Leading Edge Slats on the Me-109

[II/JG53 Rolf]

AOA - Sir, you have just done the same thing. While he posted numerous pilot records about slats, you choose one from a single book as a proof... Is the book reliable in all aspects? Does the author really understand aerodynamics? Now I don't have the book in my place, so I can't check it, but it seems to me that this is one I've actually read and there were several mistakes caused by authors misunderstanding of how things work and were designed.

It sort of reminds me a book by Stephen Bungay who was trying to mathematically prove that the 8 machine guns of a spit/hurry were more effective than 2 cannons of Bf-109 E...

Now to your quote - "...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..." Sir, Less experienced pilots is the key here. It means they ignored the warning the slats had given them and continued pulling on the stick ... It was mistake of a pilot not a plane... and less experienced pilots avoided near stall conditions at all... and it and it has been reported many times...

World would be a better place if we listened to each other instead of shouting...

And THE QUESTION about slats has both answers actually - they do both in logical sequence...

[raaaid]

stall is not equal to spin

you know what stall is?

think youre flying level but actually going so slow you are aactually falling as a rock

at some point the game modelled this

[ACE-OF-ACES]

Originally Posted by II/JG53 Rolf

AOA - Sir, you have just done the same thing. While he posted numerous pilot records about slats, you choose one from a single book as a proof...

Ah.. I see where you are confused

Note what I posted was a quote of an actual WWII Bf109 pilot.. Not my 'take' or 'interpretation' of what the actual WWII Bf109 pilot said.

Which is very different from the website Crumpp provided where the webiste provides you their 'take' and/or 'interpretation' of what the WWII pilots actually were trying to say or meant to say.. I guess some folks need others to do their thinking for them?

Hope that helps!

Now allow me to point out to those reading this post how Rolf and Crump totally ignored the actually WWII Bf109 pilot's quote I provided that said uneven slat activation can cause spins and tried to make this about me!

Nice try guys!

Gold star for effort!

But no sale!

[II/JG53 Rolf]

AOA - Sir, with all respect, could you explain how could uneven deployment of slats cause the above effect? I mean it, sir. No irony. Say, we have a Bf-109 E4 in a tight right horizontal turn trying to gain enough lead to kill a spit. It's on the edge of stall. Does it mean that the slat on the right thing wouldn't deploy entirely but, say, lower part more than the upper part. There was construction a diagram shown here, where it shouldn't be possible so it must have been malfunction - and sir, all planes were not the same (e.g. max speeds show average number, actual outputs of the plane could be +/- 5-10%, up to 20% in case of Russian planes). Or does it work differently (I could be missing something.)

And your point about me ignoring something in your post wasn't valid I am afraid, as I tried to explain that the cause could have been the actual experience of the pilot. There was mentioned before that there could be mechanical problems with slats because of dust, so they didn't deploy evenly or at all. However, I would say that this is simple malfunction, not a construction thing.

[ACE-OF-ACES]

Originally Posted by II/JG53 Rolf

AOA - Sir, with all respect, could you explain how could uneven deployment of slats cause the above effect? I mean it, sir.

No need for me to explain it..

In that based on Erwin Leykauf quote, an actual WWII Bf109 pilot we know that it happened, i.e.

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

Agreed?

Or are you saying you know better than Erwin Leykauf? Or that Erwin Leykauf was lying when he said that?

Eitherway you seem a little confused..

Allow me to bring you up to speed!

Back on page 19 robtek ask for PROOF, i.e.

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.

To which I did not bother providing in that I knew robtek would just poo poo anything I did provide

After that Crumpp felt the need to chime in with his cut-n-paste Bf109 myths site 'take on' what actual WWII pilots said as proof that uneven slat activation can NOT cause a spin because the Bf109 myth site, FOR SOME REASON left that part of Erwin Leykauf quote out of thier section called "Wing leading edge slats - good or bad?".

My guess is that it was just to black and white for them to 'spin' (pun intended) what Erwin Leykauf said into something positive..

So the Bf109 myth site conventally left that part of the quote out of their section devoted to uneven slat activation issue.

Talk about poster boys for 109 bias!

After seeing that weak attempt by Crumpp to present the biased Bf109 myth site reinterpretation of WWII pilot quotes as proof I decided to post Erwin Leykauf quote here as PROOF of what I was saying

Hope that helps!

[II/JG53 Rolf]

AOA - Sir, how could this happen? If the slat opened on the lower wing, it would increase lift there thus preventing stall for a few moments. What the pilot said was that less experienced pilot went into the stall/spin (stall first spin later) when this happened. On previous pages there was a description of RL pilot doing the same with only one difference - he was very experienced and recovered without a problem. The point is - you have a pilot with say 150 hours in the heat of the fight to the death who is turning hard to avoid being shot at or to gain a shot on an enemy - he could have missed those warnings. So the pilot told the truth, but as in many examples from that era it is only part of it. In the same manner you are ignoring his quotes telling the opposite. If we just step back a bit - to sum it up:
1) Slats were designed to open unevenly because the aerodynamic effects were uneven on both wings, especially in high AOA.
2) Slats helped at stall speeds at low speeds, discussion is held about high speed with not much evidence for either case in this thread.
3) Slats could have malfunctions as any other part of a plane - not all planes and pilots have the best ground crew. The slat then could open partially which could cause inexperienced pilot to stall/spin.
4) Recovery from the spin of slats equipped 109 was considered easy.
5) This whole thread was started because of stall and spin characteristics of bf-109 in CLOD game .

