Leading Edge Slats on the Me-109

[*Buzzsaw*]

Originally Posted by Crumpp

The slats are a very practical method of allowing the pilot to quickly, precisely, and safely achieve CLmax.

Actually your comments are an exaggeration.

What the slats do is allow a pilot the confidence that if he pulls too much G and stalls his aircraft, the likelyhood of a violent spin is diminished and the knowledge he should be able to recover relatively easily.

The slats in themselves do not give any guarantee of a stall not occurring, they merely make the event, when it occurs, less violent.

The pilot still must be able to judge whether or not his aircraft is about to depart, and how many G's he is able to pull before departure may occur.

The slats opened prior to the stall, by RAF estimation, approx. 1/2 a G, and in pulling further G's and in order to avoid a stall, the pilot had to know the further signs of a stall approach, in the same way a Spitfire or Hurricane pilot was required to monitor his aircraft's behaviour.

In addition, the installation of the slats was not without penalty. As noted, the slats by deploying, increased the lift generated by the outer section of the wing, but they also generate more drag and reduce the speed of the aircraft. For earlier models of the 109, in particular the E, the chances of the slats deploying assymetrically in a turn was a factor, which was noted to cause aileron snatching and which could cause the aircraft to change direction without the pilot's intention.

[NZtyphoon]

Originally Posted by *Buzzsaw*

Actually your comments are an exaggeration.

What the slats do is allow a pilot the confidence that if he pulls too much G and stalls his aircraft, the likelyhood of a violent spin is diminished and the knowledge he should be able to recover relatively easily.

The slats in themselves do not give any guarantee of a stall not occurring, they merely make the event, when it occurs, less violent.

The pilot still must be able to judge whether or not his aircraft is about to depart, and how many G's he is able to pull before departure may occur.

The slats opened prior to the stall, by RAF estimation, approx. 1/2 a G, and in pulling further G's and in order to avoid a stall, the pilot had to know the further signs of a stall approach, in the same way a Spitfire or Hurricane pilot was required to monitor his aircraft's behaviour.

In addition, the installation of the slats was not without penalty. As noted, the slats by deploying, increased the lift generated by the outer section of the wing, but they also generate more drag and reduce the speed of the aircraft. For earlier models of the 109, in particular the E, the chances of the slats deploying assymetrically in a turn was a factor, which was noted to cause aileron snatching and which could cause the aircraft to change direction without the pilot's intention.

From what I have read 109 pilots did have concerns about the slats banging open, causing a jolt because of aileron snatching and sometimes upsetting the pilot's aim. Fact is that all designs are a compromise in one way or t'other - like I keep saying slats were no better nor worse at aiding control than other aerodynamic aids. In the end it was the pilot's skills and experience that made a real difference; learning how to get the best out of the aircraft was a great survival technique.

[Crumpp]

Actually your comments are an exaggeration

Let's be specific and point exactly what you think I "exaggerated" otherwise your post is simple trolling and bait attempt to define me as being "red vs blue".

Buzzsaw, you state exactly the same thing I have without any change.

[Crumpp]

4.4. Stalling Tests

We find that under all conditions tested, the Bf-109 has:

no tendency to spin.

http://kurfurst.org/Tactical_trials/...ls/Morgan.html

[Robo.]

Originally Posted by Crumpp

no tendency to spin.

The in-game 109 has not any unusal tendency to spin - you will stall her of course when you do a mistake and lose control. That is a very good match with the 'us experienced pilots'. I would say that the problem lies in the spin recovery, e.g. once the a/c enters the spin, it is more difficult to recover than it should be.

[Crumpp]

you will stall her of course when you do a mistake and lose control

Again, they act like training wheels on a bicycle. In otherwords, it should be EXTREMELY difficult to spin the aircraft and very easy to recover.

once the a/c enters the spin

The advantage of the slats is in preventing spins. Find a report on the spin characteristics of the Bf-109.

There is an engineering reason there is not one.

[Robo.]

So are you saying that the 109 was unspinnable? Even if the pilot made a mistake?

I see the point that the a/c in game is now too difficult to recover and I agree it should be addressed.

[NZtyphoon]

Originally Posted by Crumpp

Again, they act like training wheels on a bicycle. In otherwords, it should be EXTREMELY difficult to spin the aircraft and very easy to recover.



The advantage of the slats is in preventing spins. Find a report on the spin characteristics of the Bf-109.

There is an engineering reason there is not one.

Interesting in light of the fact that one of the reasons the 109 was chosen over the He 112 was because test pilot Hermann Wurster was able to demonstrate a series of spins, 21 to port, 17 to starboard, before a group of Luftwaffe officials. Clearly the 109 was easy to recover from spins - the E probably a little more difficult than a Jumo engined prototype - but the slats were not some miracle cure for spins.

[WTE_Galway]

Originally Posted by *Buzzsaw*

Actually your comments are an exaggeration.


In addition, the installation of the slats was not without penalty. As noted, the slats by deploying, increased the lift generated by the outer section of the wing, but they also generate more drag and reduce the speed of the aircraft. For earlier models of the 109, in particular the E, the chances of the slats deploying assymetrically in a turn was a factor, which was noted to cause aileron snatching and which could cause the aircraft to change direction without the pilot's intention.

Hence the often quoted anecdotal comments by Luftwaffe veterans that the "better" 109E pilots would deliberately alternate between slats in and out, using the slats temporarily to tighten the turn or pull lead and then almost immediately easing on the stick to regain lost speed.


- Erwin Leykauf, German fighter pilot, 33 victories. Source: Messerschmitt Bf109 ja Saksan Sotatalous by Hannu Valtonen; Hurricane & Messerschmitt, Chaz Bowyer and Armand Van Ishoven:

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

"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."

[Crumpp]

they also generate more drag and reduce the speed of the aircraft

Right....

What you don't understand is that speed reduction reduces radius and improves turn performance until Va is reached.

The airplane that slows down the fastest to Va will win the instantenous turn fight.

Hence the often quoted anecdotal comments by Luftwaffe veterans that the "better" 109E pilots would deliberately alternate between slats in and out, using the slats temporarily to tighten the turn or pull lead and then almost immediately easing on the stick to regain lost speed.

Exactly.

He is flying a yo-yo and not a constant altitude turn. By combining the climb advantage of the Bf-109 at low speed climbs with the advantage of the slats, Erwin Leykauf is defeating the constant altitude turn performance advantage of the Spitfires he is fighting.

In most cases this steep climb at low airspeed was the only manceuvre whereby the Me.109 pilot could keep away from the Hurricane or Spitfire.

http://kurfurst.org/Tactical_trials/...ls/Morgan.html

The Bf-109 and Spitfire are about as equal a match of dogfighters as one can get.

Above quote from 'Last of the few' by Max Arthur, combat report of a pilot of the 64th Squadron RAF, F/O Michael Wainwright.

Are you fishing and this is bait?

What was the condition of the Bf-109 and the pilot? Was the aircraft damaged? Was the pilot wounded? Was it a real spin or did the pilot pass out??

In otherwords, it is an interesting story but without the details definately does not contradict the findings of the RLM or the RAE.