Tag Archives: Browning Machine Gun Caliber .50 AN-M2

14 October 1944

Ann Gilpin Baumgartner, circa 1944. (National Air and Space Museum)

14 October 1944: Ann Gilpin Baumgartner, a member of the Women Airforce Service Pilots (WASPs) assigned as Assistant Operations Officer of the Fighter Section, Flight Test Division, at Wright Field, Dayton, Ohio, made an evaluation flight of the Bell YP-59A Airacomet, becoming the first woman to fly a turbojet-propelled airplane.

The Airacomet was designed and built by the Bell Aircraft Corporation as an interceptor, powered by two turbojet engines. There were three XP-59A prototypes. The first one flew at Muroc Army Airfield on 1 October 1942. The Army Air Corps had ordered thirteen YP-59A service test aircraft. The first of these flew in August 1943 at Muroc.

The Bell YP-59A was conventional single place airplane with retractable tricycle landing gear. It was primarily of metal construction, though the control surfaces were fabric-covered. Its dimensions differed slightly from the XP-59A, having shorter wings with squared of tips, and a shorter, squared, vertical fin. There were various other minor changes, but the exact specifications of the YP-59As are uncertain.

Bell YP-59A-BE Airacomet 42-108775 at Wright Field. (U.S. Air Force)

The primary difference, though, was the change from the General Electric I-A turbojet to the I-16 (later designated J31-GE-1). Both were reverse-flown engines using a single-stage centrifugal compressor and a single-stage turbine. The I-16 produced 1,610 pounds of thrust (7.16 kilonewtons). They were 6 feet, 0 inches long, 3 feet, 5.5 inches in diameter and weigh 865 pounds (392 kilograms),

Even with the two I-16s producing 720 pounds of thrust (3.20 kilonewtons) more than the the XP-59A’s I-A engines, the YP-59A’s performance did not improve. Engineers had a lot to learn about turbojeft engine inlet design.

The YP-59A had a maximum speed of 409 miles per hour (658 kilometers per hour) at 35,000 feet (10,668 meters), and its service ceiling was 43,200 feet (13,167 meters).

Bell YP-59A-BE Airacomet 42-108775 at Wright Field. (U.S. Air Force)

The P-59 was ordered into production and Bell Aircraft Corporation built thirty P-59A and twenty P-59B fighters. These were armed with one M4 37mm autocannon with 44 rounds of ammunition and three Browning AN-M2 .50-caliber machine guns with 200 rounds per gun.

Although a YP-59A had set an unofficial altitude record of 47,600 feet (14,508 meters), the Airacomet was so outclassed by standard production fighters that no more were ordered.

Bell YP-59A-BE Airacomet 42-108775 at Wright Field. (U.S. Air Force)
Ann G. Baumgartner stands on the wing of a North American Aviation T-6 Texan. (U.S. Air Force)

Ann Gilpin Baumgartner was born 27 Aug 1918, at the U.S. Army Hospital, Fort Gordon, Augusta, Georgia. She was the daughter of Edgar F. Baumgartner, engineer and patent attorney, and Margaret L. Gilpin-Brown Baumgartner. After graduating from Walnut Hill High School, Natick, Massachussetts, she studied pre-med at Smith College, Northampton, Massachussetts. She played soccer and was on the swimming team. She graduated in 1939.

Miss Baumgartner worked as a reporter for The New York Times. She took flying lessons at Somerset Hills Airport, Basking Ridge, New Jersey, and soloed after only eight hours. She then bought  Piper Cub to gain flight experience.

Ann G. Baumgartner, WASP Class 43-W-3. (U.S. Air Force)

After being interviewed by Jackie Cochran, Baumgartner joined the Women Airforce Service Pilots (WASPs) 23 March 1943, a member of Class 43-W-3, graduating 11 September 1943 with Class 43-W-5. She was then assigned to Camp Davis Army Airfield, Holly Ridge, North Carolina, where she towed targets for anti-aircraft artillery training.

Miss Baumgartner  was transferred to Wright Field, Dayton, Ohio (now, Wright-Patterson Air Force Base), where she flew the B-24 Liberator and B-29 Superfortress heavy bombers, P-38 Lightning, P-47 Thunderbolt, YP-59A Airacomet, P-82 Twin Mustang fighters, and the Luftwaffe Junkers Ju 88 medium bomber.

