), at low altitude there is not much difference.

Originally posted by Porta
In general, I find Mtt claims on production planes to be OK (you have to take in account the tolerances too, e.g. ± 3% in horizontal speed).

Generally yes, as an example in the Erla set (12 Erla built planes 1 Mtt built), 8 planes (all Erla built) are within claimed ± 3% tolerances (3 above and 5 below base line). The rest 5 (4 Erla 1 Mtt) are below claimed tolerences.

Originally posted by Porta
Does the article contain any calculations or graphs?. If yes, it might be interesting to get even if I don't speak finnish.

Yes, the serie contains plenty of graphs. SILH 2/2005 contained part 5 of the serie and there should be at least 2 parts more in the future.

gripen

[Kurfürst]

Originally posted by gripen
The MT-215 was a factory overhauled airframe (like most FAF G-2s) ie condition was like a new.

[/B]

Don`t be shy to post the Werknummer, it would be nice to realize the plane was manufactured 3/4 years ago.

Originally posted by gripen The tail wheel was fixed down sooner or later in all FAF G-2s once these got bigger tail wheel (like in pretty much all G-1s and G-2s in LW service too). BTW most FAF G-2s had bigger tail wheel allready when delivered. Shortly the MT-215 was a very typical FAF Bf 109G-2.

[/B]

I can show you dozens of LW 109G-2s with retractable tailwheel, and it boggles my mind how can a more draggy, worn airframe representative of the new ones with retractable tailwheel.

It`s a nice way for Gripen to chop down another 15 kph airspeed from the 109G`s true max. speed and show it as garbage.

Originally posted by gripen
The MTT tested this plane in 7 different configurations and of these 4 were without tropical filter and I have been talking about values without filter. Besides filter was very commonly used by FAF due to sandy airfields.

The G-6 was by far most important Bf 109 variant produced; there were more G-6s (and practically same G-14s) produced than entire production of F and K models together. And it was also main variant in FAF service.

The G-6 is a very rational choosing infact.

[/B]

It is 'very rational' if one wants to arrive at the lowest possible values. As mentioned the G-6/trop is by far the slowest variant of all Bf 109Gs, despite the G-6/trop was produced in small quantities along G-6s, given that by the time the G-6 prod started, Africa was lost, no need for it.  

Originally posted by gripen
Raunio notes condition of the tested G-2/trop and also notes the estimated speed for the plane in normal condition (which is actually well within MTT 3% tolerances).

[/B]

The Brits estimate for the damaged plane if in normal condition 395 mph at 1475 HP.

Fact is the Germans and Soviets measured 403 to 416 mph at 1310 HP.

Can I ask why Raunio ignores good tests results from Germany and the USSR, and relies on estimates on caputred, damaged plane?

It`s certainly a good way to arrive at the lowest possible values and to understate the aircraft`s performance.

Originally posted by gripen
The G-6 tested by the brits seem to be actually faster than G-6 tested by MTT in the same condition.

[/B]

Blanket statment, no facts, irrelevant.

Originally posted by gripen
Apparently Mr. Kurfürst has not even seen the Hörner's study or understood it.

Appearantly Mr. Gripen worked up himself that I pointed out that Mr. Kurfürst saw Hörner's study and knows well it is full of very serious like a completely wrong dataset to start with.

I guess that makes selective use of sources for Mr. Gripen far more difficult than usually.

Originally posted by gripen
It's somewhat simplified and more like theoretical example but all values are realistic.

[/B]

BS.

Hörner claims 3040 kg takeoff weight, which is a takeoff weight of a G-2 or G-4, though the Fig2 shows the G-6 with gun blisters. Without exception, the official t-o weight of the G-6 varied between 3150 and 3196 kg.

Thus H understimates the weight of the plane greatly, and a result underestimates the effiency.

Hörner claims a mere 610 kph top speed for the plane at 1200 HP/22k ft. This translates to 1.3ata.

The GLC charts show the official speed at this speed as 630 kph. Mtt documents show 621 kph with gunpods attached. Even Erich Brown noted 619 kph for the G-6 with gunpods, at 3400 kg vs. 3040kg in Horner`s tests. G-2 tested by Russians achieved 666 kph, another G-2 in Rechlin achieved 650 kph. A DB document gives for a 3070 kg 109G 620 kph speed, by far the lowest value seen.

