A newbies impression of the 109 and spit

Just to throw in:

If it was for rules these two men would never have survived:

http://209.157.64.200/focus/f-news/1071076/posts

http://www.dailymail.co.uk/news/arti...-survived.html

BTW there are some similar stories.

Sometimes, for whatever reason, rules can be bent.

[Kurfürst]

Impressive... these guys should try lottery!

[winny]

Originally Posted by Kurfürst

Absolutely, however some of the limitation were not soft ones. Say the manual may say spinning is not permitted below a said altitude, and it may well be on the safe side. However it wasn't there without a reason. The rules could only be bent to a certain degree, and after that line was left behind, there was no coming back, and no telling of stories.



Mother Nature took care about enforcing it though..



It's not petty, it's realistic. If a plane can only take 12 gs before breaking up, it will at 12.1 g. If its humanly impossible to get it out from spin without having 5-10 000 feet of altitude, you will die in it.

What I find petty is that when some guy damands the same papers he has seen about 2 years ago already (back then the excuse was that it's a 'forgery'), he knows very well about it, then when he is presented with it, he changes to subject and tries argues that it really isn't to be taken so seriously.

The Pilot's notes describe the behaviour of an aircraft accurately. They cannot be just dismissed with that 'oh, its not set in stone'.



Sure not, though I've heard some times the damages were deducted, if it was for careless flying. Combat of course is a different matter, anything goes. As Crumpp said, you take a ris k and choose between certain death and likely death, as cruel as it is.

The question is alway: Which one is which? Is flying within the limits or pressing your luck is more beneficial to your survival in combat? Sometimes its the former sometimes its the latter, and the unlucky ones do not tell stories.

Physics just keep working all the same, those rules cannot be bent.

I'm not arguing the physics. At all. I'm also definitely talking combat.
I'm highlighting the fact that context is important too.

History is important, i've read of at least 2 RAF pilot's intentionally spinning as a way to lose altitude whilst being shot at, and I think at least 1 LW guy. I'd have to check thru piles of books...

I'm sure that plenty of pilot's were killed by their own machines failing well within the limits, after all these were hand built. I'm equally sure some went through the limits and survived. It's being made out in this thread that because the pilot's notes say that xyz will get you killed, you get killed every time. I'm merely pointing out that this is actually xyz will probably get you killed.

I maintain that pilots notes alone are not proof of anything other than recommendations. There are too many variables to simply rely on a set of instructions.

[Kurfürst]

Basically, I agree with you. I don't think the positions that far away from each other either, its just difficult to form thoughts accurately in text on a discussion board. No, nothing is automatic, happening all the time as a certain results if you do something wrong, though the probability is high enough to warrant a warning in the pilot's little book.

OTOH I believe Pilot's instructions report a plane's characteristics faithfully. I guess we can agree on this.

Originally Posted by winny

I'm not arguing the physics. At all. I'm also definitely talking combat.
I'm highlighting the fact that context is important too.

History is important, i've read of at least 2 RAF pilot's intentionally spinning as a way to lose altitude whilst being shot at, and I think at least 1 LW guy. I'd have to check thru piles of books...

I'm sure that plenty of pilot's were killed by their own machines failing well within the limits, after all these were hand built. I'm equally sure some went through the limits and survived. It's being made out in this thread that because the pilot's notes say that xyz will get you killed, you get killed every time. I'm merely pointing out that this is actually xyz will probably get you killed.

I maintain that pilots notes alone are not proof of anything other than recommendations. There are too many variables to simply rely on a set of instructions.

BTW what commonly passes unnoticed: it's the fact that to break up the overload has to be applied for a certain minimum time.

This is a subject that is up to now not well understood by scientists and some research is done on this aspect. But basically if something usually breaks up at Xg it may not so if the time of exposure is very very small.

You will certainly believe like me that 30g is something human bones do not withstand, don't you.

