"The Sound Barrier"

[TeaSea]

Just watched this movie, released in 1952, which is a fictional story of British aviation attempts to break the sound barrier.

Interesting point, when the movie was produced and released, no one in Britain knew that Chuck Yeager had flown faster than the speed of sound in 1947, and that the U.S. had aircraft that could routinely fly faster than the speed of sound.

That information was released in.....1952 (right after the movie came out).

Good flick though.

[Skittles]

Just watched this movie, released in 1952, which is a fictional story of British aviation attempts to break the sound barrier.

Interesting point, when the movie was produced and released, no one in Britain knew that Chuck Yeager had flown faster than the speed of sound in 1947, and that the U.S. had aircraft that could routinely fly faster than the speed of sound.

That information was released in.....1952 (right after the movie came out).

Good flick though.

Britain had supersonic capability by the time the Americans did it.

Eric Brown was due to pilot the Miles M52, which by all accounts would have broken the barrier, only for it to be cancelled last minute.

[tigisfat]

Britain had supersonic capability by the time the Americans did it.

Eric Brown was due to pilot the Miles M52, which by all accounts would have broken the barrier, only for it to be cancelled last minute.


By your own account, it sure doesn't sound like the Britain had any sort of supersonic capabillity by the time America did.

We must count the true and first supersonic flight. If you want to reach that far, then there are reports of spitfires and mustangs in dives breaking the sound barrier. They'd hit a region where elevator control would go screwy and people on the ground would hear a boom.

[TeaSea]

I should amend my comments to state that no one in the public knew about the sound barrier being broken.

The British military had already themselves broken the sound barrier in 1948 with the DH-108 which was not actually specifically designed to achieve that aim. The Miles aircraft was designed to achieve this, and again, on paper looks like it would have, but it did not. The Miles project was a testbed and contributed significantly to development of both British and U.S. Aircraft based on a mutual agreement between the two countries made in 1944. In 1946 the British Labour Government killed the project as part of post war austerity measures. That left the U.S. as the only Western country with the resources to safely advance beyond the sound barrier. That research and was made available to the British (per the 1944 agreement) and indeed, British research contributed heavily to the U.S. achievement in 1947 (the Bell X1 and the Miles design look very similar). The DH-108 used design concepts from the U.S. development also, as well as from German advances in swept wing technology.

The Luftwaffe may well have broken the sound barrier well in advance of that, but the evidence is hearsay and not documented. The USAF testing of the ME-262 revealed that in shallow dive it could have broken the sound barrier, at least on paper. Actual aircraft would not have survived pulling out of the dive. They were too far beyond VNE. It's been claimed that the Komet also did this, however, once again the documentation is hearsay, and it's doubtful that the Komet would have survived the experience. The DH-108 does look similar to the ME-163 Komet...and apparently had the same kind of unenviable safety record, but that might have been a result of the testing (the DH 108 was never a production airplane, existing only as various prototypes).

I believe the quality of German aircraft production at this stage of the war was pretty poor, even on their "wonder weapons". As the USAF discovered after the war, the potential designs and numbers, though impressive, could not be achieved due to the poor production values. That doesn't mean the aircraft still weren't impressive, they just never met their full potential.

[Skittles]

By your own account, it sure doesn't sound like the Britain had any sort of supersonic capabillity by the time America did.

We must count the true and first supersonic flight. If you want to reach that far, then there are reports of spitfires and mustangs in dives breaking the sound barrier. They'd hit a region where elevator control would go screwy and people on the ground would hear a boom.

It's not similar to Spits/mustangs breaking the sound barrier in the slightest!

The Miles M-52 was specifically designed to break the sound barrier. Scale aircraft achieved mach 1.3u8 with the aircraft remaining perfectly controllable, both in transonic and subsonic flight. In 1944 Britain signed a deal with the US to exchange data on high speed aircraft. Britain provided every drop of data about the M-52, then the US cancelled the agreement, effectively stealing the data.

The Bell was completely and utterly incapable of supersonic flight until the variable incidence tail designed for the M-52 was grafted onto the back of it.

The program was cancelled because of budget cuts. At the time, the only thing remaining was for the aircraft to be built and flown. The design was complete. It was scheduled to break the sound barrier in 1946, a full year before the Bell did it using Miles's designs.

