On the 50th anniversary of the first supersonic flight, Chuck Yeager relives his gutsy assault on the sound barrier and tells how it was done. Other top test pilots of the day—those who survived—describe the dangers, mysteries, and thrill of trying to fly faster than sound at the dawn of the jet age. Heavily re-edited and re-narrated Secret History episode, "Breaking the Sound Barrier", July 7, 1997
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00:00Tonight, on NOVA, great machines.
00:05Well, there are a lot of people that said it was impossible.
00:09That's why they talked about the sonic wall. That means like a brick wall.
00:13Even greater heroes.
00:15It was an uncontrollable situation once you hit that certain speed.
00:20Who risked it all to make aviation history.
00:23It was a very important secret, and it paid off.
00:26Now, get the real story behind the race to fly faster than sound.
00:32Music
00:53Major funding for NOVA is provided by
00:57Dedicated to education and quality television.
01:02And by
01:27There was a feeling that this was a barrier that couldn't be overcome
01:34because airplanes would go out of control and nothing could be done to bring them in.
01:40Well, there are a lot of people that said it was impossible.
01:43That's why they talked about the sonic wall.
01:45That means like a brick wall.
01:47And a lot of people accepted that.
01:51The day that a plane first flew faster than sound was a milestone in the history of aviation.
01:58Many thought it couldn't be done.
02:01But great risks were taken and lives were lost to prove the skeptics wrong.
02:07There was a huge amount of vibration juddering through the aircraft
02:13as you got closer to the speed of sound.
02:16Each bite beyond a certain limit was fraught with the possibility of disaster.
02:25In the quest to break the sound barrier, Britain came up with this bullet-shaped design.
02:31But the aircraft was mysteriously cancelled before it ever got off the ground.
02:37It was the United States that would be first,
02:40and the key to its success was a closely guarded secret.
02:45It took the rest of the world five years to find out how we flew above the speed of sound.
02:51Had we blabbed our mouth, you know, they'd have known it at that time.
02:57World War II
03:09It was during World War II that pilots first experienced the problem of flying too close to the speed of sound.
03:17It happened when fighter planes went into steep attacking dives.
03:23Some went so fast they were buffeted by forces they could not control.
03:29This occurred as planes approached the speed of sound itself, 760 miles an hour at sea level.
03:44John Golley, a British pilot, accidentally flew into trouble during a raid over occupied France.
03:52Well, I was flying the Typhoon, which was really a seven-ton brute.
03:57It was a big, big chap, three times the size of a Spitfire, twice the size of a Hurricane.
04:03It was physically hard to handle when you threw it around, but it was fast.
04:10We had no indication that we might be approaching the speed of sound.
04:17We had no idea, none whatsoever.
04:21Now, I found that first dive that I did was fairly horrific.
04:26The speed built up enormously. We were going way over 500 miles an hour.
04:31And one had tremendous vibration.
04:34It was frightening in the sense that one was fighting to control the aircraft.
04:40And one's hands were on the spade grip of the control column, which was getting stiffer and stiffer.
04:47All we knew was that we had to get the bloody things out of the dive to survive, and it took a lot of effort.
04:56No one knew what happened to planes as they approached the speed of sound.
05:00For some reason, they began to behave unpredictably.
05:04Pilots began to speak of an impenetrable wall to high-speed flight, a sound barrier.
05:11No official records were kept, but some wartime pilots simply disappeared during high-speed dives.
05:18The guys were missing, and we didn't know.
05:21We didn't know what happened to them, whatever.
05:24Their controls could have locked up for some reason or another, which we never knew.
05:28We never discussed it.
05:30All we knew was that if a guy didn't come back, he'd had it.
05:36American pilots faced similar problems.
05:39Twenty-eight German planes were shot down by flying ace Robert Johnson,
05:44but he nearly died when his Thunderbolt flew too close to the speed of sound.
05:49Well, it looked a little bit like an elephant going into combat compared to the Spitfires and those type airplanes.
05:57But it was the fastest prop-driven airplane that we had.
06:02I, like everybody else, I was wanting to see how fast I could go.
06:08Johnson took the plane up to about 30,000 feet and turned it into a steep dive.
06:14My nose, which I thought was straight down, suddenly tucked under, and my controls locked.
06:22And you could not budge the controls, no matter how hard you wanted to.
06:26And believe me, your mind was going like this, what to do, what to do, what to do.
06:32Well, you were so frightened that you tried everything.
06:35And, of course, then at the bottom of the dive, as it pulled out, you'd black out,
06:40so you didn't come through until you were back up to about 19,000 feet.
06:45Johnson was lucky.
06:47His controls began to work again when dense air slowed the plane down as it descended.
06:55One of the few women test pilots in the 40s also accidentally flew too close to the sound barrier.
