Ticket Through The Sound Barrier (1966)

commercial air travel is old enough to have a history yet imagine just 41 years ago Henry Ford introduced the first all metal aircraft his Tri motor capable of cruising with 14 passengers at a breath taking 100 mph by the early 1930s the Curtis Condor last of the biplane era was making scheduled transcontinental runs steart thises had already learned to smile away the discomforts of cramped legs and tired bodies after World War II four engine airliners dominated the skies lifting up to 100 passengers across continents and oceans now hardly two decades later the luxury of jet travel puts Paris only a coffee break from London and San Francisco but dinner and a fulllength color feature from New York the next chapter in the brief history of commercial flight will be the new supersonic transport our story today on science reporter [Music] hello I'm John Fitch MIT science reporter today we're at NASA's as research center near San Francisco California to learn about the next generation of commercial aircraft the supersonic transport 20 years ago knowledgeable men were seriously wondering whether man could ever fly faster than the speed of sound debate ceased abruptly on October 17th 1947 when Captain Charles joerger piloted his research craft the X1 through the sound barrier thus marking the beginning of a new epic empowered flight today manned supersonic flight is commonplace military aircraft such as the versatile F-111 the giant b58 or the mysterious yf12a to name only a few normally Cruise it speeds well over the speed of sound and the experimental X15 has briefly pushed even beyond the 4,000 mph mark But military and experimental design objectives are basically simpler than commercial objectives performance and Mission accomplishment are their key yard sticks cost is secondary commercial airlines on the other hand naturally look first to questions of operating efficiency and cost a supersonic transport must cost no more to operate per passenger mile than do today's subsonic Jets a transport must be durable able to withstand continuous use for up to 15 years and it cannot itself cost too much nor can it require major alterations in existing airport facilities another factor of concern the SF planet is the Sonic Moon populations near airports and on flight paths are certain to protest a constant bombardment by shock waves the British British and the French were the first to commit themselves publicly to building a commercial supersonic transport the jointly developed Concord the Concord scheduled to begin test flying in about 2 and 1/2 years and be in service by early 1971 is a fixed deltawing craft designed to fly with 136 passengers at speed somewhat over Mach 2 twice the speed of sound or roughly 1400 miles hour it has long been known that Russia also plans to develop an SST and this model unveiled at the 1965 Paris Air Show provided westerners with their first official glimpse of the Soviet tu1 144 in 1963 President Kennedy announced that America would Leap Frog to competition and develop her own larger faster SST designed to carry 200 passengers at three times the speed of sound many tried methods of aircraft construction have had to be scrapped for the American SST in the first place aluminum which is what most planes including the Concord are made of won't stand the heat created by friction with the air at speeds much over Mach 2 a sustained 630° f is routine for a plane cruising at Mach 3 so hot you could grill a side of beef on the Leading Edge of the wing to meet the US goals aluminum had to be replaced by a totally new structural material finally a lightweight titanium alloy with a melting point of 3000° f was selected having picked their material engineers then could concentrate on a second major problem aerodynamic design wind tunnel tests like this show that aircraft traveling faster than sound run into two types of drag in addition to the normal drag of air flow over its surfaces the plane compresses walls of dead air shock waves in front of its surfaces these shock waves can be observed and studied through a special op itical system in supersonic wind tunnels such as this one Engineers have found that a sleek and piercing design is most efficient the fuselage must be long and pointed the wings must be swept and flat like cutting edges finally designers had to cope with a third major component of aircraft design the engine a new breed of jet engine had to be developed that would push out a little air at extremely high velocities rather than a lot of air at lower velocities using the basic research information from NASA's ases and Langley research centers two aircraft companies undertook the design of an SST these radically different looking aircraft are the results of their work here in am's 40x 80t subsonic wind tunnel the biggest in the world large scale models of these two configurations are being tested for their aerodynamic characteristics at slow speeds to learn more about these ssts we talked to Mr Mark Kelly chief of A's large-scale aerodynamics branch these airplanes are designed to cruise at nearly 2,000 mph which is more than three times as fast as our current subsonic jet transports but how's that going to affect the time say to go from New York to Los Angeles well you should be able to get from New York to Los Angeles in less than 2 hours that's uh less than the time difference between the two cities you mean you can actually land before you take off according to the clock that's right how many people will will ride in one of these between 200 and 250 depending on the mix between tourist and first class I so we still have the three and three and two and two 200 to 250 people uh means this is going to be a big plane as well as a fast one that's right it will