Tag Archives: Alvin Melvin Johnston

15 April 1952

The Boeing YB-52 Stratofortress, 49-231, takes off from Boeing Field at 11:09 a.m., 15 April 1952. (Robert F. Dorr Collection)
The Boeing YB-52 Stratofortress, 49-231, takes off from Boeing Field at 11:09 a.m., 15 April 1952. (Robert F. Dorr Collection)

15 April 1952: At 11:09 a.m., Boeing’s Chief of Flight Test, Alvin M. “Tex” Johnston, and Lieutenant Colonel Guy M. Townsend, U.S. Air Force, ran all eight turbojet engines to full power and released the brakes on the YB-52 Stratofortress prototype, 49-231.

With an awesome eight-engine roar, the YB-52 sprang forward, accelerating rapidly, wings curving upward as they accepted the 235,000-pound initial flight gross weight. At V2 (takeoff speed) the airplane lifted off the runway, because of the 6-degree angle of incidence of the wing, and at 11:08 a.m. we were airborne. The initial flight of the YB-52 had begun.

Tex Johnston: Jet-Age Test Pilot, by A.M. “Tex” Johnston with Charles Barton, Smithsonian Books, Washington, D.C., 1992, Chapter 13 at Pages 397–398.

Alvin M. "Tex" Johnston, test pilot, after the first flight of the Boeing XB-52 Stratofortress prototype, 2 October 1952. (LIFE via Jet Pilot Overseas)
Alvin M. “Tex” Johnston, Boeing Chief of Flight Test, after the first flight of the Boeing XB-52 Stratofortress prototype, 2 October 1952. (LIFE via Jet Pilot Overseas)

The YB-52 remained over the Seattle area for approximately 40 minutes while Johnson and Townsend ran through a series of systems checks. When completed, they climbed to 25,000 feet (7,620 meters) and flew the new bomber to Larson Air Force Base at Moses Lake, Washington, where they stayed airborne for continued testing. The Stratofortress finally touched down after 3 hours, 8 minutes—the longest first flight in Boeing’s history up to that time. Johnston radioed that the airplane performed exactly as the engineers had predicted.

Boeing YB-52 Stratofortress 49-231. (Boeing)

The YB-52 had actually been ordered as the second of two XB-52s, but modifications and additional equipment installed during building resulted in enough differences to warrant a designation change. The first XB-52, 49-230, should have been the first to fly, but it was damaged during ground testing.

Boeing XB-52 Stratofortress 49-230. (U. S. Air Force)

The Boeing XB-52 and YB-52 were prototypes for a very long range strategic bomber. Both were built with a tandem cockpit for the pilot and co-pilot, similar to the earlier B-47 Stratojet. The wings were swept and mounted high on the fuselage (“shoulder-mounted”). The eight turbojet engines were in in two-engine nacelles mounted on pylons, below and forward of the wings. This had the effect of preventing the airplane’s center of gravity from being too far aft, and also provided cleaner air flow across the wings. The B-52’s landing gear has four main struts with two wheels, each. They can turn to allow the airplane to face directly into the wind while the landing gear remain aligned with the runway for takeoff and landing. With the landing gear under the fuselage, the wings could be constructed with greater flexibility.

Boeing YB-52 Stratofortress 49-231. (U.S. Air Force)
Boeing YB-52 Stratofortress 49-231. (U.S. Air Force)

The YB-52 was 152 feet, 8 inches (46.533 meters) long with a wingspan of 185 feet, 0 inches (56.388 meters). The prototype’s overall height was 48 feet, 3.6 inches (14.722 meters). The vertical fin could be folded over to the right so that the B-52 could fit into a hangar. The total wing area was 4,000 square feet (371.6 square meters). The wings’ leading edges were swept aft to 36° 54′. Their angle of incidence was 6° and there was 2° 30′ dihedral. The YB-52 had an empty weight of 155,200 pounds (70,398 kilograms) and gross weight of 405,000 pounds (183,705 kilograms).

The YB-52 was powered by eight Pratt & Whitney Turbo Wasp YJ57-P-3 turbojet engines. The J57 was a two-spool, axial-flow turbojet developed from an experimental turboprop engine. It had 16-stage compressor section (9 low- and 7-high-pressure stages), 8 combustors and a 3-stage turbine section (1 high- and 2 low-pressure stages). The YJ57-P-3s had a continuous power rating of 8,700 pounds of thrust (38.70 kilonewtons). The YJ57-P-3 was 183.5 inches (4.661 meters) long, 41.0 inches (1.041 meters) in diameter and weighed 4,390 pounds (1,991 kilograms).

The YB-52 had a cruise speed of 519 miles per hour (835 kilometers per hour) and maximum speed of 611 miles per hour (983 kilometers per hour) at 20,000 feet (6,096 meters). Its range was 7,015 miles (11,290 kilometers).

The two prototypes were unarmed.

