Leading Edge Slats on the Me-109

[ACE-OF-ACES]

Originally Posted by TomcatViP

AoA with such a name you shld know that it is both. And then with logics in mind it's the 2nd arguments tht is the most valid

In the absurd an anti spin decice IS a device reducing the chance of a spin to occur

You know, flight manuals are full of such simplification. A pilot is not a always a Phd holder in physics. It can eitherbe a carpenter, a greedy politicians or a nightclub hotess!

So using your logic..

The purpose of the breaks in my car are NOT to stop my car..

The purpose of the breaks in my car are to prevent me from getting speeding tickets..

Hmmm..

Sorry but no sale!

Ill stick with the intended purpose of the breaks in my car and not the multitude of what if's purposes the breaks in my car can be associated with to try and make a point..

Nice try though! You and Crump get a gold star for effort!

[robtek]

Sorry AoA, but with such arguments you are soo far out, that you will find it hard to see the objective, imo, of course.

And Taildraggernut, you are promoting the theory that the Spitfire didn't flip over and started a spin if pulled too hard in a high speed turn?? Really???
Afaik this was used by experienced pilots as a last ditch maneuvre to escape from a 109 on their tail.

[taildraggernut]

Originally Posted by robtek

Sorry AoA, but with such arguments you are soo far out, that you will find it hard to see the objective, imo, of course.

And Taildraggernut, you are promoting the theory that the Spitfire didn't flip over and started a spin if pulled too hard in a high speed turn?? Really???
Afaik this was used by experienced pilots as a last ditch maneuvre to escape from a 109 on their tail.

Are you suggesting that Spitfire pilots had to exploit a lateral instability as opposed to deliberately entering the spin by actually making pro-spin inputs? really?

putting an aircraft into a spin is a technique available to any pilot in any aircraft as a deliberate manouver.

[ACE-OF-ACES]

Originally Posted by robtek

Sorry AoA, but with such arguments you are soo far out, that you will find it hard to see the objective, imo, of course.

Don't be sorry

In that I fully expected you and yours standard off topic reply in an attempt to take the focus off what I said..

Not to mention how you and yours totally ignored the points I brought up about the historic accounts of the Bf109 slats causing more spin issues than they solved..

[robtek]

Originally Posted by ACE-OF-ACES

Don't be sorry

In that I fully expected you and yours standard off topic reply in an attempt to take the focus off what I said..

Not to mention how you and yours totally ignored the points I brought up about the historic accounts of the Bf109 slats causing more spin issues than they solved..

Now there you have to bring some proof that the assymetric action of the flaps, which was intended, was causing spins.

And the points you've brought are as usual black and white with no room for intermediate.

[Al Schlageter]

Originally Posted by robtek

Now there you have to bring some proof that the assymetric action of the flaps, which was intended, was causing spins.

And the points you've brought are as usual black and white with no room for intermediate.

Isn't this thread about SLATS?

[ACE-OF-ACES]

Originally Posted by robtek

Now there you have to bring some proof that the assymetric action of the flaps, which was intended, was causing spins.

First you 'flip' and said 'with such arguments I am soo far out'.. Now you 'flop' and want me to provide proof of such arguments that are too far out?

Why bother, Ill just give you a few more min to 'flip' back and poo poo it again.

Originally Posted by robtek

And the points you've brought are as usual black and white with no room for intermediate.

Agreed..

But I can not take all the credit for these points.. I was simply pointing out what pilots who have flown the 109 had to say about the uneven slat activation.

[Crumpp]

Stalling the 109
Me 109 E:
"The airplane was equipped with a 60 foot trailing static head and a swiveling pitot head. Although, as may be imagined, operation of a trailing static from a single-seater with a rather cramped cockpit is a difficult job, the pilot brought back the following results:
Lowering the ailerons and flaps thus increases CL max of 0.5. This is roughly the value which would be expected from the installation. Behaviour at the stall. The airplane was put through the full official tests. The results may be summarized by saying that the stalling behaviour, flaps up and down, is excellent. Both rudder and ailerons are effective right down to the stall, which is very gentle, the wing only falling about 10 degrees and the nose falling with it. There is no tendency to spin. With flaps up the ailerons snatch while the slats are opening, and there is a buffeting on the ailerons as the stall is approached.. Withs flaps down there is no aileron snatch as the slats open, and no pre-stall aileron buffeting. There is no warning of the stall, flaps down. From the safety viewpoint this is the sold adverse stalling feature; it is largely off-set by the innocuous behaviour at the stall and by the very high degree of fore and aft stability on the approach glide.
It is important to bear in mind that minimum radii of turn are obtained by going as near to the stall as possible. In this respect the Bf.109E scores by its excellent control near the stall and innocuous behaviour at the stall, giving the pilot confidence to get the last ounce out of his airplanes turning performance."- RAF Royal Aircraft Establishment (RAE) Farnborough handling trials,Bf.109E Wn: 1304. M.B. Morgan and R. Smelt of the RAE, 1944.