While at Wright Field, Miss Baumgartner met Major William Price Carl, who was an engineer associated with the P-82. They were married 2 May 1945, and would have two children.

Miss Baumgartner was released from service 20 December 1944, when the WASPs were disbanded. Following World War II, she was employed as an instrument flight instructor for United Air Lines.

After they retired, Mr. and Mrs. Carl sailed the Atlantic Ocean aboard their sailboat, Audacious.

Mrs. Carl was the author of A WASP Among Eagles and The Small World of Long-Distance Sailors.

Ann Gilpin Baumgartner Carl died at Kilmarnock, Virginia, 20 March 2008, at the age of 89 years. She and her husband, who had died one month earlier, were buried at sea.

Mrs. Ann Baumgartner Carl (1918–2008)

© 2017 Bryan R. Swopes

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14 October 1938

The Curtiss-Wright XP-40 prototype, 38-10, on its first flight, 14 October 1938. Test pilot Ed Elliot is in the cockpit. (San Diego Air and Space Museum Archives) 16_008532

14 October 1938: At Buffalo, New York, test pilot Everett Edward Elliot made the first flight in the new Curtiss-Wright Corporation’s Model 75P, a prototype for a single-engine pursuit plane which had been designated XP-40 by the U.S. Army Air Corps.

Curtiss-Wright’s Chief Engineer, Donovan Reese Berlin, had taken the tenth production P-36A Hawk, Air Corps serial number 38-10, and had its air-cooled radial engine replaced with the Harold Caminez-designed, liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Co. V-1710-C13 (V-1710-19).

Donovan Reese Berlin. (Niagara Aerospace Museum)

The V-1710-19 was a single overhead cam (SOHC) 60° V-12 engine with four valves per cylinder and a compression ration of 6.65:1. It had a Normal Power rating of 910 horsepower at 2,600 r.p.m. at Sea Level, and 1,060 horsepower at 2,950 r.p.m. for Takeoff. At 10,000 feet (3,048 meters), the V-1710-19 had Maximum Continuous Power rating of 1,000 horsepower at 2,600 r.p.m., and Military Power rating of 1,150 horsepower at 2,950 r.p.m. The engine required 100/130-octane aviation gasoline. It drove a three-bladed Curtiss Electric constant-speed propeller through a 2:1 gear reduction. The V-1710-19 was 8 feet, 1.75 inches (2.483 meters) long, 3 feet, 4.75 inches (1.035 meters) high and 2 feet, 4.94 inches (0.735 meters) wide. It weighed 1,320 pounds (599 kilograms).

Curtiss-Wright XP-40 38-10 (SDASM 16_008531)

At 1,829.39-cubic-inches (29.978 liters), the original Pratt & Whitney Twin Wasp S1C1-G (R-1830-17) 14-cylinder radial engine had greater displacement and produced 80 horsepower more for takeoff than the Allison V-12. The long, narrow V-12, though, allowed for a much more streamlined engine cowling for higher speed and greater efficiency.

XP-40 16_008533
Curtiss-Wright XP-40 prototype. (SDASM 16_008534)
The Curtiss XP-40 prototype at Langley Field in the original configuration. (NASA)
The Curtiss-Wright XP-40 in the original configuration at Langley Field. (NASA)
Everett Edward Elliot (1907–1981).

In the early testing, the XP-40 was much slower than expected, reaching only 315 miles per hour (507 kilometers per hour). (The P-36A Hawk had a maximum speed of  313 miles per hour). Engineers experimented with different placement for the coolant radiator, oil coolers and the engine air intake. The Air Corps project officer, Lieutenant Benjamin Scovill Kelsey, had the prototype sent to the National Advisory Committee for Aeronautics (NACA) Research Center at Langley Field, Virginia, where the full-size airplane was placed inside a wind tunnel.

Over a two-month period, NACA engineers made a number of improvements. The radiator was moved forward under the engine and the oil coolers utilized the same air scoop. The exhaust manifolds were improved as were the landing gear doors.

When they had finished, Lieutenant Kelsey flew the modified XP-40 back to Curtiss. Its speed had been increased to 354 miles per hour (570 kilometers per hour), a 12% improvement.

By December 1939 the airplane had been further improved and was capable of 366 miles per hour (589 kilometers per hour).

