Allied tests of captured Bf-109's

Glider · Mar 24, 2008

Lesof
There is a lot of sense in this posting. If we stand back and look at the situation there were three main questions
a) Did the test pilot take the aircraft past the deployment of the slats. Yes
b) Was Gunther Rall afraid of his aircraft No
c) Could a British test pilot get the absolute best our of a foriegn aircraft No

Taking C a little further. Did it matter?
The idea behind these tests it to equip your pilots with the best information on how to handle a foriegn pilot who is in combat with you. If the Test pilot can get a similar level of performance out of an aircraft that an average opposing squadron pilot can obtain, then I suggest the job has been done.
Aces can always get the extra 5% out of an aircraft.

Re the 109, the average German Pilot couldn't turn inside the Spitfire, indeed a number of experienced pilots even expert pilots couldn't turn inside the Spitfire.
The fact that (possibly) in certain circumstances the 109 might have a theoretical advantage is almost irrelevant, as the average Allied pilot could and did turn inside the 109.

There are numerous quotes from pilots of all levels of experience that the Spitfire did this and precious few examples on the 109 doing this.

claidemore · Mar 24, 2008

I don't know if Lew Lewendon is still with us, but I'll bet if you asked him if he was as good a pilot as Rall or Graf or Krupinski, he would just shrug his shoulders and smile. Ask Corky Meyer the same question, probably get a similar reaction, as well as an explanation on the differences between a fighter pilot and a test pilot, apples and oranges.

BTW; the allied planes were not flown by expereinced ace pilots either, they were flown by the test pilots at AFDU. Two planes being flown by two test pilots, arguably with equal skill and experience. The planes themselves were specifically selected to match the performance of those in service. In fact the first Spit XIV was found to have better performance than operational planes, so another MkXIV was used.

For comparison purposes, the trials provide useful information. (despite dummies like me misquoting from the wrong tests!)

AFDU, Air Fighting Developement Unit, was developed specifically to test captured enemy equipment. It grew out of RAE Farnborough which had been testing and developing planes since Word War One. They tested and flew 109E/F/Gs, Bf110/410, Ju88, 4 different FW190s, He111, He177, and others. They were also the guys responsible for sticking a Merlin in the P51. Not exactly a bunch of noobs.

https://www.airforcehistory.hq.af.mil/PopTopics/airtechintel.htmamateurs.

AFDU was responsible for developing tactics to counter these various e/a, they were very successful in that role, with the allied airforces attaining complete air superiority over Europe.

Kurfürst · Mar 24, 2008

Glider said:
Re the 109, the average German Pilot couldn't turn inside the Spitfire, indeed a number of experienced pilots even expert pilots couldn't turn inside the Spitfire.
The fact that (possibly) in certain circumstances the 109 might have a theoretical advantage is almost irrelevant, as the average Allied pilot could and did turn inside the 109.

There are numerous quotes from pilots of all levels of experience that the Spitfire did this and precious few examples on the 109 doing this.

That`s your opinion of course. I am not sure on what it is based on.

And this is RAE`s opinion, on the 109E :

When the Me.109 was following the Hurricane or Spitfire, it was found that our aircraft turned inside the Me.109 without difficulty when flown by determined pilots who were not afraid to pull their aircraft round hard in a tight turn. In a surprisingly large number of cases, however, the Me. 109 succeeded in keeping on the tail of the Spitfire or Hurricane during these turning tests, merely because our Pilots would not tighten up the turn suficiently from fear of stalling and spinning.

...

The gentle stall and good control under g [of the 109E] are of some importance, as they enable the pilot to get the most out of the aircraft in a circling dog-fight by flying very near the stall. As mentioned in section 5.1, the Me.109 pilot succeeded in keeping on the tail of the Spitfire in many cases, despite the latter aircraft's superior turning performance, because a number of the Spitfire pilots failed to tighten up the turn sufficiently. If the stick is pulled back too far on the Spitfire in a tight turn, the aircraft may stall rather violently, flick over on to its back, and spin. Knowledge of this undoubtedly deters the pilot from tightening his turn when being chased, particularly if he is not very experienced.

