Tag Archives: Pratt & Whitney Turbo Wasp JT3D-1

23 November 1959

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Boeing 720-022 c/n 17907, N7201U. (Boeing)
Boeing 720-022 c/n 17907, N7201U, parked on the taxiway at the south shore of Lake Washington. (Boeing)

23 November 1959: The first Boeing 720 airliner, a 720-022, registered as N7201U, made its first flight at Renton, Washington. The 720 was a development of the 707 and no prototype was built. N7201U was used by Boeing for flight testing and was then delivered to United Airlines, 1 October 1960. The airline named the new 720 Jet Mainliner Capt. F. M. Crismore. Over the next two years, United acquired 29 Boeing 720s.

N7201U was sold to Contemporary Entertainment, owned by singer Bobby Sherman and his manager, Ward Sylvester, in January 1973. It was repainted in a gold and black livery and christened The Starship. As a VIP transport, it was used by such rock bands as Led Zeppelin, Deep Purple, The Rolling Stones, Alice Cooper and Elton John. It was last chartered by Peter Frampton.

N7201U was withdrawn from service in 1977 and after being stored for several years, was broken up at Luton Airport near London, England, in 1982.

The Boeing 720 was a variant of the Model 707, intended for short to medium range flights. It had 100 inches (2.54 meters) removed from the fuselage length and improvements to the wing, decreasing aerodynamic drag.

Boeing built 154 720 and 720B airliners from 1959 to 1967.

The Boeing 720 was operated by a flight crew of four and could carry up to 149 passengers. It was 136 feet, 2 inches (41.25 meters) long with a wingspan of 130 feet, 10 inches (39.90 meters) and overall height of 41 feet, 7 inches (12.65 meters). The airplane had an empty weight of 103,145 pounds (46,785 kilograms) and Maximum Takeoff Weight of 220,000 pounds (100,800 kilograms).

The Boeing 720 was powered by four Pratt & Whitney Turbo Wasp JT3C-7 turbojet engines, a civil variant of the military J57 series. The 720B was equipped with the more efficient P&W JT3D-1 turbofan engines. The JT3C-7 was a “two-spool” axial-flow engine with a 16-stage compressor (9 low- and 7 high-pressure stages), 8 combustion tubes, and a 3-stage turbine (1 high- and 2 low-pressure stages). It was rated at 12,030 pounds of thrust (53.512 kilonewtons) for takeoff.

The JT3D-1 was a dual axial-flow turbofan engine, with a 2-stage fan section 13-stage compressor (6 low- and 7 high pressure stages), 8 combustion chambers and a 4-stage turbine (1 high- and 3 low-pressure stages). This engine was rated at 14,500 pounds of static thrust (64.499 kilonewtons) at Sea Level, and 17,000 pounds (75.620 kilonewtons), with water injection, for takeoff (2½ minute limit). Almost half of the engine’s thrust was produced by the fans. Maximum engine speed was 6,800 r.p.m. (N1) and 10,200 r.p.m. (N2). It was 11 feet, 4.64 inches (3.471 meters) long, 4 feet, 5.00 inches (1.346 meters) wide and 4 feet, 10.00 inches (1.422 meters) high. It weighed 4,165 pounds (1,889 kilograms). The JT3C could be converted to the JT3D configuration during overhaul.

The maximum cruise speed was 611 miles per hour (983 kilometers per hour) and maximum speed was 620 miles per hour (1,009 kilometers per hour). Range at at maximum payload was 4,370 miles (7,033 kilometers).

The last flight of a Boeing 720 was on 9 May 2012, when a 720B aircraft used by Pratt and Whitney Canada as a test aircraft was placed in the National Air Force Museum of Canada at Trenton, Ontario.