Boeing YB-52 Stratofortress 49-231

The B-52 was produced by Boeing at its plants in Seattle and Wichita from 1952 to 1962, with a total of 744 Stratofortresses built. The last version, the B-52H, entered service with the Strategic Air Command in 1960. The final B-52, B-52H-175-BW Stratofortress 61-0040, was rolled out at Wichita, Kansas, 26 October 1962. This airplane remains in service with the United States Air Force. The newest B-52 in service, 61-0040 is 56 years old and has flown more than 21,000 hours.

All previous versions, B-52A through B-52G, have long been retired to The Boneyard and scrapped. Of the 102 Boeing B-52H Stratofortress bombers, 76 are still in the active inventory. One, 61-007, known as Ghost Rider, was recently taken from Davis-Monthan and after an extensive restoration and update, returned to service.

The YB-52 prototype was retired to the National Museum of the United States Air Force in the late 1950s. By the mid-60s it was determined to be excess and was scrapped.

Captain William Magruder (standing) Boeing Chief Test Pilot Alvin M. Johnston (center) and Lieutenant Colonel Guy M. Townsend with the Boeing YB-52 Stratofortress 49-231. (Boeing)
Left to right: Captain William Magruder, USAF; Boeing Chief Test Pilot Alvin M. Johnston; and Lieutenant Colonel Guy M. Townsend, USAF, with the Boeing YB-52 Stratofortress, 49-231. (Boeing)

© 2019, Bryan R. Swopes

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11 March 1957

The Boeing 367-80, prototype of the Model 707 airliner, being brepared for taakeoff on teh morning of 11 March 1957, Boeing Field, Seattle, Washington. (Leonard Mccombe/LIFE Magazine)
The Boeing 367-80, N70700, prototype for the Model 707 airliner and KC-135 air tanker, being prepared for takeoff on the morning of 11 March 1957, Boeing Field, Seattle, Washington. (Leonard Mccombe/LIFE Magazine)
Pre-flight inspection at Boeing Field, Seattle, Washington. In the background are newly-built Boeing B-52 Stratofortress bombers. (Leonard Mccombe/LIFE Magazine)
Pre-flight inspection at Boeing Field, Seattle, Washington. In the background are newly-built Boeing B-52 Stratofortress bombers. (Leonard Mccombe/LIFE Magazine)
Tex Johnston checks that the ramp is clear for engine start. Ready to start number one. (Leonard Mccombe/LIFE Magazine)
Tex Johnston checks that the ramp is clear for engine start. Ready to start number one. (Leonard Mccombe/LIFE Magazine)

11 March 1957: The Boeing jet airliner prototype, the Model 367-80, N70700, made a transcontinental demonstration flight from Seattle’s Boeing Field (BFI) to Friendship National Airport (BWI), Baltimore, Maryland. The aircraft commander was Boeing’s Chief of Flight Test, Alvin Melvin (“Tex”) Johnston. Test pilots James Russell (“Jim”) Gannett and Samuel Lewis (“Lew”) Wallick, Jr., completed the flight crew. The flight covered 2,350 miles (3,782 kilometers) and took 3 hours, 48 minutes.

Cruising at 0.86 Mach. (Leonard Mccombe/LIFE Magazine)
Cruising at 0.86 Mach. The four Pratt & Whitney JT3C turbojet engines are turning 100% r.p.m. (Leonard Mccombe/LIFE Magazine)
The flight deck of the Boeing 367-80 during the transcontinental demonstration flight, 11 March 1957. (Leonard Mccombe, LIFE magazine)
The flight deck of the Boeing 367-80 during the transcontinental demonstration flight, 11 March 1957. The flight attendants are (left) Miss Shirlee Mae Adams of American Airlines, and Miss Jackee Gibson of Braniff International Airways.(Leonard Mccombe/LIFE magazine)
Reporters balance a pen and a coin in the Dash 80's vibration-free cabin. (Leonard Mccombe/LIFE Magazine)
Reporters balance a pen and a coin in the Dash 80’s vibration-free cabin. (Leonard Mccombe/LIFE Magazine)
A news reporter types his story during the transcontinental flight. (Leonatd Mccombe/LIFE Magazine)
A news reporter types his story during the transcontinental flight. (Leonard Mccombe/LIFE Magazine)
Boeing test pilot S.L. "Lew" Wallick updates the chart with the Dash 80's present position. (Leonard Mccombe/LIFE Magazine)
Boeing test pilot Samuel Lewis (“Lew”) Wallick, Jr., updates the chart with the Dash 80’s present position. (Leonard Mccombe/LIFE Magazine)
Flight attendants from Pan American World Airways, American Airlines and Trans World Airlines made up the cabin crew. (Leonard Mccombe/LIFE Magazine)
Flight attendants from three customer airlines made up the cabin crew of the Boeing 367-80. Left to right, they are: Miss Shirlee Mae Adams, American Airlines; Miss Jo Ann Reeber, Braniff International Airways; and Miss Jackee Gibson, Trans World Airways. (Leonard Mccombe/LIFE Magazine)

Jet Airliner Crosses U.S. At Record Clip

Seattle-To-Baltimore Flight Made In 3 Hours, 48 Minutes

WASHINGTON, March 12 (AP) A Boeing 707 jet passenger plane set a new transcontinental speed record for commercial aircraft yesterday, flying the 2,325 miles from Seattle to Baltimore in 3 hours and 48 minutes.