The Curtiss-Wright XP-40 prototype in a wind tunnel at Langley Field, 24 April 1939. (NASA)
Curtiss XP-40 in the NACA Full Scale Wind Tunnel at Langley Field, Virginia, April 1939. (NASA)
Curtiss-Wright XP-40 in the NACA Full Scale Wind Tunnel at Langley Field, Virginia, 24 April 1939. (NASA)

The Curtiss Hawk 75P, XP-40 38-10, was 31 feet, 1 inch (9.574 meters) long with a wingspan of 37 feet, 4 inches (11.354 meters) and overall height of 12 feet, 4 inches (3.734 meters). It had an empty weight of 5,417 pounds (2,457.1 kilograms) and maximum gross weight of 6,870 pounds (3,116.2 kilograms).

The prototype had a maximum speed of 342 miles per hour (550 kilometers per hour) at 12,200 feet (3,719 meters) with a gross weight of 6,260 pounds (2,839.5 kilograms). Its range was 460 miles (740 kilometers) flying at 299 miles per hour (481 kilometers per hour) with 100 gallons (378.5 liters) of fuel. With 159 gallons (601.9 liters) and with speed reduced to 200 miles per hour (322 kilometers per hour), the XP-40 had a maximum range of 1,180 miles (1,899 kilometers).

The prototype was armed with two air-cooled Browning AN-M2 .50-caliber machine guns mounted above the engine and synchronized to fire forward through the propeller arc.

The Air Corps placed an initial order for 524 P-40s. This was the largest single order for airplanes by the U.S. military up to that time. The first production model was the P-40 Warhawk, armed with two .50-caliber machine guns. There was only one P-40A variant which was a P-40 modified as a camera aircraft. The definitive pursuit model was the P-40B Warhawk, which retained the two .50-caliber guns of the P-40 and added two Browning M2 .30-caliber machine guns to each of the wings.

A Curtiss-Wright P-40B Warhawk, 79th Pursuit Squadron, 20th Pursuit Group, Hamilton Field, California, 1940. (U.S. Air Force)

The P-40B was best known as the airplane flown by the American Volunteer Group fighting for China against the Japanese. They were called the “Flying Tigers”. Between 1939 and 1945, Curtiss built 13,738 P-40s in many configurations. They flew in combat in every theater of operations during World War II.

A Curtiss-Wright Hawk 81-A3 (Tomahawk IIb) of the American Volunteer Group, Kunming, China, 1942. (U.S. Air Force)

© 2018, Bryan R. Swopes

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2 September 1944

Lt. (j.g.) George H.W. Bush, USNR, VT-51, in cockpit of TBM-1C Avenger Bu.No. 46214, USS San Jacinto (CVL-30), 1944. (U.S.Navy)

2 September 1944: Lieutenant (Junior Grade) George Herbert Walker Bush, United States Naval Reserve, led a flight of four TBF/TBM Avenger torpedo bombers of Torpedo Squadron 51 (VT-51), from the Independence-class light aircraft carrier USS San Jacinto (CVL-30), against a radio transmission station on the island of Chichi-Jima.

The Avenger had a crew of three. Along with Lt (j.g.) Bush were Lt. (j.g.) William G. White, USNR, gunner, and radio operator ARM 2/c John Lawson Delaney, USNR.

Undated photo of future United States President George H.W. Bush as a United States Navy pilot seated in the cockpit of an Avenger. (U.S. Navy)

Each airplane was armed with four 500-pound¹ general purpose bombs. The flight was joined by eight Curtiss-Wright SB2C Helldiver dive bombers of VB-20, escorted by twelve Grumman F6F-5 Hellcat fighters of VF-20, from USS Enterprise (CV-6).

Chichi-Jima is the largest island in the Ogasawara Archipelago of the Bonin Islands, approximately 150 miles (240 kilometers) north of Iwo Jima and 620 miles (1,000 kilometers) south of Tokyo, Japan. The United States Hydrographic Survey described the island in 1920 as “very irregular in shape,” approximately 4¼ miles (7.2 kilometers) long and 2 miles (3.2 kilometers) wide. The area of the island is presently given as 23.45 square kilometers (9.05 square miles). Its highest point is 326 meters (1,070 feet) above Sea level. The island has a small sea port where midget submarines were based beginning in August 1944. Chichi-Jima was heavily garrisoned with 20,656 Imperial Japanese Army and Navy personnel, and 2,285 civilian workers.²

A Curtiss-Wright SB2C Helldiver over Chichi Jima. (U.S. Navy)

Lieutenant Bush’s flight was scheduled for a time over target of 0825–0830. They encountered heavy antiaircraft fire and Bush’s Avenger was hit. With the torpedo bomber on fire, Bush continued the attack and later reported good results. Unable to return to the aircraft carrier, he flew away from the island to limit the risk of capture of the crew by the enemy when they bailed out.

