Tag Archives: Prototype

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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16 February 1967

Wilfried von Englehardt tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA in an out-of-ground effect hover, with engine cowlings removed, 16 February 1967. (Eurocopter)
Wilfried von Englehardt tests the prototype Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, in an out-of-ground effect hover with engine cowlings removed, 16 February 1967. (Eurocopter)
Wilfried von Englehardt (Académie de l’Air et de l’Espace)
Wilfried von Englehardt (Académie de l’Air et de l’Espace)

16 February 1967: At Ottobrun, Germany, test pilot Wilfried von Engelhardt made the first flight of the Bölkow-Entwicklungen KG Bo-105 prototype V-2, D-HECA, a twin-engine, rigid rotor helicopter. This was the second prototype. The first one was destroyed by ground resonance during pre-flight testing.

Messerschmitt AG merged with Bölkow-Entwicklungen KG in June 1968, becoming  Messerschmitt-Bölkow. The following year, the new company merged with Blohm & Voss to become Messerschmitt-Bölkow-Blohm, or MBB. The Bo-105 entered production in 1970.

The Bo-105 is a 5-place light helicopter powered by two turboshaft engines. It has a four-bladed rigid (or hingeless) main rotor. This gives it a high degree of maneuverability, and it is capable of performing aerobatic maneuvers. The two-bladed tail rotor is mounted high on a pylon and gives exceptional ground clearance for a helicopter of this size. There are two “clam shell” doors located at the rear of the cabin section, giving access to a large flat floor. The helicopter has been widely used by military, law enforcement and as an air ambulance.

Messerschmitt-Bölkow-Blohm Bo-105 V-2, D-HECA. (Eurocopter)
Bölkow-Entwicklungen KG prototype Bo-105 V-2, D-HECA, during flight testing. (Eurocopter)

The Bo-105 is 38 feet, 11 inches (11.86 meters) long. The diameter of the main rotor is 32 feet, 3.5 inches (9.84 meters). Overall height is 9 feet, 10 inches (3.00 meters). The helicopter has an empty weight of 2,813 pounds (1,276 kilograms) and maximum takeoff weight of 5,511 pounds (2,500 kilograms).

The prototype was powered by two Allison 250-C18 turboshaft engines, with increasingly more powerful 250-C20, -C20B and C-28C engines being added through the production run. The Allison 250-C18 is a 2-spool, reverse-flow, gas turbine engine with a 6-stage axial-flow, 1-stage centrifugal-flow, compressor section, and a 4-stage axial-flow turbine (2-stage gas producer, and 2-stage power turbine). The 250-C18 is rated at 317 shaft horsepower at 6,000 r.p.m. (100% N2). These were very light weight engines, ranging from just 141 to 173 pounds (64.0 to 78.5 kilograms).

The helicopter’s cruise speed is 127 miles per hour (204 kilometers per hour) and maximum speed is 167 miles per hour (242 kilometers per hour). The range is 691 miles (1,112 kilometers. Service ceiling is 17,000 feet (5,180 meters).

The Bo-105 was produced in Germany, Canada, Spain, Indonesia and the Philippines from 1967 to 2001. More than 1,500 have been built.

Wilfried von Englehart tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, at Ottobrun, Germany, 16 February 1967. (Eurocopter)
Wilfried von Englehart tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, at Ottobrun, Germany, 16 February 1967. (Eurocopter)

Wilfried  Baron von Englehardt died 24 January 2015 at the age of 86 years.

Wilfried Baron von Englehardt 1928-2015)
Wilfried Baron von Englehardt (11 September1928–24 January 2015)

© 2017, Bryan R. Swopes

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16 February 1946

The prototype Sikorsky S-51 commercial helicopter, NX19800, in flight between Bridgeport and East Hartford, Connecticut, 1946. (Sikorsky Historical Archive)
The prototype Sikorsky S-51 commercial helicopter, NX92800, in flight between Bridgeport and East Hartford, Connecticut, 1946. (Sikorsky Historical Archive)

16 February 1946: The Sikorsky S-51 prototype, NX92800, made its first flight. The test pilot was Dimitry D. (“Jimmy”) Viner, who later made the first civilian rescue using a helicopter. The S-51 was the first helicopter intended for commercial use, though it was also widely used by military services worldwide. (The prototype was later delivered to Aéronavale, French Naval Aviation.)