07:02Anne Carl was doing some aerobatic flying in the Thunderbolt when she dived into danger.
07:11Funny things began to happen.
07:13Inside the cockpit, dust was flying around.
07:18The stick would bang over against my leg.
07:23I tried various things.
07:26It was certainly not a pleasant feeling to have the plane out of control.
07:32We were just going so fast that I didn't think I could probably get out.
07:37Like Johnson, Carl also regained control of her plane just in time.
07:42As we were coming out of the dive, I wondered why I was saved, as a matter of fact.
07:50I thought it was an experience that I would certainly not forget.
07:56But some pilots who flew too near the barrier didn't survive.
08:01I was just standing out there watching, waiting to take off,
08:05and I saw these two airplanes just come screaming down, straight down.
08:11And there wasn't much else to watch except they went in, into the water.
08:19We didn't know what had happened.
08:21We assumed that they just plain old dived in, and they did plain old dive in,
08:26but we didn't know that they could not get out of it.
08:31It was an uncontrollable situation once you hit that certain speed.
08:38It was the threat of Germany's rapid advances in aviation
08:42that finally inspired both America and Britain
08:45to look further into the problems of high-speed flight.
08:50In 1942, a German fighter plane, the Focke-Wulf 190,
08:55became known to the Allied forces.
08:59Its speed and maneuverability were an unwelcome surprise.
09:04The Focke-Wulf 190 certainly provided an additional spur
09:08to the British designers and test flyers to get the edge on the 190.
09:17But we were on the edge all the time of having to push, push, push
09:21to get that little bit of extra, which would make a difference
09:24between life and death in some of the aircraft.
09:27The Focke-Wulf 190 was a very good example of that.
09:31It was a very good example of what the British were capable of.
09:35The Focke-Wulf 190 was a very good example of what the British were capable of.
09:39It was a very good example of what the British were capable of.
09:44But this was a very difficult period
09:46because we were approaching the speed of sound.
09:50And airplanes were becoming uncontrollable
09:53because it wasn't realized what the problem was.
09:56This was something quite new.
09:58The speed of sound was getting faster and faster
10:01and the planes were getting faster and faster
10:04and the planes were getting faster and faster
10:07and the planes were getting faster and faster
10:10and the planes were getting faster and faster
10:12and this was something quite new.
10:14The so-called sound barrier was beginning to be approached.
10:21In the 1940s, wind tunnels were of little value
10:24in the effort to understand why pilots were losing control.
10:30At the critical speeds just above and below the speed of sound,
10:34shockwaves in the tunnel would choke off the airflow around the model.
10:39The problems of trying to face up to the control difficulties
10:44as we approached the speed of sound
10:46was that we couldn't reproduce these in wind tunnels.
10:49No wind tunnel could give us the speed of flow over a model airplane
10:55which would reproduce what we were experiencing
10:58in the real airplane going at close to the speed of sound.
11:01So the only way to approach this was in full-scale testing
11:06of actual airplanes flying at actual speeds.
11:12In Britain, a select group of pilots was asked
11:15to risk their lives to get the answers.
11:18One of them was Eric Brown,
11:20a member of a government high-speed test unit.
11:23His assignment was to deliberately fly a Spitfire
11:27into this dangerous region.
11:29Of course, when you're young,
11:31and you're in a job like a research test pilot,
11:34you are very keen to try and beat this so-called barrier.
11:39There is always that feeling you have,
11:42a ridiculous feeling the young have of immortality,
11:46and I think this is what allows you to press on.
11:52The plan was to approach the sound barrier in stages
11:55to minimize the chance of disaster.
11:57But it meant flying a plane faster than had ever been done before.
12:03I took the aircraft up to a very high altitude
12:06of the order of 40,000 feet.
12:10There we would have a flat-out run at full throttle
12:14for about five minutes
12:16to build up the maximum steady speed we could.
12:19I pushed the aircraft over into a dive
12:22off the order of 30 to 40 degrees.
12:27At that particular angle,
12:29you could begin to feel a huge amount of vibration
12:33juddering through the aircraft,
12:35a lot of noise around the cockpit.
12:38Most frightening of all,
12:40it became harder and harder to pull the Spitfire out of the air.
12:45Most frightening of all,
12:47it became harder and harder to pull the Spitfire out of its dive.
12:51The elevator, the movable part of the tail
12:54that changes the angle of the dive, wouldn't work,
12:57no matter how hard the pilot pulled back on the control stick.
13:02I was certainly of the opinion that I was getting to my limit.
13:08There is always the risk
13:10that your muscles will not hold out in this situation
13:14and you will relax your grip on the stick,
13:17and then that will allow the aircraft, of course,
13:20to go steeper and steeper,
13:23with end result probably fatal.
