Tag Archives: Boeing B-29 Superfortress

14 October 1947

Captain Charles Elwood (“Chuck”) Yeager, U.S. Air Force, with “Glamorous Glennis,” the Bell XS-1. (U.S. Air Force/National Air and Space Museum)

14 October 1947: At approximately 10:00 a.m., a four-engine Boeing B-29 Superfortress heavy bomber, piloted by Major Robert L. Cardenas, took off from Muroc Air Force Base (now know as Edwards Air Force Base) in the high desert north of Los Angeles, California. The B-29’s bomb bay had been modified to carry the Bell XS-1, a rocket-powered airplane designed to investigate flight at speeds near the Speed of Sound (Mach 1).

A Bell XS-1 rocketplane carried aloft in the bomb bay of a modified Boeing B-29-96-BW Superfortress, serial number 45-21800. (NASA)
Captain Chuck Yeager with the Bell XS-1 on Muroc Dry Lake, 1947. (Chuck Yeager collection)

Air Force test pilot Captain Charles Elwood (“Chuck”) Yeager, a World War II fighter ace, was the U.S. Air Force pilot for this project. The X-1 airplane had been previously flown by company test pilots Jack Woolams and Chalmers Goodlin. Two more X-1 aircraft were built by Bell, and the second, 46-063, had already begun its flight testing.

Captain Yeager had made three glide flights and this was to be his ninth powered flight. Like his P-51 Mustang fighters, he had named this airplane after his wife, Glamorous Glennis.

Bob Cardenas climbed to 20,000 feet (6,096 meters) and then put the B-29 into a shallow dive to gain speed. In his autobiography, Yeager wrote:

One minute to drop. [Jack] Ridley flashed the word from the copilot’s seat in the mother ship. . . Major Cardenas, the driver, starts counting backwards from ten. C-r-r-ack. The bomb shackle release jolts you up from your seat, and as you sail out of the dark bomb bay the sun explodes in brightness. You’re looking at the sky. Wrong! You should have dropped level. The dive speed was too slow, and they dropped you in a nose-up stall. . .

Cockpit of Bell X-1, 46-062, Glamorous Glennis, on display at the National Air and Space Museum. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution)

“I fought it with the control wheel for about five hundred feet, and finally got her nose down. The moment we picked up speed I fired all four rocket chambers in rapid sequence. We climbed at .88 Mach. . . I turned off two rocket chambers. At 40,000 feet, we were still climbing at .92 Mach. Leveling off at 42,000 feet, I had thirty percent of my fuel, so I turned on rocket chamber three and immediately reached .96 Mach. . . the faster I got, the smoother the ride.

“Suddenly the Mach needle began to fluctuate. It went up to .965 Mach—then tipped right off the scale. . . .”

—Brigadier General Charles E. Yeager, U.S. Air Force (Retired), Yeager, An Autobiography, by Chuck Yeager and Leo Janos, Bantam Books, New York, 1985, Pages 120, 129–130.

Chuck Yeager and flown the XS-1 through “the sound barrier,” something many experts had believed might not be possible. His maximum speed during this flight was Mach 1.06 (699.4 miles per hour/1,125.7 kilometers per hour).

Bell X-1 46-062 in flight. Note the “shock diamonds” visible in the rocket engine’s exhaust. (Photograph by Lieutenant Robert A. Hoover, U.S. Air Force)

The Bell XS-1, later re-designated X-1, was the first of a series of rocket powered research airplanes which included the Douglas D-558-II Skyrocket, the Bell X-2, and the North American Aviation X-15, which were flown by the U.S. Air Force, U.S. Navy, NACA and its successor, NASA, at Edwards Air Force Base to explore supersonic and hypersonic flight and at altitudes to and beyond the limits of Earth’s atmosphere.

The X-1 is shaped like a bullet and has straight wings and tail surfaces. It is 30 feet, 10.98 inches (9.423 meters) long with a wing span of 28.00 feet (8.534 meters) and overall height of 10 feet, 10.20 inches (3.307 meters). Total wing area is 102.5 square feet ( 9.5 square meters). At its widest point, the diameter of the X-1 fuselage is 4 feet, 7 inches (1.397 meters). The empty weight is 6,784.9 pounds (3,077.6 kilograms), but loaded with propellant, oxidizer and its pilot with his equipment, the weight increased to 13,034 pounds (5,912 kilograms). The X-1 was designed to withstand an ultimate structural load of 18g.