Dimitry D. ("Jimmy") Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)
Dimitry D. (“Jimmy”) Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)

The S-51 was a commercial version of the Sikorsky R-5 series military helicopters. It was a four-place, single engine helicopter, operated by one pilot. The cabin was built of aluminum with Plexiglas windows. The fuselage was built of plastic-impregnated plywood, and the tail boom was wood monocoque construction.

The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. (All metal blades soon became available.) The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left.

The helicopter’s fuselage was 41 feet, 7.5 inches (12.687 meters). The main rotor had a diameter of 48 feet (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.2.565 meters) giving the helicopter an overall length of 57 feet, 1 inch (17.399 meters). It was 13 feet, 1.5 inches (4.001 meters) high. The landing gear tread was 12 feet (3.7 meters).

The S-51 had an empty weight of 4,050 pounds (1,837.05 kilograms) and maximum takeoff weight of 5,500 pounds (2,494.76 kilograms). Fuel capacity was 100 gallons (378.5 liters).

Sikorsky S-51 NC92813, Los Angeles Airways, departs on a commercial flight, Los Angeles, California, 1947. (LAT)
Sikorsky S-51 NC92813, Los Angeles Airways, departs on a commercial flight, Los Angeles, California, 1947. (Los Angeles Times)

The helicopter was powered by a 986.749-cubic-inch-displacement (16.170 liter) air-cooled, supercharged, Pratt & Whitney Wasp Jr. T1B4 (R-985 AN-5) direct-drive,  nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine had a compression ratio of 6:1 and was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.

The S-51 had a maximum speed (VNE) of 107 knots (123.1 miles per hour/198.2 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914.4 meters).

Of 220 helicopters in the S-51 series built by Sikorsky, 55 were commercial models.

One of Los Angeles Airways' Sikorsky S-51 helicopters takes off from roof of the the Terminal Annex Post Office, Los Angeles, California, 1 October 1947. (Los Angeles Times Photographic Archive/UCLA Library)
One of Los Angeles Airways’ Sikorsky S-51 helicopters takes off from roof of the the Terminal Annex Post Office, Los Angeles, California, 1 October 1947. (Los Angeles Times Photographic Archive/UCLA Library)

© 2017, Bryan R. Swopes

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15 February 1946

Douglas XC-112A Liftmaster 45-873 (U.S. Air Force)
Douglas XC-112A 45-873 (W.T. Larkins Collection/Wikipedia)

15 February 1946: First flight of Douglas XC-112A (s/n 36326) 45-873.

In 1944, the U.S. Army Air Corps had requested a faster, higher-flying variant of the Douglas C-54E Skymaster, with a pressurized cabin. Douglas Aircraft Company developed the XC-112A in response. It was completed 11 February 1946 and made its first flight 4 days later. With the end of World War II, military requirements were scaled back and no orders for the type were placed.

Douglas saw a need for a new post-war civil airliner to compete with the Lockheed L-049 Constellation. Based on the XC-112A, the prototype Douglas DC-6 was built and made its first flight four months later, 29 June 1946.

The Air Force ordered the twenty-sixth production Douglas DC-6 as a presidential transport, designated VC-118, The Independence. Beginning in 1951, the Air Force ordered a variant of the DC-6A as a the C-118A Liftmaster military transport and MC-118A medical transport. The U.S. Navy ordered it as the R6D-1.

The Douglas DC-6 was flown by a pilot, co-pilot, flight engineer and a navigator on longer flights. It was designed to carry between 48 and 68 passengers, depending on variant.

The DC-6 was 100 feet, 7 inches (30.658 meters) long with a wingspan of 117 feet, 6 inches (35.814 meters) and overall height of 28 feet, 5 inches (8.612 meters). The aircraft had an empty weight of 55,567 pounds (25,205 kilograms) and maximum takeoff weight of 97,200 pounds (44,090 kilograms).