13:33Another member of the team, Tony Martindale,
13:36barely survived the crash.
13:39The engine on his Spitfire exploded
13:41as he approached the speed of sound.
13:44Its propeller came off.
13:47He escaped with a broken back.
13:50Others weren't so lucky.
13:53Four of the six test pilots from the high-speed unit
13:56died at Farnborough doing these tests.
14:01Those test pilots had always a difficult time,
14:05but no time more difficult than when they were being sent up
14:10to try and approach the speed of sound
14:13with unknown control responses from aeroplanes.
14:23Bailing out at those sort of speeds,
14:25there weren't ejector seats in those days,
14:28into nearly 500 mile an hour slipstream
14:31was a thing which was only just survivable
14:34and in many cases not survivable.
14:38Several test pilots sadly were lost
14:40because the aeroplane went uncontrollable.
14:47Very early on, we had a young Canadian pilot
14:52and he was sent to us in the high-speed unit
14:56and he was in a dive
14:59and he must have let things go a little too far
15:03and it steepened all the way
15:06and he went straight into the ground at very high speed indeed.
15:24But the risks and sacrifice
15:26helped reveal why these World War II fighter planes
15:30were going out of control.
15:34At slow speeds, the air flowed smoothly over the thick wings.
15:39But near the speed of sound,
15:41air traveled so fast that it formed shockwaves,
15:44causing it to break away from the wing surface.
15:47The air would become turbulent,
15:49disrupting the wing and tail controls.
15:52Worse still, the lift generated by the air moved backwards,
15:57tipping the plane into an uncontrollable dive.
16:04What was happening, the centre of pressure on the wing was changing
16:08and firstly lateral control,
16:11the sideways tilt of the aeroplane,
16:13was going beyond anything it could be coped with.
16:16The nose would drop, speed would increase
16:19and then a sudden pitch-up would occur
16:22as the breakaway of the air flow over the wings took place.
16:26And all this was new,
16:28so we were really in a difficult era at that time.
16:34By flying planes with different wing thicknesses,
16:37it was discovered that the thinner the wing,
16:40the less the air flowing over the top is speeded up.
16:44This prevents it from breaking away from the wing surface,
16:48allowing the controls to keep the plane in level flight.
16:53Well, we were learning quite a lot about the wings of the aircraft.
16:58We realised that thinness was essential
17:03if you were going to really get high speeds,
17:07so there were structural problems for the designers.
17:16A second lesson was learned as well.
17:19The sound barrier could not be broken in a propeller-driven plane.
17:23At very high speeds,
17:25shockwaves also begin to form on the spinning propeller blades,
17:29so the faster it goes, the less efficient the propeller becomes.
17:38Fundamentally, the drag of the propeller was so high
17:43that it would never allow the aircraft to attain those speeds
17:49without running into virtually a brick wall.
17:54And we just had to wait till something better came along.
18:04By the early 1940s,
18:06there was a promising new engine in development.
18:10It had been invented by Frank Whittle,
18:12an officer in the British Royal Air Force.
18:16Whittle's invention was simple but revolutionary,
18:19with few moving parts.
18:21A spinning turbine and compressor that fed air to fuel burners.
18:26It was the jet engine.
18:33The way that the jet was able to outpace
18:37and eventually surpass and replace the piston engine
18:41was that it could be developed
18:44with fairly unsophisticated fuels
18:49like paraffin, kerosene,
18:51to give much greater powers and much greater thrust
18:55to push aeroplanes forward.
18:57It could be achieved through the rather primitive thing
19:00of a large whirling propeller.
19:04What the jet engine did was provide a simple solution
19:09to how to push the aeroplane forward
19:13by squirting a jet out of the back
19:16faster than the speed of sound.
19:19And therefore the aeroplane had to respond
19:21by going faster than the speed of sound itself.
19:26But the performance of Whittle's early designs
19:28was far from supersonic.
19:31Invented in 1929,
19:33the engine was hard to build
19:35and required new heat-resistant metals.
19:38The British government thought the difficulties were insurmountable
19:42and ignored Whittle for eight years.
19:46Germany took the lead in jet technology,
19:49flying the world's first jet-powered plane in August 1939.
19:55Called the HE-178,
19:57it was the brainchild of Ernst Heinkel,
19:59a forward-thinking aircraft manufacturer.
20:05He made use of the talents of a young engineer,
20:07Hans von Ohain,
20:09who invented the jet that powered the 178.
20:15The 178 was not built, really,
20:21for very high speed.
20:26It was an experimental aircraft.
20:31Heinkel envisioned from the success of the 178
20:37to go to a next aeroplane,
20:40which is much faster
20:43and possibly go beyond the speed of sound.
