Tag Archives: Allison Division of General Motors

20–21 April 1964

Lockheed L100-20 N1130E, in flight. Both outboard engines are shut down and the propellers feathered. (Lockheed Martin)
Lockheed L-100 Hercules N1130E, in flight. Both outboard engines are shut down and the propellers feathered. (Lockheed Martin)

20–21 April 1964: Nearly ten years after the first flight of the Lockheed YC-130 Hercules prototype, the Lockheed Model 382, serial number 3946, the commercial version of the military C-130E, made the longest first flight in history when it flew for 25 hours, 1 minute, after taking off from Marietta, Georgia. The aircraft was certified by the Federal Aviation Administration 16 February 1965.

Lockheed personnel celbrate the 25 hour, 1 minute first flight of the commercial L100 Hercules. (Lockheed Martin)
Lockheed personnel celebrate the 25 hour, 1 minute first flight of the commercial L-100 Hercules. (Lockheed Martin)

The L-382 was powered by four Allison 501-D22 turboprop engines, rated at 3,755 shaft horsepower at 13,820 r.p.m., and driving four-bladed Hamilton Standard Hydromatic constant-speed, reversible-pitch propellers with a diameter of 13 feet, 6 inches ( meters). at 1,020 r.p.m.

Maximum operating altitude 32,600 feet ( meters)

N1130E at Fairbanks, leased to Alaska Airlines. (Lockheed Martin)
N1130E at Fairbanks, leased to Alaska Airlines, 1965. (Lockheed Martin)

N1130E was retained by Lockheed as a demonstrator, however it was briefly leased to Alaska Airlines in March 1965, and returned the following month.

The L-382 was converted to the L382E-44K-20 standard in April 1968, with a 5 foot, 0 inch (1.524 meters) segment added to the fuselage behind the cockpit, and a 3 foot, 4 inch (1.016 meter) section behind the wing.

N1130E's fuselage was cut in two places to accommodate an 8 foot, 4 inch ( meter) stretch. (Lockheed Martin)
N1130E’s fuselage was cut in two places to accommodate an 8 foot, 4 inch (2.540 meter) stretch. (c-130hercules.net)
N1130E after conversion to the L100-20 configuration, at Lockheed-Burbank Airport, 1968. (Unattributed)
N1130E after conversion to the L100-20 configuration, at Lockheed-Burbank Airport, 1968. (c-130hercules.net)

N1130E was leased to Delta Air Lines in October 1968, and returned after six months.

Lockheed sold N1130E to Pepsico Airlease Corporation, who leased the freighter to Flying W Airways. It was reregistered as N50FW. In March 1973 Pepsico sold it to Philippine Aerotransport and it was operated for the Philippine government, first as PI-97, and then RP-97.

The first commercial Lockheed L-100, s/n 3946, in service with the Republic of the Philippines. (Ken Fielding via flickr)
The first commercial Lockheed L-100, s/n 3946, in service with the Republic of the Philippines. (Ken Fielding via flickr)

After sixty-two years, the Lockheed Hercules remains in production, and both military and civil versions are in service worldwide.

Lockheed Martin Model 382J Super Hercules (Lockheed Martin)
Lockheed Martin Model 382J Super Hercules, N100J. (Lockheed Martin)

© 2017, Bryan R. Swopes

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16 April 1949

Prototype Lockheed YF-94 48-356, first flight, 16 April 1949. (U.S. Air Force)
Prototype Lockheed YF-94 48-356, first flight, 16 April 1949. (U.S. Air Force)
Anthony M. "Tony" LeVier.
Anthony M. “Tony” LeVier.

16 April 1949: At Van Nuys Airport, California, test pilot Tony LeVier and flight test engineer Glenn Fulkerson made the first flight of the Lockheed YF-94 prototype, serial number 48-356. The aircraft was the first jet-powered all-weather interceptor in service with the United States Air Force and was the first production aircraft powered by an afterburning engine.