The X-1 is powered by a four-chamber Reaction Motors, Inc., XLR11-RM-3 rocket engine which produced 6,000 pounds of thrust (26,689 Newtons). This engine burns a mixture of ethyl alcohol and water with liquid oxygen. Fuel capacity is 293 gallons (1,109 liters) of water/alcohol and 311 gallons (1,177 liters) of liquid oxygen. The fuel system is pressurized by nitrogen at 1,500 pounds per square inch (10,342 kilopascals).

The X-1 was usually dropped from a B-29 flying at 30,000 feet (9,144 meters) and 345 miles per hour (555 kilometers per hour). It fell as much as 1,000 feet (305 meters) before beginning to climb under its own power.

The X-1’s performance was limited by its fuel capacity. Flying at 50,000 feet (15,240 meters), it could reach 916 miles per hour (1,474 kilometers per hour), but at 70,000 feet (21,336 meters) the maximum speed that could be reached was 898 miles per hour (1,445 kilometers per hour). During a maximum climb, fuel would be exhausted as the X-1 reached 74,800 feet (2,799 meters). The absolute ceiling is 87,750 feet (26,746 meters).

The X-1 had a minimum landing speed of 135 miles per hour (217 kilometers per hour) using 60% flaps.

The three X-1 rocketplanes made a total of 157 flights with the three X-1. The number one ship, Glamorous Glennis, made 78 flights. On 26 March 1948, with Chuck Yeager again in the cockpit, it reached reached Mach 1.45 (957 miles per hour/1,540 kilometers per hour) at 71,900 feet (21,915 meters).

The third X-1, 46-064, made just one glide flight before it was destroyed 9 November 1951 in an accidental explosion.

The second X-1, 46-063, was later modified to the X-1E. It is on display at the NASA Dryden Research Center at Edwards Air Force Base.

Glamorous Glennis is on display at the Smithsonian Institution National Air and Space Museum, next to Charles A. Lindbergh’s Spirit of St. Louis.

Bell X-1, 46-062, Glamorous Glennis, on display in the Milestones of Flight gallery at the National Air and Space Museum, Washington, D.C. (Photo by Eric Long, National Air and Space Museum, Smithsonian Institution)

© 2017, Bryan R. Swopes

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21 September 1942

A Boeing XB-29 takes off from Boeing Field, Seattle, Washington. (SDASM)
Edmund T. ("Eddie") Allen
Edmund T. (“Eddie”) Allen

21 September 1942: At Boeing Field, Seattle, Washington, the Boeing Model 345, the first of three XB-29 prototypes, Air Corps serial number 41-002, took off on its first flight.

Edmund T. “Eddie” Allen, Director of Aerodynamics and Flight Research, was in command, with Al Reed, Chief of Flight Test and Chief Test Pilot, as co-pilot. They climbed to 6,000 feet (1,829 meters) and began testing the XB-29’s stability and control, control power and response, and stall characteristics.

The flight was uneventful. Landing after 1 hour, 15 minutes, Allen is supposed to have said, “She flew!”

Eddie Allen lean’s out of a cockpit window following the first taxi test of the XB-29. (Boeing)

The XB-29 was 98 feet, 2 inches (29.921 meters) long with a wing span of 141 feet, 3 inches (43.053 meters), and 27 feet, 9 inches (8.458 meters) high to the top of its vertical fin. The prototype bomber had a gross weight of 105,000 pounds (47,627 kilograms).