The initial production DC-6 was powered by four 2,804.4-cubic-inch-displacement (45.956 liter), air-cooled, supercharged Pratt & Whitney Double Wasp CA15 two-row, 18 cylinder radial engines with a compression ratio of 6.75:1. The CA15 had a Normal Power rating of 1,800 h.p. at 2,600 r.p.m. at 6,000 feet (1,829 meters), 1,600 horsepower at 16,000 feet (4,877 meters), and 2,400 h.p. at 2,800 r.p.m with water injection for take off. The engines drove  three-bladed Hamilton Standard Hydromatic 43E60 constant-speed propellers with a 15 foot, 2 inch (4.623 meter) diameter through a 0.450:1 gear reduction. The Double Wasp CA15 was 6 feet, 4.39 inches (1.940 meters) long, 4 feet, 4.80 inches (1.341 meters) in diameter, and weighed 2,330 pounds (1,057 kilograms).

The Douglas DC-6 had a cruise speed of 311 miles per hour (501 kilometers per hour) and range of 4,584 miles (7,377 kilometers).

XC-112A 45-873 was redesignated YC-112A and was retained by the Air Force before being transferred to the Civil Aeronautics Administration at Oklahoma City, where it was used as a ground trainer. 36326 was sold at auction as surplus equipment, and was purchased by Conner Airlines, Inc. Miami, Florida and received its first civil registration, N6166G, 1 August 1956. The YC-112A was certified in the transport category, 20 August 1956.

Conner Airlines sold 36326 to Compañia Ecuatoriana de Aviación (CEA), an Ecuadorian airline. Registered HC-ADJ, Ecuatoriana operated 36326 for several years.

It was next re-registered N6166G, 1 August 1962, owned by ASA International. A few months later, 1 May 1963, 36326 was registered to Trabajeros Aereos del Sahara SA (TASSA) a Spanish charter company specializing in the support of oil drilling operations in the Sahara, registered EC-AUC.

XC-112A was operated as a DC-6, EC-AUC, by TASSA Air Charter, seen here at London Gatwick, 29 August 1964. (RuthAS)
The XC-112A was operated as EC-AUC by TASSA Air Charter, seen here at London Gatwick, 29 August 1964. (RuthAS)

In 1965, with a private owner, 36326 was once again re-registered N6166G. Just two weeks after that, 1 June 1965, 36326 was registered to TransAir Canada as CF-TAX.

A TransAir DC-6
A TransAir DC-6

Two years later, 13 June 1967, Mercer Airlines bought 36326. This time the airplane was registered N901MA. Mercer was a charter company which also operated a Douglas C-47 and Douglas DC-4.

N901MA at Hollywood-Burbank Airport (Bureau d'Archives des Accidents d'Avion)
N901MA at Hollywood-Burbank Airport (Bureau d’Archives des Accidents d’Avion)

A Las Vegas, Nevada, hotel chartered Mercer Airlines to fly a group of passengers from Ontario International Airport (ONT), Ontario, California, to McCarran International Airport (LAS). On 8 February 1976, 36326, operating as Mercer Flight 901, was preparing to fly from Hollywood-Burbank Airport (BUR) where it was based, to ONT. The airliner had a flight crew of three: Captain James R. Seccombe, First Officer Jack R. Finger,  Flight Engineer Arthur M. Bankers. There were two flight attendants in the passenger cabin, along with another Mercer employee.

Weather at BUR was reported as 1,000 feet (305 meters) scattered, 7,000 feet (2,134 meters) overcast, with visibility 4 miles (6.4 kilometers) in light rain and fog. The air temperature was 56 °F. (13.3  °C.), the wind was 180° at 4 knots (2 meters per second).

At 10:35 a.m. PST (18:35 UTC), Flight 901 was cleared for a rolling takeoff on Burbank’s Runway 15. While on takeoff roll, Flight Engineer Bankers observed a warning light for engine #3 (inboard, starboard wing). He called out a warning to the Captain, however, the takeoff continued.