Two prototypes were built at Lockheed Plant B-9, located on the east side of Van Nuys Airport. Two TF-80C-1-LO (later redesignated T-33A) Shooting Star two-place trainers, 48-356 and 48-373, were modified with the installation of air intercept radar, an electronic fire control system, radar gun sight, four Browning AN-M3 .50-caliber (12.7 × 99 NATO) aircraft machine guns and a more powerful Allison J33-A-33 turbojet engine with water-alcohol injection and afterburner. The rear cockpit was equipped as a radar intercept officer’s station.

Right side profile of the Lockheed YF-94A Starfire prototype, 48-356, during its first flight, 16 April 1949. (San Diego Air & Space Museum Archives)
Right side profile of the Lockheed YF-94 prototype, 48-356, during its first flight, 16 April 1949. (San Diego Air & Space Museum Archives)

It was initially thought that the project would be a very simple, straightforward modification. However, the increased weight of guns and electronics required the installation of a more powerful engine than used in the T-33A. The new engine required that the aft fuselage be lengthened and deepened. Still, early models used approximately 80% of the parts for the F-80C fighter and T-33A trainer. The Air Force ordered the aircraft as the F-94A. Improvements resulted in an F-94B version, but the definitive model was the all-rocket-armed F-94C Starfire.

The Allison J33-A-33 was a single-shaft turbojet engine with a single-stage centrifugal-flow compressor, 14 combustion chambers and, a single-stage axial flow turbine. The engine was rated at 4,600 pounds of thrust (20.46 kilonewtons) and 6,000 pounds (26.69 kilonewtons) with afterburner. The J33-A-33 was 17 feet, 11.0 inches (5.461 meters) long, 4 feet, 1.3 inches (1.252 meters) in diameter and weighed 2,390 pounds (1,084 kilograms).

Originally a P-80C Shooting Star single-place fighter, 48-356 had been modified at Lockheed Plant B-9 in Van Nuys to become the prototype TF-80C two-place jet trainer (the designation was soon changed to T-33A), which first flew 22 March 1948. It was then modified as the prototype YF-94. 48-356 was later modified as the prototype F-94B. It is in the collection of the Air Force Flight Test Museum, Edwards Air Force Base, and is in storage awaiting restoration.

Underside of the prototype Lockheed YF-94A Starfire, 49-356, during its first flight, 16 April 1949. (San Diego air & Space Museum Archives)
Underside of the prototype Lockheed YF-94, 49-356, during its first flight, 16 April 1949. (San Diego Air & Space Museum Archives)

© 2017, Bryan R. Swopes

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14 April 1947

Douglas test pilot Gene May with a D-558-I Skystreak high-speed research airplane. (Douglas Aircraft Company)
Douglas Aircraft Company test pilot Eugene Francis May. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

14 April 1947: Douglas Aircraft Company test pilot Eugene Francis (“Gene”) May took the Number 1  U.S. Navy/NACA/Douglas D-558-I Skystreak high-speed research aircraft, Bu. No. 37970, for its first flight at at Muroc Army Airfield. The aircraft had been transported from the Los Angeles factory to Muroc by truck.

The Skystreak was a joint United States Navy/National Advisory Committee for Aeronautics (NACA) research aircraft designed to explore flight at high subsonic speed. The Phase I Skystreak was designed by a team led by Douglas Chief Engineer Edward Henry Heinemann. Flight testing was conducted at the NACA High Speed Flight Station at Muroc Army Airfield (later known as Edwards Air Force Base). Three D-558-Is were built, followed by the Phase II, swept-wing, Mach 2, D-558-II Skyrocket rocketplane.

The D-558-I carried extensive flight test instrumentation for its time. The wings had 400 orifices for air pressure sensors. During the test series, aircraft stability in the range of 0.82–0.99 Mach was investigated. One of the Skystreaks may have briefly exceeded Mach 1 as it came out of a dive.