weigh about 500,000 lb compared to our heaviest present jets are around 325,000 lb how long will it be about uh 270 ft nearly as long as a football field our present jets are about 50 ft long well since this is a supersonic airplane why is it that you're testing it here in um in a subsonic wind tunnel well this is because no one wants to land at supersonic speeds and in fact uh the landing and takeoff requirements for the supersonic transport are quite stringent uh it must have comparable safety uh the same as a super as the subsonic Jets and uh actually is required to make less noise than the sub Sonic Jets uh specifically uh our design objectives are to be capable of taking off out of a 10,500 ft runway on a hot day with an engine failed really mhm and the maximum takeoff speed is to be limited to 160 knots maximum approach speed is limited to 135 these uh conditions represent a pretty uh significant design problem for the supersonic transport well how are you to solve these problems well I can show this best by uh looking at the models that we have of the two different approaches uh to the supersonic transport mhm well this is a 1 scale model of the Boeing supersonic transport design the pilots would sit up in this uh area during landing and takeoff operations the forward portion of the nose is move downward to improve uh visibility during landing and takeoff for crws it's up in position as shown here and the pilots see out of these side windows M now the big feature of this airplane of course is the variable sweep Wing which we can show back here this is the same principle that is used on the uh tfx uh fighter oh I see now the wing is shown here in its swept back position for supersonic Cruise cruise this is approximately 70° of sweep of the Leading Edge there is a pivot in the wing in this general area which allows us to UNS sweep the wing to approximately 20° of sweep for landing and takeoff operations this allows us to generate uh the high lifts required to slow the airplane down uh we can show you the air the wing configuration for landing and takeoff on the other side getting a little old this yeah this is the way the wing looks during landing and takeoff operations you'll notice in addition to having the wing unwept mhm we have put Leading Edge slats on the forward portion of the wing the purpose of the slats is to maintain a uniform flow over the upper surface of the wing we also have trailing Edge flaps on the a portion and these deflect the air downwards over the AF portion of the wing to generate as much lift as possible now why is it that you want all this extra lift during landing and takeoff this lift is required in order to meet the contract objectives of maintaining the takeoff distance less than 10,500 ft and maintaining the takeoff speed less than 160 knots and we want to do this with as small a wing as possible well you mentioned a third objective that is uh not to have a noise be any louder than with ordinary plane this is correct and one way this is accomplished is uh through the use of of larger engines which uh we see here on this design these engines have over 2 and 1/2 times the thrust of the subsonic Jets the airplane uh therefore can climb at much higher angles and will be further away from the community this reduces the noise that the community receives now we can take a look at the locked model and see how another contractor has approached the same problem with a completely different design right this is a quarter scale model of the double Delta fix geometry supersonic transport configuration again the pilots sit up in this area of the fuselage and the nose droops away uh for improve visibility during landing and takeoff operations what what do you mean by a double Delta well the wing sh back is comprised of two Delta or triangular shaped uh portions this forward Delta and the main half Delta shown here well now if this doesn't uh change position how do you get the extra lift that you need for this take off and Landing problem this is obtained in a combination of three ways first this forward Delta is used to generate a high energy Vortex like a hurricane that's right which generates a low pressure field over the AFT main Wing M then the wing itself is much larger than on the uh variable sweep airplane and finally we rotate the airplane to higher angles to generate tilt it up that's right to a higher angle when we do this we lower these Leading Edge flaps to maintain smooth air flow over the the upper surface of the wing I noticed that this plane doesn't have a horizontal tail like most airplanes that I'm familiar with well that's correct and the tail is replaced by control surfaces here on the a portion of the wing all the way across the uh half span these are moved up and down to make the airplane go up and down or one up and the other down in the opposing Wing to Rolling airplane oh these are the engines under the wing that's right they're about the same as the uh about the same as the other well tell me uh Mr Kelly have these both these planes met these design objectives that you've been talking about they have come very close to meeting the design objectives and I believe that with continued development effort they will meet the design objectives at the end got some more work to do that's right well I'm assuming they do uh what will happen next well the next step will be an evaluation of the two uh designs by a government evaluation team with a recommendation as to which airplane uh should be taken into flight test development there are people who recommend that the competition be maintained on both aircrafts through a flight test stage well thank you very much Mr K in addition to static tests in a wind tunnel some of the dynamic aspects of SST performance can best be tested in actual