Boeing XB-29-BO, 41-002, the first XB-29 built. (U.S. Air Force)
Boeing XB-29-BO, 41-002, the first of three prototypes. (U.S. Air Force)

The prototype bomber was powered by four air-cooled, supercharged and fuel-injected 3,347.662-cubic-inch-displacement (54.858 liter) Wright Aeronautical Division Duplex-Cyclone 670C18H1 (R-3350-13) twin-row 18-cylinder radial engines with a compression ratio of 6.85:1. The R-3350-13 was rated at 2,000 horsepower at 2,400 r.p.m., and 2,200 horsepower at 2,800 r.p.m. for takeoff, burning 100-octane gasoline. These engines drove 17-foot-diameter (5.182 meters) three-bladed Hamilton Standard constant-speed propellers through a gear reduction of 0.35:1. The R-3350-13 was 76.26 inches (1.937 meters) long, 55.78 inches (1.417 meters) in diameter, and weighed 2,668 pounds (1,210 kilograms). Wright built 50 of these engines.

Boeing XB-29 41-002. (SDASM)

The XB-29 had a maximum speed of 368 miles per hour (592 kilometers per hour) and cruised at 255 miles per hour (410 kilometers per hour). Its service ceiling was 32,100 feet (9,784 meters).

The airplane was designed to carry 20,000 pounds (9,072 kilograms) of bombs. Though the prototypes were unarmed, the production B-29s were defended by 10 Browning AN-M2 .50-caliber machine guns in four remotely-operated power turrets, with 2 more .50-caliber machine guns and a single AN-M2 20mm autocannon in the tail.

Boeing XB-29 41-002. (SDASM)

The B-29 Superfortress was the most technologically advanced—and complex—aircraft of the War. It required the manufacturing capabilities of the entire nation to produce. Over 1,400,000 engineering man-hours had been required to design the prototypes.

The B-29 was manufactured by Boeing at Seattle and Renton, Washington, and at Wichita, Kansas; by the Glenn L. Martin Company at Omaha, Nebraska; and by Bell Aircraft Corporation, Marietta, Georgia. There were three XB-29 prototypes, 14 YB-29 pre-production test aircraft, 2,513 B-29, 1,119 B-29A, and 311 B-29B Superfortress aircraft. The bomber served during World War II and the Korean War and continued in active U.S. service until 1960.

The first prototype, 41-002, was scrapped in 1948.

Boeing B-29A-30-BN Superfortress 42-94106, circa 1945. (U.S. Air Force)
Boeing B-29A-30-BN Superfortress 42-94106, circa 1945. (U.S. Air Force)

© 2018, Bryan R. Swopes

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15 August 1951

William Barton Bridgeman (TIME Magazine)
William Barton Bridgeman (Boris Artzybasheff/TIME Magazine)

15 August 1951: Just 8 days after he set an unofficial world speed record of  Mach 1.88 (1,245 miles per hour; 2,033.63 kilometers per hour) Douglas Aircraft Company test pilot William Barton (“Bill”) Bridgeman flew the rocket-powered United States Navy/National Advisory Committee on Aeronautics (NACA) Douglas D-558-II Skyrocket, Bu. No. 37974, to a world record altitude at Edwards Air Force Base in the high desert of Southern California.

The Skyrocket was airdropped at 34,000 feet (10,363 meters) from a highly-modified U.S. Navy P2B-1S Superfortress, Bu. No. 84029. The mother ship was a U.S. Air Force Boeing B-29-95-BW Superfortress, 45-21787, transferred to the Navy and flown by another Douglas test pilot, George R. Jansen.

Douglas D-558-II Skyrocket, Bu. No., 37974, NACA 144, is dropped from the Boeing P2B-1S Superfortress, Bu. No. 84029, NACA 137. (NASA)
Douglas D-558-II Skyrocket, Bu. No., 37974, NACA 144, is dropped from the Boeing P2B-1S Superfortress, Bu. No. 84029, NACA 137. (NASA)

The flight plan was for Bridgeman to fire the rocket engine and allow the Skyrocket to accelerate to 0.85 Mach while climbing. The Skyrocket was powered by a Reaction Motors LR8-RM-6 engine, which produced 6,000 pounds of thrust. As the rocketplane continued to accelerate to Mach 1.12, the test pilot was to pull up, increasing the angle of climb while holding an acceleration rate of 1.2 Gs. This would result in a constantly increasing angle of climb. When it reached 50°, Bridgeman was to maintain that, climbing and accelerating, until the rocket engine ran out of fuel.

