US Supersonic Transport (SST) Program 1960-1971

[Merv_P]

Hi!

Another mid-60s concept, similar to the fifth picture down, via "2001". I know there's only so many ways to configure a flight-cabin but the influences from that period are clear.

 

[blackkite]

Thank you for the wonderful photograph which can feel the future.
Please enjoy next pictures.
I have never seen precise line drawings for L-2000-7A/7B final design especially front view. If someone find it, I believe it will be a big and historic discovery. Lockheed/FAA still have it or burned it all same as Fugaku? ;D

 

[blackkite]

From Flightglobal
Pan Am’s order of the Aerospatiale-BAC Concorde in 1963 sent the US government scurrying to sponsor a domestic alternative. Three years later, the Federal Aviation Administration, promising to subsidise 75% of development costs, had to choose between two proposals: the variable-sweep wing Boeing 2707-200 or the less complex, fixed-wing Lockheed L-2000-7.

On New Year’s Eve 1966, the agency delivered its verdict: Boeing, which still had no supersonic military or commercial aircraft in production, would build America’s answer to the Concorde. Lockheed, despite already fielding the Mach 3.2 SR-71 and the supersonic F-104, lost the battle. Boeing’s variable-sweep approach was deemed riskier, but it was quieter and potentially more versatile.

Lockheed’s disappointment could only grow deeper two years later, when Boeing unveiled the redesigned B2707-300, which removed the variable-sweep mechanism and replaced it with a double delta-wing not unlike the one on the L-2000-7.

Whatever disillusionment Lockheed felt would have been short-lived, however, as the FAA’s forecasts predicting a market for 500 supersonic transports (SSTs) never materialised.

In his memoir, Lockheed’s legendary chief engineer Clarence “Kelly” Johnson, said his employer was “fortunate” to lose the contract.

Despite the backing of the Nixon administration, a US Senate nervous about government spending and inflation refused to pass a 1972 budget that included funding to continue developing the B-2707.

It was the end of a potentially transformative programme. The US government’s specification for the SST would have produced a more attractive product for airlines. Though narrower than the widebody B-2702, the L-2000-7 still would have seated 258 in dual-class layout, compared to about 100 for Concorde.

Lockheed’s thinner fuselage minimised drag, allowing it to fly hundreds of miles further than the B-2707, while faster by nearly one-third compared to the Mach 2.0 Concorde.

All of those advantages may still have not been enough to make the L-2000-7 truly practical as a commercial product. Johnson himself acknowledged the limitations of propulsion technology in the early 1970s – especially in terms of take-off noise. At the time of his memoir in the mid-1980s, Johnson believed the industry was still at least one or two generations away from producing an engine with the right thrust-to-weight and noise characteristics.

 

[Triton]

Interesting how the world changed between 1963 and 1972.

 

[blackkite]

L2000-7 has excellent aerodynamic characteristic, it's lift/drag ration(8.2-8.3) is higher than Boeing 2707-300's(7.34). But Boeing 2707-300 has good lift/drag ratio(14.2) in subsonic flight. It can operate economically in all flight envelope.
L2000-7 was economical in mach 2.7 cruse, but noisy in landing same as Concorde. Because when she want to decrease speed, she need high angle of attack.
High angle of attach is draggy, and need high engine power.

 

[blackkite]

Hi! I believe following drawings are not final design, especially wing trailing edge. These drawing's nose upper window shape are little different from mockup's one. Outboard engine thrust line little direct outside.
Or short nozzle shows JTF-17 and long nozzle shows GE4/J5?
The caudal portion of the body of Lockheed L-2000-7B is form which has leaped up upwards.

Source : Lockheed Horizons.

 

[carsinamerica]

L2000-7 has excellent aerodynamic characteristic, it's lift/drag ration(8.2-8.3) is higher than Boeing 2707-300's(7.34). But Boeing 2707-300 has good lift/drag ratio(14.2) in subsonic flight. It can operate economically in all flight envelope.
L2000-7 was economical in mach 2.7 cruse, but noisy in landing same as Concorde. Because when she want to decrease speed, she need high angle of attack.
High angle of attach is draggy, and need high engine power.

