Author Topic: 109G/la-5/7 and the slats (Read 7093 times)

Grendel · « **Reply #30 on:** October 25, 2004, 11:39:10 AM »

Yup, F-86 Sabre had identical automatic slats like the 109. Nothing strange in that system.

And for one quote about slats being poor I can find two from pilots, who liked the slats.

GScholz · « **Reply #31 on:** October 25, 2004, 02:31:01 PM »

Quote

Originally posted by GRUNHERZ
Its 10 years, the slats were there the whole time.

Yes, but I was more refering to the war years when the pilots would have complained about the supposed ill effects of the slats in combat, and how unlikely it is that the slats would have been kept in the design if they did so.

Angus · « **Reply #32 on:** October 25, 2004, 03:28:51 PM »

I also like my barn door,whose excellent mountings consist of rollers and tracks.
They are not imprevious to failiure though, and some of the people opening them don't like them at all...

What I am saying.
1.Probably most 109 pilots liked the slats, not all.
2. Slats like this are not imprevious to malfunction.

BTW, with slats opening as niklas sais only under high A.o.A., why have some pilots complained about them clonking in and out all the time? Surely, he means stall condition right?

GScholz · « **Reply #33 on:** October 25, 2004, 03:48:31 PM »

Quote

Originally posted by Angus
BTW, with slats opening as niklas sais only under high A.o.A., why have some pilots complained about them clonking in and out all the time? Surely, he means stall condition right?

I'd love to see you provide some evidence of that, even anectodal evidence.

HoHun · « **Reply #34 on:** October 25, 2004, 03:55:14 PM »

Hi Angus,

>"That kind of automatic slat has to be very well balanced and glide easily to have the desired effect. A slightly damaged automatic slat may open at higher A.o.A. than the normal opening one. This will cause assymetrical lift and unacceptable roll disturbances at high A.o.A."

"Moving parts can fail."

I consider that an irrelevant truism.

An aircraft has many more moving parts than the slats, and many of these moving parts fail with more serious consquences than the slats.

>So, mud, ice, and lack of lube, dents, holes, rust and so on come to mind.

Chewing out the crew chief comes to mind.

Do you have any evidence connecting poor maintenance to imperfect slat operation at all?

In my opinion you're attempting a molehill-to-mountain stunt here.

Regards,

Henning (HoHun)

Angus · « **Reply #35 on:** October 25, 2004, 05:39:03 PM »

Dear HoHun.
This line was taken out of a commercial pilot aerodynamic teaching book. Call that irrelevant truism if you prefer.
Same to my statement of moving parts being able to fail. I would add to that as a prefix "external" in particular.
What comes to my mind of the possibilities I mentioned as highly likely, - and it actually has nothing to do with the crew chief- is ICE.
As for this:
"Do you have any evidence connecting poor maintenance to imperfect slat operation at all? "
Firstly I point my finger again to the quote pasted some three times into this thread, i.e:
" A slightly damaged automatic slat may open at higher A.o.A. than the normal opening one. This will cause assymetrical lift and unacceptable roll disturbances at high A.o.A"
I actually stumbled across this after this thread started. A pilot friend of mine left his book in my place (to my utmost pleasure), and for your knowledge, the 109 is never mentioned in the book.
So, that is where my connection POOR MAINTENANCE>IMPERFECT SLAT FUNCTION comes from.
And to the final:
"Do you have any evidence connecting poor maintenance to imperfect slat operation at all?"
I take that as regarding in particular the 109 or the LW. Otherwise I'd point again what is taught on aerodynamic courses.
So:
Answer is basically "NO" I don't. In fact I have at the moment, no evidence whatsoever that there was anything wrong with anything regarding the once mighty WW2's Luftwaffe's maintenance at all.
However, I'd consider it totally childish to assume that their maintenance would at all times have been perfect. Combat conditions are not always perfect, that is as simple as it gets.

But I'll dig up some stuff, will just take a wee bit.
(other channels than internet)

Regards

Angus

niklas · « **Reply #36 on:** October 26, 2004, 04:19:45 AM »

Quote

Originally posted by Angus
BTW, with slats opening as niklas sais only under high A.o.A., why have some pilots complained about them clonking in and out all the time? Surely, he means stall condition right?