At one point it attained a speed of 698 miles an hour.

A.M. (Tex) Johnston, Boeing chief of flight tests, said he would fly back to Seattle tomorrow with stops at Chicago’s O’Hare Airport and at Denver. He planned a series of local flights for congressmen, Pentagon officials and experts.

The big plane averaged 612 miles an hour for its Puget Sound-to-Chesapeake Bay flight, and sliced 10 minutes off the unofficial transport plane record it set between Seattle and Washington, D.C., in 1955.

There were 52 persons aboard, all but 20 of them newsmen.

‘Jet Stream’ Helps

The 707 left Boeing Field at 10:06 a.m., EST. East of Spokane at 31,000 feet, it hit the “jet stream,” a vast windstream with speeds of up to 125 miles an hour.

These winds enabled the plane to attain supersonic speeds in relation to the ground over northwestern Montana and northern Idaho. However, the plane was actually in subsonic flight and did not break the “sound barrier.”

While in the jet stream, the plane’s peak air speed was 596 miles an hour, but at one point the stream boosted this by 102 miles an hour, for a top speed of 698 in relation to the ground.

Fighter Holds Record

The official transcontinental speed record was set by a one-place F-84F jet fighter two years ago—652½ mph for the 2,446 miles from Los Angeles to New York City. [LCOL Robert R. Scott, USAF, 9 March 1955—TDiA]

The fastest unofficial transcontinental crossing listed by the Defense Department: 715 mph for the 2,700 miles from Riverside, Calif., to Boston last Jan. 25, by a Boeing B-47 bomber.

The 707 is to be delivered to its first airline buyers—Pan American and American—late next year and early in 1959.

The plane’s cost varies from 4½ to 5½ million dollars, depending on size and range, Various models will carry from 120 to 162 passengers.

Toledo Blade, Tuesday, 12 March 1957, Page 2 at Columns 2–4

Boeing's Chief of Flight Test, Alvin M. "Tex" Johnston updates a memeber of teh cabin crew on the progress of the flight. (Leonard Mccombe/LIFE Magazine)
Boeing’s Chief of Flight Test, Alvin M. “Tex” Johnston, updates a member of the cabin crew, Miss Jackie Gibson of Braniff International Airways, on the progress of the Dash 80’s transcontinental flight. (Leonard Mccombe/LIFE Magazine)
Boeing's Chief of Flight Test guides the Dash 80 to a touchdown on Runway 10, Friendship National Airport, (Leonard Mccombe/LIFE Magazine)
Boeing’s Chief of Flight Test Alvin M. “Tex” Johnston guides the Dash 80 to touchdown on Runway 10, Friendship National Airport, 2:02 p.m., Eastern Standard Time, 11 March 1957. (Leonard Mccombe/LIFE Magazine)
Tex Johnston with flight attendants from Boeing's customers: Pan American World Airways, American Airlines and Trans World Airways. (Leonard Mccombe/LIFE Magazine)
Tex Johnston with three flight attendants from Boeing’s customers: Miss Jackie Gibson, Braniff International Airways; Miss Shirlee Mae Adams, American Airlines; and Miss Jo Ann Reeber, Trans World Airways. (Leonard Mccombe/LIFE Magazine)
Boeing 367-80 N70700 parked at teh international terminal, Friendship National Airport, Baltimore, Maryland. (Leonard Mccombe/LIFE Magazine)
Boeing 367-80 N70700 parked at the international terminal, Friendship National Airport, Baltimore, Maryland. (Leonard Mccombe/LIFE Magazine)
N70700's route of flight, 0706–1102, 11 March 1957. (Leonard Mccombe/LIFE Magazine)
N70700’s route of flight, 0706–1102, 11 March 1957. (Leonard Mccombe/LIFE Magazine)

Boeing had risked $16,000,000 in a private venture to build the Dash 80 in order to demonstrate its capabilities to potential civilian and military customers, while rivals Douglas and Lockheed were marketing their own un-built jet airliners. Put into production as the U.S. Air Force KC-135A Stratotanker air refueling tanker and C-135 Stratolifter transport, a civil variant was also produced as the Boeing 707 Stratoliner, the first successful jet airliner. Though they look very similar, the 707 is structurally different than the KC-135 and has a wider fuselage.

The prototype Boeing Model 367-80 was operated by a pilot, co-pilot and flight engineer. The airplane’s wing was mounted low on the fuselage and the engine nacelles were mounted on pylons under the wing, as they were on Boeing’s B-47 Stratojet and B-52 Stratofortress. The wings and tail surfaces were swept to 35° at 25% chord, and had 7° dihedral. The Dash 80 was 127 feet 10 inches (38.964 meters) long with a wingspan of 129 feet, 8 inches (39.522 meters) and overall height of 38 feet (11.582 meters). The tail span is 39 feet, 8 inches (12.090 meters). The empty weight of the 367-80 was 75,630 pounds (34,505 kilograms) and the gross weight, 190,000 pounds (86,183 kilograms).