20:49He said to all of us,
20:52this is the beginning of a new time
20:56of higher and higher speed.
21:00That's what he said.
21:02By 1944, Germany possessed aircraft
21:05that could fly nearer to the speed of sound
21:08than those of any other country.
21:14One of them, the Messerschmitt 262, a jet fighter,
21:18could travel at 540 miles an hour.
21:21Some wrongly claimed it had been built
21:24to fly at the speed of sound.
21:28Heinrich Bovey was a German test pilot
21:31who flew the plane many times.
21:37One pilot, a man called Muttke,
21:41thought he had passed the speed of sound.
21:44But the plane had problems at high speed.
21:47The sound was too loud,
21:49and it was difficult to fly.
21:52The rivets popped out,
21:55and the skin on the fuselage buckled.
21:59So, I don't believe it,
22:02and neither do the experts.
22:10The 262's aircraft was built
22:13to fly at the speed of sound.
22:16I don't believe it, either.
22:46It came in a top-secret intelligence report
22:49delivered to the British Prime Minister in 1943.
22:54At the time, Britain only had one functional jet plane in the air,
22:58an experimental aircraft.
23:01The classified briefing contained reconnaissance photos
23:04of German airfields that showed
23:07just how far the Allies were lagging behind.
23:11The things one could see
23:14were marks on grass airfields,
23:17and this gave evidence of jet engines
23:20before we knew anything more about them.
23:23And what were we doing about it?
23:26And we were doing jolly little, in fact,
23:29apart from desultory help to Whittle.
23:32So there's no doubt that these intelligence reports
23:35did spur on the air ministry
23:38to produce really fast jet airplanes,
23:41which could possibly, if the war went on significantly further,
23:45have an influence in the actual front-line battles.
23:52There was a second spur as well,
23:55a British agent's report of a German plan for a supersonic jet.
24:00It was only a design study,
24:03but Germany's technological know-how had to be taken seriously.
24:08It was thought that it was about time we looked
24:11to see whether we should go towards flying faster than the speed of sound.
24:16A new concept altogether,
24:18although there had been, even before the war,
24:21thoughts that one day we might be going faster than sound,
24:25but how it would be done, nobody had the foggiest idea.
24:37In 1943, the British government asked a small plane manufacturer
24:41called Miles Aircraft
24:44to design and construct the world's first supersonic plane.
24:48Miles built training planes, not high-speed aircraft,
24:52but the company had a reputation for innovative design.
24:57The engineers faced a daunting task,
25:00to build a plane capable of flying at 1,000 miles an hour,
25:04almost twice as fast as any aircraft had ever flown before.
25:11We were a little bit shaken, of course,
25:14because up to that time we'd thought that the speed of sound
25:18was something in the distance which we couldn't approach.
25:22I mean, we'd make airplanes go faster and faster,
25:25but the speed of sound was so far ahead,
25:28we just couldn't get through the sonic barrier.
25:31The ministry required us to make the airplane
25:34and get it flying at 1,000 miles an hour in nine months,
25:37which even at that time we thought was a bit much.
25:42But of course we thought we could do it. We'd make anything fly.
25:47What they came up with was the M-52,
25:50a totally new concept in aircraft design.
25:55The only object that we have information on
25:58going faster than the speed of sound, that was bullets,
26:01so that we went for the information on bullets
26:04and used that information for the fuselage.
26:09The thinner the wing, the faster it will go,
26:12so you had to have a very thin wing.
26:14So anyway, we chose a thin wing and then had to test it.
26:18Much of the testing and construction of Britain's supersonic plane
26:22was recorded by a Miles aircraft camera team.
26:25The footage has not been shown before.
26:29The wing was put onto an ordinary 200 horsepower Miles aircraft
26:34and it was flown and it behaved very well.
26:41But we were quite confident that the tests we did would work
26:44because we checked them as we went along the line.
26:48Just two months after the British team began work,
26:52the United States entered the race to break the sound barrier.
27:02The decision was made at a wartime gathering
27:05of some of the country's top aviation experts.
27:10They were worried about America falling behind not so quickly.
27:14They were worried about America falling behind Nazi Germany.
27:21The country did have a new jet fighter
27:23and those present watched a film of the plane being put through its paces.
27:34The XP-59A, as it was called, relied on the Whittle jet engine,
27:39a gift from the British.
27:41But despite its jet power,
27:43the XP-59 did not perform any better than propeller-driven planes.
27:49The P-59A didn't go through the speed of sound quite,
27:53but it did go faster than present fighters a little bit.
27:59And so the feeling was, in the Air Force,
28:03that this was a step ahead.
28:06But there were many steps still to go.
28:12What the country needed, it was decided, was its own supersonic plane.