Immediately after takeoff, a propeller blade on #3 failed. The intense vibration from the unbalanced propeller tore the #3 engine off of the airplane’s wing, and it fell on to the runway below.

The thrown blade passed through the lower fuselage, cut through hydraulic and pneumatic lines and electrical cables and then struck the #2 engine (inboard, port wing), further damaging the airplane’s electrical components and putting a large hole in that engine’s forward accessory drive case. The engine rapidly lost lubricating oil.

Flight 901 declared an emergency and requested to land on Runway 07, which was approved by the Burbank control tower, though they were informed that debris from the engine was on the runway at the intersection of 15/33 and 07/25. The airplane circled to the right to line up for Runway 07.

Just prior to touchdown, warning lights indicated that the propeller on the #2 engine had reversed. (In fact, it had not.) Captain Seccombe announced that they would only reverse #1 and #4 (the outboard engines, port and starboard wings) to slow 36326 after landing, and the airplane touched down very close to the approach end of the runway.

Because of the damage to the airplane’s systems, the outboard propellers would not reverse to slow the airplane and the service and emergency brakes also had failed. N901MA was in danger of running off the east end of the 6,055 foot (1,846 meters) runway, across the busy Hollywood Way and on into the city beyond.

The flight crew applied full power on the remaining three engines and again took off.  The landing gear would not retract. The electrical systems failed. The #2 engine lost oil pressure and began to slow.

The DC-6 circled to the right again and headed toward Van Nuys Airport (VNY), 6.9 miles (11.1 kilometers) west of Hollywood-Burbank Airport. They informed Burbank tower that they would be landing on Van Nuys Runway 34L which was 8,000 feet (2,438 meters) long. Because of the emergency, the crew remained on Burbank’s radio frequency. The #2 engine then stopped but the propeller could not be feathered.

Bob Hope Burbank irport is at the right edge of this image, and Van Nuys Airport is at the left. Woodly Golf Course is just south of VNY. (Google Earth image)
Hollywood-Burbank Airport (BUR) is at the right edge of this image, and Van Nuys Airport is at the left. Woodley Lakes Golf Course is just south of VNY. (Google Earth image)

Van Nuys weather was reported as 600 feet (183 meters) scattered, 10,000 feet (3,048 meters) overcast, with visibility 10 miles (16.1 kilometers) in light rain, temperature 55 °F. (12.8 °C.). The airliner was flying in and out of the clouds and the crew was on instruments. [1045: “Special, 1,200 scattered, 10,000 feet overcast, visibility—10 miles, rainshowers, wind—130° at 4 kn, altimeter setting—29.93 in.”]

Because of the drag of the unfeathered engine #2 propeller and the extended landing gear, the Flight 901 was unable to maintain altitude with the two remaining engines. The airplane was not able to reach the runway at VNY.

A forced landing was made on a golf course just south of the airport. The airplane touched down about 1 mile south of the threshold of Runway 34L on the main landing gear and bounced three times. At 10:44:55, the nose then struck the foundation of a partially constructed building, crushing the cockpit. All three flight crew members were killed by the impact.

N901MA-2
Douglas YC-112A serial number 36326, N901MA, shortly after crash landing at Woodley Golf Course, Van Nuys, California, 8 February 1976. (Bureau d’Archives des Accidents d’Avions)

Both flight attendants were trapped under their damaged seats but were able to free themselves. They and the passenger were able to escape from the wreck with minor injuries.

Los Angeles City Fire Department firefighters attempted to rescue the crew by cutting into the fuselage. Even though the area around the airplane had been covered with fire-retardant foam, at about 20 minutes after the crash, sparks from the power saw ignited gasoline fumes. Fire erupted around the airplane. Ten firefighters were burned, three severely. N901MA was destroyed.