It's widely accepted that it would do it with no problems whatsoever. After all, the only thing left to do was cut a whole in the model and stick a person in it.

So yes, Britain did have true supersonic capability (to a significantly higher speed than the Bell).

[tigisfat]

It's not similar to Spits/mustangs breaking the sound barrier in the slightest!

The Miles M-52 was specifically designed to break the sound barrier. Scale aircraft achieved mach 1.3u8 with the aircraft remaining perfectly controllable, both in transonic and subsonic flight. In 1944 Britain signed a deal with the US to exchange data on high speed aircraft. Britain provided every drop of data about the M-52, then the US cancelled the agreement, effectively stealing the data.

The Bell was completely and utterly incapable of supersonic flight until the variable incidence tail designed for the M-52 was grafted onto the back of it.

The program was cancelled because of budget cuts. At the time, the only thing remaining was for the aircraft to be built and flown. The design was complete. It was scheduled to break the sound barrier in 1946, a full year before the Bell did it using Miles's designs.

It's widely accepted that it would do it with no problems whatsoever. After all, the only thing left to do was cut a whole in the model and stick a person in it.

So yes, Britain did have true supersonic capability (to a significantly higher speed than the Bell).

So, what speed was it estimated to have been able to attain?

[Skittles]

So, what speed was it estimated to have been able to attain?

It DID attain mach 1.38.

[tigisfat]

It DID attain mach 1.38.

You said a scale model did it. Is it fair to assume the full sized aircraft would've gone faster.

[TeaSea]

Well,

I didn't mean for this to turn into a US vs. UK fight, because it really isn't.

I would make two assertions,

First, that the claim that the U.S. "stole" the technology stems from a post war frustration with the British Govt's cut of a program that was poised to achieve a dramatic leap forward in aviation technology. The actual term for "Sound Barrier" stems from a British journalist's mis-characterization of a problem in physics as described by researchers in the field. This created a vision of some sort of invisible barrier which would destroy all aircraft that approached it. This wasn't true of course, and engineers knew that, but it was built up in the public's imagination. When the desire to "break" that barrier was established, and then walked away from, there was significant frustration in the press. Further, since the U.S. was still developing the technology and became the beneficiary of the joint research, the assertion was made that the U.S. "stole" the technology. That ignores the pre-war research done, primarily by the NACA in the U.S. on the same problem, which was shared with the UK under the terms of the agreement. The Miles project benefited from that research, just as the Bell X1 benefited from the Miles aircraft.

Secondly, with the cancellation of the joint project on the UK side, the US had no one to provide research to. There were certain parts of the US project which was kept close hold, mostly due to patent restrictions but there's no evidence that the US unilaterally walked away from it's agreements with the UK. By now, both the US and the UK had a pretty good understanding of the engineering science involved in building fast aircraft, but were now moving in different directions.

Nonetheless, British pride took a significant hit with he cancellation of the Miles project, and in frustration the allegation has always been that the US researchers somehow stole the secrets of supersonic flight. I've seen nothing to justify that claim. It appears rather that the two nations benefited from their joint research, but in different ways, and that the UK decision not pursue the sound barrier was an internal political decision. I would also point out that in the immediate post war years the UK was attempting to determine it's defense priorities and what would be important for the next generation of aircraft. So, while we as aviation enthusiasts can criticize that decision, we do so with the benefit of hindsight and with no real perspective on the problems of the UK national defense strategy at that time and its priorites. In other words, we don't know what we don't know.

I would add, that most engineers agree the Miles prototype undoubtedly was capable of breaking the sound barrier. The fact remains however, that it did not.

[Ken Stallings]

Just watched this movie, released in 1952, which is a fictional story of British aviation attempts to break the sound barrier.

Interesting point, when the movie was produced and released, no one in Britain knew that Chuck Yeager had flown faster than the speed of sound in 1947, and that the U.S. had aircraft that could routinely fly faster than the speed of sound.

That information was released in.....1952 (right after the movie came out).

Good flick though.