Note that RAE didn`t even use flaps to aid the turn in the 109E.

That`s a very nice picture of that 109F, Bill, that you for sharing ! Do you have any more details on that aircraft, experience with it, perhaps?

Soren · Mar 24, 2008

kool kitty89 said:
Soren,
According to Kurfürst's last post the slat problems were still present on the initial Bf 109F as well and it was solved on later F models:

The design wasn't the same, only parts of the hingearm mechanism, some linkages were removed and the design of the slat itself was new.

Soren · Mar 24, 2008

Glider,

There's more than enough evidence to prove that the British test pilots did NOT go beyond slat deployment in the 109G, alone the comment made in their own report more than settling that fact.

drgondog · Mar 24, 2008

That`s a very nice picture of that 109F, Bill, that you for sharing ! Do you have any more details on that aircraft, experience with it, perhaps?[/QUOTE]

Kurfurst - I had than one mislabeled as the G2 some time ago and noticed only recently that it was an F.

Short answer - no. I think it was the F that you mentioned earlier that had crash landed and was repaired. It was part of a show in which a Ju 88, an Me 110 and the 109F were flown by the RAF to each US base to familiarize American pilots with flight controls (as a potential escape vehicle) as well as lectures on the characteristics.

I'll dig around and see if I can find the others. Of course you are welcome to use it - thyere are no copyright issues that I can imagine.

Regards,

Bill

Glider · Mar 24, 2008

This is my posting from the previous thread. The sections in bold report what happened after the slats deployed and pressure continued until the stall.
That they should do this one one aircraft and not another makes no sense.

Apart from their excessive heaviness at high speeds, the most serious defect of the Me. 109 ailerons is a tendency to snatch as the wing tip slots open. This is particularly noticeable when manoeuvring. For example, if the stick is pulled back in a tight turn, putting additional g on the aircraft, the slots open at quite a high airspeed; as they open, the stick suddenly snatches laterally through several inches either way, sufficiently to upset a pilot's aim in a dog fight. The snatch appears to be associated with the opening of the slots, for once they are fully open a steady turn can be done, with no aileron vibration, until the stall is approached.

When doing tight turns with the Me. 109 leading at speeds between 90 m.p.h. and 220 m.p.h. the Spitfires and Hurricanes had little difficult in keeping on the tail of the Me. 109. During these turns the amount of normal g recorded on the Me. 109 was between 2J and 4 g. The aircraft stalled if the turn was tightened to give more than 4 g at speeds below about 200 m.p.h. The slots opened at about 1\2 g before the stall, and whilst opening caused the ailerons to snatch; this upset the pilot's sighting immediately and caused him to lose ground. When the slots were fully open the aircraft could be turned quite steadily until very near the stall. If the stick was then pulled back a little more the aircraft suddenly shuddered, and either tended to come out of the turn or dropped its wing further, oscillating meanwhile in pitch and roll and rapidly losing height; the aircraft immediately unstalled if the stick was eased forward. Even in a very tight turn the stall was quite gentle, with no tendency for the aircraft to suddenly flick over on to its back and spin. The Spitfires and Hurricanes could follow the Me. 109 round during the stalled turns without themselves showing any signs of stalling.

The comments about the 109 being embarrased clearly refers to the 109 losing its sighting position which is quite understandable
--------------------------------------------------------------------------------

In Kurfurst earlier posting the interesting thing is that both of the quotes he mentions state that the Spitfire had a tighter turning circle but that if an experienced pilot was up against a less experienced pilot then the 109 had a chance.
There should be no suprise there.

AS for the comment that Note that RAE didn`t even use flaps to aid the turn in the 109E.
As far as I can see it doesn't say that it did or didn't.

Glider · Mar 24, 2008

As an aside I would hate to fly the 2 seat 109 from the back. The engine, nose and front seat gets in the way of half the visibility. The wing looks like it gets in the way of the rest.