Unlike some of the other experimental high speed aircraft of the time, it took off from the ground under its own power rather than being carried aloft by a mother ship. While those other aircraft could briefly reach much higher speeds, the D-558-I was able to fly for extended periods in the high-subsonic range, providing scientists and engineer with a tremendous amount of data.

The research airplane was a single-place, single-engine, low-wing monoplane with retractable tricycle landing gear. The fuselage of the D-558-I was constructed of an aluminum framework covered with sheet magnesium. It was designed for an ultimate load factor of 18 gs. The wings and tail surfaces were aluminum. The airplane was painted scarlet (not orange, like its contemporary, the Bell X-1) and was known as “the crimson test tube.” The D-558-I was 35 feet, 1.5 inches (10.706 meters) long with a wingspan of 25 feet, 0 inches (7.620 meters) and overall height of 12 feet, 1.6 inches (3.698 meters). Gross weight 10,105 pounds (4,584 kilograms). It carried 230 gallons (871 liters) of kerosene in its wings.

A Douglas D-558-I Skystreak being inspected by U.S. Navy personnel at tehe Douglas Aircraft Company plant in Los Angeles, California. [Modelers: Note the GREEN anti-glare panel.] (Getty Imamages/Bettman)
The D-558-I was powered by a single Allison J35-A-11 turbojet engine. The J35 was a single-spool, axial-flow turbojet with an 11-stage compressor section, 8 combustion chambers and single-stage turbine. The J35-A-11 was rated at 5,000 pounds of thrust (22.24 kilonewtons). The engine was 12 feet, 1.0 inches (3.683 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,455 pounds (1,114 kilograms).

Bu. No. 37970 made 101 of the 228 Phase I flights. It set a world speed record 1,031.178 kilometers per hour (640.744 miles per hour), flown by Commander Turner F. Caldwell Jr., U.S. Navy,  20 August 1947.¹ (Major Marion E. Carl, U.S. Marine Corps, flew the second Skystreak, Bu. No. 37971, to 1,047.356 kilometers per hour (650.797 miles per hour),² breaking Caldwell’s record.)

After Douglas completed the contractor’s test series, the Number 1 Skystreak was turned over to the NACA High Speed Flight Station and designated NACA 140. It was not as highly instrumented as the Number 2 and Number 3 Skystreaks and was not flown, but was used as a source for spare parts for the other D-558-Is.

Douglas D-558-I Skystreak Bu. No. 37970 is on display at the National Naval Aviation Museum, NAS Pensacola, Florida.

Douglas D-558-I Skystreak, Bu. No. 37970, at the National Naval Aviation Museum, Naval Air Station Pensacola, Florida. (U.S. Navy)

¹ FAI Record File Number 9864

² FAI Record File Number 9865

© 2017, Bryan R. Swopes

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27 March 1966

Test pilot Jack L. Zimmerman with the record-setting Hughes YOH-6A Light Observation Helicopter, 62-4213. (FAI)

27 March 1966: At Edwards Air Force Base in the high desert of southern California, Hughes Aircraft Company test pilot Jack Louis Zimmerman flew the third prototype YOH-6A Light Observation Helicopter, 62-4213, to set six Fédération Aéronautique Internationale (FAI) World Record for Altitude and Time-to-Climb. The records were set in two sub-classes, based on the helicopter’s take-off weight. Fifty-one years later, one of these records still stands.

Hughes YOH-6A 62-4213 at Edwards Air Force Base, 1966. (FAI)

Zimmerman took the YOH-6A from the surface to a height of 3,000 meters (9,843 feet) in 4 minutes, 1.5 seconds (FAI Record File Number 9922); and to 6,000 meters (19,685 feet) in 7 minutes, 12 seconds (FAI Record File Number 9923). The helicopter reached an altitude in level flight of 8,061 meters (26,447 feet). (FAI Record File Numbers 9920 and 9921). 9921 remains the current record for helicopters in Sub-Class E-1b, with a takeoff weight of 500–1,000 kilograms (1,102–2,205pounds).