Bush and one other crewman (which one is not known) bailed out. While Bush parachuted safely, the second crewman’s parachute never opened. The third crewman went down with the airplane. Both Lieutenant White and Radioman Delaney were killed.

The Gato-class fleet submarine USS Finback (SS-230) was stationed near the island on lifeguard duty during the attack. At 0933, Finback was notified of an aircraft down nine miles northeast of Minami-Jima.  Escorted by two F6F fighters, the submarine headed for the location. At 1156, Finback picked up Lt. Bush, floating in his life raft. A search for White and Delaney was unsuccessful. Their bodies were not recovered.

Lt. (j.g.) George H. W. Bush, USNR, in inflatable raft, is rescued by the crew of USS Finback (SS-230), 2 September 1944. (U.S. Navy)

(Later that same day, Finback, while submerged, towed a second pilot and his life raft away from Magane-Iwa, as he held on to the sub’s periscope.)

Lieutenant Bush and the other rescued pilots remained aboard for the remainder of Finback‘s war patrol (her tenth), and were then returned to Pearl Harbor. In November he rejoined San Jacinto for operations in the Philippines.

Gato-class fleet submarine USS Finback (SS-230) off New London, Connecticut, 7 March 1949. (U.S. Navy)

George Herbert Walker Bush was born at Milton, Massachusetts, 12 June 1924, the son of Prescott Sheldon Bush and Dorothy Walker Bush. He attended high school at the Phillips Academy in Andover, Massachusetts.

One day after his 18th birthday, 13 June 1942, Bush enlisted as a seaman, 2nd class, in the United States Naval Reserve. He was appointed an aviation cadet and underwent preflight training at the University of North Carolina, Chapel Hill. He was honorably discharged 8 June, and commissioned as an ensign, United States Naval Reserve, 9 June 1943. At the age of 19 years, 2 days, he became the youngest Naval Aviator in history. (His age record was broken the following month by Ensign Charles Stanley Downey, who was commissioned 16 July 1943 at the age of 18 years, 11 months, 14 days.)

Aviation Cadet George H. W. Bush, USNR, 1942. (U.S. Navy)

Ensign Bush continued flight training at NAS Pensacola, Florida, and then the Carrier Qualification Training Unit, NAS Glenville, Illinois. After training with the Atlantic Fleet, Ensign Bush was assigned to Torpedo Squadron Fifty-One (VT-51), in September 1943. He was promoted to lieutenant (junior grade), 1 August 1944.

After leaving San Jacinto, Bush was assigned to NAS Norfolk, Virginia, from December 1944 to February 1945. He then joined Torpedo Squadron Ninety-Seven (VT-97) and then VT-153.

Lieutenant (j.g.) Bush was released from active duty on 18 September 1945, retaining his commission. He was promoted to lieutenant 16 November 1948. On 24 October 1955, Lieutenant Bush resigned from the U.S. Navy.

During World War II, George H. W. Bush flew 58 combat missions. He flew a total of 1,221 hours and made 126 carrier landings. He was awarded the Distinguished Flying Cross, the Air Medal with two gold stars (three awards), and the Presidential Unit Citation.

He would later become the forty-first President of the United States of America.

Grumman TBF or General Motors TBM Avengers over Wake Island, 1943. (U.S. Navy)

The airplane flown by Lt. (j.g.) Bush on 2 September 1944 was a General Motors TBM-1C Avenger torpedo bomber, Bu. No. 46214. This was a licensed variant of the Grumman TBF-1C Avenger, built by the General Motors Corporation Eastern Aircraft Division at Linden, New Jersey.