Chuck Yeager himself makes mention of that movie in one of his books, and the movie royally angered him. Not merely because he knew it ignored the historical achievement he was part of. But, also because the movie contained a gross inaccuracy regarding the supposed breakthrough that allowed the characters in the movie to break the barrier -- that they reversed controls.

That was something that made Yeager burst out laughing by the stupidity of it.

Again, the real breakthrough was in moving the horizontal stabilizer to get it out of the pathway of the sonic wave and allowing Yeager to retain aircraft control through the transonic realm.

Ken

[TeaSea]

Oh yeah, it was totally fiction....but a good movie. A little hokey in spots.

The argument above in terms of the US v. UK is based on that horizontal stabilizer. My problem with the US v. UK assertion is that it is false if you take into account the transfer of knowledge between the two nations both prior to the war, during the war, and in the immediate post war period.

Incidentally, the key to determining the horizontal stabilizer as the source of the compression problem came from accidents with the P-38. That is what initially got the US back into the "sound barrier" solution discussion. Prior to that the issue was described simply as "locked controls". The unique design of the P-38, through serendipity, isolated that problem.

[Ken Stallings]

Oh yeah, it was totally fiction....but a good movie. A little hokey in spots.

The argument above in terms of the US v. UK is based on that horizontal stabilizer. My problem with the US v. UK assertion is that it is false if you take into account the transfer of knowledge between the two nations both prior to the war, during the war, and in the immediate post war period.

Incidentally, the key to determining the horizontal stabilizer as the source of the compression problem came from accidents with the P-38. That is what initially got the US back into the "sound barrier" solution discussion. Prior to that the issue was described simply as "locked controls". The unique design of the P-38, through serendipity, isolated that problem.

I wouldn't pay that claim of controversy any mind. The engineers who worked the problems hold no such concerns. Programs get cancelled all the time and there are many examples of parallel development. Often the ideas likewise form parallel. Once an engineer observes that the shock wave blankets a vital control surface and he learns this makes the surface ineffective, it is intuitively obvious that a great way to overcome the problem is to simply relocate the stabilizer outside the shock wave pattern of flow -- hence the vertically adjustable horizontal stabilizer. It was an elegant and obvious solution. The real trick was in learning of its necessity, a discovery that cost the life of many a pilot! It is to those dead pilots to whom the real credit should be given.

Engineers aren't stupid. When they see a problem, the ways to solve it are often obvious and therefore being intelligent people, they tend to form solutions in the same way despite zero coordination. This explains the simultaneous development in jet engines in Italy, Germany, and Great Britain.

A look at nearly every important patent reveals that it was a close race to see who ran to the patent office first! Frequently, there were several smart men working around the same time and their ideas were surprisingly similar.

Ken

[Ken Stallings]

Prior to that the issue was described simply as "locked controls". The unique design of the P-38, through serendipity, isolated that problem.

Another case of a label causing Hollywood to get it all wrong! The label "locked controls" referred to the fact people thought they were immovable, frozen solid. In reality, it was that they could damn well move all over the place but had no air mass to work against to effect aircraft control.

The shock wave simply produced a vacuum over the control surface.

Ken

[Skittles]

Well I base my viewpoint on that of Miles staff, and more importantly that of Eric 'Winkle' Brown.

Eric was an RAE test pilot, flying a world record 487 types of aircraft in his career (not including variations - basic types only). That's as pilot in command, none of those were counted in the co-pilot seat. Generally regarded as the best test pilot who has ever lived. First ever carrier landing, most carrier landings in history etc etc. He led all high-speed tests with the Spitfire (and variable incidence wing) and was scheduled to be the chief pilot of the M52. I'll go with him!

[PRB]

Another case of a label causing Hollywood to get it all wrong! The label "locked controls" referred to the fact people thought they were immovable, frozen solid. In reality, it was that they could damn well move all over the place but had no air mass to work against to effect aircraft control.

The shock wave simply produced a vacuum over the control surface.

Ken

I've often wondered about this, and kind of "theorized" exactly what you have said here. I've never heard it described in these terms by anyone, in print or otherwise. I think you're right. The desciptions of this phenomenon always had me wondering how it could physically "lock" the controls. Didn't make sense.