Beginning with a takeoff weight between 1,000–1,750 kilograms (2,205–3,858 pounds) (Sub-Class E-1c), Zimmerman took the “loach” to a height 3,000 meters (9,843 feet) in 5 minutes, 37 seconds. (FAI Record File Number 771). The helicopter reached an altitude of 5,503 meters (16,578 feet), without payload. (FAI Record File Number 772)

[The field elevation of Edwards Air Force Base (EDW) is 2,210 feet (704 meters) above Sea Level. If the time-to-altitude flights had been made at nearby NAS Point Mugu (NTD) on the southern California coast, which has a field elevation 13 feet (4 meters), the times might have been significantly reduced. The air temperature at Edwards, though, was much colder.]

One day earlier, 26 March, Allison Engine Company test pilot Jack Schweibold flew the same YOH-6A  to set three Fédération Aéronautique Internationale (FAI) World Records for Distance Over a Closed Circuit Without Landing of 2,800.20 kilometers (1,739.96 miles).¹ One week earlier, 20 March, Jack Zimmerman had set a Fédération Aéronautique Internationale (FAI) World Record for Distance Over a Closed Circuit Without Landing of 1,700.12 kilometers (1,056.41 miles).² Fifty-one years later, these four World Records still stand.

The Hughes Model 369 was built in response to a U.S. Army requirement for a Light Observation Helicopter (“L.O.H.”). It was designated YOH-6A, and the first aircraft received U.S. Army serial number 62-4211. It competed with prototypes from Bell Helicopter Company (YOH-4) and Fairchild-Hiller (YOH-5). All three aircraft were powered by a lightweight Allison Engine Company turboshaft engine. The YOH-6A won the three-way competition and was ordered into production as the OH-6A Cayuse. It was nicknamed “loach,” an acronym for L.O.H.

The third prototype YOH-6A, 62-4213, testing the XM-7 twin M60 7.62 weapons system. (U.S. Army)

The YOH-6A was a two-place light helicopter, flown by a single pilot. It had a four-bladed, articulated main rotor which turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) Stacks of thin stainless steel “straps” fastened the rotor blades to the hub and were flexible enough to allow for flapping and feathering. Hydraulic dampers controlled lead-lag. Originally, there were blade cuffs around the main rotor blade roots in an attempt to reduce aerodynamic drag, but these were soon discarded. A two-bladed semi-rigid tail rotor was mounted on the left side of the tail boom. Seen from the left, the tail-rotor rotates counter-clockwise. (The advancing blade is above the axis of rotation.)

The YOH-6A was powered by a T63-A-5 turboshaft engine (Allison Model 250-C10) mounted behind the cabin at a 45° angle. The engine was rated at 212 shaft horsepower at 52,142 r.p.m. (102% N1) and 693 °C. turbine outlet temperature for maximum continuous power, and 250 shaft horsepower at 738 °C., 5-minute limit, for takeoff. Production OH-6A helicopters used the slightly more powerful T63-A-5A (250-C10A) engine.

The Hughes Tool Company Aircraft Division built 1,420 OH-6A Cayuse helicopters for the U.S. Army. The helicopter remains in production as AH-6C and MH-6 military helicopters, and the MD500E and MD530F civil aircraft.

Hughes YOH-6A 62-4213 is in the collection of the United States Army Aviation Museum, Fort Rucker, Alabama.

U.S. Army Hughes YOH-6A prototype 62-4213 at Le Bourget, circa 1965.

¹ FAI Record File Numbers 786, 787 and 11656.

² FAI Record File Number 762.