flight by modifying an existing aircraft to reflect various design ideas here at Ames Engineers have taken this f5d for example and changed the shape of its wing to resemble that of a deltawing supersonic transport thus they can test the lift characteristics at low speeds of this proposed SST design the f5d has a 5-year History of Flight testing various design ideas here it flies missions in the critical region of subsonic flight testing the low speed lift and stability characteristics of this particular Wing shape even at these subsonic speeds the wing Edge condenses moisture in the air that crosses it the resulting Vapor creates visible patterns of the vortices which are produced and which provide even more than the expected lift at slow speeds America's viest research craft the controversial xp70 has pioneered in high-speed test mission 2 years ago it was to go into production as the most upto-date member in our arsenal of long range bombers once Congress canel the bomber program NASA and the Air Force agreed to use the two prototypes jointly as test craft although because the XB 70 is expensive to build and operate and has only limited payload capacity it can never be used for commercial travel flying three times the speed of sound at 70,000 ft about the same speed and altitude the SST will cruise at this huge white bird now gathers invaluable data on stability and control characteristics at the same time Cruise missions check out engineering solutions to the most difficult problem of high-speed flight sustained heat hydraulic systems electrical wiring bearings and seals have all been redesigned to withstand the scorching temperature tests also gauge airframe strains and fatigue under these extraordinarily demanding flight conditions as the only large experimental aircraft able to cruise at Mach 3 the xb7 has a busy schedule and much of the information gained on these flights will be directly applicable to the SST this plane now coming in for a landing has a long history of contribution to inlight research it's a Boeing 707 prototype in fact the first 707 ever built in its day it held the Transcontinental speed record but much of its long life has been spent playing charades after flying countless missions for 707 testing engineers with a wave of their wand miraculously turned it into a 727 now here along the coast of Virginia where NASA is testing the handling and maneuverability of the two supersonic configurations it pretends to be an SST to learn more about this versatile plane and the tests it's performing we talk to Mr Robert shade project manager for ssts at Langley Research Center it's a shade that was a beautiful Landing how are you thank you what is the uh purpose of this rather unusual looking airplane well the purpose is to simulate supersonic transports during the landing approach with a large subsonic jet transport well now how can you do that I mean this is a subsonic transport it looks very much like a 707 well it looks like one but it doesn't fly like one we have inside the aircraft a Computing system that takes all of the aircraft inputs like the pilots control and the movements of the aircraft into the computer the computer analysis of the thing tells the controls what to do do to make the airplane fly just like a supersonic transport I see so there's a computer between the pilot and what actually happens that's right so if he pushes some normal control it doesn't respond just the way he might expect it to for example if he pulls a control column back uh halfway the normal airplane you see there would pitch up rather rapidly but after it goes through the computer the computer takes and takes some of this out so it pitches up a lot more slowly like a real large supersonic transport would which couldn't possibly respond as fast as a slower PL uh what is the inside that nose that sticks out like a beak well that big boom you see back there is our angle of attack which is for the airplane going up and down and angle side slip indications M and when this aircraft moves either up or down or back and forth this little vein right on the very tip end of this boom transmits signals back to the computer and then the computer takes these signals and uses them for the simulation I see that really tells you what the plane is doing that's correct but if the uh pilot can see out the window I think that would tend to to spoil the effect I mean does it really feel like he's flying at supersonic speed the only thing that he does not feel is that the pilot is closer to the center of gravity of the airplane you're not quite as far out in the front otherwise the airplane motions the movements he goes through and most of the visual cues he has are essentially the same what kind of men do you use for flying this are it regular Pilots or well we have been using two of our nesa research Pilots to conduct this low speed uh mining approach evaluation and right at the present moment we're uh uh using four outside uh Pilots to evaluate it to get a more comprehensive indication of what we have done what's their reaction to this peculiar interference with their normal controls well the most of these people that are flying it are pretty well versed in terms of test pilots and uh they're used to this sort of thing and they can sort out the good and bad things and tell us what we have here in the way of a supersonic transport well now can you try different uh designs sort of program them into the computer so definitely it isn't just any supersonic trans we have a big patch or it's about this Square that's just covered with wires we call these computer patch boards and when we fly a given configuration the patch board is pushed in to the computer and this computer then responds to this particular configuration if you want to change