f6f-5 vs 109

[Juha]

Hello Kurfürst
I have the same problem, it's so wrong . When one has time one doesn't have money to buy all the interesting books, when one gets money he doesn't have time to read all those interesting books he had bought.

KK
Lysander wasn't a liaison plane but an army co-op plane and as Hs 126 when enemy fighters saw one its survival was mostly up to pilot's skill in horizontal fight. Of course also close coordination with observer and pilot was needed. Those Lysander/Hs 126 pilots were sometimes very skillful and flew their planes to limit.

Juha

 

[FLYBOYJ]

I do not see whats the point of debate, regardless of the avarage British pilots familiarity or unfamiliarity with leading edge slats, the RAF test against the Tempest states quite clearly the pilot was emberassed by the opening of the slats, which certainly indicates (along with the relative lack of turn performance reported, ie. compared to FW 190 results) that he was not pushing the plane too hard in turns.

So whats the point in debating the details, the report is pretty clear about the a/c not being pushed to the edge. We can ponder on the why, but on what purpose...?

Because during a normal flight test profile you would investigate how all systems work within and sometimes outside normal operational profiles - I remember reading that paper when the test pilot said he was "embarrassed" by the LE slats. Keep in mind that these too would of deployed if the aircraft were being landed full stall, 3 point. After a few events I would venture to guess that the RAF pilots got used to the things and eventually allowed them to work as designed.

The point here if this pilot was "embarrased" when the slats deployed during a tight turn, he should of been horrified during stalls and landings.

How is this is relevant? - perhaps the aircraft were being flown to the extent of skill of those pilots testing it, adding to the argument of why certain 109 drivers were so sure they could out turn a Spitfire, and in the end having this issue of the LE slat deployment not a factor regardless if they (the RAE) ever did push the captured 109s to their full performance capability.

 

[Graeme]

Those Lysander/Hs 126 pilots were sometimes very skillful and flew their planes to limit.Juha

But no aerobatics, please...

 

[Juha]

Hello KF
I took a short look on Valtonen's book, in Christy's book there are also Franz Stiegler's opinion, who also compares Bf 109 and Fw 190 but on downside there is also Carlsson's "missinfo" on 109.

On British test pilots and slats, in Valtonen's book there is also the well known E. Brown's article and in it he clearly stated that slats came out 30kmh before stall all up/clean. So clearly he pulled past the opening of slats. The term Emberassed might come from the fact than in turning fight slats began popping out separately when 109 hit the wake of the other a/c and so ruined aiming. But what I remember on Finns experiences British seemed to have overstated this problem.

Juha

 

[renrich]

One of the advantages that the Hellcat had over the 109, according to Brown, and I think this is not arguable, was the view from the cockpit. I wonder if pilot visibility was as important as it sometimes is made out to be for this reason. I looked at a BF109 at the Cavanaugh Museum in Addison, Texas and although I was not allowed to sit in it it looked as if visibility would be awful. The cockpit is very heavily framed,(even worse than a "birdcage" Corsair) the pilot sits low in the airplane and I have read that it is hard to turn one's head because of the narrowness. A FW190 has good visiblity to the sides and rear except for the low semi reclining position of the pilot but vision to the front is severely curtailed. The comparison of the Hellcat and Corsair with an FW by the Navy remarked at the poor forward vision of the FW and how it would hamper deflection shooting. Nevertheless, the 109s and 190s were good at ACM so maybe good visibility is not as important as thought? Any observations?

 

[Glider]

Even if. I dare say it's rather unlikely they used the Lysander in turning combat so I doubt they would benefit from that experience.

On the contrary, if a Lysander is intercepted by a fighter all he has, is his ability to turn and manoeuvre.

Plus as you well know, my comment was against Sorens assumption Thus very few to none of the test pilots the RAF had had ever flown an a/c with slats, much less automatic LE slats.

Clearly they had flown aircraft with autmatic leading edge slats.

 

[FLYBOYJ]

On British test pilots and slats, in Valtonen's book there is also the well known E. Brown's article and in it he clearly stated that slats came out 30kmh before stall all up/clean. So clearly he pulled past the opening of slats. The term Emberassed might come from the fact than in turning fight slats began popping out separately when 109 hit the wake of the other a/c and so ruined aiming. But what I remember on Finns experiences British seemed to have overstated this problem.