© 2017 Bryan R. Swopes

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26 March 1966

Allison Engine Co. test pilot Jack l. Schweibold with teh record-setting prototype Hughes YOH-6A, 62-4213, at Edwards Air Force Base, California, 1966. (FAI)
Allison Engine Co. test pilot Jack Schweibold with the record-setting number three prototype Hughes YOH-6A Light Observation Helicopter, 62-4213, at Edwards Air Force Base, California, 1966. (FAI)

26 March 1926: Allison Engine Company test pilot Jack Schweibold flew the third prototype Hughes Aircraft Company YOH-6A Light Observation Helicopter, 62-4213, to set three Fédération Aéronautique Internationale (FAI) World Records for Distance Over a Closed Circuit Without Landing of 2,800.20 kilometers (1,739.96 miles), including an Absolute Record for Class E (Rotorcraft).¹ These records still stand.

Hughes YOH-6A 62-4213 at Edwards Air Force Base, 1966. (FAI)
Hughes YOH-6A 62-4213 at Edwards Air Force Base, 1966. (FAI)

One week earlier, 20 March 1966, Hughes Aircraft Company test pilot Jack L. Zimmerman flew the same helicopter to set another distance record of of 1,700.12 kilometers (1,056.41 miles).² One 27 March, Zimmerman would set six more world records with 62-4213.³

Jack Schweibold wrote about the record flight in his autobiography, In the Safety of His Wings (Holy Fire Publishing, DeLand, Florida, 2005). He was one of a group of military and civilian test pilots selected to attempt a series of world record flights, using the number three prototype Hughes YOH-6A, 62-4213, from 20 March to 7 April 1966.

The record attempt began at midnight to take advantage of the cold desert air. The cold-soaked YOH-6A had been fueled with pre-cooled JP-5 in order to get the maximum amount of fuel on board. In addition to the standard fuel tank, two auxiliary tanks were placed in the cabin. The helicopter was so heavy from the overload that it could not hover. Jack made a running take-off, sliding the skids across the concrete until the increasing translational lift allowed the aircraft to break free. He began a very shallow climb.

Schweibold was flying a 60 kilometer (37.28 miles) closed course, but because of the near total darkness, he flew on instruments and was guided from the ground by Air Force test range radar controllers (Spatial Positioning and Orientation Radar Tracking, call sign SPORT). Accuracy was critical. The attempt would be disqualified if the helicopter cut inside of a pylon—which Jack could not see—but if he flew too far outside, the extra distance flown would not be counted and time would be lost. The maximum range would be controlled by the amount of fuel carried in the three tanks, and by the endurance of the pilot.

Throughout the flight, Jack gradually increased the altitude, as the T-63-A-5 turboshaft would be more efficient in thinner, colder air. He was flying a precisely calculated profile, taking into consideration aerodynamic drag, the efficiency of the helicopter’s rotor system, and the performance characteristics of the engine. He had been airborne for four hours before he climbed through 10,000 feet (3,048 meters).

At 14,000 feet (4,267 meters), Schweibold was on oxygen. He continued through 20,000 feet (6,096 meters) but was having trouble staying alert. (It would later be discovered that there was a malfunction in his oxygen mask.)

On the final lap, at 22,000 feet (6,706 meters) Jack had to fly around a towering cumulus cloud and radar contact was lost. He dived to lose altitude and popped out from under the cloud about a half-mile short of the runway.

When he shut down the engine, Jack Schweibold had flown the prototype YOH-6A 2800.20 kilometers (1,739.96 statute miles), non-stop. His record still stands.

Jack set 30 FAI World Records between 1966 and 1986. 26 of these remain current.

Frederick Jack Schweibold was born at Toledo, Ohio, 8 November 1935, the son of Henry E. and Jeanette Schweibold. He attended Ohio State University and majored engineering. He had enlisted in the United States Navy Reserve in 1952 and the joined the United States Air Force in 1954 as an Aviation Cadet. Schweibold went through pilot training at Randolph Air Force Base, San Antonio, Texas, flying the T-34 and T-28. He went on to train in the B-25 at Reese Air Force Base, Lubbock, Texas. Schweibold was commissioned as a second lieutenant and received his pilot’s wings in July 1957. In  momentary decision, he selected helicopter training.