Me 109 E-4:
"I was amazed at how docile the aircraft was and how difficult it was to depart, particularly from manoeuvre - in a level turn there was lots of warning from a wide buffet margin and the aircraft would not depart unless it was out of balance. Once departted the aircraft was recovered easily by centralizing the controls."
- Charlie Brown, RAF Flying Instructor, test flight of restored Me 109 E-4 WN 3579. Source: Warbirds Journal issue 50.

Me 109 G:
"- How the Messerschmitt reacted to hard pull? Did she stall?
There is the general opinion that you could not make her stall by pulling but she could 'slip'."
- Kyösti Karhila, Finnish fighter ace. 32 victories. Source: Interview by Finnish Virtual Pilots Association.

Me 109 E:
"I was particularly interested in the operation of the slats, the action of which gave rise to aileron snatching in any high-G manoeuvres such as loops or tigh turns so I did a series of stalls to check their functioning more accurately. The stall with the aircraft clean, with half fuel load and the engine throttled right back occurred at 105 MPH (168 km/h). This was preceded by elevator buffet and opening the slats about 20 mph (30 km/h) above the stall, these being accompanied by the unpleasant aileron snatching as the slats opened unevenly. The stall itself was fairly gentle with the nose dropping and the port wing simultaneously dropping about 10 degrees."
- Eric Brown
- The author writes about an "unpleasant" event. Nothing catastrophic! Surely all of the planes of that time had features, that were unpleasant, just as well as many planes today have. Curtiss Hawk 75 was surely unpleasant to fly with the rear fuselage fuel tank filled, as flying acrobatics could get you killed. P-51 was at least unpleasant with fuselage tanks filled.

Me 109 E:
"The Bf 109s also had leading edge slats. When the 109 was flown, advertently or inadvertently, too slow, the slats shot forward out of the wing, sometimes with a loud bang which could be heard above the noise of the engine. Many times the slats coming out frightenened young pilots when they flew the Bf 109 for the first time in combat. One often flew near the stalling speed in combat, not only when flying straight and level but especially when turning and climbing. Sometimes the slats would suddenly fly out with a bang as if one had been hit, especially when one had throttled back to bank steeply. Indeed many fresh young pilots thought they were pulling very tight turns even when the slats were still closed against the wing. For us, the more experienced pilots, real manoeuvring only started when the slats were out. For this reason it is possible to find pilots from that period (1940) who will tell you that the Spitfire turned better than the Bf 109. That is not true. I myself had many dogfights with Spitfires and I could always out-turn them.
One had to enter the turn correctly, then open up the engine. It was a matter of feel. When one noticed the speed becoming critical - the aircraft vibrated - one had to ease up a bit, then pull back again, so that in plan the best turn would have looked like an egg or a horizontal ellipse rather than a circle. In this way one could out-turn the Spitfire - and I shot down six of them doing it. This advantage to the Bf 109 soon changed when improved Spitfires were delivered."
- Erwin Leykauf, German fighter pilot, 33 victories. Source: Messerschmitt Bf109 ja Saksan Sotatalous by Hannu Valtonen; Hurricane & Messerschmitt, Chaz Bowyer and Armand Van Ishoven.

Me 109 E:
"And there I discovered the first thing you have to consider in a 109. The 109 had slots. The slot had a purpose to increase the lift during takeoff and landing. In the air automatically it's pressed to the main wing. And if you turn very roughly you got a chance, it's just by power, the wing, the forewing, comes out a little bit, and you snap. This happened to me. I released the stick immediately and it was ok then. "
- Major Gunther Rall in April 1943. German fighter ace, NATO general, Commander of the German Air Force. 275 victories. Source: Lecture by general Rall.

Me 109 E/F/G: - The plane had these wing slats and you mentioned they pop open uneven?
"Two meter slots on fore wings. The reason was to increase the lift during low speed take off and landing. To reduce the length of runway you need. In the air, if you make rough turns, just by gravity, the outer slot might get out. You can correct it immediately by release of stick, you know? Only little bit, psssssssht, its in, then its gone. You have to know that. And if you know it, you prevent it."
- Major Gunther Rall. German fighter ace, NATO general, Commander of the German Air Force. 275 victories. Source: Lecture by general Rall.

Me 109 G:
"- How often did the slats in the leading edge of the wing slam open without warning?
They were exteneded always suddenly but not unexpectedly. They did not operate in high speed but in low speed. One could make them go out and in by moving the stick back and forth. When turning one slat functioned ahead of the other one, but that did not affect the steering. In a battle situation one could pull a little more if the slats had come out. They had a positive effect of the slow speed handling characteristics of the Messerschmitt.
- Could the pilot control the leading edge slats?
No. The slats were extended when the speed decreased enough, you could feel when they were extended. "
- Kyösti Karhila, Finnish fighter ace. 32 victories. Source: Interview by Finnish Virtual Pilots Association.