Juha

Great info Juha, thanks!

 

[Soren]

Source and document please..

I have given all of this to you before, you seem to forget fast, but here it is again:

Bf-109G Cd0 = 0.0023:


And the Spitfire's Cd0 you can find yourself on Mike William's site. It is 0.00229.

And this relates to 109 vs F6F, Spit or Mustang how?

Are you saying you don't follow the logic that in British testing they didn't push the 109 to its limits ? Proven once with the comment "Being embarrased by the opening of its slots" and twice when the British fail to even turn it with a Tempest while they were able to outturn a P-51B with a Fw190 Jabo bomber.

Yes, the La 7 was one of the apendices at the back of the book

La5FN.

I believe you have said this many times, and that they are referenced from Rechlin 'tests', but you produce no document or tabulated results. This is/has been the subject of a lot of debate - you state but you don't produce the data.

I have supplied you with that before as-well, but again you forget.

 

[Soren]

On British test pilots and slats, in Valtonen's book there is also the well known E. Brown's article and in it he clearly stated that slats came out 30kmh before stall all up/clean. So clearly he pulled past the opening of slats. The term Emberassed might come from the fact than in turning fight slats began popping out separately when 109 hit the wake of the other a/c and so ruined aiming. But what I remember on Finns experiences British seemed to have overstated this problem.

I disagree, esp. since the 109's slats did NOT pop in and out during turning fights because of a wake or turblunce, that is merely an old untrue myth. It never happens. If it were to happen it would mean that a normal wing would experience the same effect and a sudden drop of lift when following another a/c, but it doesn't.

Dave Southwood, a modern 109 pilot, has addressed this issue before and made it quite clear that he has never experienced such a thing in the 109G ever whilst following or turning with other a/c.

 

[HoHun]

Hi Juha,

>The term Emberassed might come from the fact than in turning fight slats began popping out separately when 109 hit the wake of the other a/c and so ruined aiming. But what I remember on Finns experiences British seemed to have overstated this problem.

Absolutely. Radinger/Schick in their "Me 109" note that the Bayerische Flugzeugwerke and the Deutsche Versuchsanstalt für Luftfahrt undertook extensive trials of the slats in a major test program (worth 2,000,000 Reichsmark), which resulted in the deletion of the locking mechanism which originally held down the slats while the flaps were extended by less than 10 degrees. (If you're familiar with the US analysis of a captured Me 110, they found the remnants of such a locking mechanism which had been disabled, so it was not only used in the Me 109.)

Another series of test flights were undertaken in 1936 to determine if there was any danger of the slats during spins. Gustav Lachmann of Handley Page suggested that the slats should be equipped with a pneumatic retraction device to safeguard against the opened slats making the spin irrecoverable, but it turned out that this device had never to be used during the trials.

The results of these test flights were that the handling characteristics of the Me 109 were made much more docile in turns and aerobatics with flaps retracted by the freely operating slats.

If you read the French comparison report on the D.520 vs. Me 109E trials, you'll find that the two fighters had virtually identical turn rates at the test altitude, but the Me 109 could be flown reliably at the edge of the stall with sufficient warning to stay in the turn, while the D.520 lacked such a warning and sooner or later flicked out of the turn when the pilot inadvertently flew it into the stall.

(The Spitfire could be reliably flown on the edge of the stall like the Messerschmitt too, relying on aerodynamic wash-out to achieve a gradual instead of an abrupt stall. For the record, I don't think the Me 109 could match the Spitfire's sustained turn, except perhaps when you take a particularly heavy and poorly performing Spitfire variant like a tropicalized Spitfire V against a very light and well turning Messerschmitt variant like the Me 109F-4.)

Regards,

Henning (HoHun)

 

[Juha]

Hello HoHun
thanks a lot for the info. I have read the French test report from Kurfürst page and also E. Brown was critical to the stall characters of D.520. He also noted that the stall of Bf 109 itself was bening and descriped it much like the Finnish test pilot Kokko, so IMHO Brown had flown 109 to its limits.
IIRC Brown wrote that like in 190 also in Spit the pilot needed skill to be able to flown the a/c to the limit.

