Messerschmitt 109 - myths and facts - article now out

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Topspeed
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Post by Topspeed » 26 Mar 2005 18:45

Uncle Joe wrote:
Topspeed, you got this wrong and badly. First, laminar flow wings tend to have poorer lift and harsh accelerated stall. The P-51 displayed both. On the other hand, good accelerated stall of the 109 was one of its best characteristics.
Everybody knows this. I am telling about a totally different phenomena.

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Post by gabriel pagliarani » 26 Mar 2005 18:52

Topspeed wrote:Mustang wings are known to bend before the g-stall occurs. In other words somewhere at 15-20 G:s. Where as 109 with a smaller wing added with lotsa dihedral cannot hack more than 11-12 Gs and a stall occured..miraculously a finnish fighter pilot lived to tell about this experience.
Ah, now I understand the sense of your posts! You are confusing g-limit with high speed stall limit. They are not the same thing! The high speed stall limit is measured when the plane is not turning in any direction but it is moving frontward close to Mach limit. Obviously this limit is linked to quote and density of the air and it could vary largely.This is an aerodynamical limit. At the contrary g-limit is a pure constructive limit and it is asimmetrical: a modern jet could survive to a +14 g (pulling the cloche) but only to a -3/5 g (when pushing the cloche) Out of those limits or the bones of the pilot will be cracked as biscuits or the plane will be opened like a banana. The cockpit of any plane is ALWAYS the real weak point of its own structure: this is the cause of asimmetrical behaviours.

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Post by gabriel pagliarani » 26 Mar 2005 19:08

Topspeed wrote:Mustang wings are known to bend before the g-stall occurs. In other words somewhere at 15-20 G:s. Where as 109 with a smaller wing added with lotsa dihedral cannot hack more than 11-12 Gs and a stall occured..miraculously a finnish fighter pilot lived to tell about this experience.
Slow down with g-numbers, Top! If your mass is 70 kg at +14g your mass is increased to a nominal weight 980 kg, at +20 g your nominal weight is 1400 kg and all the blood is drained from brain and pushed in pilot's foot while the spine is cracking bone by bone still hart-breaking point. Without wearing a "g-suite" 20g is sure death limit.

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Post by Topspeed » 26 Mar 2005 19:09

I agree ( but did not mention the G-limit ). I think you may have understood the phenomena.

In other words a P-51D could not have been put into a high speed stall because the pilot would have died before it occured and apparently also plane would have disintegrated. Teoretically it could have been reached.

P-51D pilots did wear g-suits. :)

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Post by Uncle Joe » 26 Mar 2005 19:47

Topspeed wrote:I agree ( but did not mention the G-limit ). I think you may have understood the phenomena.

In other words a P-51D could not have been put into a high speed stall because the pilot would have died before it occured and apparently also plane would have disintegrated. Teoretically it could have been reached.

P-51D pilots did wear g-suits. :)
Voi herran tähden! Et kai sinä perkele ole vaan syönyt kärpässienikeittoa, on sen verran villit jutut (ymmärrätkö mikä on g-sakkaus?)! Just short summary: seems that Topspeed has been eating mushrooms, so wild is his imagination!

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Post by Topspeed » 26 Mar 2005 20:24

I did eat Canttarelli cravy yes.

The high speed G-stall caused the pilot to hit his head on the canopy side and loose conciousness. The start of the stall happens without a warning and takes place in a split second.

Before the "stall" plane has been flying at a very high speed when the pilot rapidly applies the stick back...instead of the hoped high g turn the plane snaps violently 1,5 rolls and continues to fly in the direction where it was flying/heading before the attempted turn.

The very high G-loading lasts only a matter of few hundreds of a second.

I think in the movie Right Stuff Charles Yaeger experiences this painful phenomena with an X-2 experimental mach 2+ research aircraft.

-----------------------------------

Because of the nasty nature of this phenomena it has been eliminated from most of the fighter types ( all ? ) in the design phase. During the WW II the phenomena was more or less unknown.

-----------------------------------

Uncle Joe !

I hope you would be able to use some other kinda language ( I know people have been banned for less insulting remarks ) and just settle for the fact that you know nothing about the matter we are discussing.

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Post by SiG I » 26 Mar 2005 22:16

Huck wrote:
That article is one of the worst ever written in the history of aviation journalism. This guy, Bud, he cannot write a single paragraph without making a glaring mistake.
Throw this article into the garbage.
Hey, I never claimed to be an aviation expert, this is why I submitted this article to your comments. How about you point out some of those "glaring mistakes". I didn't find that article easy to believe, but I don't to know if there are any facts to contradict it.
Thanks in advance!

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Post by Uncle Joe » 27 Mar 2005 02:36

Topspeed wrote:I did eat Canttarelli cravy yes.