United Airlines' Boeing 720-022, N7201U. (Unattributed)
United Airlines’ Boeing 720-022, N7201U. The airliner’s name, “Jet Mainliner Capt. F. M. Crismore,” is visible under the cockpit windows. (Bill Larkins via Wikipedia)

© 2018, Bryan R. Swopes

28 October 1957

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The first production Boeing 707 after being rolled out of the final assembly plant at Renton, Washington, 28 October 1957. (Boeing)

28 October 1957: The first production Boeing 707 jet-powered commercial airliner, serial number 17586 (Line Number 1), was rolled out at the Boeing aircraft assembly plant at Renton, Washington. The Model 707 was developed from the earlier Model 367–80, the “Dash Eighty,” prototype for an air-refueling tanker which would become the KC-135 Stratotanker.

17586 was a Model 707-121. The new airliner had been sold to Pan American World Airways, the launch customer, as part of an order for twenty 707s in October 1955. The Federal Aviation Agency (FAA) assigned N708PA as its registration mark.

The first production Boeing 707 after roll out, 28 October 1957. (Boeing)

N708PA made its first flight 20 December 1957 with Boeing’s Chief of Flight Test, Alvin M. (“Tex”) Johnston. The airplane was initially used for flight and certification testing. Once this was completed, the new jet airliner was prepared for commercial service and delivered to Pan American at San Francisco International Airport (SFO), 30 November 1958. It was named Clipper Constitution.

Boeing 707-121 N708PA, photographed during its second flight, 20 December 1957. (Boeing)

In February 1965, the airliner was upgraded to 707-121B standards, which replaced the original turbojet engines with quieter, more efficient Pratt & Whitney Turbo Wasp JT3D-1 turbofan engines which produced 17,000 pounds of thrust. The wing inboard leading edges were modified to the design of the Model 720 and there was a longer horizontal tail plane.

Clipper Constitution flew for Pan Am for nearly 8 years, until 17 September 1965, when it crashed into Chances Peak, a 3,002 foot (915 meters) active stratovolcano on the Caribbean island of Montserrat. The point impact was 242 feet (74 meters) below the summit. All aboard, a crew of 9 and 21 passengers, were killed.

Boeing 707-121 N708PA retracts its landing gear after taking off at Seattle Tacoma Airport. (Unattributed)

The Boeing Model 707-121 was a four-engine jet transport with swept wings and tail surfaces. The leading edge of the wings were swept at a 35° angle. The airliner had a flight crew of four: pilot, co-pilot, navigator and flight engineer.

The 707-121 was 145 feet, 1 inch (44.221 meters) long with a wing span of 130 feet, 10 inches (39.878 meters). The top of the vertical fin stood 42 feet, 5 inches (12.929 meters) high. The 707 pre-dated the ”wide-body” airliners, having a fuselage width of 12 feet, 4 inches (3.759 meters).

The first versions were powered by four Pratt & Whitney Turbo Wasp JT3C-6 turbojet engines, producing 11,200 pounds of thrust (49,820 kilonewtons), and 13,500 pounds (60.051 kilonewtons) with water injection. This engine was a civil variant of the military J57 series. It was a two-spool axial-flow turbojet engine with a 16-stage compressor and 3 stage turbine. The JT3C-6 was 11 feet, 6.6 inches (3.520 meters) long, 3 feet, 2.9 inches (0.988 meters) in diameter, and weighed 4,235 pounds (1,921 kilograms).

The airliner’s empty weight is 122,533 pounds (55,580 kilograms). Maximum take off weight is 257,000 pounds (116,573 kilograms). At MTOW, the 707 required 11,000 feet (3,353 meters) of runway to take off.

The 707-121 had a maximum speed is 540 knots (1,000 kilometers per hour). Its range was 2,800 nautical miles (5,186 kilometers).

The Boeing 707 was in production from 1958 to 1979. 1,010 were built. Production of military variants continued until 1994.

© 2018, Bryan R. Swopes

23 October 1958

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American Airlines’ first Boeing 707-123 airliner, N7501A, is rolled out. (Boeing)

23 October 1958: American Airlines accepted delivery of its first jet airliner, Boeing 707-123 N7501A (serial number 17628, line number 7). The new airplane had made its first flight on 5 October. Christened Flagship Michigan, American Airlines advertised its new 707 as the “Astrojet.”