[Skittles]

I've often wondered about this, and kind of "theorized" exactly what you have said here. I've never heard it described in these terms by anyone, in print or otherwise. I think you're right. The desciptions of this phenomenon always had me wondering how it could physically "lock" the controls. Didn't make sense.

PRB there is another cause of this phenomenon, whereby air can be traveling over control surfaces at such a speed that it's extremely difficult or impossible to maneuver them. Generally only a problem where the surfaces are not hydraulically controlled of course.

Flight controls can stiffen for numerous reasons. A good example is in a go around procedure in a small GA aircraft. The combination of down trim generally used in the approach, getting your flaps up and full power means you have to push reasonably hard to keep the nose from going skywards.

[PRB]

PRB there is another cause of this phenomenon, whereby air can be traveling over control surfaces at such a speed that it's extremely difficult or impossible to maneuver them. Generally only a problem where the surfaces are not hydraulically controlled of course.

Flight controls can stiffen for numerous reasons. A good example is in a go around procedure in a small GA aircraft. The combination of down trim generally used in the approach, getting your flaps up and full power means you have to push reasonably hard to keep the nose from going skywards.

Rgr that Skittles. Like the A6M and other fighters of WW-II at high speed being very unresponsive in roll due to aerodynamic forces on the ailerons. But I've read descriptions of the P-38 in a dive that were very explicit in that the control column was "as though it were in a block of cement", utterly immovable. But other descriptions of the same phenomenon made it sound more like the control surfaces just had no effect, which is different...

[Ken Stallings]

I've often wondered about this, and kind of "theorized" exactly what you have said here. I've never heard it described in these terms by anyone, in print or otherwise. I think you're right. The desciptions of this phenomenon always had me wondering how it could physically "lock" the controls. Didn't make sense.

Controls can become stiff in some aircraft but not due to sonic wave patterns. Instead, the size of the control surfaces and the ability of the pilot to muscle them under the stronger wind pressures against them made it difficult to use them. The A6M Zero suffered from this problem but was not the only World War II fighter that did.

The basic problem with the shock wave was that it propagated vastly differently than did normal airflow, which tends to conform to the surface of objects. The sonic wave projects out like a cone. To go supersonic, engineers simply had to learn how to manipulate the sonic wave so that it did not blanket out any control surface and also to reduce the speed of air through the engine intake to sub-sonic so that the engines would not flame out.

Of course, since then, engineers have learned to produce scramjets, which don't bother reducing the air to sub sonic speeds, but rather manipulates the sonic wave so that it can support combution inside the engine. The description I heard was "learning to light a match in a hurricane!"

It can be called a masterpiece of fluid dynamics, well beyond my comprehension in the details.

Ken

[tigisfat]

The aeronautical contributions of the brits cannot be ignored, but if I started shopping for an L-39, and gave all my shopping and L-39 knowledge to Ken, and then I lost my money to buy one but he pressed on to buy his I wouldn't claim that I had L-39 capabilities before he did. :ernae:

[tigisfat]

Every airframe is different, and I'm sure the transsonic flight regime does different things to every aircraft.

[TeaSea]

Well I base my viewpoint on that of Miles staff, and more importantly that of Eric 'Winkle' Brown.

Eric was an RAE test pilot, flying a world record 487 types of aircraft in his career (not including variations - basic types only). That's as pilot in command, none of those were counted in the co-pilot seat. Generally regarded as the best test pilot who has ever lived. First ever carrier landing, most carrier landings in history etc etc. He led all high-speed tests with the Spitfire (and variable incidence wing) and was scheduled to be the chief pilot of the M52. I'll go with him!

I've no doubt from Brown's perspective, that this was true. With the cancellation of the Miles project, he along with his entire team would have immediately been isolated from receiving any additional engineering data from the US -- as they should have been on any classified project. That is a far cry however from claiming the US walked away from its agreements with the UK. Further, since much of the study on supersonic flight prior to the war came out of the US (in the 1920's no less), Browns assertion would ignore all that data being poured into the UK effort.

In any case, it is a shame that the Miles aircraft was never given an opportunity to be physically fly through the barrier. On that point I think we can all agree....but like I said, we do so looking backwards knowing history, and not peering forwards trying to guess what's most important.

I suppose from a long term view, it really didn't matter, except to aviation aficionado's like us.