Lieutenant Schweibold flew the Sikorsky H-19B for the Air Rescue Service, assigned to Oxnard Air Force Base, California. (The airfield is now Camarillo Airport, CMA, where I first soloed, and is about ten miles away from my desk.)

After leaving the Air Force, Jack flew Sikorsky S-55s for Chicago Helicopter Service, then Bell 47s for Butler Aviation. In 1960, he was hired by the Allison Division of General Motors as a test pilot and engineer for the new 250-series turboshaft engine.

I had the good fortune to have known Jack Schweibold. I first met him through his involvement in the Helicopter Association International biennial flight instructor recertification seminars, held during the HAI’s annual convention. He kept the seminar classes on track, and in between, was always available for questions. He was the authority on Allison’s 250-series turboshaft engines, and over the years I often called him for technical information and operational advice. On top of that, Jack Schweibold was just an all-around nice guy.

U.S. Army Hughes YOH-6A prototype 62-4213 at Le Bourget, circa 1965.
U.S. Army Hughes YOH-6A prototype 62-4213 at Le Bourget, circa 1965. (R.A. Scholefield Collection)

The Hughes Model 369 was built in response to a U.S. Army requirement for a Light Observation Helicopter (“L.O.H.”). It was designated YOH-6A, and the first aircraft received U.S. Army serial number 62-4211. It competed with prototypes from Bell Helicopter Company (YOH-4) and Fairchild-Hiller (YOH-5). All three aircraft were powered by a lightweight Allison Engine Company turboshaft engine. The YOH-6A won the three-way competition and was ordered into production as the OH-6A Cayuse. It was nicknamed “loach,” an acronym for L.O.H.

The YOH-6A was a two-place light helicopter, flown by a single pilot. It had a four-bladed, articulated main rotor which turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) Stacks of thin stainless steel “straps” fastened the rotor blades to the mast and also allowed for flapping and feathering. Hydraulic dampers controlled lead-lag. Originally, there were blade cuffs around the main rotor blade roots in an attempt to reduce aerodynamic drag, but these were soon discarded. A two-bladed semi-rigid tail rotor was mounted on the left side of the tail boom. Seen from the left, the tail-rotor rotates counter-clockwise. (The advancing blade is on top.)

Overhead photograph of a Hughes YOH-6. Note the blade cuffs. (U.S. Army)
Overhead photograph of a Hughes YOH-6A. Note the blade cuffs. (U.S. Army)

The YOH-6A was powered by a T63-A-5 turboshaft engine (Allison Model 250-C10) mounted behind the cabin at a 45° angle. The engine was rated at 212 shaft horsepower at 52,142 r.p.m. (102% N1) and 693 °C. turbine outlet temperature for maximum continuous power, and 250 shaft horsepower at 738 °C., 5-minute limit, for takeoff. Production OH-6A helicopters used the slightly more powerful T63-A-5A (250-C10A) engine.

The Hughes Tool Company Aircraft Division built 1,420 OH-6A Cayuse helicopters for the U.S. Army.  The helicopter remains in production as AH-6C and MH-6 military helicopters, and the MD500E and MD530F civil aircraft.

Hughes YOH-6A 62-4213 is in the collection of the United States Army Aviation Museum, Fort Rucker, Alabama.

The third prototype YOH-6A, 62-4213, testing the XM-7 twin M60 7.62 weapons system. (U.S. Army)
The third prototype YOH-6A, 62-4213, testing the XM-7 twin M60 7.62 weapons system. (U.S. Army)

¹ FAI Record File Numbers 786, 787 and 11656

² FAI Record File Number 762

³ FAI Record File Numbers 771, 772, 9920, 9921, 9922, and 9923

© 2017, Bryan R. Swopes

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