That is a great resource, Blackkite. Lots of helpful details. Did it get any more in-depth regarding differences between the -7A and -7B? All I've found seems to suggest that the -7B was just a 14-frame stretch between the L1 and L2 doors (though that must have been tricky with such a variable-contoured fuselage).

 

[blackkite]

Hi!

 

[blackkite]

Hi! Cabin arrangement and cockpit.

 

[fightingirish]

15 b/w pictures of US Supersonic Transport (SST) projects at Klassiker der Luftfahrt.
North American Aviation NAC-60, Boeing 2707 and Lockheed L-2000 B)



Link: Klassiker der Luftfahrt: Supersonic - US-Überschallprojekte der 60er

 

[blackkite]

Wow thanks. Lufthansa! She is -7B.

 

[blackkite]

Hi!

 

[MaxLegroom]

I'd love to have seen the whole of the fourth and sixth pictures, where did they come from? The one from the zip file, the fifth picture, I've flown that one. I'd just say that it's difficult to make a SST behave at cruise altitude in any version of Microsoft Flight Simulator. And no one's dared tackle the Lockheed L2000 or the North American NAC 60 as yet...

 

[blackkite]

Hi! Here.
https://www.google.co.jp/search?q=boeing+733+sst&source=lnms&tbm=isch&sa=X&ei=-W5cU4mwI9bs8AWfwYBY&sqi=2&ved=0CAYQ_AUoAQ&biw=1366&bih=622#q=boeing+2707+sst&tbm=isch&facrc=_&imgdii=4p8PS--wJmglDM%3A%3Bgc1aD5WjySCGQM%3B4p8PS--wJmglDM%3A&imgrc=4p8PS--wJmglDM%253A%3B1MODz0D1SLBeSM%3Bhttp%253A%252F%252Fwww.fantastic-plastic.com%252FUNITED%252520SST%252520LOW%252520ANGLE.jpg%3Bhttp%253A%252F%252Fwww.fantastic-plastic.com%252FBOEING%2525202707-200%252520SST%252520PAGE.htm%3B285%3B200

http://orbiter-forum.com/showthread.php?t=22049

 

[blackkite]

Boeing imitated the design of Lockheed also about the form of wings.
I think fuselage weight of B2707-300 was rather heavy compared with delta wing SST, because delta wing has function for strength reinforcement for the fuselage. Delta wing along the fuselage increase the moment of inertia of area of the fuselage cross section drastically.
So delta wing SST's fuselage structure is light weight.

Second moment of area - Wikipedia

en.wikipedia.org

List of second moments of area - Wikipedia

en.wikipedia.org

L-2000 was the design which was refined very much and riped.
L-2000 had the appearance which is not showy and gives a simple impression rather.

 

[MaxLegroom]

I'd agree with that, in that the wings are in a way similar. But we had, and still do, a taste for complex and wonderful rather than simple and elegant.

At the moment, I'm in a mood to play devil's advocate here and throw out the idea that perhaps North American, with its NAC 60, was right all along. I've recently scanned a copy of the Aviation Week article that includes a three view drawing and a top and side view that includes the cabin layout. It's something that, once I stitch the latter together, I'd like to post here.

 

[blackkite]

I'd agree with that, in that the wings are in a way similar. But we had, and still do, a taste for complex and wonderful rather than simple and elegant.

At the moment, I'm in a mood to play devil's advocate here and throw out the idea that perhaps North American, with its NAC 60, was right all along. I've recently scanned a copy of the Aviation Week article that includes a three view drawing and a top and side view that includes the cabin layout. It's something that, once I stitch the latter together, I'd like to post here.

Wow!! Please.
L-2000 and B2707-300 had almost same shape windows.

 

[hesham]

Hi,

http://thehuwaldtfamily.org/jtrl/research/Airplane%20Design/Supersonic-Hypersonic/NASA-SP-472,%20Supersonic%20Cruise%20Technology.pdf

 

[hesham]

L2000-7 has excellent aerodynamic characteristic, it's lift/drag ration(8.2-8.3) is higher than Boeing 2707-300's(7.34). But Boeing 2707-300 has good lift/drag ratio(14.2) in subsonic flight. It can operate economically in all flight envelope.
L2000-7 was economical in mach 2.7 cruse, but noisy in landing same as Concorde. Because when she want to decrease speed, she need high angle of attack.
High angle of attach is draggy, and need high engine power.