The high speed G-stall caused the pilot to hit his head on the canopy side and loose conciousness. The start of the stall happens without a warning and takes place in a split second.

Before the "stall" plane has been flying at a very high speed when the pilot rapidly applies the stick back...instead of the hoped high g turn the plane snaps violently 1,5 rolls and continues to fly in the direction where it was flying/heading before the attempted turn.

The very high G-loading lasts only a matter of few hundreds of a second.

I think in the movie Right Stuff Charles Yaeger experiences this painful phenomena with an X-2 experimental mach 2+ research aircraft.

-----------------------------------

Because of the nasty nature of this phenomena it has been eliminated from most of the fighter types ( all ? ) in the design phase. During the WW II the phenomena was more or less unknown.

-----------------------------------

Uncle Joe !

I hope you would be able to use some other kinda language ( I know people have been banned for less insulting remarks ) and just settle for the fact that you know nothing about the matter we are discussing.
Why should I watch my lingo when you write utter fantasies as there are certain limits on idiocy I tolerate? Some less informed may even believe your fairy tales and I am determined to prevent that. E.g. where did you get that pilot hitting his head dream as it has nothing to do with the accelerated stall phenomenon? All aircraft will stall if turned too tight. Only way to avoid this is using computer controls which override pilot´s inputs. Accelerated stall may be violent without warning, i.e. rapid flicking out of the turn, or milder phenomenon with nose dropping thru with wings level with plenty of pre-stall buffet. Still, it is accelerated stall nevertheless. For what it is worth, at e.g. 3 g Mustang´s stalling IAS was aroung 159 mph, according to the Joint Fighter Conference report.

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Post by gabriel pagliarani » 27 Mar 2005 06:53

Uncle Joe wrote: ...All aircraft will stall if turned too tight....
This is the point. High speed stall limit and low spped stall limit are measured only when the plane is frontward moving or "hand-off-the-cloche". I have read the Chuck Yeager' s report (the book was "The right stuff" and a fine movie was based on it) and the sequence of facts was the following:
1) he reached highspeed stall limit
2) one wing stalled before the other
3) as consequence the plane turned as it was pivoted on the stalled wing without exploding.
4) the plane began to fall while turning round to the stalled wing: the second miracle was in the fact the outer wing was not pulled away by inertia. X-1 and X-2 were the toughest planes ever built before.
5) the plane turned so quickly that the pilot was squeezed on the other side of the cockpit respect with the pivoted wing
6) the action of inertia on the heavy helmet caused the breaking of the brittle canopy: the same phoenomenon occurs at very today to Formel 1 pilots. Their hlemets must be blocked.
All these events in a very few time, probably less than 2-3 seconds.
I never supposed before there is some peyote in Finland too. Cantarelli? sounds italian :lol: . Nice place for a trip, indeed

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Post by Topspeed » 27 Mar 2005 08:01

Uncle Joe wrote: Accelerated stall may be violent without warning, i.e. rapid flicking out of the turn, or milder phenomenon with nose dropping thru with wings level with plenty of pre-stall buffet. Still, it is accelerated stall nevertheless. For what it is worth, at e.g. 3 g Mustang´s stalling IAS was aroung 159 mph, according to the Joint Fighter Conference report.
159 mph is hardly a high speed is it ! :lol:

What I said about Mustang not being able to high speed stall I would like to refer to the Mustangs chasing Me-163 Komets. In one such incident a Mustang pilot reached a very high speed and was able to score a Komet. While recovering from this dive the pilot suffered very high G-loading ( lost conciousness for a while ) and when he returned they found out that the wings of the plane were bent upwards for few degrees.

X-1 and X-2 having much less wing and a lot more power and speed was easily in this stall. I think we can at least agree that wing area dihedral and speed has something to do with it ? :|

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Post by Huck » 27 Mar 2005 08:18

Topspeed wrote:I did eat Canttarelli cravy yes.

The high speed G-stall caused the pilot to hit his head on the canopy side and loose conciousness. The start of the stall happens without a warning and takes place in a split second.

Before the "stall" plane has been flying at a very high speed when the pilot rapidly applies the stick back...instead of the hoped high g turn the plane snaps violently 1,5 rolls and continues to fly in the direction where it was flying/heading before the attempted turn.

The very high G-loading lasts only a matter of few hundreds of a second.

I think in the movie Right Stuff Charles Yaeger experiences this painful phenomena with an X-2 experimental mach 2+ research aircraft.

-----------------------------------

Because of the nasty nature of this phenomena it has been eliminated from most of the fighter types ( all ? ) in the design phase. During the WW II the phenomena was more or less unknown.

-----------------------------------

Great explanation Topspeed :D
Sadly it has nothing to do with high speed stalls.