Me 109 G:
"- In a battle, which was the case: did the pilot endure more than the Messerschmitt could do or vice versa?
The fact is that when you pulled hard enough the wing leading edge slats slammed open. After that the pilot could not tighten the turn. The plane would have stalled. I don't know, I never tried to find out what the plane would do after that. I never heard anybody else saying that he would have banked so hard that the slats came out. I did that a few times, for example once over the Isthmus I tried to turn after an enemy, banking so hard that both slats came out, but I had to give up.
- How did the slats behave in such a situation, did they go in and out ?
It depended on speed, if you pulled more,they came out, then back in
The slats came out completely, never half-way?
I never came to watch them so intensely. You just knew they had come out, you could see them and feel that the lift increased pretty much.
- So the plane warned that now you are on the edge.
Yes, you knew the plane is about to spin."
- Antti Tani, Finnish fighter ace. 21,5 victories. Source: Interview by Finnish Virtual Pilots Association.

Me 109 F/G:
"- Did pilots like the slats on the wings of the 109?
Yes, pilots did like them, since it allowed them better positions in dogfights along with using the flaps. These slats would also deploy slightly when the a/c was reaching stall at higher altitudes showing the pilot how close they were to stalling.....this was also useful when you were drunk "
- Franz Stigler, German fighter ace. 28 victories. Interview of Franz Stigler.

Me 109 G:
"As CL max is reached the leading edge slats deploy - together if the ball is in the middle, slightly asymmetrically if you have any slip on. The aircraft delights in being pulled into hard manuevering turns at these slower speeds. As the slats pop out you feel a slight "notching" on the stick and you can pull more until the whole airframe is buffeting quite hard. A little more and you will drop a wing, but you have to be crass to do it unintentionally."
- Mark Hanna of the Old Flying Machine Company flying the OFMC Messerschmitt Bf 109 G (Spanish version).

Me 109 G:
"There was nothing special in landing the plane. It was heavy but the wing slats opened up when speed slowed down and helped flying in slow speed."
-Kullervo Joutseno, Finnish fighter pilot. Source: Hannu Valtonen, "Me 109 ja Saksan sotatalous" (Messerschmitt Bf 109 and the German war economy), ISBN 951-95688-7-5.

Me 109 G:
"It was beneficial to keep the throttle a little open when landing. This made the landings softer and almost all three-point landings were successful with this technique. During landings the leading edge slats were fully open. But there was no troubles in landing even with throttle at idle."
-Mikko Lallukka, Finnish fighter pilot. Source: Hannu Valtonen, "Me 109 ja Saksan sotatalous" (Messerschmitt Bf 109 and the German war economy), ISBN 951-95688-7-5.Source: Hannu Valtonen, "Messerschmitt Bf 109 and the German war economy"

Me 109 G:
"We didn't have time for acrobatics but we weren't forbidden from doing them, though. Snap roll was fast and easy, and the engine didn't cough as in older planes. Immelman turn was splendid when you tightened the stick a bit on the top. The automatic wing slats did their trick and you didn't need ailerons at all for straightening the plane."
-Otso Leskinen, Finnish fighter pilot. Source: Hannu Valtonen, "Me 109 ja Saksan sotatalous" (Messerschmitt Bf 109 and the German war economy), ISBN 951-95688-7-5.

"Unexperienced pilots hesitated to turn tight, bacause the plane shook violently when the slats deployed. I realised, though, that because of the slats the plane's stalling characteristics were much better than in comparable Allied planes that I got to fly. Even though you may doubt it, I knew it [Bf109] could manouver better in turnfight than LaGG, Yak or even Spitfire."
- Walter Wolfrum, German fighter ace. 137 victories.

http://www.virtualpilots.fi/feature/articles/109myths/

[Crumpp]

If you have never flown a slat equipped aircraft, it is a different experience despite the slats being totally unnoticeable for the vast majority of their operation.

Once you have, the idiosyncrasies of the slats becomes part of the airplane and the tactile clues are comforting acknowledgements that everything is working as it should.

Once you explore the low speed performance of a slat equipped aircraft you will miss them on airplanes that lack such a device.

[ACE-OF-ACES]

Originally Posted by Crumpp

http://www.virtualpilots.fi/feature/articles/109myths/

LOL

Leave it to Crumpp to cut-n-paste quotes from a website with the title 109 myths as PROOF that uneven slat activation could NOT cause spins.. Yup no chance of bias at that website! NOT! One glance at that site and anyone can see that site goes way out of it's way to interpret what was said about uneven slat activation in the best possible light for the 109

With that said, instead of 'words' from a biased Internet website, how about 'words' from actual Bf109 pilots in a book by David Isby called The Decisive Duel: Spitfire vs 109? Will this meet your standards of proof robtek?

Originally Posted by Oberleutnant Erwin Leykauf

Less experienced pilots could put a Bf 109 into a stall and spin when the slats deployed on one wing and not the other in a tight turn. When slats deployed unevenly in tight turns, they would disrupt the airflow, causing the ailerons to ‘snatch’ enough to shake a Bf 109, spoiling the pilot’s aim

Now it is decision time.. As in who are you going to belive?

1) A biased website quote posted by Crumpp.
2) A quote of an actual WWII Bf109 pilot.

The choice is clear, but I am sure that some folks like Crumpp, Tomcat, and robtek will find creative ways to disregard what this actual WWII Bf109 pilot had to say about the slats causing spins..