On 29 October 1958, the new 707 flew from Los Angeles to New York with 39 passengers, all officials of the airline or the Civil Aeronautics Authority (CAA). The flight departed at 6:58 a.m., Pacific Standard Time (13:58 UTC), and arrived at Idlewild Airport at 2:30 p.m. Eastern Standard Time. (18:30 UTC).

American Airlines’ first regularly-scheduled commercial passenger flight with the 707 took place 25 January 1959, also from Los Angeles to Idlewild. The duration of the flight was 4 hours, 3 minutes.¹

The Boeing 707 was developed from the earlier Model 367–80, the “Dash Eighty.” It is a four-engine jet transport with swept wings and tail surfaces. The leading edge of the wings are swept at a 35° angle. The airliner had a flight crew of four: pilot, co-pilot, navigator and flight engineer. The airliner could carry a maximum of 189 passengers.

The 707-123 was 145 feet, 1 inch (44.221 meters) long with a wing span of 130 feet, 10 inches (39.878 meters). The top of the vertical fin stood 42 feet, 5 inches (12.929 meters) high. The 707 pre-dated the ”wide-body” airliners, having a fuselage width of 12 feet, 4 inches (3.759 meters). The airliner’s empty weight is 122,533 pounds (55,580 kilograms). Maximum take off weight is 257,000 pounds (116,573 kilograms).

Boeing 707-123 N7501A, American Airlines Astrojet, Flagship Michigan, at Seattle. (American Airlines)

The first versions were powered by four Pratt & Whitney Turbo Wasp JT3C-6 turbojet engines, producing 11,200 pounds of thrust (49,820 kilonewtons), and 13,500 pounds (60.051 kilonewtons) with water injection. This engine was a civil variant of the military J57 series. It was a two-spool axial-flow turbojet engine with a 16-stage compressor and 2 stage turbine. The JT3C-6 was 11 feet, 6.6 inches (3.520 meters) long, 3 feet, 2.9 inches (0.988 meters) in diameter, and weighed 4,235 pounds (1,921 kilograms).

At MTOW, the 707 required 11,000 feet (3,353 meters) of runway to take off.

The 707-123 had a maximum speed of 540 knots (1,000 kilometers per hour). It’s range was 2,800 nautical miles (5,186 kilometers).

In 1961, N7501A was upgraded to the 707-123B standard. This included a change from the turbojet engines to quieter, more powerful and efficient Pratt & Whitney JT3D-1. The JT3D-1 was a dual-spool axial-flow turbofan engine, with a 2-stage fan section, 13-stage compressor (6 low- and 7 high-pressure stages), 8 combustion chambers and a 4-stage turbine (1 high- and 3 low-pressure stages). This engine was rated at 14,500 pounds of static thrust (64.499 kilonewtons) at Sea Level, and 17,000 pounds (75.620 kilonewtons), with water injection, for takeoff (2½ minute limit). Almost half of the engine’s thrust was produced by the fans. Maximum engine speed was 6,800 r.p.m. (N1) and 10,200 r.p.m. (N2). It was 11 feet, 4.64 inches (3.471 meters) long, 4 feet, 5.00 inches (1.346 meters) wide and 4 feet, 10.00 inches (1.422 meters) high. It weighed 4,165 pounds (1,889 kilograms). The JT3C could be converted to the JT3D configuration during overhaul.

The 707-123B wings were modified to incorporate changes introduced with the Boeing 720, and a longer tailplane installed.

N7501A was sold to Tigerair, Inc., 12 April 1978. It was then sold to Cyprus Airways in March 1979, and reregistered 5B-DAM. When landing at Bahrain International Airport, 19 August 1979, the airliner’s nose wheel collapsed and it was damaged beyond economical repair.

Boeing 707-123B 5B-DAM (s/n 17628) at Bahrain International Airport after sustaining damage when its nose wheel collapsed on landing, 19 August 1979. (Steve Fitzgerald/Wikimedia Commons)

The Boeing 707 was in production from 1958 to 1979. 1,010 were built. Production of 707 airframes continued at Renton until the final one was completed in April 1991.