28:20The United States had been exploring the feasibility
28:23of high-speed flight for more than a decade.
28:27But it was clear that unless its research efforts were stepped up,
28:31the country would fall seriously behind.
28:42So the Bell Aircraft Corporation, as it was called in the 1940s,
28:46was enlisted to build America's first supersonic plane.
28:53Its founder, Larry Bell,
28:55had a reputation for getting things done fast and on budget.
29:01But outside Bell, many doubted his chance of success.
29:06There were a considerable amount of pessimism
29:09about what was the environment at that present time.
29:12And this fit down to the designers even, themselves.
29:15How strong do I have to build the airplane?
29:18What do I have to build the airplane to accommodate?
29:21And these were unknowns and big questions at that time.
29:26Well, there were a lot of people that said it was impossible.
29:29And that's why they talked about the sonic wall.
29:32The sonic wall, that means like a brick wall.
29:35And a lot of people accepted that.
29:39My personal feeling is that let's go step by step
29:43and use all the tools and knowledge in Europe,
29:46anywhere we could find it,
29:48and put it together and see what we come up with.
29:56It is unclear just how much information was exchanged
29:59between the British and American teams.
30:04But for some across the Atlantic,
30:06the memory of the collaboration remains a bitter one.
30:12The idea was that they had decided
30:15that it was a good idea to make a supersonic airplane,
30:19and they had heard that we were making one.
30:22So they came over to England with the idea
30:25that they would have all the information that we had accumulated,
30:28the idea being that a fortnight later we would go to America
30:31and they would give us all the information that Americans had got.
30:35But after the Americans had got the information,
30:38taken the drawings away, within a fortnight,
30:40when we were trying to arrange the visit,
30:42they just said, sorry, secrecy.
30:44The Pentagon says you can't.
30:49But the real threat was Germany.
30:51If America was months behind the British,
30:54it was even further behind the Germans.
30:58By 1944, Germany already had a vehicle
31:01that could travel faster than sound.
31:06The V-2 rocket,
31:08a weapon of terror unprecedented in modern warfare.
31:14Because it was supersonic, the V-2 arrived before you heard it coming.
31:19You heard it coming after it had gone off bang on the ground,
31:23and it was pretty disturbing to the populace.
31:26The Germans had what in effect was interplanetary missiles,
31:32when nothing else had been thought in that line before.
31:38And a missile like the V-2
31:40was aerodynamically much simpler than a supersonic aircraft.
31:48By early 1945, the Miles engineers in Britain
31:52were constructing a full-scale mock-up of their plane.
31:58They were confident it would work.
32:01But they did have plans to cope with the disaster.
32:05The cockpit was held on by four or five metal bars.
32:10Those had explosive charges round them,
32:13and if he had to get out, he would explode those,
32:18and the whole cockpit would leave the aeroplane,
32:21and he would be in a capsule, which would be completely safe.
32:25It was really a modern ejector seat,
32:28so we were doing what they are now doing 50 years ago.
32:33The cockpit was exceptionally small,
32:37therefore the pilot had to be of small stature.
32:42You were almost supine in the aircraft,
32:46and the nose wheel, when it retracted,
32:50was lying straight between the pilot's legs,
32:53so it was going to be pretty well of my stature,
32:57I'm of the order of 5 feet 7,
33:00and you couldn't really get anybody bigger than that.
33:05The pilots themselves, they thought it was a jolly fine idea,
33:08they all wanted to have a go.
33:10Oh yes, they thought it was absolutely an excellent idea to have a go.
33:13There was no suggestion that there was unfair risk
33:16in any context at all.
33:20By the end of the war,
33:23no country had built a plane that could fly faster than sound.
33:32But the Germans had come fairly close.
33:39How close they had been became clear
33:42when the Allies got their hands on the Messerschmitt 163,
33:46a rocket-powered plane.
33:49It flew to the very edge of the sound barrier,
33:52but its wings were not suitable for supersonic flight.
33:59The M163 was the first really genuine flying rocket aeroplane,
34:06with an endurance of only about 10 minutes of flight at full power,
34:11but getting on for the speed of sound,
34:15about 90% up towards it,
34:18and pretty formidable,
34:20but also killed a lot of its very brave test pilots.
34:27It was dangerous because, firstly,
34:29it was going faster than anyone had encountered before,
34:32and therefore going out of control on occasion,
34:36and secondly, because these rocket fuels blew up
34:40and blew the thing to smithereens.
34:45And there were other dangers to high-speed flight.
34:51The Bell engineers were worried
34:53about the stresses the plane would encounter,
34:57so they designed it to withstand loads
35:00up to 18 times the force of gravity,
35:04far beyond what was needed.
35:09Equally problematic was the choice of engines.
35:14Rocket motors were prone to explosions,
35:17but they could deliver enormous thrust.