And thanks for posting the page from Groehler's book in Production rate thread, I have noticed earlier that Valtonen has been in times careless in his notes, not mentioning all of his sources or leaving some pages away from where he has obtained his info.

Juha

 

[drgondog]

I disagree, esp. since the 109's slats did NOT pop in and out during turning fights because of a wake or turblunce, that is merely an old untrue myth. It never happens. If it were to happen it would mean that a normal wing would experience the same effect and a sudden drop of lift when following another a/c, but it doesn't.

Dave Southwood, a modern 109 pilot, has addressed this issue before and made it quite clear that he has never experienced such a thing in the 109G ever whilst following or turning with other a/c.

Soren - both could be 'right'. Dave could be right that it never happened to him.

In turbulence there are indicial random velocity vectors... and non-predictible.

If you have a 'block' of particularly turbulent air impinging on a wing, the vertical components (of flow) could conceivably cause a local stall condition..

It (local vertical indicial gust) could conceivably happen in level flight in rough weather.

What would not be expected to occur would be a sustained and continuous set of similar conditions which would sustain the stall conditions for a period of time.

 

[Soundbreaker Welch?]

Another thing is modern WWII recreators probably try to not fly in as dangerous weather conditions as pilots were forced to fly in WWII.

109's probably had to operate in strong winds, some thunderstorms, and even snowstorms. Nowdays they try to limit that, because it's dangeous flying.

 

[Glider]

All
This might be of interest, in an old magazine I have found an article by Eric Brown where he describes a flight in the Me109G-6/U2 in 1944.
The article is in Air Enthusiast June 1973 and yes I did buy it new. As the magazine is still going I have sent them a message asking if I can scan and post it but until I hear back this will have to do.


Getting into it he describes the cockpit as being small and narrow but that the cockpit framing didn't produce serious blind spots but that the armour glass was very slightly smoky and the aircraft didn't seem as well built as the earlier versions they had seen. The blind flying panel was better equipped than the Fw190.

The forward view is described as terrible but the aircraft was easily steerable due to the toe pedal-operated wheel brakes and throttle response was particularly good.

On take off is was best to raise the tail early due to the poor forward view but that this was easy to do as the thrust line was higher on the 109 compared to most allied aircraft. Take off was commendably short and considerably better than the Spitfire IX whilst the strong swing to port was easily held with the rudder. The only thing to be wary of was that the 109 had to be flown off the ground. Any attempt to pull it off earlier resulted in the aileron snatching as the wing slots opened unevenly. That said with a good throttle response and a short take off run, that shouldn't be a problem.

The 109 climbed well and at a steep angle, Stability being excellent in the longitudinal and lateral planes, but neutral directionally. Control harmony for a fighter was considered poor, the rudder was light, the ailerons moderately light and the elevators very heavy.
Over application of the longitudinal control in manoeuvres easily induced the slats to deploy which in turn gave rise to aileron snatching, completely ruining the sighting on any aircraft being attacked.I suspect this is what is meant by embarrassed

At its cruising speed the Gustav is described as being delightful to fly but this changed at speed. In a dive at 400mph he says that they were very heavy almost as if they had seized. The maximum dive that he achieved in the 109 below 10,000ft was 440mph and the solidity of the control was such, that he considered this to be the absolute limit.

Above 25,000 ft he believed the 109 to be an efficient dogfighter and attacker of bomber formations.

He was particularly interested in the slats and their operation, the operation of which when doing high G manoeuvres resulting aileron snatching. These tests were undertaken with a clean aircraft and half a fuel load.

The first tests were stalls and this occurred at 105mph and was proceeded by elevator buffet and the opening of the slats about 20mph above the stall. The stall itself was fairly gentle with the nose dropping and the port wing simultaneously dropping about 10 degrees.
The stall in landing configuration was similar.

Dummy attacks were undertaken on a Lancaster and a Mustang III where it was found that the slipstream of these aircraft caused the intermittent operation of the BF109's slats throwing off the sighting.
Landing
The approach was steeper than with the Spitfire but the elevator feel is described as very positive giving delightfully accurate control at 118 mph. A substantial change of attitude was needed on the flare and even after touchdown, lift did not spill rapidly and bouncing could easily occur on rough ground. Once down, the brakes could be applied harshly to give a short landing run but care had to be taken to avoid a swing.