Cutaway scale model of the Boeing 367-80 showing interior arrangement. (Boeing)

N70700 was powered by four Pratt & Whitney Turbo Wasp JT3C engines. This engine is a civil variant of the military J57 series. It is a two-spool, axial-flow turbojet engine with a 16-stage compressor and 2-stage turbine. The JT3C-6 (used in the first production 707s) was rated at 11,200 pounds of thrust (49.82 kilonewtons), and 13,500 pounds (60.05 kilonewtons) with water/methanol injection). The JT3C is 11 feet, 6.6 inches (3.520 meters) long, 3 feet, 2.9 inches (0.988 meters) in diameter, and weighs 4,235 pounds (1,921 kilograms).

These gave the 367-80 a cruise speed of 550 miles per hour (885 kilometers per hour) and a maximum speed of 0.84 Mach (582 miles per hour, 937 kilometers per hour) at 25,000 feet (7,620 meters). The service ceiling was 43,000 feet (13,106 meters). Its range was 3,530 miles (5,681 kilometers).

Boeing continued to use the 367–80 for testing, finally retiring it 22 January 1970. At that time, its logbook showed 2,346 hours, 46 minutes of flight time (TTAF). It was flown to Davis-Monthan Air Force Base, Tucson, Arizona, and placed in storage. In 1990, Boeing returned it to flyable condition and flew it back it to Renton where a total restoration was completed. Many of those who had worked on the Dash 80, including Tex Johnston, were aboard.

The pioneering airplane was presented to the Smithsonian Institution and is on display at the National Air and Space Museum, Steven V. Udvar-Hazy Center. The Boeing 367-80 was designated an International Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers.

(The Boeing Model 367-80 is on display at the Steven F. Udvar-Hazy center, Smithsonian Institution National Air and Space Museum. (Photo by Dane Penland, National Air and Space Museum, Smithsonian Institution)
The Boeing Model 367-80 is on display at the Steven F. Udvar-Hazy Center, Smithsonian Institution National Air and Space Museum. (Photo by Dane Penland, National Air and Space Museum, Smithsonian Institution)

Highly recommended: Tex Johnston, Jet-Age Test Pilot, by A.M. “Tex” Johnston with Charles Barton, Smithsonian Books, Washington, D.C., 1991

© 2019, Bryan R. Swopes

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20 December 1957

Boeing 707-121 N708PA, photographed during its second flight. (Boeing via Space.com)
Boeing 707-121 N708PA, photographed during its second flight on the afternoon of 20 December 1957. (Boeing)
Boeing 707-121 N708PA makes its first takeoff at 12:30 p.m., on a rainy afternoon, 20 December 1957. (Unattributed)
Boeing 707-121 N708PA makes its first takeoff at 12:30 p.m. on a rainy afternoon, 20 December 1957. (Boeing)

20 December 1957: The first production Boeing 707 jet-powered commercial airliner, N708PA, made its first flight at Renton, Washington. Alvin M. “Tex” Johnston, Boeing’s Chief of Flight Test, was in command, with co-pilot James R. Gannet and flight engineer Tom Layne. Takeoff was at 12:30 p.m., PST. Poor weather limited the first flight to just 7 minutes. The new airliner landed at Boeing Field. Later that day, a second flight was made, this time with a duration of 1 hour, 11 minutes.

N708PA (Serial Number 17586, Line Number 1) 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.

Boeing test pilot Alvin M. "Tex" Johnston in the cockpit of of the 367–80. (LIFE)
Boeing’s Chief of Flight Test, Alvin M. “Tex” Johnston, in the cockpit of of the 367–80, “Dash Eighty,” 1954. (LIFE Magazine via Jet Pilot Overseas)

The Boeing Model 707 was developed from the earlier Model 367–80, the “Dash Eighty,” prototype for an air-refueling tanker which would become the KC-135A Stratotanker. The 707 was a four-engine jet transport with swept wings and tail surfaces. The leading edge of the wings were swept at a 35° angle.

N708PA was initially used for flight testing by Boeing. Once this was completed, it was prepared for commercial service and delivered to Pan American at San Francisco International Airport (SFO), 30 November 1958. Pan Am named the new airliner Clipper Constitution.

Boeing 707-121 708PA under maintenance at Renton, Washington. (Boeing)
Boeing 707-121 N708PA under maintenance at Renton, Washington. (Boeing)

In February 1965, the airliner was upgraded to 707-121B standards, which replaced the original turbojet engines with quieter, more efficient Pratt & Whitney 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 seven years, until 17 September 1965 when it crashed into Chances Peak, a 3,002 foot (915 meters) volcano 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, with both Boeing and Pan American corporate markings. (Unattributed)
Boeing 707-121 N708PA, with both Boeing and Pan American corporate markings. (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 airliner’s empty weight is 122,533 pounds (55,580 kilograms). Maximum take off weight is 257,000 pounds (116,573 kilograms).