35:21Others believed the more reliable jet engine was the answer,
35:25but jets of the day lacked the power to reach supersonic speed,
35:30except in steep and risky dives.
35:38After much debate, it was the rocket engine that finally won U.S. approval,
35:42but the choice was not without controversy.
35:46Personally, I had some reservations about a rocket
35:49when you see them operate because it's like a small explosion,
35:52but it would get you to the area of interest a heck of a lot quicker,
35:57and I'm not sure that we knew that much about a jet engine.
36:01The time to get there and all the aerodynamic problems
36:04of getting the air to the engine,
36:06the rocket appeared to be the simplest.
36:12Britain had a good reason for not following the American lead.
36:17Whittle had made a special engine,
36:19being six or seven times the thrust of any propeller-driven
36:22or jet engine at that time,
36:25and with such a tremendous increase in power, the sky was the limit.
36:29We were expecting to fly at about six months' time,
36:32at that stage, for the test flights.
36:36But early in 1946,
36:39Miles Aircraft received a letter from the Ministry of Aircraft Production
36:43cancelling the project.
36:46We were all extremely surprised.
36:49All the problems we thought were over.
36:52We got a sound aeroplane.
36:54Everybody agreed it was going to be a success.
37:00So when you've got a success,
37:02such an advance compared with anybody else in the world,
37:05and you just get a memo,
37:07''Please stop.''
37:09One is shaken, to say the least of it.
37:12If somebody had given us a reasonable reason for its cancellation,
37:16we wouldn't have been too worried.
37:18We'd just accept it.
37:20But not giving a reason for it, just cutting it out.
37:23It's like getting an aeroplane onto the airfield,
37:26ready for test flying, and then somebody says,
37:29''Oh, don't bother, throw it away.''
37:32I mean, it just is out of this world.
37:35You can't believe such a thing is happening.
37:41I really couldn't see the logic in the cancellation.
37:45Everything pointed to a good potential chance of success.
37:49And I was really quite hopping mad at the time when it was cancelled.
38:00For 50 years, the cancellation of the M-52
38:04has been the subject of argument and secrecy.
38:08Ben Lockspizer was the civil servant who abandoned the project.
38:12He said it was too dangerous.
38:15The reasons why he came to this decision are only now becoming clear.
38:20At the end of the war, Lockspizer accompanied the M-52
38:25At the end of the war, Lockspizer accompanied
38:29a number of British and American scientists
38:32who visited a secret aircraft research laboratory near Munich in Germany.
38:37All that remains today is the blocked-up entrance.
38:41But some of Germany's most talented aircraft designers once worked here
38:46on designs that convinced Lockspizer
38:49the M-52 would never break the sound barrier.
38:54I had the opportunity just after the end of the war to fly into Germany
38:59to have a look at what they were doing or had been doing.
39:04One of the eye-openers which certainly impressed Benny Lockspizer very much
39:11was the quite novel idea of highly swept-back wings.
39:17And they had advanced swept-back wings
39:20which enabled them to go much nearer to the speed of sound.
39:24Benny Lockspizer came back from Germany
39:27convinced that swept wings were the only solution.
39:30And so he cancelled the Miles airplane on the grounds.
39:35If he allowed it to go forward, he'd be putting test pilots
39:39at very grave risk of the airplane going out of control.
39:44In December 1945, just days before Britain's hopes were ended,
39:50the United States rolled out its first test plane.
40:01Called the Bell X-1, American engineers had also designed
40:05a thin, straight wing for their supersonic hopeful.
40:11The Bell team had considered giving the X-1 swept-back wings
40:15because they delayed the formation of shockwaves
40:18and so helped to minimize the turbulence.
40:21But in 1945, the idea was untested.
40:24And the Americans realized swept wings weren't essential for supersonic flight.
40:29If the aim was to fly rapidly through the sound barrier,
40:33thin, straight wings could do the job just as well.
40:37Without question, we actually had more information on the straight wing.
40:41So if you sized up the various advantages and disadvantages,
40:46we had the smallest degree of risk
40:50to enter an area that we didn't have all the answers for,
40:54to go with a straight, thin wing.
40:57Frankly, I was a little surprised that the British didn't go ahead
41:01because I have a good feeling
41:04they could have made it.
41:07With all due respect to the people responsible for the cancellation,
41:11I think they made a mistake.
41:16Cluster meteors of the RAF high-speed flight are out for new records.
41:20Britain was not the first to break the sound barrier,
41:23but for a while at least, it did have the world's fastest plane.
41:27The meteor broke the speed record in 1946,
41:31flying at 616 miles per hour.
41:34But it would never fly faster than sound.