By the way,


I have the report about Lockheed Horizons SST evolution,if someone want it.

 

[flateric]

...

 

[Jemiba]

The latter one somehow reminds me of the Fokker/Republic Aviation D-24 Alliance.

 

[blackkite]

NASA designed several shape SST. But their design did not realize. What a pity. Simple is the best.

 

[MaxLegroom]

It's still a bit of a Frankenstein monster, but here's the layout of the NAC 60, from Aviation Week, Feb. 10, 1964.

 

[blackkite]

Oh thanks, 170 seats for passengers.

 

[car15]

Here is my CL 823 in Eastern Air Lines colors.

 

[hesham]

Wow,amazing Model Car15.

 

[blackkite]

http://factgrabber.com/index.php?q=Lockheed_L-2000&lcid=J8knqQep5skGGSaBZIlkqYa5xplkiWbJJ5EHwea5JxkG

Lockheed L-2000
The Lockheed L-2000 was Lockheed's entry in a government-funded competition to build the United States' first supersonic transport (SST) in the 1960s. The L-2000 lost the contract to the Boeing 2707, but that competing design was ultimately canceled for political, environmental and economic reasons. In 1961, President John F. Kennedy committed the government to subsidizing 75% of the development of a commercial airliner to compete with the Anglo-French Concorde then under development. The director of the Federal Aviation Administration (FAA), Najeeb Halaby, elected to improve upon the Concorde's design rather than compete head-to-head with it. The SST, which might have represented a significant advance over the Concorde, was intended to carry 250 passengers (a large number at the time), fly at Mach 2.7-3.0, and have a range of 4,000 nmi (7,400 km). The program was launched on 5 June 1963, and the FAA estimated that by 1990 there would be a market for 500 SSTs. Boeing, Lockheed and North American officially responded. North American's design was soon rejected, but the Boeing and Lockheed designs were selected for further study.

Contents
1 Development 1.1 Early design studies
1.2 Later design studies
1.3 Design competition

2 Specifications (L-2000-7A)
3 See also
4 References

Development

Early design studies

Like Boeing, Lockheed had done a number of "paper studies" on various SST designs, starting in 1958. Lockheed sought an airplane with cruise speeds of around 2,000 mph (3,219 km/h) with takeoff and landing speeds that compared to large subsonic jets of the same era. They also desired a plane whose center of pressure could be managed throughout the entire speed range. Lockheed knew a variable geometry, swing-wing design could accomplish this goal, but felt it was too heavy; however, they preferred a fixed-wing solution. In a worst-case scenario, they were willing to design a fixed-wing aircraft using fuel for ballast. Early designs followed Lockheed's tapered straight wing much like the type used on the F-104 Starfighter, with a delta-shaped canard for aerodynamic trim. The problem was that in wind-tunnel tests the shift in the airplane's C/L was substantial. A delta wing was substituted which alleviated a portion of the movement, but it was not deemed sufficient. By 1962, Lockheed arrived at a highly swept, bat-wing design featuring four-engine pods buried in the wings and a canard. The improvement was closer to their goal, but still not optimal. By 1963, they extended the leading edge of the wing forward a bit to eliminate the need for the canard, and re-shaped the wing into a double-delta shape with a mild twist and camber. This, along with careful shaping of the fuselage, was able to control the shift in the center of pressure caused by the highly-swept forward part of the wing developing lift supersonically. The engines were shifted from being buried in the wings to individual pods slung below the wings.