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 (3,352.8 meters) of runway to take off.

The 707-121 had a maximum speed of 540 knots (1,000 kilometers per hour). It’s 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 707 airframes continued at Renton until the final one was completed in April 1991. As of 2011, 43 707s were still in service.

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

© 2016, Bryan R. Swopes

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2 October 1952

Boeing XB-52 Stratofortress 49-230 takes off for the first time, at Boeing Field, Seattle, Washington, 2 October 1952. (LIFE Magazine via Jet Pilot Overseas)

2 October 1952: The Boeing XB-52 Stratofortress prototype, 49-230, made its first flight at Boeing Field, Seattle, Washington, with test pilot Alvin M. “Tex” Johnston in command.  Lieutenant Colonel Guy M. Townsend, U.S. Air Force, acted as co-pilot.

The first of two prototype long-range, high-altitude, heavy bombers, the XB-52 had been damaged during ground testing and extensive repairs were required, which delayed its initial flight. The second prototype, YB-52 49-231, made the type’s first flight nearly six months earlier, on 15 April 1952.

Alvin M. “Tex” Johnston, test pilot, after the first flight of the Boeing XB-52 Stratofortress prototype, 2 October 1952. (LIFE Magazine via Jet Pilot Overseas)

The prototype Stratofortress the largest jet aircraft built up to that time. It was 152.7 feet (46.543 meters) long with a wingspan of 185.0 feet, (56.388 meters) and 48.25 feet (14.707 meters) to the top of the vertical fin. The leading edges of the wings were swept back 36° 54′.  The XB-52 had an empty weight of 155,200 pounds (70,398 kilograms) and its maximum takeoff weight was 390,000 pounds (176,901 kilograms). Fuel capacity was 27,417 gallons (103,785 liters).

Lieutenant Colonel Guy M. Townsend, U.S. Air Force. (Jet Pilot Overseas)
Lieutenant Colonel Guy M. Townsend, U.S. Air Force. (Jet Pilot Overseas)

The XB-52 was powered by eight Pratt & Whitney YJ57-P-3 turbojet engines, with a normal power rating of 8,700 pounds static thrust at Sea Level (38.700 kilonewtons). The prototype bomber had  a cruising speed of 519 miles per hour (835 kilometers per hour), and a maximum speed of 611 miles per hour (983 kilometers per hour) at 20,000 feet (6,048 meters). The planned bombing altitude was 46,500 feet (14,173 meters) and it had a service ceiling of 52,300 feet (15,941 meters). The XB-52 had an initial rate of climb of 4,550 feet per minute (23.11 meters per second) at Sea Level. Its maximum unrefueled range was 7,015 miles (11,290 kilometers).

Pilot’s cockpit, Boeing XB-52. (Boeing)
Boeing XB-52 Stratofortress 49-230. (U.S. Air Force)
Boeing XB-52 Stratofortress 49-230. (U.S. Air Force)
Boeing XB-51 Stratofortress 49-230 with a North American F-86 Sabre chase plane. (U.S. Air Force)
Boeing XB-52 Stratofortress 49-230 with a North American F-86 Sabre chase plane. (U.S. Air Force)
Boeing XB-52 Stratofortress 49-230. (U.S. Air Force)
Boeing XB-52 Stratofortress 49-230. (U.S. Air Force)

In its original configuration, the XB-52 was armed with two .50-caliber machine guns in a turret in the tail, with 600 rounds of ammunition per gun, though these guns were not installed on 49-230. The XB-52 was designed to carry a single 25,200 pound (11,431 kilogram) T-28E2 Samson bomb, or other conventional or nuclear weapons.

XB-52 49-230 was used in flight testing for its entire service life. The airplane was scrapped in the mid-1960s.

744 B-52 bombers were built by Boeing at Seattle, Washington and Wichita, Kansas, with the final one, B-52H-175-BW 61-0040, rolled out 22 June 1962.

75 B-52H Stratofortresses are still in service with the United States Air Force.

Boeing XB-52, with Tex Johnston and Guy Townsend in the tandem cockpit. (Boeing)
Boeing XB-52 Stratofortress 49-230 (U.S. Air Force)
Boeing XB-52 Stratofortress 49-230 with two Pratt & Whitney J75 turbojets in single-engine nacelles on the outer pylons, circa 1959. (U.S. Air Force)

© 2017 Bryan R. Swopes

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1 September 1946

Alvin M. “Tex” Johnston with the Thompson Trophy and the Allegheny-Ludlum Trophy, 1946 National Air Races. (San Diego Air and Space Museum Archives)

1 September 1946: Just one year after World War II came to an end, the National Air Races returned to Cleveland, Ohio. Grandstands were set up at the site of the Fisher Body Aircraft Plant No. 2, where assemblies for B-25 and B-29 bombers had been produced.