41:38That same year, British test pilot Geoffrey de Havilland
41:42was also vying for the speed record with a different kind of aircraft.
41:46Called the DH-108 Swallow,
41:49it was designed to study the high-speed performance of swept wings.
41:56On the eve of its speed record,
41:59on the eve of its speed record attempt,
42:02de Havilland took the plane out for a final test flight.
42:07He was never seen alive again.
42:11The Swallow had disintegrated during a high-speed dive.
42:15Like so many before him,
42:17de Havilland fell victim to the destructive force of shockwaves
42:21as he approached the speed of sound.
42:25The U.S. was now alone in the quest to break the sound barrier.
42:30In 1947, the Bell X-1 was handed over to the Air Force
42:35to test the plane's high-speed potential.
42:38The pilot chosen to attempt the sound barrier
42:41was Captain Chuck Yeager.
42:44I came up as number one because, number one, I could fly airplanes.
42:48I'd been to test pilot school, and I understood machinery.
42:52And because the X-1 would blow up on you real easy
42:55if you didn't know the system.
42:57And consequently, I knew the systems.
42:59A lot of the systems in the X-1
43:01were systems that my dad used in the natural gas fields in West Virginia.
43:05And I used to work on the diaphragms and the pressure regulators
43:09that were in the X-1, or similar.
43:11And so it was easy for me.
43:14He had a mind of his own, and that's good.
43:17He listened to you.
43:19He listened to you, but you couldn't pull anything over on him.
43:23I mean, you couldn't sneak in something,
43:25hey, how about you try this, because he wouldn't buy it.
43:29He's a very savvy, practical individual.
43:41The Bell X-1 was taken to Muroc Flight Test Center in California
43:45for its record-breaking attempt.
43:49In order to conserve fuel for the flight,
43:52the X-1 did not take off from the ground.
43:55Instead, it was flown up to its launch height,
43:58strapped underneath a B-29 bomber.
44:03It was built extremely strong, like a battleship, for a purpose,
44:08in case we had problems near the speed of sound.
44:11And it was built about twice the strength
44:14of a normal fighter airplane at that time.
44:17And that corresponds to being able to carry its weight,
44:22about 16 times its weight, 16 G.
44:26So that means the pilot could maneuver the airplane
44:29up to 16 times his weight and the airplane's weight
44:32before the wings would fail.
44:35The rocket engine in the X-1 did not inspire the same confidence.
44:40The dangerous and unforgiving nature of rocket operations
44:44was a constant source of worry.
44:47I went one time in the B-29
44:50and watched the operation to check out the rocket engine.
44:54To me, I felt the whole risk of the program at that time
44:59with those speeds we had reached.
45:01Our problems may have been around the rocket engine or the fuel
45:05or something that someone's goofed up mechanically.
45:09But on October 10th, the rocket motor behaved perfectly.
45:13Yeager reached 658 miles an hour.
45:17But at the edge of the barrier,
45:19he hit the very problem that had foiled everyone else.
45:24When we got the airplane up to 94% of the speed of sound
45:27and I'm sitting out there and I decided to turn the airplane,
45:31I pulled back on the control, nothing happened.
45:34The airplane just went the way it was headed.
45:36I said, man, we've got a problem.
45:38So I raked the rockets off and jettisoned the liquid oxygen
45:41and alcohol and came down and landed.
45:43And got the engineers together and we had a little heart-to-heart talk.
45:46We've got a problem.
45:48And because the airplane may pitch up or pitch down,
45:51I've lost the ability to control it.
45:53The X-1 would need more than a rocket engine
45:56and thin wings to break the speed of sound.
45:59Fortunately, the engineers thought they had the answer,
46:02a new all-moving tail.
46:05Other planes could only move a small portion of the tail.
46:08On the X-1, the entire assembly could move.
46:11It hadn't been used before,
46:13but they thought it might stabilize the plane.
46:16First, it had to be checked out.
46:20And it's really interesting.
46:22See, being a mechanic,
46:24all we did was take cowling oil, squirt three-in-one oil on it
46:27and run it up and down and up and down until it worked.
46:31On October 14, 1947,
46:34they tried the new tail out for the first time.
46:39In fact, all the mechanics, everybody was around the radar truck
46:43because that's where you had our communication coming in.
46:47And we stood there waiting, listening.
46:55When you get up to around 12,000 feet,
46:58you've got a seat-type parachute on.
47:00You get on a ladder.
47:02They let you down till you're opposite the door,
47:04and you slide in feet first.
47:08Yeager was in considerable pain.
47:11On the eve of the flight,
47:13he'd fallen off a horse and broken his ribs.
47:21You're in a very dark hole under the B-29,
47:25and when you drop clear of the B-29, you're in bright sunlight.
47:29Eight, seven, six, five,
47:33four, three, two, one.