The Avenger was designed by Robert Leicester Hall, Chief Engineer and Test Pilot for the Grumman Aircraft Engineering Corporation, Bethpage, New York. The prototype XTBF-1 made its first flight 1 August 1941. It was a large single-engine aircraft, operated by a crew of three (pilot, radio operator and ball turret gunner). It was equipped with folding wings for storage on aircraft carriers. Production of the torpedo bomber began with the opening of a new manufacturing plant, Sunday, 7 December 1941. The first production Avenger was delivered to the U.S. Navy in January 1942.

The TBF-1 and TBM-1 were 40 feet, 11 inches (12.471 meters) long, with a wingspan of 54 feet, 2 inches (16.510 meters) and overall height of 16 feet, 5 inches (5.004 meters). The airplane had an empty weight of 10,545 pounds (478 kilograms), and its maximum gross eight was 17,895 pounds (8,117 kilograms). The Avenger was the largest single-engine aircraft of World War II.

LCDR Albert B. Cahn, USN, gives the take-of signal to a General Motors TBM-1C Avenger of Torpedo Squadron 51 (VT-51) aboard the light aircraft carrier USS San Jacinto (CVL-30), during exercises on 16 May 1944. (U.S. Navy)

The Avenger was powered by one of several variants of the Wright Aeronautical Division Cyclone 14 (R-2600): GR2600B698 (R-2600-8 and -8A); GR2600B676 (R-2600-10); and 776C14B31. The R-2600 was series of air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.688 liter), two-row 14-cylinder radial engines. The engines used in the Avengers all had a compression ratio of 6.9:1, supercharger ratios of 7.06:1 and 10.06:1, and propeller gear reduction ratio of 0.5625:1.

The R-2600-8, -8A and -10 had Normal Power ratings of 1,500 horsepower at 2,400 r.p.m. at Sea Level, and 1,700 horsepower at 2,600 r.p.m. for takeoff. The R-2600-20 was rated at 1,600 horsepower at 2,400 r.p.m., and 1,900 horsepower at 2,800 horsepower, respectively.

Dimensions and weights varied. The R-2600-8 and -8A were 64.91 inches (1.649 meters) long. The -10 was 74.91 inches (1.903 meters) long, and the length of the -20 was 66.08 inches (1.678 meter). The R-2600-8 and 8A and -10 were 54.26 inches (1.378 meters) in diameter. The -20 was 54.08 inches (1.374 meters). The -8 and -8A both weighed 1,995 pounds (905 kilograms). The -10 weighed 2,115 pounds (959 kilograms) and the -20 weighed 2,045 pounds (928 kilograms).

The engines drove a three-bladed Hamilton Standard Hydromatic constant-speed propeller.

The TBF/TBM had a cruise speed of 147 miles per hour (237 kilometers per hour) and maximum speed of 276 miles per hour (444 kilometers per hour) at 16,500 feet (5,029 meters). The service ceiling was 30,100 feet (9,174 meters). Its maximum range was 1,010 miles (1,625 kilometers).

The Avenger was armed with one air-cooled Browning AN-M2 .50-caliber machine gun mounted in each wing, firing forward. Another .50-caliber machine gun was installed in an electrically-operated dorsal ball turret. In the ventral position was a Browning M2 .30-caliber aircraft machine gun in a flexible mounting.

The primary weapon of the Avenger was carried in an enclosed weapons bay. It could be armed with one Mk. 13 aerial torpedo, ³ or up to 2,000 pounds (907 kilograms) of bombs.

A Grumman TBF-1 Avenger 4-T-2 of Torpedo Squadron Four (VT-4) drops a Mk. 13 aerial torpedo, circa 1942. Following the destruction of Torpedo Eight at the Battle of Midway, aerial torpedo attacks were rarely used by the U.S. Navy. (U.S. Navy)

The Grumman Aircraft Engineering Corporation produced TBF Avengers from Early 1942 until 1943, when production was taken over by the General Motors Corporation Eastern Aircraft Division. Grumman produced 2,290 TBFs, while Eastern built 9,836 TBMs.

Lieutenant Bush’s aircraft carrier, USS San Jacinto (CVL-30), was an Independence-class light carrier. It had been started by the New York Shipbuilding Corporation as a Cleveland-class light cruiser, USS Newark (CL-100), but was converted during construction. Construction took 11 months and the ship was launched 26 September 1943. It was commissioned 15 November 1943.