I think it's time for a short aerodynamics lesson.
First, when does the stall occur? A wing flies at a certain incidence on airflow, called angle of attack, AoA. As AoA gets bigger so does the coefficient of lift and the lift itself. However, for each wing there is a maximum AoA, past which the wing stalls. This happens regardeless of any other factor, once max AoA is reached the wing will stall. Now, what happens at higher speeds? how come that it is more difficult to stall the plane at higher speeds? The answer is simple, as speeds goes up so does the lift, therefore in order to keep the plane level at a higher speed, the plane will fly at a smaller AoA than at lower speeds, which makes it harder to reach max AoA and stall the plane.

What happens when pilot tries to maneuver? Once the acceleration increases, the weight increases, so the lift has to increase too, in order to keep the plane on its path. What means an increase in lift? You got it, an increase in AoA. You won't need to pull the stick to much and you'll stall again, even if you're flying much faster than the "stall speed". This is what Uncle Joe said: as speed increases you'll be able to pull more Gs, but stall will occur enventually. Indeed, there is a speed where it is possible to overG the plane before stalling. This speed is usually called "corner speed" because it allows to maximize the turn performance of the planes, enabling turns at 7G without danger of stalling (note though, jet fighters are able to sustain corner speed, prop fighters were not).

You can read on the chart below, the stall speeds for various load factors (please note that chart was ploted for a 8000lb Mustang, which in practice was an empty one).
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Post by Huck » 27 Mar 2005 08:29

Topspeed wrote:
Uncle Joe wrote: Accelerated stall may be violent without warning, i.e. rapid flicking out of the turn, or milder phenomenon with nose dropping thru with wings level with plenty of pre-stall buffet. Still, it is accelerated stall nevertheless. For what it is worth, at e.g. 3 g Mustang´s stalling IAS was aroung 159 mph, according to the Joint Fighter Conference report.
159 mph is hardly a high speed is it ! :lol:
At 250mph Mustang can pull 8G before stalling. At higher speeds Mustang pilot can overG the plane before stalling it.
However, this is nothing special. Most piston fighters did that at lower speeds.
Topspeed wrote:What I said about Mustang not being able to high speed stall I would like to refer to the Mustangs chasing Me-163 Komets. In one such incident a Mustang pilot reached a very high speed and was able to score a Komet. While recovering from this dive the pilot suffered very high G-loading ( lost conciousness for a while ) and when he returned they found out that the wings of the plane were bent upwards for few degrees.

X-1 and X-2 having much less wing and a lot more power and speed was easily in this stall. I think we can at least agree that wing area dihedral and speed has something to do with it ? :|
G-lock is a different phenomenon, it has nothing to do with high speed stalls. At accelerations higher than 5G pilots experience tunnel vision (gray/blackouts), and at 7G possible complete loss of vision and/or consciousness (depending on duration of exposure to high Gs).

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Post by Topspeed » 27 Mar 2005 08:32

I confess that when stating 10-12 G:s with a Me 109 and 15-20 G:s with a Mustang I had no factual basis on my claim. Thanks for the accurate data you brought along Huck.
Possibly the Mustang wings bent at 10 G:s and a violent stall which causes to loose conciousnesss with a Me 109 occurred at 7-8 G:s.


Either way; what I mean is that Mustang wings bent before the stall occurred at high speed ( 470-550 mph ) and Me 109 when pulling too hard caused the plane to flip on its longitudal axis very rapidly to the left ( torque related )...plane remained intact.

I did practise this phenomena with a flying scalemodel of both Me 109 and P-51D ( same scale and same engine ). Results indicated the same I stated here earlier. 109 model snapped rapidly if one applies stick back from a high speed...when doing the same with a Mustang and it initiated a loop without a problem.

I restate what I said in the beginning of this debate; Me 109 high speed stall is vicious and takes place without a warning. It may be also called accelerated stall as Uncle Joe here mentioned.

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Post by Topspeed » 27 Mar 2005 08:44

Huck wrote: G-lock is a different phenomenon, it has nothing to do with high speed stalls. At accelerations higher than 5G pilots experience tunnel vision (gray/blackouts), and at 7G possible complete loss of vision and/or consciousness (depending on duration of exposure to high Gs).
G-lock...okay I understand...did X-1 have a G-lock too ?

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Post by Huck » 27 Mar 2005 08:57

Topspeed wrote:
Huck wrote: G-lock is a different phenomenon, it has nothing to do with high speed stalls. At accelerations higher than 5G pilots experience tunnel vision (gray/blackouts), and at 7G possible complete loss of vision and/or consciousness (depending on duration of exposure to high Gs).
G-lock...okay I understand...did X-1 have a G-lock too ?
G-LOC (gravity-induced loss of consciousness) is not plane related. One can have G-LOC in a roller coaster.

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