47:38Go!
47:46When I got above 94% of the speed of sound,
47:49the nose begins to come up on the airplane.
47:52I just cranked the leading edge up on the horizontal stabilizer
47:55to keep the nose down.
47:57When it went a little faster, the mach meter went off the scale.
48:01And when it did, all the buffeting smoothed out
48:04because of the supersonic flow of the whole airplane.
48:07And I knew that we'd gotten above the speed of sound.
48:14And about that time,
48:17on the ground around the radar truck,
48:20we heard a sonic boom.
48:25And we had a satisfying feeling
48:29that we'd gone beyond the speed of sound.
48:33We had the unknowns that were suspected
48:36why Chuck removed them.
48:40That's it.
48:47The big thing that came out of the whole program
48:50was that we found out
48:52in order to control the airplane through Mach 1,
48:55we had to have a flying tail on it.
48:58That was the first time we had experimented
49:01with this flying tail on the X-1.
49:04That really was the answer to flying at supersonic speed.
49:12At last, there was something to celebrate.
49:15But instead of a party, the Air Force ordered a news blackout.
49:19The flying tail and other details of the plane
49:22had to be kept secret.
49:26It lasted two months.
49:28In December, the story of the flight was on all the front pages.
49:32The Air Force was furious
49:34and tracked down the news editor of an aviation magazine
49:37that had broken the story.
49:40The military considered it a breach of national security
49:44and called in the FBI.
49:48I thought it was ridiculous.
49:51The Air Force had had a press conference in July
49:54in which they had unveiled the X-1
49:57and released all of the technical specifications
50:00of its performance.
50:04There was no technical information in our story
50:07that hadn't been released six months before.
50:12The all-moving tail wasn't even mentioned in the article.
50:16The FBI investigation was quietly dropped.
50:21But with the Cold War beginning, the need for secrecy remained.
50:26It was a very important secret.
50:29You know, I'd been in the military long enough
50:32and I'd fought in wars and understood security,
50:35and it paid off.
50:37It took the British and the French and the Soviet Union
50:40five years to find out that little trick
50:43that we found out with the X-1.
50:45It gave us a quantum jump on the rest of the world in aerodynamics.
50:48Had we blabbed our mouth, you know, they'd have known it at that time.
50:56During the Korean War, Chuck Yeager saw evidence
50:59that the all-moving tail was kept secret from the Soviet Union.
51:04But it seems the Miles team knew all along.
51:08We thought the ordinary controls wouldn't work
51:11above the speed of sound,
51:14so we had to make an all-moving tailplane
51:16because an ordinary elevator would mostly not function at all.
51:20We'd go up to the speed of sound, lose all air control,
51:23and the aircraft would crash.
51:25One year after the X-1's historic flight,
51:29Britain broke the sound barrier with a one-third scale model of the M-52.
51:34Although unmanned and radio-controlled,
51:37it did finally vindicate the worthiness of its supersonic design.
51:43The model also used a rocket engine,
51:46not a jet, to power it through.
51:49It would be six more years before the first jet-propelled plane
51:53would break the sound barrier in level flight.
52:01The Bell X-1 was the first of an entirely new generation
52:05of experimental aircraft.
52:08It forever changed America's approach to aviation research,
52:12combining the forces of industry, government, and the military
52:16to build what none of them could do alone.
52:23With the X-1's success came the needed funds
52:26to delve further into the limits of flight,
52:30generating a host of faster, more sophisticated military aircraft.
52:39The fastest, the X-15, flew at nearly seven times the speed of sound.
52:46The lessons learned ultimately made possible
52:49the dream of supersonic passenger travel.
52:56Chuck Yeager in the X-1 started the ball rolling down this road
53:01which will take us into hypersonic speeds in years to come,
53:06in which the men in the street can fly right around the world
53:10in relatively few hours.
53:15Even space exploration owes much to the pioneers,
53:19who half a century ago refused to take no for an answer.
53:30An entirely new era in military and civilian aviation has been opened
53:35as a result of the determination and bravery of pilots
53:39who risked all to achieve the impossible.
53:43NASA Jet Propulsion Laboratory, California Institute of Technology
54:13www.pbs.org
54:44Next time on NOVA...
54:47An IRA bomb has been planted.
54:50Someone must defuse it.
54:52Quickly.
54:53Safely.
54:54There's a piece of fishing line dangling off one of the doors.
54:57You might be in trouble.
54:58It's the most incredible power I've ever seen unleashed
55:02and all from striking a box of matches.
55:04Politics and science make an explosive mix
55:08in Bomb Squad.
55:13www.nasa.gov
55:16www.spacevidcast.com
55:19www.spacevidcast.com
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56:19NOVA is a production of WGBH Boston.