Now you know that acceleration is delta(v)/delta(t) with v being the instantaneous velocity and t time.

Now when I jump from a chair my velocity will be not zero, let's say it is about 2 m/s right before I touch the ground. Now when touching the ground the velocity is reduced to zero, so delta(v) = 2 m/s. This happens basically instantly that's why delta(t)<<1. Which will make the acceleration incredibly high. Delta(t) just needs to be smaller than a millisecond to have a decceleration of 200g. Of course my reflects will absorb the shock but even if I'd just fell to the floor or jumped with stiff legs I would not break them. As much as I can break a plastic spoon easily with my two hands without much effort while it won't break if I threw it with force to the ground.

I for my part as an engineer and scientist am much thrilled and fascinated by this kind of intriguing phenomenon.

Of course this whole thing highly depends on the material as from daily experience I would say that elastic materials can take this ultra short loads much more easily than brittle material.

I guess that the lower the overload the longer the exposure times. So it is not unthinkable that if the overload was only for a little time the plane still might have survived it even if the book told that this never was going to happen.

Also remember that the limits for which the planes were designed were theoretical values based on experimental data on material properties obtained through probe measuring and some hand formula and sort of thump rules. These values also contained a certain margin that was dimension by some regulatory rules based on more thump rules.

No finite element methods back then.

Obviously a pilot would not or only in dispair engage in a manoeuver that he would be certain to break his plane with. Nevertheless his plane might not have broken up against all odds, if he was really lucky.

[winny]

Originally Posted by Kurfürst

Basically, I agree with you. I don't think the positions that far away from each other either, its just difficult to form thoughts accurately in text on a discussion board. No, nothing is automatic, happening all the time as a certain results if you do something wrong, though the probability is high enough to warrant a warning in the pilot's little book.

OTOH I believe Pilot's instructions report a plane's characteristics faithfully. I guess we can agree on this.

To be fair to you, you haven't been the main culprit withe the regulations thing.

I feel that there is a strange attitude to using combat reports and pilot's recollections as evidence.
They are the only primary source available on the subject of how these aircraft performed, doing what they were designed, tested and regulated to do. Fly in combat. To ignore them is missing the whole picture. Numbers and physics are equally important. To ignore them is also missing the whole picture.

I read a LW account by one of the top pilots. He said he managed to turn inside a spitfire by flying and managing to maintain such a position that only the slats on one wing were deployed he shot it down, by the same token I've read Brian Lane's account of a 5 minute dogfight with a 109 where he rode they very edge of the stall, behind a 109 who's slats were deployed and who was suffering aileron snatching. He got behind after 2 full 360's, the 109 rolled out and dived away. I believe them both.

[Crumpp]

[QUOTEImpressive... these guys should try lottery][/QUOTE]

That is exactly it. Impressive and far from normal.

Also remember that the limits for which the planes were designed were theoretical values based on experimental data on material properties obtained through probe measuring and some hand formula and sort of thump rules. These values also contained a certain margin that was dimension by some regulatory rules based on more thump rules.

No finite element methods back then.

They are not theoretical values for structures. They could teach us a thing or two about subsonic aerodyanmics and piston engine aircraft design. The area's they lacked in were transonic realm, supersonic realm, and stability/control engineering.

Aircraft structure load limits are tested to destruction and are measured data.

Do you know how they tested the structural strength of a wing?

Simple, they suspended it and loaded it up with sandbags until it breaks. Now there are some things you have to do to make it applicable to air loads but that is the basic concept.

Today we use hydraulics.....

http://www.youtube.com/watch?v=Ai2HmvAXcU0

[Crumpp]

I maintain that pilots notes alone are not proof of anything other than recommendations

That is not true at all. They are the defined limits of the airworthiness of the design.

[NZtyphoon]

Flight situation not noted in Pilot's Notes:

[Crumpp]

NzTyphoon,

Good humerous story. Does not have anything to do with Operating Notes, though.