¹ Please see “This Day in Aviation” for 25 January 1959 at: https://www.thisdayinaviation.com/2023/01/25/

© 2023, Bryan R. Swopes

15 August 1962

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An American Airlines Boeing 707-023B Astrojet (720B) at Los Angeles International Airport, 26 December 1962. (Photograph courtesy of Jon Proctor)
An American Airlines Boeing 707-023B Astrojet (720B) at Los Angeles International Airport, 26 December 1962. (Photograph courtesy of Jon Proctor)

15 August 1962: American Airlines’ Captain Eugene M. (“Gene”) Kruse set two National Aeronautic Association Class C-1 records for Speed Over a Commercial Air Route, East to West Transcontinental, when he flew a Boeing 720B Astrojet from New York to Los Angeles, 2,474 miles (3,981.5 kilometers), in 4 hours, 19 minutes, 15 seconds, at an average speed of 572.57 miles per hour (921.46 kilometers per hour). 61 years later, these records still stand.

Screen Shot 2015-01-02 at 12.22.27The National Aeronautic Association has placed Captain Kruse’s records on its “Most Wanted” list: long-standing flight records that it would like to see challenged. Rules require that a new record exceed the old by at least a 1% margin. The performance needed to establish a new record would be 578.30 miles per hour (930.68 kilometers per hour).

The Boeing 720 was a variant of the Model 707, intended for short to medium range flights. It had 100 inches (2.54 meters) removed from the fuselage length and improvements to the wing, decreasing aerodynamic drag.

The Boeing 720 was operated by a flight crew of four and could carry up to 149 passengers. It was 136 feet, 2 inches (41.25 meters) long with a wingspan of 130 feet, 10 inches (39.90 meters) and overall height of 41 feet, 7 inches (12.65 meters). The airplane had an empty weight of 103,145 pounds (46,785 kilograms) and Maximum Takeoff Weight of 220,000 pounds (100,800 kilograms).

The Boeing 720 was powered by four Pratt & Whitney Turbo Wasp JT3C-7 turbojet engines, a civil variant of the military J57 series. The 720B was equipped with the more efficient P&W JT3D-1 turbofan engines. The JT3C-7 was a “two-spool” axial-flow engine with a 16-stage compressor (9 low- and 7 high-pressure stages), 8 combustion tubes, and a 3-stage turbine (1 high- and 2 low-pressure stages). It was rated at 12,030 pounds of thrust (53.512 kilonewtons) for takeoff. The JT3D-1 was a dual axial-flow turbofan engine, with a 2-stage fan section 13-stage compressor (6 low- and 7 high pressure stages), 8 combustion chambers and a 4-stage turbine (1 high- and 3 low-pressure stages). This engine was rated at 14,500 pounds of static thrust (64.499 kilonewtons) at Sea Level, and 17,000 pounds (75.620 kilonewtons), with water injection, for takeoff (2½ minute limit). Almost half of the engine’s thrust was produced by the fans. Maximum engine speed was 6,800 r.p.m. (N1) and 10,200 r.p.m. (N2). It was 11 feet, 4.64 inches (3.471 meters) long, 4 feet, 5.00 inches (1.346 meters) wide and 4 feet, 10.00 inches (1.422 meters) high. It weighed 4,165 pounds (1,889 kilograms). The JT3C could be converted to the JT3D configuration during overhaul.

The maximum cruise speed was 611 miles per hour (983 kilometers per hour) and maximum speed was 620 miles per hour (1,009 kilometers per hour). Range at at maximum payload was 4,370 miles (7,033 kilometers).

Boeing built 154 720 and 720B airliners from 1959 to 1967.

The last flight of a Boeing 720 was on 9 May 2012, when a 720B aircraft used by Pratt and Whitney Canada as a test aircraft was placed in the National Air Force Museum of Canada at Trenton, Ontario.

© 2018, Bryan R. Swopes