The Thompson Trophy Race was one of the most popular events because it was in view of the crowds. Sponsored by Thompson Products Company (the predecessor of TRW), it was a ten-lap pylon race flown at low altitude around a 30-mile (48.3 kilometers) course. There were two divisions. The R Division was for airplanes with reciprocating engines, and the J Division was for turbojet powered airplanes.

The National Air Races 4-pylon course, flown in 1947, 1947 and 1948. (airrace.com)

The race course was laid out as a parallelogram, with two 10-mile (16.1 kilometer) sides, and two 5-mile (8.0 kilometer) sides. There were two 75° turns and two 105° turns.

In addition to the Thompson Trophy, the race winner would receive $20,000 in prize money (about $342,400 in 2018 U.S. dollars). There were additional $2,000 prizes for the leader of each lap. A pilot who set a speed record during the race would win the Allegheny-Ludlum Trophy and $2,000.

Entrants for the 1946 race included many well-known air racers, test pilots and combat pilots. They included Cook Cleland, a U.S. Navy dive bomber pilot and test pilot; Woodrow W. (“Woody”) Edmondson, an aerobatic pilot; Howard Clifton (“Tick”) Lilly, a test pilot for the National Advisory Committee for Aeronautics (NACA, predecessor of NASA); Alvin Melvin (“Tex”) Johnston, an experimental test pilot with the Bell Aircraft Corporation; Anthony W. (“Tony”) LeVier, Chief Engineering Test Pilot for the Lockheed Aircraft Corporation, and an experienced pylon racer; Earl Hill Ortman, test pilot for Douglas Aircraft Company, and also an experienced racer; Howard L. Pemberton; Bruce Raymond; Robert Swanson; Charles (“Chuck”) Tucker, who had flown P-40s with the “Flying Tigers” in China, and an Army Air Corps test pilot; George Schwarz Welch, the Army Air Corps hero of Pearl Harbor, and test pilot for North American Aviation, Inc.; and Sylvester Joseph (“Steve”) Wittman, an aircraft designer and air racer.

Before the war, the races used specially-constructed racing aircraft and production civil aircraft. Following the war, the expense of developing a purpose-built, competitive air racer was no longer feasible, so surplus military fighters were used.

Of the twelve airplanes competing in the 1946 Thompson Race, there was one Bell Aircraft Corporation P-39Q Airacobra; four Bell P-63 Kingcobras; one Goodyear Aircraft Corporation FG-1D Corsair (a licensed variant of the Vought-Sikorsky F4U Corsair); a Lockheed Aircraft Corporation P-38L Lightning; and five North American Aviation, Inc., P-51D Mustangs.

Jack Woolams, Chief Test Pilot for Bell Aircraft Corporation, Experimental Test Pilot Tex Johnston, and Bell’s Chief Engineer, Robert Morris Stanley, had determined that a properly prepared Bell P-39 Airacobra could outrun and outfly a North American Aviation P-51 Mustang in the Thompson race.

A Bell Aircraft mechanic was sent to inspect surplus P-39s in storage at Ponca City, Oklahoma. He selected two nearly-new P-39Q Airacobras, each with less than 50 hours flight time. Woolams and Johnston paid $3,000 for the two fighters and they were flown back to the Bell plant at Buffalo, New York.

Jack Woolams’ Cobra I was a P-39Q-10-BE, U.S. Army Air Corps serial number 42-20733. Tex Johnston’s Cobra II was also a P-39Q-10-BE, 42-20869 (Bell serial number 26E-324).

The Bell P-39 Airacobra was a single-engine, single-place low-wing monoplane with retractable tricycle landing gear. An Allison V-1710 V-12 engine was mounted behind the cockpit in an unusual mid-engine configuration, with a drive shaft passing under the cockpit floor and turning the propeller through a remotely-mounted 1.8:1 gear reduction unit. This allowed the fighter to be armed with a large 37 mm autocannon which fired through the propeller hub.

Bell P-39Q-20-BE Airacobra 44-3887 at the National Museum of the United States Air Force)

The P-39Q was the final production version of the Airacobra. It was 30 feet, 2 inches (9.195 meters) long with a wingspan of 34 feet, 0 inches (10.363 meters) overall height of 12 feet, 5 inches (3.785 meters). The wings’ angle of incidence was +2° and there was 4° 0′ dihedral. The total wing area was 213 square feet (19.78 square meters). The horizontal stabilizer had +2° 15′ incidence and no dihedral.   The P-39Q had an empty weight of 5,692 pounds (2,704 kilograms), and maximum gross weight of 8,350 pounds (3,787 kilograms).