Yet, Horner manage to claim an even lower figure, 610 kph.
But no matter than Horner got speed, weight and power wrong, Gripen still got the guts to call them 'realistic' in public.


Besides, I`d love  to see any test of any 109G that would run at a mere 610 kph. Not that it couldn`t exist, especially bad planes show up on occasion, but then it`s a cherry picked worst case.


As an example propeller efficiency is estimated to be 85% unlike Mr. Kurfürst announces above.

Mr. Gripen makes a twist as usual, since Mr. Kurfürst was talking of powerplant effiency, for which Horner arrives at a very high figure of 100% effiency. Mr Horner arrived at this using very high prop effiency of 85%, and adding an assumed thrust value of 11 to 13%, arriving at a ridiculus '98% of the power output is converted to thrust' statement.



 Besides used values result suprisingly good agreement with flight tested data.

Blanket statmenent again, but we got used to that from you.

Show me a SINGLE flight test of a 109G achieving only 610 kph with 1200HP in clean condition.

I am all ears.


   Hörner did work in MTT and he actually studied the drag of the Bf 109. After war he (really) wrote the book on fluid dynamics.  


Nice and all, fact still remains that Horners starting data is bad in almost every way, and based on that he arrives at a ridiculus drag coefficient of .036 whereas Mtt official documents clearly state 0.023.

Considering Horner wrote that article in 1965, 20 years after he worked at Mtt....

Well sadly I am right again, it`s another nice show of the selective source choosing agenda from Gripen.

[Crumpp]

What are the primary sources concerning 109s?

Simply ask any professional Historian what is more credible.  A document or an eyewitness.


All the best,

Crumpp

[gripen]

Originally posted by Kurfürst

Don`t be shy to post the Werknummer, it would be nice to realize the plane was manufactured 3/4 years ago.

Everyone understands that factory overhauled plane is an used one, everyone also understands that factory overhauled is like a new condition. There is nothing to argue.

If you are interested about werkenummers and other info on FAF G-2s, get Valtonen's book or SIHL (several articles on these planes).

Originally posted by Kurfürst
I can show you dozens of LW 109G-2s with retractable tailwheel, and it boggles my mind how can a more draggy, worn airframe representative of the new ones with retractable tailwheel.

I can show you FAF G-2s with retractable tailwheel, but these were minority and got sooner or later bigger tailwheel. Situation was exactly same in the LW.

The MT-215 was not a worn airframe, it was in good condition. Overall it was a typical FAF G-2 (about 2/3 of FAF G-2s were factory overhauled when delivered).

Originally posted by Kurfürst

It is 'very rational' if one wants to arrive at the lowest possible values. As mentioned the G-6/trop is by far the slowest variant of all Bf 109Gs, despite the G-6/trop was produced in small quantities along G-6s, given that by the time the G-6 prod started, Africa was lost, no need for it.  

As noted above, I'm refering values tested without filter.

Originally posted by Kurfürst
The Brits estimate for the damaged plane if in normal condition 395 mph at 1475 HP.

I quess you mean at 1,42ata/2800rpm setting? Yep, that's within 3% tolerance using values from SIHL article. BTW the report does not actually say for which setting the estimate is calculated.  

Originally posted by Kurfürst
Fact is the Germans and Soviets measured 403 to 416 mph at 1310 HP.

Fact is that for example in the Erla set the lowest value for a factory new Bf 109G (seem to be a G-1) is 612 km/h using 1,3ata/2600rpm setting.

Originally posted by Kurfürst
Can I ask why Raunio ignores good tests results from Germany and the USSR, and relies on estimates on caputred, damaged plane?

AFAIK you can post your questions to SIHL, they use to publish readers questions and also answer them. Just post your question to:

Suomen Ilmailuhistoriallinen Lehti
Mäkelänkatu 5 B 10
00550 Helsinki
FINLAND

Based on the article and data I'm aware, Raunio has used huge amount of good test data from Germany for the article and has never ignored well documented test data regardless the source. The data on captured planes is mentioned in the end of the performance part and nothing on the article seem to rely on this data.

Certainly you can send them data if you have good and well documented test results from Germany or Russia. Note that I have nothing directly to do with the magazine, I'm just a reader who has given them some data.

Originally posted by Kurfürst

Blanket statment, no facts, irrelevant.

I can read the values from the article and compare them and the G-6 tested by the Brits seem to be faster than the one tested by Mtt (without filter etc.).