No. A stall situation would have been already too late.
Wing trials for the 109 without slats and washout instead showed a dangerous roll tendency, so they stayed with the slats.
And i wouldn´t give too much weight on pilots opinion. Let them fly the machines, but don´t expect the ultimative understanding why this or that feature was used on the machine.
I read of a pilot who described that they landed the 109 in service much harder than trained. Instead of coming in steep and letting it down on flaps and slats they came in flat at much higher speed. Maybe they didn´t like the slats because they didn´t use them, but that doesn´t mean that the slats weren´t an useful feature.
At the end no pilot can tell you how the 109 would have behaved at critical high AoA situations without slats because they were always "there". I´m sure after flying without slats they´d have been glad to have them back.

niklas

HoHun · « **Reply #37 on:** October 26, 2004, 02:46:57 PM »

Hi Angus,

>This line was taken out of a commercial pilot aerodynamic teaching book. Call that irrelevant truism if you prefer.

What is the relevance of the lines you quoted for the commercial pilot? His attention is drawn to the necessity of free and light movement of the slats so that he knows what to look for in a pre-flight check, and he is taught the symptons of imperfect slat operation so that he can properly report them to the ground crews.

What is the relevance of the lines you quoted for the design and tactical suitability of the Me 109? It's the attempt to apply it out of context which makes it an irrelevant truism - it just points out the possibility of a failure without giving the slightest information on the likelihood of that failure actually happening.

>Same to my statement of moving parts being able to fail. I would add to that as a prefix "external" in particular.

It was standard operating procedure for the Luftwaffe to push the slats into the closed position on parking the aircraft. De facto, the slats were an internal mechanism.

>>"Do you have any evidence connecting poor maintenance to imperfect slat operation at all?"

>Answer is basically "NO" I don't.

Well, that makes it all look like idle speculation, don't you think? :-)

Regards,

Henning (HoHun)

Angus · « **Reply #38 on:** October 28, 2004, 06:57:28 PM »

Dear HoHun.
I have to give some feedback to your post. Sorry I couldn't sooner, - been tied up at work. (Surprizingly, mechanical stuff).
I shall begin with the top point a the subect of this thread:

"Do slats have negativce effect (like sudden "snaps") on 109Gs/la-5/7 in r/l if you pull the stick suddenly @ lo-turning speeds? I notice that slats dont always come out evenly and i think that's what's causing the 109G or la-7 to snap in AH2."

This is something I have stumbled across before in my reading and studying of WW2 aviation history.
I already posess some anecdotal and documented data about this.
I rather regard this as a thing to look into, rather than discarding it from the beginning, whatever the reason.
My thesis on this is that this could possibly be caused by malfunctioning slats (a war issue) rather than the slats being an imperfect design or aerodynamical princip.
My first look into this rather suggested that if there was a problem at all, it would be such an issue. You prefer to call that truism.
Anyway, any critic on the slats gets debated on this thread.
If I would draw a conclusion from your input, adding the input of Izzie, no less, the result would be that slats are imprevious to trouble at all,and all evidence poining elswhere is false or not properly backed up.
However there is still plenty of data around here to be looked into, so this thred will stay on for a bit I am afraid.
I do sense a certain evasiveness when it comes to a hard point, which I tested here. Your question:
"Do you have any evidence connecting poor maintenance to imperfect slat operation at all? "
My answer:
"I take that as regarding in particular the 109 or the LW. Otherwise I'd point again what is taught on aerodynamic courses.
So:
Answer is basically "NO" I don't. In fact I have at the moment, no evidence whatsoever that there was anything wrong with anything regarding the once mighty WW2's Luftwaffe's maintenance at all. "
Yet you choose to quote this as such with an answer as well:
">>"Do you have any evidence connecting poor maintenance to imperfect slat operation at all?"

>Answer is basically "NO" I don't.