The carrier was 622.5 feet (189.7 meters) long, with a beam of 71.5 feet (21.8 meters) and draft of 26 feet (7.9 meters). It had a full load displacement of 15,100 long tons (16,912 short tons, or 15,342 metric tons). The ship was powered by steam turbines producing 100,000 horsepower and driving four shafts. San Jacinto was capable of a maximum 31.6 knots (36.4 miles per hour, or 58.5 kilometers per hour).

San Jacinto had a complement of 1,549 men, and carried 45 airplanes. For defense, it was armed with 28 Bofors 40 millimeter anti-aircraft guns and 40 Oerlikon 20 millimeter autocannon.

San Jacinto was decommissioned 1 March 1947 and was later scrapped.

USS Independence (CVL-30), late 1943. (U.S. Navy)

On 7 October 2006, the tenth and final Nimitz-class supercarrier was christened USS George H.W. Bush (CVN-77) in honor of President Bush’s service to his country.

USS George H. W. Bush (CVN-77). (U.S. Navy)

¹ The most common U.S. 500-pound general purpose bomb of World War II was the AN-M64. Nominally a 500-pound (227 kilogram) bomb, the munition actually weighed from 516.3 to 535.4 pounds (234.2 to 242.9 kilograms), depending on the explosive used. It contained 266 pounds (120.7 kilograms) of TNT, or 258.5 pounds (117.3 kilograms) of a 50/50 TNT and Amatol mixture. For easy identification, these were marked with a single 1-inch (2.54 centimeter) wide yellow band painted at the nose and tail. Composition B bombs, which were marked with two yellow identification bands, contained 272.7 pounds (123.7 kilograms) of explosive, while the heaviest was filled with 278.3 pounds (126.2 kilograms) of Tritonal. This variant was marked with three yellow bands. The bomb, without fins or fuses, was 36 inches (0.914 meters) long. The overall length was 59.16 inches (1.503 meters), including nose and tail fuses. The maximum diameter was 10.9 inches (0.277 meters).

² Personnel numbers as of 3 September 1945.

³ The U.S. Navy Torpedo, Mark 13, was a gyroscopically-steered single-speed anti-ship torpedo designed to be dropped from aircraft. It was 13 feet, 8.55 inches (4.180 meters) long, 1 foot, 10.42 inches (0.570 meters) in diameter and weighed 1,949 pounds (884 kilograms) ± 20 pounds (9 kilograms). The warhead contained a 400 pound (181 kilogram) TNT explosive charge.  The Mk. 13 was driven by a two-stage alcohol-fueled geared steam turbine, turning 10,983 r.p.m., with the coaxial counter-rotating propellers turning 1,150 r.p.m. It was capable of running at 33.5 knots (38.6 miles per hour, or 62.0 kilometers per hour), with a range of 6,300 yards (5.8 kilometers). This same type torpedo was used by the U.S. Navy’s PT boats late in the war.

Thanks to regular TDiA reader Joolz Adderly for suggesting this topic.

© 2017, Bryan R. Swopes

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2 September 1937: Grumman F4F Wildcat

Grumman XF4F-2, Bu. No. 0383, in flight. (Grumman Aircraft Engineering Corporation via World War Photos)

2 September 1937: First flight, Grumman XF4F-2 Bu. No.¹ 0383, a prototype fighter for the United States Navy and Marine Corps. The airplane was designed by Grumman’s Chief Engineer, Robert Leicester Hall.

Grumman XF4F-2 Bu. No. 0383. (Grumman Aircraft Engineering Corporation via World War Photos)

The prototype was damaged when it nosed over during a forced landing, 11 April 1938. The pilot, Lieutenant Gurney, was not injured. 0383 was rebuilt as an XF4F-3. The Navy ordered the fighter into production as the F4F-3 Wildcat. XF4F-3 0383 was destroyed in an accident, 16 December 1940. The pilot was killed.

Grumman XF4F-2 Bu. No. 0383 dead-stick landing accident near Naval Aircraft Factory, Philadelphia, 11 April 1938. (Grumman Aircraft Engineering Corporation)

The Grumman F4F-3 Wildcat was a single-engine, single-place, mid-wing monoplane fighter designed for operation from aircraft carriers. F4F-4 and later variants had folding wings for a smaller “foot print” while stored aboard.