Later design studies

The new design was designated L-2000-1 and was 223 ft (70 m) long with a narrow-body 132 in (335.2 cm) wide fuselage to meet aerodynamic requirements, allowing for passenger seating of five abreast seating in coach and a four-abreast arrangement in first-class seating. A typical mixed-class seating layout would equal around 170 passengers, with high-density layouts exceeding 200 passengers. The L-2000-1 featured a long, pointed nose that was almost flat on top and curved on the bottom, which allowed for improved supersonic performance, and could be drooped for takeoff and landing to provide adequate visibility. The wing design featured a sharp forward inboard sweep of 80°, with the remaining part of the wing's leading edge swept back 60°, with an overall area of 8,370 ft² (778 m²). The high sweep angles produced powerful vortices on the leading edge which increased lift at moderate to high angles of attack, yet still retained stable airflow over the control surfaces during a stall. These vortices also provided good directional control as well, which was somewhat deficient with the nose drooped at low speeds. The wing, while only 3% thick, provided substantial lift due to its large area, which, aided by vortex lift, allowed takeoff and landing speeds comparable to a Boeing 707. Additionally, a delta wing is a naturally rigid structure which requires little stiffening. The plane's undercarriage was a traditional tricycle type with a twin-wheeled nose gear. Each of the two six-wheeled main gear utilized the same tires used on the Douglas DC-8, but which were filled with nitrogen and to lower pressures. To provide an optimum entry date into service, Lockheed decided to use a beefed-up turbofan derivative of the Pratt & Whitney J58. The J58 had already successfully proven itself as a high-thrust, high-performance jet engine on the top-secret Lockheed A-12 (and subsequently on the Lockheed SR-71 Blackbird.) Due to its being a turbofan, it was deemed to be quieter than a typical turbojet at low altitude and low speed, required no afterburner for takeoff, and allowed reduced power settings. The engines were placed in cylindrical pods with a wedge-shaped splitter, and a squarish intake providing the inlet system for the aircraft. The inlet was designed with the goal of requiring no moving parts, and was naturally stable. To reduce the noise from sonic booms, rather than penetrate the sound barrier at a more ideal 30,000 ft (9,144 m), they intended to penetrate it at 42,000 ft (12,802 m) instead. It would not be possible on hot days, but on normal days this would be achievable. Acceleration would continue through the sound barrier to Mach 1.15, at which point sonic booms would be audible on the ground. The plane would climb precisely to minimize sonic boom levels. After an initial level-off at around 71,500 ft (21,793 m), the plane would cruise climb upwards, ultimately reaching 76,500 ft (23,317 m). Descents would also be performed in a precise way to reduce sonic boom levels until subsonic speeds were reached. By 1964, the US Government issued new requirements regarding the SST Program which required Lockheed to modify their design, by now called the L-2000-2. The new design had numerous modifications to the wing; one change was rounding the front of the forward delta in order to eliminate the pitch-up tendency. To increase high-speed aerodynamic efficiency, the wing's thickness was reduced to 2.3%, the leading edges were made sharper, the sweep angles were changed from 80/60° to 85/62°, and substantial twist and camber were added to the forward delta; much of the rear delta was twisted upwards to allow the elevons to remain flush at Mach 3.0. In addition, wing/body fairings were added on the underside of the fuselage where the wings are located, allowing a more normally-shaped nose to be used. To retain low-speed performance, the rear delta was enlarged considerably; to increase the payload, the trailing edge featured a forward sweep of 10°. The new nose reduced the overall length to 214 ft (65.2 m) while retaining virtually the same internal dimensions. Wingspan was identical as before, and despite the thinner wing, the increased wing area of 9,026 ft² (838.5 m²) allowed the same takeoff performance. The airplane's overall lift-to-drag ratio increased from 7.25 to 7.94. During the course of the L-2000-2's development, the engine previously selected by Lockheed was no longer deemed acceptable. During the time frame between the L-2000-1 and L-2000-2, Pratt and Whitney designed a new afterburning turbofan called the JTF-17A, which produced greater amounts of thrust. General Electric developed the GE-4 which was an afterburning turbojet with variable guide-vanes, which was actually the less powerful of the two at sea level, but produced more power at high altitudes. Both engines required some degree of afterburner during cruise. Lockheed's design favored the JTF-17A over the GE-4, but there was the risk that GE would win the engine competition and Lockheed would win the SST contract, so they developed new engine pods that could accommodate either engine. Aerodynamic modifications allowed a shorter engine pod to be used and which utilized a new inlet design. This inlet featured minimal external cowl angles and was precisely contoured to allow a high-pressure recovery using no moving parts, and allowed maximum performance with either engine option. To allow additional airflow for noise-reduction, or to aid afterburner performance, a set of suck-in doors was added to the rear portion of the pod. To provide mid-air braking capability for rapid deceleration and rapid descents, and to assist ground braking, part of the nozzle could be employed as a thrust reverser at speeds below Mach 1.2. The pods were also repositioned on the new wing to better shield them from abrupt changes in airflow. The additional thrust from the new engines allowed supersonic penetration to be delayed until up to 45,000 ft (13,716 km) under virtually all conditions. Since at this point the possibility of supersonic overland flight was still considered to be an option, Lockheed also considered larger, shorter-ranged versions of the L-2000-2B. All designs weighed exactly the same, with a new tail design, changes to the fuselage length, extensions to the forward delta, increased capacity, and variations in fuel capacity. The largest version featured capacity for 250 domestic passengers, while the medium version featured transatlantic capability with 220 passengers. Despite the fuselage length changes, there was no appreciable increase in the risk of the aircraft pitching upwards too far (over-rotation) on takeoff.