The rest of the article gives a summary of the Air Fighter Development Squadrons results against the Spit LF IX, Spit XIV and the Mustang but these are well known.

 

[Soren]

Yeah, this aileron snatching is something which never happens according to veteran as-well as modern 109 pilots. The 109E had some problems with the slats jamming, making them rather dangerous in turns, and this was solved with a new slat operating design from the F series onwards.

So I have a feeling that either Brown has never said the above, or that there was something wrong with the slat mechanism on the a/c he flew.

Dave Southwood:
"One interesting feature is the leading edge slats. When these deploy at low speeds or in a turn, a 'clunk' can be heard and felt, but there is no disturbance to the aircraft about any axis. I understand that the Bf109E rolled violently as the slats deployed, and I am curious to know the difference to the Gustav that caused this."

 

[drgondog]

Yeah, this aileron snatching is something which never happens according to veteran as-well as modern 109 pilots. The 109E had some problems with the slats jamming, making them rather dangerous in turns, and this was solved with a new slat operating design from the F series onwards.

So I have a feeling that either Brown has never said the above, or that there was something wrong with the slat mechanism on the a/c he flew.

Dave Southwood:
"One interesting feature is the leading edge slats. When these deploy at low speeds or in a turn, a 'clunk' can be heard and felt, but there is no disturbance to the aircraft about any axis. I understand that the Bf109E rolled violently as the slats deployed, and I am curious to know the difference to the Gustav that caused this."

Soren - it still isn't out of the question that Brown was flying a fully functioning 109G, ditto Southwood.

My father never remarked about slat snatching for the two seater he flew at Gablingen but he flew the 190D-9 much more and I don't recall that he even rat raced with Mustangs in the 109. The one thing he remarked on was the significant increase in stiffness of controls above 300kts in the 109 in both roll and turn.

But back to Brown. There is no reason to suppose he didn't fly the 109 thoroughly based on the above recount of 'snatching'..

Free floating LE Slats should always be subjected to possible differential deployment in medium high to high AoA manuevers or gusting/turbulence.

The question is 'So what' if easily corrected and sustained manuevering isn't difficult as a result. In a turn, the high wing is always at a slightly higher 'effective AoA' and any turbulence Could cause (not Will Cause) deployment - from incidental to complete - depending on that pressure differential at that point at that time. Apparently this wasn't a severe issue to most 109 drivers.

The elevator buffet/slat open on landing approach would be a classic example of slightly changing differences in AoA which could cause a slat to partially deploy.

 

[Glider]

I admit the bit that caught my eye was the aircraft being 'clean' with a half tank of fuel. This would indicate to me that the gun pods had probably been removed before the flight.

I would certainly agree that when your in a situation where there is a difference in the pressure on the wings then its likely that the automatic LE slats would deploy individually, I don't see how you can stop them.

 

[Soren]

I think the final proof that he [Brown] wasn't flying a properly functioning a/c lies in the mentioned stall speed of 105 mph. That is way too high for the Bf-109G, the true stall speed being around 85 mph flaps gear up. That's a 20 mph difference, strongly indicating something was wrong with the slats. Heck the landing speed is 90 mph.

 

[drgondog]

I think the final proof that he [Brown] wasn't flying a properly functioning a/c lies in the mentioned stall speed of 105 mph. That is way too high for the Bf-109G, the true stall speed being around 85 mph flaps gear up. That's a 20 mph difference, strongly indicating something was wrong with the slats. Heck the landing speed is 90 mph.

Soren - Good point.

Possible explanation for this is 'take no chances' with an unfamiliar bird. I landed the 51 always about 5kts above the manual - 'just because that's what He did''

 

[Juha]

Soren
where You get the info, FAF's Bf 109 G6 manual says that landing speed was circa 160kmh that is 100mph, Brown's stall speed 105mph all up is reasonable, and in line with British MTO tests
Kurfrst - No. 209 Group : TEST OF ME.109G-2 (TROP).

"Stalling speed is 102 m.p.h. indicated flaps and wheels down, and 112 m.p.h. with flaps and wheels up."

Juha