"Feb. 8, 1976: Firemen scatter after saw ignites gas fumes at crash site of DC-6 in Van Nuys. Three trapped crew members of Mercer Enterprises DC-6 charter plane died. Ten firemen were injured." (Boris Yaro/Los Angeles Times)
“Feb. 8, 1976: Firemen scatter after saw ignites gas fumes at crash site of DC-6 in Van Nuys. Three trapped crew members of Mercer Enterprises DC-6 charter plane died. Ten firemen were injured.” (Boris Yaro/Los Angeles Times)

At the time of the accident, YC-112A 36326 was just three days short of the 30th anniversary of its completion at Douglas. It had flown a total of 10,280.4 hours. It was powered by three Pratt & Whitney R-2800-83 AMS, and one R-2800-CA18 Double Wasp engines. All four engines drove three-bladed Curtiss-Wright Type C632-S constant-speed propellers. The failed propeller had been overhauled then installed on N901MA 85 hours prior to the 8 February flight.

The National Transportation Safety Board investigated the accident. It was found that a fatigue fracture in the leading blade of the propeller blade had caused the failure. Though the propeller had recently been overhauled, it was discovered that the most recent procedures had not been followed. This required that the rubber deicing boots be stripped so that a magnetic inspection could be made of the blade’s entire surface. Because this had not been done, the crack in the hollow steel blade was not found.

© 2017, Bryan R. Swopes

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11 February 1939

Wreck of the Lockheed XP-38 at Cold Stream, New York. (Associated Press)
Wreck of the Lockheed XP-38 at Cold Stream Golf Course, Hempstead, New York, 11 February 1939. (Associated Press)

11 February 1939: Barely two weeks after its first flight, First Lieutenant Benjamin Scovill (“Ben”) Kelsey, U.S. Army Air Corps, took the prototype Lockheed XP-38, 37-457, on a record-breaking transcontinental flight from March Field, Riverside, California, to Mitchel Field, Long Island, New York.

Lieutenant Kelsey departed March Field at 6:32 a.m., Pacific Standard Time, (9:32 a.m., Eastern) and flew to Amarillo, Texas for the first of two refueling stops. He arrived there at 12:22 p.m., EST, and remained on the ground for 22 minutes. The XP-38 took off at 12:44 p.m., EST, and Kelsey flew on to Wright Field, Dayton, Ohio. He landed there at 3:10 p.m. EST.

Kelsey was met by Major General H.H. Arnold, and it was decided to continue to New York. The XP-38 was airborne again at 3:28 p.m., EST, on the final leg of his transcontinental flight.

The prototype Lockheed XP-38 37-457, being refueled at Wright Field, Dayton, Ohio, during the transcontinental speed record flight, 11 February 1939. (Unattributed)
The prototype Lockheed XP-38, 37-457, being refueled at Wright Field, Dayton, Ohio, during the transcontinental speed record attempt, 11 February 1939. (Unattributed)

Kelsey was overhead Mitchel Field, New York at 4:55 p.m., Eastern Standard Time, but his landing was delayed by other airplanes in the traffic pattern.

On approach, the XP-38 was behind several slower training planes, so Lieutenant Kelsey throttled back the engines. When he tried to throttle up, the carburetor venturis iced and the engines would not accelerate, remaining at idle. The airplane crashed on a golf course short of the airport.

Wreckage of the prototype Lockheed XP-38 37-457 at Cold Stream Golf Course, Hempstead, New York, 11 February 1939. (Unattributed)
Wreckage of the prototype Lockheed XP-38, 37-457, at Cold Stream Golf Course, Hempstead, New York, 11 February 1939. (Unattributed)

The total elapsed time was 7 hours, 45 minutes, 36 seconds but Kelsey’s actual flight time was 7 hours, 36 seconds. The prototype had averaged 340 miles per hour (547 kilometers per hour) and had reached 420 miles per hour (676 kilometers per hour) during the Wright Field-to-Mitchel Field segment.

Kelsey’s transcontinental flight failed to break the transcontinental speed record set two years earlier by Howard R. Hughes by 17 minutes, 11 seconds. It should be noted, however, that Hughes H-1 Racer flew non-stop from coast to coast, while the XP-38 required two time-consuming fuel stops.

Wreck of the prototype Lockheed XP-38 37-457 on the Cold Stream Golf Course, Hempstead, New York, 11 February 1939. (Unattributed)
Wreck of the prototype Lockheed XP-38, 37-457, on the Cold Stream Golf Course, Hempstead, New York, 11 February 1939. (Unattributed)

The XP-38 was damaged beyond repair, but its performance on the transcontinental flight was so impressive that 13 YP-38s were ordered from Lockheed by the Air Corps.