[Crumpp]

Actually I remember a thread that proved your theories the RAE had no established stability and control standards completely false.

Really?

Wow, you should tell the engineering departments of every major university because they are teaching the wrong information.

Maybe you should tell one of the pioneers of stability and control engineering. A British engineer who strived during the war and after to get the RAE on a defined standard after his experience working with the NACA. What is even more funny is the fact stick force per G, which Gates developed, was adopted by the NACA as part of the 1942 standard!

The United States NACA adopted a British engineers ideas and made them standard long before the British RAE listened to their own guy! That was the basis of his invitation to come to the United States and observe the stability and control developments at the NACA.

Here is the first page of the proposed standards for longitudinal stability, in fact.

I think World War II in Europe ended in May 1945. Pretty sure September 1947 is after the conflict was over....

[Crumpp]

everything behind the firewall is a 109....including the slats.

Exactly!

You have an airframe designed for one engine that is now having to work with another one.

This is why STC's are required and you just cannot swap motors in certified design airplanes.

The merlin prop swung at a lower rpm, weight is different, and the thrustline was higher. At least it turned in the same direction.

You do understand airframe are built to counteract the effects of spiral slipstream and torque?

That is why engine mounts/firewalls are angled and verticle stabilizers angled.

Mounting an engine with different properties results in different handling qualities.

Why are we even discussing this and what does it have to do with effect of the slats?

Is it just your justification for using an example which has nothing to do with the original topic?

[taildraggernut]

Originally Posted by Crumpp

Really?

Wow, you should tell the engineering departments of every major university because they are teaching the wrong information.

Maybe you should tell one of the pioneers of stability and control engineering. A British engineer who strived during the war and after to get the RAE on a defined standard after his experience working with the NACA. What is even more funny is the fact stick force per G, which Gates developed, was adopted by the NACA as part of the 1942 standard!

The United States NACA adopted a British engineers ideas and made them standard long before the British RAE listened to their own guy! That was the basis of his invitation to come to the United States and observe the stability and control developments at the NACA.

Here is the first page of the proposed standards for longitudinal stability, in fact.

I think World War II in Europe ended in May 1945. Pretty sure September 1947 is after the conflict was over....

Theres standards and then theres standardisation, you can have standards without standardisation, it simply means there was not a universally applied standard, I asure you the British aircraft industry was not a free-for all where they let the tea ladies get in on the act because it 'looked pretty', there were people who were very aware of what stability and control was within the RAE.
I am not arguing a point about whether a universal standard was adopted, I'm arguing against your bizarre claims the British had 'no' standards and therefore the RAE reports on the 109 may as well have been performed by monkeys.....until of course you want to 'cherry pick' anything positive.

[ACE-OF-ACES]

Originally Posted by II/JG53 Rolf

AOA - Sir, how could this happen?

Does not mater how..

In that based on Erwin Leykauf quote, an actual WWII Bf109 pilot we know that it happened, i.e.

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

Agreed?

Either way you seem a little confused..

Allow me to bring you up to speed!

This all started with me saying the following..

Originally Posted by ACE-OF-ACES

Especially in light of the fact that there are many accounts of how leading edge slats CAUSED spins!!

Where, for what ever reason, the leading edge slats did not deploy evenly and thus induces (CAUSE) the plane to spin..

Not to mention the accounts of the leading edge slats POPPING out suddenly such that they 'changed' the aerodynamics such that the pilot had to quickly adjust his controls.. In essence startling the pilot such that he may have over compensated and CAUSE the plane to stall or even spin

To which robtek responded asking for proof of the accounts, i.e.

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.

Initially I didn't bother digging up the historic accounts because I knew robtek would just poo poo anything I did provide..

But after that Crumpp felt the need to chime in with his cut-n-paste Bf109 myths site 'take on' what actual WWII pilots said as proof that uneven slat activation can NOT cause a spin because the Bf109 myth site, for some reason they conventually left that part of Erwin Leykauf quote out of their section called "Wing leading edge slats - good or bad?".

My guess is that it was just to black and white for them to 'spin' (pun intended) what Erwin Leykauf said into something positive..

But I digress..

After seeing that weak attempt by Crumpp to present the Bf109 myth site reinterpretation of what WWII pilot said as PROOF

I decided to post Erwin Leykauf quote here as PROOF of what I was saying..

IMHO there is no debating this issue

Unless your willing to say Erwin Leykauf was mistaken and you know better than he on how the Bf109 flys, or your willing to say Erwin Leykauf was lying?

So in summary

1) I pointed out uneven activation of the slats can cause spins..
2) rotek ask for proof of uneven activation of the slats can cause spins.. (aka bring it)
3) I provided proof of uneven activation of the slats can cause spins.. (aka brung it)

Hope that helps!