The production P-39Q was powered by a liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-E19 (V-1710-85) single overhead camshaft (SOHC) 60° V-12 engine with four valves per cylinder and a compression ratio of 6.65:1. The V-1710-85 had a continuous power rating of 810 horsepower at 2,600 r.p.m. at Sea Level, and 1,000 horsepower at 2,600 r.p.m. at 14,000 feet (4,267 meters). The engine’s takeoff power rating was 1,200 horsepower at 3,000 r.p.m., and its military power rating was 1,125 horsepower at 3,000 r.p.m., at 14,600 feet (4,450 meters). 100/130 octane aviation gasoline was required. The Allison drove a three-bladed Aeroproducts Division A632S-C1 hydraulically-operated constant-speed propeller with a diameter of 11 feet, 7 inches (3.531 meters) through a 2.23:1 gear reduction. The V-1710-85 was 16 feet, 2.00 inches (4.928 meters) long, 3 feet, 1.56 inches (0.954 meters) high, and 2 feet, 5.28 inches (0.744 meters) wide. It weighed 1,435 pounds (651 kilograms).

Cutaway illustration showing the unusual mid-engine arrangement of the Bell P-39 Airacobra. (Allison Division of General Motors)

The Bell P39Q-10-BE had a maximum speed of 385.0 mph (619.6 kilometers per hour) at 11,000 feet (3,353 meters). Its service ceiling was 34,300 feet (10,455 meters), absolute ceiling, 35,700 feet (10,881 meters), and its range was 1,075 miles (1,730 kilometers).

The P-39Q was armed with one Browning M4 37 mm autocannon with 30 rounds of explosive ammunition, and four Browning AN-M2 .50-caliber machine guns, with two in the nose with 200 rounds per gun, and one mounted under each wing in pods with 300 rounds per gun. The M4 cannon fired a 1.34 pound (608 grams) high-explosive shell at 2,000 feet per second (610 meters per second). The gun had a rate of fire of 150 rounds per minute.

The Bell Aircraft Corporation built 9,558 P-39s. 4,905 of these were P-39Qs. 705 were the P-39Q-10-BE variant.

Jack Woolams (left) and Tex Johnston pose with their air racers, Cobra I and Cobra II, at the Bell Aircraft Corporation plant, August 1946. (airrace,com)

Bell Aircraft provided hangar space for the two Airacobras, and assigned an engineer and five mechanics to the project. Cobra I was painted red with black accents. It was issued Civil Aeronautics Administration experimental registration NX92847. Its race number, 75, was painted on the wings and fuselage. Cobra II was painted yellow with black trim, and registered NX92848. Its race number was 84.

Both airplanes were stripped of armament, armor and self-sealing fuel tanks. The landing gear was modified to reduce its retraction time from 22 seconds to just 4 seconds. The standard fabric-covered ailerons, rudder and elevators were covered with sheet aluminum. Adjustable trim tabs were deleted. Gyroscopic instruments were removed. The pitot tube was moved from the left wing tip and placed on a long boom projecting through the propeller hub. Thin, light-weight Goodyear fuel bladders were installed, not only reducing weight, but increasing the Airacobras’ fuel capacity by 10%. The roll-down side windows of the P-39 were replaced by fixed Plexiglas panels.

Bell P-39Q-10-BE NX92848, Cobra II, Tex Johnston’s Thompson Trophy Race winner. (San Diego Air and Space Museum Archives)

Engineers at Allison recommended that a modified Allison XV-1710-135 (E31) engine be used for the two racers. The modified engines used an increased-diameter supercharger impeller and undersized pistons to reduce cylinder wall friction. Using 140-octane Mobil aviation gasoline, they produced 2,000 horsepower at 3,200 r.p.m. with 86 inches (291 kilopascals) of manifold pressure. The high power output required that the engine be provided with a continuous injection of a precisely-measured water and ethyl/methyl alcohol solution when operating above 57 inches (193 kilopascals) of manifold pressure. An 85 gallon (322 liter) tank for the injection mixture was placed in the nose.

Tex Johnston’s Thompson Trophy-winning Bell P39Q Airacobra, “Cobra II.” (San Diego Air and Space Museum Archives)

The increased power of the modified XV-1710-135 required that the P-39’s standard three-bladed propeller be replaced by a four-bladed unit from the P-63 Kingcobra. This was an Aeroproducts A624S constant-speed propeller with hollow steel blades. Its diameter was 11 feet, 0 inches (3.531 meters). The propeller gear reduction ratio remained the same, at 2.23:1, as did the remote gear box, at 1.8:1.

Allison V-1710-E19 (V-1710-85) with extension drive shaft and remote propeller drive gear unit. (Allison Division of General Motors)

The V-1710-E31 was longer and heavier than the -E19 because of an outboard reduction gear box. It was 17 feet, 4.00 inches (5.283 meters) long, 3 feet, 0.75 inches (0.933 meters) high, with the same 2 foot, 5.28 inch (0.744 meters) width. It weighed 1,500 pounds (680 kilograms).

Jack Woolams’ P-39 Cobra I leads a P-51D Mustang around a pylon turn during qualifying, August 1946. (LIFE Magazine via Jet Pilot Overseas)

When race qualifications were held, Tex Johnston was placed first with his yellow Cobra II. His average speed was 409.091 mph (658.368 kilometers per hour). George Welch was second with his P-51D, number 37. Jack Woolams and Cobra I were third.