Initially, the plan was to continue climbing after engine shutdown until the D-558-II was approaching stall at the highest altitude it could reach while on a ballistic trajectory. There were differing expert opinions as to how it would behave in the ever thinner atmosphere. On the morning of the flight, Douglas’ Chief Engineer, Ed Heinemann, ordered that Bridgeman push over immediately when the engine stopped.

Bill Bridgeman stuck to the engineers’ flight plan. As the Skyrocket accelerated through 63,000 feet (19,200 meters), it started to roll to the left. He countered with aileron input, but control was diminishing in the thin air. The next time it began there was no response to the ailerons. Bridgeman found that he had to lower the Skyrocket’s nose until it responded, then he was able to increase the pitch angle again. At 70,000 feet (21,336 meters), travelling Mach 1.4, he decided he had to decrease the pitch angle or lose control. Finally at 76,000 feet (23,165 meters), the engine stopped. Following Heinemann’s order, Bridgeman pushed the nose down and the D-558-II went over the top of its arc at just 0.5 G.

Bill Bridgeman. (Unattributed)
Bill Bridgeman. (Unattributed)

“In the arc she picks up a couple of thousand feet. The altimeter stops its steady reeling and swings sickly around 80,000 feet. The altitude is too extreme for the instrument to function.

“Eighty thousand feet. It is intensely bright outside; the contrast of the dark shadows in the cockpit is extreme and strange. It is so dark lower in the cockpit that I cannot read the instruments sunk low on the panel. The dials on top, in the light, are vividly apparent. There seems to be no reflection. It is all black or white, apparent or non-apparent. No half-tones. It is a pure, immaculate world here.

“She levels off silently. I roll right and there it is. Out of the tiny windows slits there is the earth, wiped clean of civilization, a vast relief map with papier-mâché mountains and mirrored lakes and seas. . . .

“It is as if I am the only living thing connected to this totally strange, uninhabited planet 15 miles below me. The plane that carries me and I are one and alone.”

The Lonely Sky, William Bridgeman with Jacqueline Hazard, Castle and Company LTD, London, 1956, Chapter XXII at Page 268.

After the data was analyzed, it was determined that William Bridgeman and the Douglas Skyrocket had climbed to 79,494 feet (24,230 meters), higher than any man had gone before. This was the last flight that would be made with a Douglas test pilot. The rocketplane was turned over to NACA, which would assign it the number NACA 144.

A Douglas D-558-II Skyrocket, Bu. No. 37974. glides back toward Rogers Dry Lake at Edwards Air force Base. A North American Aviation F-86E-1-NA Sabre, 50-606, flies chase. Major Charles E. "Chuck" Yeager frequently flew as a chase pilot for both Bill Bridgeman and Scott Crossfield. (NASA)
A Douglas D-558-II Skyrocket, Bu. No. 37974, glides back toward Rogers Dry Lake at Edwards Air Force Base. A North American Aviation F-86E-1-NA Sabre, 50-606, flies chase. Lieutenant Colonel Frank K. “Pete” Everest and Major Charles E. “Chuck” Yeager frequently flew as chase pilots for both Bill Bridgeman and Scott Crossfield. (NASA)

Bill Bridgeman had been a Naval Aviator during World War II, flying the Consolidated PBY Catalina and PB4Y (B-24) Liberator long range bombers with Bombing Squadron 109 (VB-109), “The Reluctant Raiders.” Bridgeman stayed in the Navy for two years after the war, then he flew for Trans-Pacific Air Lines in the Hawaiian Islands and Southwest Airlines in San Francisco, before joining Douglas Aircraft Co. as a production test pilot, testing new AD Skyraiders as they came off the assembly line at El Segundo, California. He soon was asked to take over test flying the D-558-2 Skyrocket test program at Muroc Air Force Base.

The D-558-II Skyrocket was Phase II of a planned three phase experimental flight program. It was designed to investigate flight in the transonic and supersonic range. It was 46 feet, 9 inches (14.249 meters) long with a 25 foot (7.62 meter) wing span. The wings were swept back to a 35° angle. The Skyrocket was powered by a Westinghouse J34-WE-40 11-stage axial-flow turbojet engine, producing 3,000 pounds of thrust, and a Reaction Motors LR8-RM-6 four-chamber rocket engine, which produced 6,000 pounds of thrust. The rocket engine burned alcohol and liquid oxygen.