Design competition

By 1966, the design took on its final form as the L-2000-7A and L-2000-7B. The L-2000-7A featured a re-designed wing and fuselage lengthened to 273 ft (83 m). The longer fuselage allows for a mixed-class seating of 230 passengers. The new wing featured a proportionately larger forward delta, with greater refinement to the wing's twist and curvature. Despite having the same wingspan, the wing-area was increased to 9,424 ft² (875 m²), with a slightly reduced 84° sweepback, and an increased 65° main delta wing, with reduced forward sweep along the trailing edge. Unlike previous versions, this aircraft featured a leading-edge flap to increase lift at low speeds, and to allow a slight down-elevon deflection. The fuselage, as a result of greater length, changes to the wing design, and attempts to further reduce drag, featured a slight vertical thinning in the fuselage where the wings were, a more prominent wing/body "belly" to carry fuel and cargo, a longer nose, and a refined tail. Since the airplane was not as directionally stable as before, the plane featured a ventral fin, located on the underside of the trailing fuselage. The L-2000-7B was extended to 293 ft (89 m), utilizing a lengthened cabin and a more pronounced upward-curving tail to reduce the chance of the tail striking the runway during over-rotation. Both designs had the same maximum weight of 590,000 lb (267,600 kg), and the aerodynamic lift-to-drag ratio was increased to 8:1. Full-scale mock-ups of the Boeing 2707-200 and L-2000-7 designs were presented to the FAA, and on December 31, 1966 the Boeing design was selected. The Lockheed design was judged simpler to produce and less risky, but its performance during takeoff and at high speed was slightly lower. Because of the JTF-17A, the L-2000-7 was also predicted to be louder as well. The Boeing design was considered more advanced, representing a greater lead over the Concorde and thus more fitting to the original design mandate. Ironically, Boeing eventually changed its advanced variable-geometry wing design to a simpler delta-wing similar to Lockheed's design, but with a tail. If Lockheed had built its simpler design, it might have flown by 1971. With technical problems, delays, cost overruns, and environmental and economic questions, the Boeing SST was ultimately canceled on 20 May 1971 after the US Congress stopped federal funding for the SST program on 24 March 1971.

Specifications (L-2000-7A)

General characteristics
Capacity: 273 passengers
Length: 273 ft 2 in (83.26 m)
Wingspan: 116 ft (35.36 m)
Height: ()
Wing area: 9,424 ft² (875 m²)
Empty weight: 238,000 lb (107,900 kg)
Max takeoff weight: 590,000 lb (276,600 kg)
Powerplant: 4× GE4/J5M or Pratt & Whitney JTF17A-21L

Performance
Cruise speed: Mach 3.0
Range: 4,000 nmi (7,400 km)
Service ceiling: 76,500 ft (23,317 km)

