Horton

[Crumpp]

While nobody fully understood swept wing theory, the Germans were light years ahead of anybody else.

In fact, Sir Sydney Camm, the designer of the Hurricane initially remarked, "Has anyone seen such a bloody useless" design concept upon seeing the German swept wing designs.

[ACE-OF-ACES]

Originally Posted by Crumpp

That is not correct.

That is your opinion and your welcome to it.. But I think Ill stick with what STORMBIRDS and Jenkins had to say on the subject. S!

[Crumpp]

That is your opinion

That is not my opinion Tagert. It is what is written in:

The Birth of Sweepback - Related Research at LFA-GermanyPeter G. Hamel∗

Given at:

AIAA Atmospheric Flight Mechanics Conference and Exhibit
11-14 August 2003, Austin, Texas

Would you like a paper from Boeing summing up the German contribution to aerodynamics during WWII? I am sure you will hate it and be very disappointed.

You do know the father of modern fluid dynamics was not only German, there are pictures of him with von Kármán in the article.

Do you have a clue who Theodore von Kármán is and his role during the war?

The leading academics in aeronautical sciences were for the most part, colleagues and all knew each other before the war. Theodore von Kármán, the leading US scientist in aerodynamics, was a student of Ludwig Prandtl.

http://en.wikipedia.org/wiki/Ludwig_Prandtl

[ACE-OF-ACES]

Originally Posted by Crumpp

That is not my opinion

Well I don't know what else to tell you Crump

Other than I choose to take STORMBIRDS and Jenkins statements over yours with regards to the reasons why the Me262 wings were swept..

Why? Well I consider them to be more of an expert on the topic than you..

Please don't take it personal!

Which should be understandable when you consider the fact that Dennis Jenkins has written more aviation books than most people own or have read, and that the folks at STORMBIRDS clearly did their homework during the process of building reproductions of the Me262, that were so good that messerschmitt gave them continuation serial numbers

It just makes sense to go with what they said over what you said

Please don't take it personal!

But look at the bright side..

I did agree with what you had to say with regards to the Germans fully understanding swept wing theory during the war, when you said

Originally Posted by Crumpp

Nobody fully understood swept wing theory until after the war.

But as for the details as to the reason the wing was swept on the Me262, Ill have to stick with STORMBIRDS and Jenkins

S!

[Crumpp]

over yours

Let's examine your sources and compare it to mine.


Stormbirds, it is the Me-262 project. A company with the objective of selling airplanes. They are not a scientific organization.

The Me 262 is available for sale and would make an excellent center piece for any museum or private collection. The price has been reduced from $1.1M to $650K USD. In addition to "Gelbe 5", the third and final flying Me 262 example is nearing completion and is also available for sale. The flying aircraft is a two-seat example which can be converted to a single seat for movies, airshows, etc. and is priced at $2.5M USD. Interesting trades and possible financing considered.

http://www.stormbirds.com/project/general/updates.htm

Your other source is Dennis Jenkins. A very knowledgeable man and a consulting engineer who spent 20 years working in the Space Shuttle program. However he is not a primary source nor was he there conducting research in wartime Germany.

http://www.amazon.com/Dennis-R.-Jenk...ntt_dp_epwbk_0

He wrote books for profit in other areas of interest.

The article presented at:

AIAA Atmospheric Flight Mechanics Conference and Exhibit
11-14 August 2003, Austin, Texas

Is from a scientific organization and not for profit.

Once more, it comes directly from the horses mouth. The scientist involved were all friends and colleagues both before and after the war.

Special tribute must be given to Theodore von K´arm´an who for a
second time (after World War I) brought together scientists whose
personal contacts had been destroyed by World War II.

The author of the article knew these men and was a colleage.

Director retired, Institute of Flight Research, German Aerospace Center (DLR), Lilienthalplatz 7, D-38108 Braunschweig, Germany,

Once more, it is impossible to say that Mtt was not aware of the benefits of swept wing design. They were the first company in the world to design an aircraft purposely to take advantage of swept wing technology.

It was already stated that the first true industry project utilizing an
aft-swept-wing concept was the P 1101 designed by Messerschmitt
in 1944/45 (Ref. 6). After the availability of German captured windtunnel
test data and industrial design details, direct derivatives of
this configuration were developed in the United States at Bell23
(X-5) and in Sweden at SAAB (J-29) with the expertise of former

So while the statement the Me-262 was not originally designed with swept wing technology is factual, it is not factual to claim it did not benefited from Mtt knowledge and the German leadership of the world in swept wing research.

Here is the paper from Boeing summarizing the contribution of German research and development during the war.

the effect of the advances demonstrated by the German research and development efforts during WW 2 were profound.