Well, that makes it all look like idle speculation, don't you think? :-)
"
Dear HoHun, I am not sure where exactly I stepped on your tail to deserve this.
So here comes a test, a question for you:
"Do you have any evidence that the LW's maintenance work was always in perfect order throughout all of WW2"?
With a cut & paste permission, it's a YES or NO question.

Regards.

Angus.

P.S. I do have some stuff to add here soon. Just remembered also that there is a nice link regarding the positive side of fully working slats on the Spit I turning thread in this forum.

Tilt · « **Reply #39 on:** October 29, 2004, 07:05:42 AM »

Well in AH stuff does not break down or fail to operate unless its been subject to impact of some sort.

Hence unreliability is not modelled.

Slats used were very simple devices and many more components on an ac were prone to failure or/and mal adjustment.

The price paid for slats was the poor final departure characturistic.........

on some ac this was worth it on some not.

HoHun · « **Reply #40 on:** October 29, 2004, 10:26:01 AM »

Hi Angus,

>So here comes a test, a question for you:
>"Do you have any evidence that the LW's maintenance work was always in perfect order throughout all of WW2"?
>With a cut & paste permission, it's a YES or NO question.

Actually, It's a rethorical question.

And a von Däniken-style rethorical question, as it implies that in the absence of definite proof to the opposite, any speculation is valid.

However, the scientific approach has to follow von Ranke's definition that history can only be based on contemporary evidence.

Regards,

Henning (HoHun)

Angus · « **Reply #41 on:** October 29, 2004, 12:37:21 PM »

Dear HoHun.
I rather suspected that you were somewhat a philosopher, now that theory is strengthened.
I haven't clicked on youe links yet. (Erich Von Daniken?). So this is not completely based on your feedback.
Well, I am disappointed that you did not answer my question, for it would not have been rethorical at all,- most of us know that the status of the LW late in WW2 could best be described as poor.
But hell, you choose to stick to Von Ranke's documentatism, clinch on it hard enough, and hardly anything can be proved.
Turning that around, I can still ask that question. Let's assume that the late-war-bombed-up Luftwaffe had troubles with keeping enough servicable aircraft in the air, - which I think even you agree that was the case.
So, can you definately proof that they still kept their aircraft in perfect condition?
Yes or No?

I have some more questions for you later

Regards

Angus

KurfÃ¼rst · « **Reply #42 on:** October 29, 2004, 12:59:27 PM »

Angie, just for the record, late-war-bombed-up Luftwaffe fighter units had about 70-80% servicibilty rate.

I guess it`s only partially has to do with the devotion of them schwarze mann. The other half was the huge amount of brand new planes piled up in the storage centers. Why bother to repair, if you can just grab a new one?

OFF : I cannot imagine the consequences if the admin at HoHun`s workplace would ban the access to wikipedia. He`s a total addict of it.

HoHun · « **Reply #43 on:** October 29, 2004, 01:04:25 PM »

Hi Angus,

>I rather suspected that you were somewhat a philosopher, now that theory is strengthened.

You got that wrong. I'm somewhat of a scientist, as science is the only proven method to arrive at verifiable conclusions.

>Well, I am disappointed that you did not answer my question, for it would not have been rethorical at all

You got that wrong, too. If you don't recognize your question as rethorical, keep thinking about it until you do.

>Turning that around, I can still ask that question.

Just try to think up an answer that would satisfy von Ranke. Then you'll recognize why your question is deeply un-scientific.

>I have some more questions for you later

They will have to wait until you've understood the folly of your first question.

Regards,

Henning (HoHun)

Angus · « **Reply #44 on:** October 29, 2004, 02:01:59 PM »

Dear HoHun.
Now don't get too pompous mate.
My question is no less worthy than yours, and you also chose to answer mine in a most un-scientific way, clipping it in your quote.
After all, they are almost identical. Prove it was- prove it wasn't may be an issue, so maybe I should rephrase it to "What do you think".
But alas, yes or no may be too complicated.
And since you clinch on to Von Ranke, that's where you get, ain't gonna be yer buddy there.

Yet....
I still belive that there is some source to the myth of slats being able to cause negative effect at times, and that the explanation may possibly be a war-problem issue than the aerodynamic effect.

All ears.....

Regards

Angus