Hunter368 · Mar 24, 2008

Glider said:
This is my posting from the previous thread. The sections in bold report what happened after the slats deployed and pressure continued until the stall.
That they should do this one one aircraft and not another makes no sense.

That was covered already why that would not be true Glider. See post #4 on this thread, it covers it nicely and clearly.

drgondog · Mar 24, 2008

Glider said:
As an aside I would hate to fly the 2 seat 109 from the back. The engine, nose and front seat gets in the way of half the visibility. The wing looks like it gets in the way of the rest.

Flying a 51 from the back seat can't be much better.. I had to wind my way down the transient to the active but it wasn't that bad taking off.

By his accounts it was a pleasant aircraft to fly, but felt the Fw 190 was lighter on the controls and more fun to fly at medium to high speeds.

Glider · Mar 24, 2008

So the theory is that the pilots made it up?

Has anyone got a link to the full comparison report. I thought that I did but it seems to be missing some parts that you are all quoting from. That may well be the cause of some of my confusion

Hunter368 · Mar 24, 2008

Glider said:
So the theory is that the pilots made it up?

Has anyone got a link to the full comparison report. I thought that I did but it seems to be missing some parts that you are all quoting from. That may well be the cause of some of my confusion

Glider I was referring to the following comments:

"109E and early F had the slats operated by wing arms, the late F and all G series had it deployed by bearings, probably hence the much smoother operation noted by Southwood on the G-2. Changes in the K also had the slats made out of steel.

Condition of the aircraft is an interesting thing, as all the 109 tested by the Brits were in damaged state; the 109E WNr 1304 was captured by the French after it belly landed behind the lines, and had some engine troubles with the oil; the F-2 they had a similiar story, but was probably in the worst shape of all; I believe they got a belly landed F-4, but I have no details of it; the G-2/trop Black Six was found in the desert in North Africa, with battle damage, splinters on the propeller and malfuncitioning radiator flaps.

Only the G-6/U2 that landed in error in Britainwas in normal condition, however that one had gunpods, being a Wilde Sau nightfighter (and probably some service history and repairs/rebuilds behind it, given it supposed to be GM-1 carrier, yet had no GM-1 system and was issued to a Wilde Sau unit.. probably rebuilt as a normal Gustav after sustaining battle damage)."

drgondog · Mar 24, 2008

What is and has been missing from these discussions and candidly from just about every comparative report I have ever seen is the Test Plan.

Every Test Program should have well articulated objectives and the strategies to achieve them.

If one of your objectives is to try to get enough data to draw conclusions, you not only should fly within repeatable boundary conditions but also with different pilots flying the same profiles to sort out some of the subjectivity that will be introduced by skill variances.

I haven't yet seen anything in Any report, or any book on the subject of Axis vs Allied Fighter comparisons which even contains the following:

Turn Comparison Tests;
Three airspeed values, three altitudes - left and right turns.
Start in Trail, pursue aircraft in front until gain or lose ground in the turn.
Repeat series after exchanging pilots
Repeat series for different flap settings within airspeed limitations
etc, etc

This is a key difference between cobbling together a flight comparison between two skilled pilots who encounter each other and decide to 'rat-race' and professional test pilots trying to filter out as many variables as much as possible.

In the example Dan gave, he is of course right about skill levels of a Krupinski or Rall or a Preddy or Gabreskis against even a skilled test pilot.. but I would add something here also.

Give Rall or Yeager or Krupinski 50 hours (probably much less) in your airplane and he will whip you one on one in his 'new bird' - this is the difference between talent and situational awareness versus a skilled excution of describable manuevers and flight conditions in a test program.

So, one can say they don't believe the test results for a variety of reasons -

but I haven't seen anyone put a finger on exactly what the Test Plan was, whether it was detailed in execution, what conditions they set for comparisons, etc., or even the differences described quantitatively?

What we have seen are persistent comments regarding why the Test Plan was flawed - and I believe they could well be flawed - just nobody has pulled out the smoking gun...

Fear of leading edge slats is not high on the list of 'probable cause' explaining the report.