There were three D-558-2 Skyrockets. Between 4 February 1948 and 28 August 1956, they made a total of 313 flights. Bill Bridgeman’s speed and altitude record-setting Skyrocket, Bu. No. 37974, NACA 144, is in the collection of the Smithsonian Institution National Air and Space Museum.

Douglas D-558-2 Skyrocket, Bu. No. 37974, NACA 144. (NASA)

© 2016, Bryan R. Swopes

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5 August 1945

Martin-Omaha B-29-45-MO Superfortress 44-86292, Enola Gay, being moved into position over the pit to load Little Boy, 5 August 1945. (U.S. Air Force)

5 August 1945: In the afternoon, the Glenn L. Martin Company B-29-45-MO Superfortress 44-86292 was towed into position over a 13-foot × 16-foot (3.9 × 4.9 meters) concrete pit on the island of Tinian in the Marshall Group. Down in that pit was the most destructive weapon of war yet devised by man: The Mark I, code named Little Boy.

Little Boy was a nuclear bomb, designed to explode with unimaginable force when two masses of highly enriched uranium were forced together at very high speed. This was a “gun-type” bomb, considered to be so simple that it was not even tested before it was used.

Several hours later, at 0245 6 August 1945, the B-29, which had been named Enola Gay, took off from North Field and headed toward Hiroshima, Japan.

Bomb Unit L-11 in the pit before loading aboard Enola Gay, 5 August 1945. (U.S. Air Force)

© 2015, Bryan R. Swopes

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18 February 1943, 12:26 p.m., Pacific War Time

The second prototype Boeing XB-29 Superfortress, 41-0003, takes off from Boeing Field, 12:09 p.m., 18 February 1943. (Boeing)
The second prototype Boeing XB-29 Superfortress, 41-0003, takes off from Boeing Field, 12:09 p.m., 18 February 1943. (Boeing)

18 February 1943: At 12:09 p.m., Boeing Aircraft Company Chief Test Pilot Edmund Turney (“Eddie”) Allen took off from Boeing Field, Seattle, Washington, in the Number 2 prototype XB-29 Superfortress long-range heavy bomber, serial number 41-0003. Allen’s co-pilot was engineering test pilot Robert R. Dansfield. The rest of the XB-29 flight crew were Charles Edmund Blaine, flight test engineer; Fritz Mohn, senior inspector; Vincent W. North, aerodynamicist; Harry William Ralston, radio operator; Barclay J. Henshaw, flight test analyst; Thomas R. Lankford, engineer; Robert Willis Maxfield, flight test engineer; Raymond Louis Basel, flight test engineer; Edward I. Wersebe, flight test engineer.

Edmund T. ("Eddie") Allen. (San Diego Air and Space Museum Archive)
Edmund Turney Allen. (San Diego Air and Space Museum Archive)

41-0003 had first flown on 30 December 1942, piloted by Allen. During this flight, the prototype bomber suffered a major engine fire and Eddie Allen’s performance in returning the airplane to the airport later earned him the U.S. Army’s Air Medal, awarded on the specific orders of President Harry S. Truman.

Problems with the XB-29s’ Wright R-3350-13 engines had caused major delays in the B-29 testing program. The Number 2 aircraft had its engines replaced with those from the first XB-29, 41-0002. By 18 February, 41-0003 had made only eight flights, with a total flight time of 7 hours, 27 minutes.

The ninth test flight of 41-0003 was planned to test the climb performance to 25,000 feet (7,620 meters) and to collect engine cooling data.

At 12:17 p.m., 41-0003 was climbing through 5,000 feet (1,524 meters) when the #1 engine (the outboard engine on the left wing) caught fire. The engine was shut down and CO2 fire extinguishers were activated. Eddie Allen began a descent and turned back toward Boeing Field.

The wind was out of the south at 5 miles per hour (2.24 meters per second) so it was decided to land on Runway 13, the southeast/northwest runway. At 12:24, radio operator Harry Ralston reported that the XB-29 was 4 miles (6.4 kilometers) northeast of the field at 1,200 feet (366 meters).