Grumman XF4F-2. (The hoisting chains are air-brushed out.) (Grumman Aircraft Engineering Corporation)
Grumman XF4F-3 Wildcat, Bu. No. 0383, circa April 1939. The vertical fin is taller and squared-off. (United States Navy, Naval History and Heritage Command NH 97481)

The F4F-3 Wildcat was 28 feet, 10½ inches (8.801 meters) long with a wingspan of 38 feet, 0 inches (11.582 meters). The height over the propeller with the airplane in 3-point attitude was 11 feet, 9 inches (3.581 meters). The wings had a total area of 260 square feet (24.16 square meters). They had 0° incidence and no leading edge sweep. Thewings had 5° dihedral. The F4F-3 had an empty weight of 5,293 pounds (2,401 kilograms) and gross weight of 7,432 pounds (3,371 kilograms) with 147 gallons (556 liters) of gasoline.

Grumman F4F-3 Wildcat. (Grumman Aircraft Engineering Corporation)

The F4F-3 was powered by an air-cooled, supercharged, 1,829.39-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp SSC7-G (R-1830-86) two-row, 14-cylinder radial engine with a compression ratio of 6.7:1. The R-1830-86 had a normal power rating of 1,100 at 2,550 r.p.m., from Sea Level to 3,300 feet (1,006 meters), and 1,000 horsepower at 2,550 r.p.m. at 19,000 feet (5,791 meters). It was rated at 1,200 horsepower at 2,700 r.p.m. for takeoff. The engine turned a three-bladed Curtiss Electric propeller with a diameter of 9 feet, 9 inches (2.972 meters) through a 3:2 gear reduction. The R-1830-86 was 4 feet, 0.19 inches (1.224 meters) in diameter, 5 feet, 7.44 inches (1.713 meters) long, and weighed 1,560 pounds (708 kilograms).

Grumman XF4F-3 Wildcat Bu. No. 0383. (Grumman Aircraft Engineering Corporation)

The F4F-3 had a maximum speed of 278 miles per hour (447 kilometers per hour) at Sea Level, and 330 miles per hour (531 kilometers per hour at 19,000 feet (5,791 meters). It could climn to 20,000 feet (6,096 meters) in 7.6 minutes. The service ceiling was 30,500 feet (9,296 meters) and its maximum range was 1,280 miles (2,060 kilometers).

Grumman F4F-3 Wildcat, Bu. No. 1844 at Bethpage, New York, awaiting delivery to the U.S. Navy. (Grumman Aircraft Engineering Corporation)

The F4F-3 Wildcat was armed with four Browning AN-M2 .50-caliber machine guns. Later variants would have six guns.

The F4F Wildcat was produced by Grumman and the General Motors Corporation Eastern Aircraft Division as the FM-1. Grumman shifted to production of the F6F Hellcat in early 1943. GM continued to build Wildcats until the end of the War. A total of 7,885 were built.

Grumman F4F-3 Wildcat Bu. No. 1844. (Grumman Aircraft Engineering Corporation)
Grumman F4F-3 Wildcat Bu. No. 1844. (Grumman Aircraft Engineering Corporation)
Grumman F4F-3 Wildcat, Bu. No. 1844. (Grumman Aircraft Engineering Corporation)
Grumman F4F-3 Wildcat.(Grumman Aircraft Engineering Corporation)
Grumman F4F-3 Wildcat Bu. No. 1845, Summer 1940. (Grumman Aircraft Engineering Corporation)
Grumman F4F-3 Wildcat, circa 1942. (Smithsonian Institution National Air and Space Museum NASM 2009-9043)
Grumman F4F-3 Wildcat in three-color camouflage (LIFE Magazine)
Grumman F4F-3 Wildcat (LIFE Magazine)
Grumman F4F-3 Wildcat Bu. No. 2638, Bethpage, L.I., N.Y. This airplane was assigned to NACA Langley from 4 April–22 August 1941. Chief Engineer Robert Leicester Hall, front, kneeling, second from left (dark pullover sweater with light, open collar). Test pilot Corky Meyer in cockpit). (Grumman Aircraft Engineering Corporation)
Corky Meyer demonstrates deployment of life raft, 19 November 1942. (Grumman Aircraft Engineering Corporation)

¹ “Bu. No.” is the abbreviation for the Navy’s Bureau of Aeronautics serial number assigned to each aircraft.

© 2019, 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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