Taken as a whole (rather than as mere bits and parts of interesting gadgets), the German work helped crystallize, reinforce and “make very real and immediate” the conclusions men like von Kármán and Dryden, and policy makers in the military and government with whom they were influential, were reaching in attempting to create a strategic roadmap for scientific research and weapons development in the new post-war world.

From a Letter written by Theodore von K´arm´an:

G.S. Scharer (sic)
Volkenrode
Germany
5/10/45

B. Cohn
Boeing Aircraft Co
Seattle Wash USA

Dear Ben,

It is hard to believe that I am in Germany within a few miles of the front line. Everything is very quiet and I am living very normally in the middle of a forest. We have excellent quarters including lights hot water heat had electric razors etc.

We are seeing much of German aerodynamics. They are ahead of us on a few items which I will mention. The Germans have been doing extensive work on high speed aerodynamics. This has led to one very important discovery. Sweepback or sweepforward (sic) has a very large effect on critical Mach No.
This is quite reasonable on second thought. The flow parallel to the wing can not effect (sic) the critical Mach No and the component normal to the airfoil is the one of importance. Thus the critical M is determined by the airfoil section normal to the wing and by the sweepback.

..............................................This is not complicated by adding a body at the center but is badly effected (sic) by most nacelles.

..................Naturally many control and stability problems are to be encountered in using large amounts of sweep. (Here out of ink!)

.................................................. .........................................

Sincerely,

George

Notice the Me-262 has nacelles while the Me-163 and P-1101 do not.

In summary, you can form your opinion based off your commercial and far removed from the original, sources. They fit your agenda and you are most welcome to it.

I personally believe the scientist who were there from both sides and the engineers that did the design work both during and after the war.

The characterization that the wing sweep of the Me-262 was accidental is factually not correct. It is intellectually dishonest.

[ACE-OF-ACES]

Originally Posted by Crumpp

I personally believe...

Now don't take this personal..

But I really don't care about what you 'personally belive'

All I care about is what can be 'proven'

If we don't draw the line there, than what is to stop those who 'belive' the Germans were assisted by aliens from outer space?

Answer.. Nothing

So with that said.. Ill have to stick with what STORMBIRDS and Jenkins said wrt the reason the Me262 wings were swept..

Why?

Well for one thing I consider them to be more of an expert on the topic than you..

That and if there was any 'proof' to support the connections your making.. they would have made note of it..

Especially STORMBIRDS who are clearly pro German tech biased..

But unlike you they have a reputation to consider.. Which probably explains why they stop short of saying and/or making the connections your making..

So with that said, we will just have to agree to disagree as to the reason the wings were swept on the Me262

S!

[Crumpp]

Dr. Theodor von Kármán holds an important position among the contributors to aerodynamic theory, particularly in the area of supersonic flight. Known as “the father of supersonic flight,” he made major contributions to aviation and space technology, theoretical aerodynamics, and the application of theory to improve aircraft performance. He also helped develop the use of rocketry for creating weapons of defense.

By the age of 22, von Kármán had graduated from Royal Joseph University in Hungary with a mechanical engineering degree and highest honors. He enrolled in the advanced study of mechanical engineering after serving his mandatory military service and received his doctorate under the tutelage of the famous aerodynamicist, Ludwig Prandtl.

http://www.centennialofflight.gov/es...arman/TH21.htm

[Crumpp]

ACE-OF-ACES

Of course, there is evidence to support all opinions on any subject.

http://www.ufodigest.com/

Why would they go to all the trouble of sweeping the inner wings forward 18 degree is they knew in advance it would not increase the critical Mach number?

Our critical Mach number is raised by reciprocal of the cosine of the angle of sweep. So for 18 degrees of sweep we see a 1.05146 increase to critical mach.

So mach limit of Mach .8 becomes a new limit of .84.

Now at sea level that is represents a 30mph increase in speed!

Now the drag reduction is proportional to cos^2<angle of sweep>

Or a 9.5% reduction in drag.....

Not a bad call on the part of Mtt to add 18 degrees sweep based off their advanced knowledge of swept wing theory. By keeping the sweep moderate, they certainly avioded all the stability and control issues found with sweep angles and engine nacelles.

What is your opinion based on again?

[ACE-OF-ACES]

So what part of we will have to agree to disagree are you struggling with?

[Crumpp]

Why would they go to all the trouble of sweeping the inner wings forward 18 degree is they knew in advance it would not increase the critical Mach number?

So what part of we will have to agree to disagree are you struggling with?

I am confused on just what your opinion is now.

Any engineer or someone familiar with aircraft performance can easily tell you it does increase the critical mach number and the top speed.

What are we agreeing to disagree on?