The airplane was in the landing pattern turning from the downwind leg to the base leg when at 12:25 an explosion occurred. Ralston was heard to say, “Allen, better get this thing down in a hurry. The wing spar is burning badly.”

In order to save weight, the crank case of the Wright R-3350 engine was made of magnesium, a flammable metal which burned at a very high temperature. With an engine on fire, the bomber’s wing structure was extremely vulnerable.

The prototype bomber was now shedding parts and left a trail behind it on the ground. The fire was now burning inside the fuselage. Three crew members bailed out but the altitude was too low and they were killed.

At 12:26 p.m., Boeing XB-29 41-0003 crashed into the Frye Meat Packing Plant, south of downtown Seattle, and exploded. Nearly 5,000 gallons (18,927 liters) of gasoline started a massive fire. The 8 men still aboard the prototype bomber were killed, as were 20 employees inside the building. A firefighter who responded was also killed.

The Frye packing plant on fire, 18 February 1943. (Seattle Post Intelligencer)

Three XB-29 prototypes were built. The XB-29 was 98 feet, 2 inches (29.896 meters) long with a wing span of 141 feet, 3 inches (43.053 meters), and 27 feet, 9 inches (8.458 meters) high to the top of its vertical fin. The prototype bomber had a gross weight of 105,000 pounds (47,627.2 kilograms).

Boeing XB-29-BO, 41-002, the first XB-29 built. (U.S. Air Force)
Boeing XB-29-BO, 41-002, the first XB-29 built. (U.S. Air Force)

The XB-29 was powered by four 3,347.662-cubic-inch-displacement (54.858 liter) air-cooled, supercharged, Wright Aeronautical Division Cyclone 18 670C18H1 (R-3350-13) two-row 18-cylinder radial engines (also known as the Duplex-Cyclone) with a compression ratio of 6.85:1. The R-3350-13 had a Normal Power rating of 2,000 horsepower at 2,400 r.p.m., and 2,200 horsepower at 2,800 r.p.m. for takeoff, using 100 octane aviation gasoline. The engines turned 17-foot-diameter (5.182 meters) three-bladed Hamilton Standard Hydromatic constant-speed propellers through a 0.35:1 gear reduction. The R-3350-13 was 76.26 inches (1.937 meters) long, 55.78 inches (1.417 meters) in diameter, and weighed 2,668 pounds (1,210 kilograms).

The XB-29 had a maximum speed of 368 miles per hour (592 kilometers per hour) and cruised at 255 miles per hour (410 kilometers per hour). Its service ceiling was 32,100 feet (9,784 meters). The airplane was designed to carry 20,000 pounds (9,072 kilograms) of bombs.

The B-29 Superfortress was the most technologically advanced—and complex—aircraft of the War. It required the manufacturing capabilities of the entire nation to produce. Over 1,400,000 engineering man-hours had been required to design the prototypes. It would be manufactured by Boeing at Seattle and Renton, Washington and at Wichita, Kansas; by Glenn L. Martin Company at Omaha, Nebraska; and by Bell Aircraft Corporation, Atlanta, Georgia.

There were three XB-29 prototypes; 14 YB-29 pre-production test aircraft; 2,513 B-29; 1,119 B-29A; and 311 B-29B Superfortress aircraft. The bomber served during World War II and the Korean War and continued in active U.S. service until 1960.

The employees of the Boeing plant at Wichita, Kansas donated the money to build a B-29 to be named in honor of Eddie Allen. B-29-40-BW 42-24579 flew 24 combat missions. On its final mission over Tokyo, Japan, the Eddie Allen was so badly damaged that, though it was able to reach its base on the island of Tinian, it never flew again.

Boeing B-29 Superfortress "Eddie Allen." (U.S. Air Force)
Boeing Wichita-built B-29-40-BW Superfortress 42-24579, “Eddie Allen,” of the 45th Bombardment Squadron (Very Heavy), 40th Bombardment Group (Very Heavy), XX Bomber Command, circa 1944. (U.S. Air Force)
Boeing's acknoledgemnt of the sacrifice of its flight test crew, 18 February 1943,
Boeing’s acknowledgement of the sacrifice of its flight test crew, 18 February 1943, from the annual report to the shareholders.

© 2017, Bryan R. Swopes

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