Overhead view of the wrecked prototype Lockheed XP-38 37-457 at Cold Stream Golf Course, Hempstead, New York, 11 February 1939. (U.S. Army)
Overhead view of the wrecked prototype Lockheed XP-38, 37-457, at Cold Stream Golf Course, Hempstead, New York, 11 February 1939. (U.S. Army)

Designed by an engineering team led by Hall L. Hibbard, which included the legendary Clarence L. “Kelly” Johnson, the XP-38 was a single-place, twin-engine fighter designed for very high speed and long range. It was an unusual configuration with the cockpit and armament in a center nacelle, with two longitudinal booms containing the engines and propellers, turbochargers, radiators and coolers. The Lightning was equipped with tricycle landing gear. The nose strut retracted into the center nacelle and the two main gear struts retracted into bays in the booms. To reduce drag, the sheet metal used butt joints with flush rivets.

The XP-38 was 37 feet, 10 inches (11.532 meters) long with a wingspan of 52 feet (15.850 meters) and overall height of 12 feet, 10 inches (3.952 meters). Its empty weight was 11,507 pounds (5,219.5 kilograms). The gross weight was 13,904 pounds (6,306.75 kilograms) and maximum takeoff weight was 15,416 pounds (6,992.6 kilograms).

Lockheed XP-38 37-457. (San Diego Air and Space Museum Archive)

The Lightning was the first production airplane to use the Harold Caminez-designed, liquid-cooled, supercharged, 1,710.60-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710 single overhead cam 60° V-12 engines. When installed on the P-38, these engines rotated in opposite directions. The XP-38 used a pair of experimental C-series Allisons, with the port V-1710-C8 (V-1710-11) engine being a normal right-hand tractor configuration, while the starboard engine, the V-1710-C9 (V-1710-15), was a left-hand tractor. Through a 2:1 gear reduction, these engines drove the two 11-foot (3.353 meters) diameter, three-bladed Curtiss Electric variable-pitch propellers inward to counteract the torque effect of the engines and propellers. (Viewed from the front of the airplane, the XP-38’s starboard propeller turned clockwise, the port propeller turned counter-clockwise. The direction of rotation was reversed in the YP-38 service test prototypes and production P-38 models.) The engines have long propeller gear drive sections to aid in streamlining aircraft, and are sometimes referred to as “long-nose Allisons.”

The V-1710-11 and -15 had a compression ratio of 6.65:1. They had a continuous power rating of 1,000 horsepower at 2,600 r.p.m. at Sea Level, and 1,150 horsepower at 2,950 r.p.m. for takeoff. The combination of a gear-driven supercharger and an exhaust-driven General Electric B-1 turbosupercharger allowed these engines to maintain their rated power levels to an altitude of 25,000 feet (7,620 meters).

The -11 and -15 were 7 feet, 10.46 inches (2.399 meters) long. The -11 was 3 feet, 6.59 inches (1.082 meters) high and 2 feet, 4.93 inches (0.7348 meters) wide. It weighed 1,300 pounds (589.7 kilograms). The -15 was 3 feet, 4.71 inches (1.034 meters) high, 2 feet, 4.94 inches (0.7351 meters) wide, and weighed 1,305 pounds (591.9 kilograms).

The XP-38 had a maximum speed of 413 miles per hour (664.66 kilometers per hour) at 20,000 feet (6,096 meters) and a service ceiling of 38,000 feet (11,582.4 meters).

The XP-38 was unarmed, but almost all production Lightnings carried a 20 mm auto cannon and four Browning .50-caliber machine guns grouped together in the nose. They could also carry bombs or rockets and jettisonable external fuel tanks.

Testing continued with thirteen YP-38A pre-production aircraft and was quickly placed in full production. The P-38 Lightning was one of the most successful combat aircraft of World War II. By the end of the war, Lockheed had built 10,037 Lightnings.

© 2017, Bryan R. Swopes

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