Originally posted by Kurfürst
Hörner claims 3040 kg takeoff weight,

No, Hörner claims that weight as gross weight and that seem to be realistic for a G-6 flying at FTH.

Originally posted by Kurfürst
Hörner claims a mere 610 kph top speed for the plane at 1200 HP/22k ft. This translates to 1.3ata.

That's well within normal tolerances for the G-6 (as an example see the Erla set).

Originally posted by Kurfürst
Mr. Gripen makes a twist as usual, since Mr. Kurfürst was talking of powerplant effiency, for which Horner arrives at a very high figure of 100% effiency. Mr Horner arrived at this using very high prop effiency of 85%, and adding an assumed thrust value of 11 to 13%, arriving at a ridiculus '98% of the power output is converted to thrust' statement.

Mr. Kurfürst makes himself laughable. Given power (1200hp) is available from the shaft and the exhaust thrust is additional.

Originally posted by Kurfürst
Blanket statmenent again, but we got used to that from you.

Again I can read the values from article and compare them to flight tested and the agreement is good.

Originally posted by Kurfürst
Show me a SINGLE flight test of a 109G achieving only 610 kph with 1200HP in clean condition.

Well, there is a example above and if you want more just go to FAF museum archives and ask for check flight cards from the VL and you can find even much lower values (plenty of them).

Originally posted by Kurfürst
Well sadly I am right again, it`s another nice show of the selective source choosing agenda from Gripen.

Feel free to waste energy to personal attacks. No one cares.

gripen

[gripen]

Originally posted by Kurfürst

Considering Horner wrote that article in 1965, 20 years after he worked at Mtt....

Actually the first version of his book was written 1945-1946. In addition some of his wartime works are still available from the archives if someone is willing to dig a bit.

gripen

[gripen]

I did study history of the MT-215 a bit and it was actually a brand new plane WNr. 14783 built by WNF. For the ferry flight to Finland it got naturally LW paintings and Stkz. GJ+QA.

gripen

[Crumpp]

I've seen Wright Field Microfilm stamps in documents coming from many archives. BAMA might be the most probable and also most difficult to search.

That is because the entire technical documents collection of the NASM came from Wright Patterson.  It was moved to the NASM in the 1970's IIRC.


Wright Patterson no longer keeps a collection of technical documents.  They do have some copies of certain documents donated since the move.

Getting to the subject of foreign testing.  It defies common sense to think that a foreign government in time of war would be the "experts" in any equipment other than there own.  Simply look at the BMW801D2 the RAE tested out of Faber's FW190A3.  The RAE conducted trials running a motor that could not develop full power due to the anti-knock characteristics of natural petroleum fuels.  

After the trials they bench tested the motor and discovered that by using different plugs and timing they could run the motor smoothly.  Unfortunately they never flight tested that motor.  If they had then numbers would have probably been much closer to the German flight test numbers.



That very same month the RAE got their hands on Faber's aircraft, the Germans changed the composition of C3 fuel further compounding the RAE's difficulties.  The fuel changes usually accompany both timing and spark plug changes in general.  Additionally different varients of the FW190 had different motor set ups requiring different adjustments, plugs, and fittings.  



Fuel improvements continued up until the end of the war.  It was not until June 1944 that the allies were even aware of the early 1940 to 1943 changes!  Even then they could not be sure as they just did not have enough samples to make a conclusive determination.



The variants also had multiple design changes.  6 Different cowlings were in service, Multiple internal and external intakes, 5 different props in service, 2 different Lufterrads, 3 different exhaust set ups.  

Frankly the design changes are just too numerous to list in a thread.

Many of these changes had an effect on performance.  In fact it is much easier to find "flight tested data" that performs nothing like Focke Wulf or Rechlin test's of a frontline air superiority fighter version than to find flight test's of in service aircraft set ups.  For every set up that makes it into service, there are a multitude which do not.

For example, in this report different propellers set ups are tested.  Only one hub made it into service and NONE of the blades:



You can see by the wide range of performance exhibited, it is very easy to present "tested" data that presents a completely false picture of actual performance.

Add in the normal maintenance quirks of the design and it becomes laughable to think any test of an aircraft presents "the best" performance a design can achieve other than one conducted by the manufacturer or the end user.  At best, such tests only reveal the "at least" performance.  During the war, the allies could say this enemy design was capable of "at least" doing this well.

Pushing these tests only revels agendas.

All the best,

Crumpp