Jack Valentine Woolams, Chief Experimental Test Pilot, Bell Aircraft Corporation. (John Trudell/Ancestry)

Jack Valentine Woolams was killed on 30 August, two days before the race, when his Cobra I crashed into Lake Ontario while returning to the Bell plant for an engine change. The Airacobra’s windshield may have collapsed at over 400 miles per hour (644 kilometers per hour).

The Thompson Trophy Race was held on Sunday, 1 September 1946. Tex Johnston, leading the field, took off and retracted his landing gear, climbing to 300 feet (91 meters). As he approached the first turn, he rolled Cobra II into a 4G turn (75.5° angle of bank) and dove to 60 feet (18 meters). As he made the turn, he was already pulling far ahead of the other racers.

George Welch dropped out when his Merlin engine began overheating. Tony LeVier’s P-38 Lightning, race number 3, held on to second place. By the ninth lap, Tex Johnston was passing the airplanes at the back of the field.

On the final turn, Johnston rolled into a 90° bank, and at only 50 feet (15 meters) above the ground, passed inside a Bell P-63 Kingcobra at 430 miles per hour (692 kilometers per hour) to win the race. His average speed for the ten laps was 373.908 mph (601.746 kilometers per hour).

After winning the 1946 Thompson Trophy Race, test pilot Tex Johnston kisses his wife, DeLores. (LIFE Magazine via Jet Pilot Overseas.)
Tex Johnston with the Thompson Trophy, 1946 National Air Races, Cleveland, Ohio. (LIFE Magazine)

Tony LeVier and his Lightning were in second place at 370.193 mph (595.768 kilometers per hour). Finishers 3, 4 and 5 were P-51D Mustangs. Number 6 was the lone FG-1D Corsair, followed by another P-51D. Proving that Woolams, Johnston and Stanley knew their airplane, the final three finishers were the three remaining P-63 Kingcobras.

An oil-streaked, race-winning Bell P-39Q Airacobra, NX92848, Tex Johnston’s Cobra II. The modified Allison engine’s undersized pistons allowed excessive blow-by. (San Diego Air and Space Museum Archives)

Cobra II competed in the 1947 Thompson Trophy Race. Flown by Bell Aircraft Corp. test pilot Gerald A. (“Jay”) Demming, and carrying the race number 11, it finished in third place behind two Goodyear F2G-1 Super Corsairs. Demming’s average speed was 367.625 miles per hour (591.635 kilometers per hour).

In the 1948 Thompson race, Cobra II, still carrying the number 11, was flown by Charles Brown. For this year, the race was twenty laps of a shorter, 15 mile (24.1 kilometer) course. Cobra II had qualified in first place with an average speed of 418.300 miles per hour (673.189 kilometers per hour). Brown led the race for 18 laps. His highest speed for a single lap was 413.907 miles per hour (666.119 kilometers per hour). He had to land, though, when the modified Allison engine began losing power. The race was won by a P-51D Mustang.

Bell P-39Q-10-BE Airacobra NX92849
Cobra II at the 1947 National Air Races, with race number 11. It was flown in the Thompson Trophy race by Bell test pilot Jay Demming, who placed third. (SDASM)

The history of Cobra II is elusive until it was purchased by Ed Maloney in 1960. It was sold to Michael D. Carroll in 1967. Carroll was the owner of Signal Trucking Co., and lived in Palos Verdes, California. The Airacobra was now registered N9824. Carroll had the airplane’s wings shortened by 4 feet per side (1.2 meters), and renamed it Cobra III.

On 10 August 1968, Carroll and Cobra III took of from Long Beach Airport (LGB), enroute to Orange County Airport (SNA), at nearby Santa Ana, California. At 11:15 a.m., the racer crashed at the Seal Beach Naval Weapons Station. Carroll bailed out, but his parachute did not open and he was killed. His body was located 125 feet (38 meters) from the wreckage. There was no post-crash fire. Lieutenant Commander Jack Kellicott, U.S. Navy, said that the airplane had run out of fuel.

Tex Johnston left Bell Aircraft Corporation and moved on to Boeing in Seattle, initially testing the swept-wing XB-47 Stratojet. He made the first flights of the YB-52 and XB-52 Stratofortress; the Model 367-80 (the “Dash 80”), which he notoriously rolled over Lake Washington, 6 August 1955; the KC-135A Stratotanker; and the Model 707 airliner. As Boeing’s Chief of Flight Test, Tex Johnston set the standard by which modern flight testing is carried out.

Alvin Melvin (“Tex”) Johnston, Chief of Flight Test. (The Boeing Company)

Highly recommended: Tex Johnston, Jet-Age Test Pilot, by A.M. “Tex” Johnston with Charles Barton, Smithsonian Books, Washington, D.C., 1991

© 2018, Bryan R. Swopes

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