from a variable sweep SST or Super S transport to a Delta configuration you just take the patch board out and put another patch board back in and then the airplane flies like the other configuration is it too early yet to say which uh designs look promising well uh all I can say is they all fly they all fly uh is part of the purpose of this to see whether Pilots can actually handle these airplanes this is the biggest thing we're after we don't know for sure until the actual airplane is built whether the supersonic transports will fly like we think they will mhm and this is just the next step we're trying to do here to get a better feel for what the ssts will be doing when they fly not all SST testing is best done in the Wind Tunnel or in the air often Engineers want to try out out a whole variety of conditions including some that might prove unsafe in flight to see how these tests are conducted we talked with Mr Seth Anderson chief of the flight and simulation Branch here at ases as you can imagine it's rather expensive to operate a large jet transport for that reason we do quite a bit of our work with groundbased simulators and this way we can cover a broad range of parameters and then use the flight test results to validate the uh ground base results mhm we have one of the simulators here oh is this a supersonic transport it's a cab that's used to represent some of the supersonic transports characteristics mhm this cab can actually move oh it rolls plus or minus 12° pitches up and down and moves through an altitude range of about 3 ft this gives a pilot a lot more realism a much better feel of actually flying an airplane than if he were standing still flying by the seat of his pants that's correct now what does he see a movie of a a typical flight path on the screen no it's not a movie John it's a projection of a landing that's given by the uh projectors on top of the cab through a closed circuit TV system television and it's actually in color to add more realism again and this equipment is in another room and the camera is driven over a landscape to to show his approach to his landing and to the actual touchdown on the runway I when he moves a control in the cab does that sort of move the camera over the landscape well not directly we do have to go through a computer setup to give the actual super transport's characteristics oh I see so when he moves the control it may not respond instantaneously it responds more like a big sluggish airplane perhaps is correct uh can we see this in operation why don't we take a rage okay what you go first there as you can see this is the most important part of the cab only the the where the crew is actually operating why don't you sit in the co-pilot seat and we'll have a preview of an SST aircraft making a landing I've never even had a chance to do this in a regular plane this is great you got all the instruments here that you would in a SST as you can see we don't have a full set of instruments we have only those that are required for research purposes mhm are you ready in the Computing room Roger anytime you're ready here we have the altimeter as you can see we're starting out at 1,000 ft mhm we'll be making our Approach at 130 knots oh so we're not supersonic coming in here we've slowed down a lot all right this is the final portion of a supersonic flight and you'll be given a little bit of an idea of how it looks to approach with a large aircraft and I want you to note in particular the response for this type of a vehicle okay you're ready well go ahead fine let's go we're now in motion making our Approach at uh roughly 1,000 ft we'll be coming down on the Glide path now at 500 ft per minute is that the airport there ahead the airport's directly head I'll give you a little idea of the maneuvering this vehicle we'll start over to the left and make an offset correction before we get down to the runway I can really feel that I see what you mean it does respond very slowly when you uh yeah remember this is a very large aircraft and the response of a large aircraft is necessarily slower for safety and structural reasons mhm we'll actually overshoot the runway and come back get led up you can see we make a correction to go up if we're too low and go down if we're too high can you make this uh behave like a delta or a swept Wing or any type you want yes by proper adjustment of the uh stability parameters we can simulate any of the supersonic transport configurations now we're getting we now just a little bit above Glide path you can see the runway directly ahead of us about 300 less than 300 [Music] ft this approach is being made under visual conditions but you can imagine that uh the entire approach down very close to the ground could be made under instrument conditions was not ready to touch down not ready to touch down there we are on the runway I could even feel a touch you can notice the light comes on to indicate that we're actually on the ground MH well that was a very smooth Landing that's just typical of the many Landings that have been made to ensure that the supersonic transport can carry out a mission in a safe and efficient manner well thank you very much Mr Anderson once the testing has been completed and the results evaluated the decision on a specific version of the SST can be made by 1974 America's supersonic transport should be in the skies but as progress would have it this newest of airplanes is already in a manner of speaking becoming obsolete research is even now underway on the next generation of vehicle one that feels most comfortable at speeds between 6 and 16,000 mph a thin rocket-shaped scram jet the Hypersonic plane they call it no longer seems even improbable that one day New York to London may be measured in minutes I'm John pitch MIT science reporter [Music]