See also

Comparable aircraft
Boeing 2707
Concorde
Tupolev Tu-144

Related lists
List of Lockheed aircraft

References

Boyne, Walter J, Beyond the Horizons: The Lockheed Story. New York: St. Martin's Press, 1998. ISBN 0-31219-237-1.
Francillon, René J, Lockheed Aircraft Since 1913. Annapolis, Maryland: Naval Institute Press, 1987. ISBN 0-87021-897-2.
- See more at: http://factgrabber.com/index.php?q=...qYa5xplkiWbJJ5EHwea5JxkG#sthash.MS9wx4ou.dpuf

 

[JimK]

Here is a color version of the image of the North American Aviation NAC-60 posted in reply #561.
A chart showing the construction and material breakdown of the same design.

 

[blackkite]

Oh stiffened titanium covers!! It's not stainless steel honeycomb sandwich. Different from XB-70.
Wing leading edge was stainless steel honeycomb sandwich.

 

[MaxLegroom]

Thanks for the excellent pictures on the NAC-60. I'd almost like to print that color picture and hang it in the living room! Actually, at this stage, I'm trying to find more on the NAC-60 than I've seen so far. Considering that the Flight International article on the three competitive designs in '64 commented on the completeness of the North American proposal, I'm all the more curious about it.

 

[fightingirish]

An article at "Klassiker der Luftfahrt".

Link: http://www.klassiker-der-luftfahrt....agierjets-projekte-aus-den-60er-jahren/488216
Pictures: http://www.klassiker-der-luftfahrt....erschallprojekte-der-60er/467607/fsuebersicht


I won't attach these pictures to this topic now, since most of them have been posted before.

 

[MaxLegroom]

Re: US SST Research

That made for interesting reading, though I'd not want to be the one working on that articulated nose gear.

The economics are also interesting in that the $2290 fare they estimate would be required, adjusted for inflation using the CPI Inflation Calculator, would be less than the $5200 and some change that Delta charges to fly business class in a 747.

 

[hesham]

Hi,


I think the upper and lower drawings of those SST aircraft was from Douglas.

 

[hesham]

Hi,


here is a clearer artist drawing to Douglas Model-2229;


http://books.google.com.eg/books?id=UVJTRxhEEo4C&printsec=frontcover&dq=flying+magazine+1961&hl=en&sa=X&ei=ijAMVIPhFKLR7AawnYDADg&ved=0CC0Q6AEwBTgK#v=onepage&q=flying%20magazine%201961&f=false

 

[hesham]

My memory is too bad,


I never saw like this Boeing SST design before ?,page 27;


http://books.google.com.eg/books?id=XSBdL3exIJUC&pg=PA68&dq=flying+magazine+1960&hl=en&sa=X&ei=sZkNVIU7jNVq1ZuByA8&ved=0CBkQ6AEwADgK#v=onepage&q&f=false

 

[MaxLegroom]

I read into that article a bit further, and they also had the SST design that was clearly derived from their B-70 design. The article was interesting, but goes over ground that, in hindsight, we know well.

 

[hesham]

I read into that article a bit further, and they also had the SST design that was clearly derived from their B-70 design. The article was interesting, but goes over ground that, in hindsight, we know well.

Hi MaxLegroom,


for SST version of B-70 or M-3000,plese see;


http://www.secretprojects.co.uk/forum/index.php/topic,20815.msg204768.html#msg204768

 

[hesham]

Hi,


here is a Lockheed SST Model of 1966,page 82;


http://books.google.com.au/books?id=-lIEAAAAMBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false

 

[MaxLegroom]

Much appreciated, though I mined the heck out of that thread already, when I was looking for more stuff on the NAC 60. More stuff, this time, may require a road trip. I was merely commenting how much one of those designs, and there is a better picture, or several, on this forum of it, resembles Boeing's idea for what became the B-70.

I've been interested in modeling these SSTs for Flight Simulator, and at this point, I'd even consider the idea of remodeling the 2707. The model of it that currently exists was lacking in quite a few ways, even if he did get the control sticks right in the virtual cockpit.

Of course, the last link simply allows me to wallow in things 1960's...

 

[circle-5]

Douglas Model 2229 SST flight deck model.