Having said that, if the 109G2 airframe was bent, if the engine was below standard, if one pilot or low time pilots flew the 109 against superior talent, if something was mechanically wrong with the slats, if flight control surfaces were damaged or improperly rigged, etc - any of those parameters would affect a well designed objective comparison for specific profiles.

I'm in agreement with Dan that a Comparison Flight Test is not The 'answer' but it is, if properly planned and executed, a potential high value approach to yielding conclusions regarding relative strengths and weaknesses.

Hunter368 · Mar 24, 2008

Agreed

Soren · Mar 24, 2008

Fact still is that the captured 109G wasn't flown to its limits, as both German, British, Finnish Soviet testimony as-well as aerodynamics confirm.

Furthermore the a/c tested were all either damaged, featuring gun-pods, underperforming engines, flown with the wrong fuel and last but not least flown by pilots extremely inexperienced in the type, not even having recieved any pre-flight instructions on any of the a/c's characteristics.

And thus the British trials with the 109 are, like I've always said, worth completely nothing.

If we want to compare a/c accurately we must only rely on aerodynamics and the figures achieved by the a/c's country of origin, as this is the only way to ensure that the a/c is in prestine condition and performing its best.

drgondog · Mar 24, 2008

Hunter368 said:
Condition of the aircraft is an interesting thing, as all the 109 tested by the Brits were in damaged state; the 109E WNr 1304 was captured by the French after it belly landed behind the lines, and had some engine troubles with the oil; the F-2 they had a similiar story, but was probably in the worst shape of all; I believe they got a belly landed F-4, but I have no details of it; the G-2/trop Black Six was found in the desert in North Africa, with battle damage, splinters on the propeller and malfuncitioning radiator flaps.

Only the G-6/U2 that landed in error in Britainwas in normal condition, however that one had gunpods, being a Wilde Sau nightfighter (and probably some service history and repairs/rebuilds behind it, given it supposed to be GM-1 carrier, yet had no GM-1 system and was issued to a Wilde Sau unit.. probably rebuilt as a normal Gustav after sustaining battle damage)."

Hunter - I think the 109F pic I posted above is the F-4

drgondog · Mar 24, 2008

drgondog said:
Hunter - I think the 109F pic I posted above is the F-4

The second thing I wonder is why we would assume the aircraft remained in damaged condition?

God knows there were lots of damaged aircraft captured in Sicily and Italy to scavenge parts - and failing that the Brits knew how to work with sheet metal, etc to rebuild what they didn't have parts for?

Hunter368 · Mar 24, 2008

Soren said:
Fact still is that the captured 109G wasn't flown to its limits, as both German, British, Finnish Soviet testimony as-well as aerodynamics confirm.

Furthermore the a/c tested were all either damaged, featuring gun-pods, underperforming engines, flown with the wrong fuel and last but not least flown by pilots extremely inexperienced in the type, not even having recieved any pre-flight instructions on any of the a/c's characteristics.

And thus the British trials with the 109 are, like I've always said, worth completely nothing.

If we want to compare a/c accurately we must only rely on aerodynamics and the figures achieved by the a/c's country of origin, as this is the only way to ensure that the a/c is in prestine condition and performing its best.

I would have to agree, both of Allied planes and Axis planes.

kool kitty89 · Mar 25, 2008

Glider,
Let me try to sum up what's wrong with the reasoning on the "embarrassed" issue:

You say that the "embarassed by opening of the slots" statment refers to the aileron snatch, but this quote is from the 1944 Me-109G vs Tempest turn tests. And the test reffering to the "snatch" is a 1940 Bf 109E test. And as explained the 109G would not have suffered from aileron snatch.

Juha · Mar 25, 2008

Now Eric Brown wrote on his flights in the G-6/U2 that the opening of the slots ruined sighting and noticed that the flaw of 109E was still there. Brown flew the plane, after all. But on the other hand I have always thought that he was overcritical on 109G-6.

Finns wrote that when the slots opened one felt jerks/twitchs on the stick and elevators lightened but the control remained up to extreme limits.

Juha

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