Tony Levier and Glenn Fulkerson in the prototype Lockheed YF-94. (Lockheed Martin)
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.
Prototype Lockheed YF-94 48-356, first flight, 16 April 1949. (U.S. Air Force)
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.
The prototype Lockheed YF-94 test fires its four .50-caliber guns at Van Nuys, California. (Lockheed Martin)
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 prototype Lockheed YF-94, 48-356. (U.S. Air Force)
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.
Probably the best-known Lockheed F-94 variant is the all-rocket-armed F-94C Starfire. (Lockheed Martin)
The Boeing YB-52 Stratofortress, 49-231, takes off from Boeing Field at 11:08 a.m., 15 April 1952. (Robert F. Dorr Collection)
15 April 1952: At 11:08 a.m., Boeing’s Chief of Flight Test, Alvin M. “Tex” Johnston, and Lieutenant Colonel Guy M. Townsend, U.S. Air Force, ran all eight turbojet engines to full power and released the brakes on the YB-52 Stratofortress prototype, 49-231.
With an awesome eight-engine roar, the YB-52 sprang forward, accelerating rapidly, wings curving upward as they accepted the 235,000-pound initial flight gross weight. At V2 (takeoff speed) the airplane lifted off the runway, because of the 6-degree angle of incidence of the wing, and at 11:08 a.m. we were airborne. The initial flight of the YB-52 had begun.
—Tex Johnston: Jet-Age Test Pilot, by A.M. “Tex” Johnston with Charles Barton, Smithsonian Books, Washington, D.C., 1992, Chapter 13 at Pages 397–398.
Alvin M. “Tex” Johnston, Boeing Chief of Flight Test, after the first flight of the Boeing XB-52 Stratofortress prototype, 2 October 1952. (LIFE via Jet Pilot Overseas)
The YB-52 remained over the Seattle area for approximately 40 minutes while Johnson and Townsend ran through a series of systems checks. When completed, they climbed to 25,000 feet (7,620 meters) and flew the new bomber to Larson Air Force Base at Moses Lake, Washington, where they stayed airborne for continued testing. The Stratofortress finally touched down after 3 hours, 8 minutes—the longest first flight in Boeing’s history up to that time. Johnston radioed that the airplane performed exactly as the engineers had predicted.
Boeing YB-52 Stratofortress 49-231. (Boeing)
The YB-52 had actually been ordered as the second of two XB-52s, but modifications and additional equipment installed during building resulted in enough differences to warrant a designation change. The first XB-52, 49-230, should have been the first to fly, but it was damaged during ground testing.
Boeing XB-52 Stratofortress 49-230. (U. S. Air Force)
The Boeing XB-52 and YB-52 were prototypes for a very long range strategic bomber. Both were built with a tandem cockpit for the pilot and co-pilot, similar to the earlier B-47 Stratojet. The wings were swept and mounted high on the fuselage (“shoulder-mounted”). The eight turbojet engines were in in two-engine nacelles mounted on pylons, below and forward of the wings. This had the effect of preventing the airplane’s center of gravity from being too far aft, and also provided cleaner air flow across the wings. The B-52’s landing gear has four main struts with two wheels, each. They can turn to allow the airplane to face directly into the wind while the landing gear remain aligned with the runway for takeoff and landing. With the landing gear under the fuselage, the wings could be constructed with greater flexibility.
Boeing YB-52 Stratofortress 49-231. (U.S. Air Force)
The YB-52 was 152 feet, 8 inches (46.533 meters) long with a wingspan of 185 feet, 0 inches (56.388 meters). The prototype’s overall height was 48 feet, 3.6 inches (14.722 meters). The vertical fin could be folded over to the right so that the B-52 could fit into a hangar. The total wing area was 4,000 square feet (371.6 square meters). The wings’ leading edges were swept aft to 36° 54′. Their angle of incidence was 6° and there was 2° 30′ dihedral. The YB-52 had an empty weight of 155,200 pounds (70,398 kilograms) and gross weight of 405,000 pounds (183,705 kilograms).
The YB-52 was powered by eight Pratt & Whitney Turbo Wasp YJ57-P-3 turbojet engines. The J57 was a two-spool, axial-flow turbojet developed from an experimental turboprop engine. It had 16-stage compressor section (9 low- and 7-high-pressure stages), 8 combustors and a 3-stage turbine section (1 high- and 2 low-pressure stages). The YJ57-P-3s had a continuous power rating of 8,700 pounds of thrust (38.70 kilonewtons). The YJ57-P-3 was 183.5 inches (4.661 meters) long, 41.0 inches (1.041 meters) in diameter and weighed 4,390 pounds (1,991 kilograms).
The YB-52 had a cruise speed of 519 miles per hour (835 kilometers per hour) and maximum speed of 611 miles per hour (983 kilometers per hour) at 20,000 feet (6,096 meters). Its range was 7,015 miles (11,290 kilometers).
The two prototypes were unarmed.
Boeing YB-52 Stratofortress 49-231. (U.S. Air Force)
The B-52 was produced by Boeing at its plants in Seattle and Wichita from 1952 to 1962, with a total of 744 Stratofortresses built. The last version, the B-52H, entered service with the Strategic Air Command in 1960. The final B-52, B-52H-175-BW Stratofortress 61-0040, was rolled out at Wichita, Kansas, 26 October 1962. This airplane remains in service with the United States Air Force. The newest B-52 in service, 61-0040 is 62 years old and has flown more than 21,000 hours.
The Boeing YB-52 Stratofortress, 49-231, lands on Rogers Dry Lake, circa 1953. (U.S. Air Force 071204-F-9999J-039)
All previous versions, B-52A through B-52G, have long been retired to The Boneyard and scrapped. Of the 102 Boeing B-52H Stratofortress bombers, 76 are still in the active inventory. One, 61-007, known as Ghost Rider, was recently taken from Davis-Monthan and after an extensive restoration and update, returned to service.
The YB-52 prototype was retired to the National Museum of the United States Air Force in the late 1950s. By the mid-60s it was determined to be excess and was scrapped.
Left to right: Captain William Magruder, USAF; Boeing Chief Test Pilot Alvin M. Johnston; and Lieutenant Colonel Guy M. Townsend, USAF, with the Boeing YB-52 Stratofortress, 49-231. (Boeing)
10:21 a.m., PST, 14 April 1981: The first space shuttle, Columbia, touches down on Runway 23, Edwards Air Force Base, California, completing the first space flight of the United States’ shuttle program.
With its two-man crew, commander, veteran astronaut John W. Young, and pilot Robert L. Crippen, Columbia traveled 1,074,567 miles (1,729,348 kilometers) on its 37-orbit journey, in 54 hours, 20 minutes, 53 seconds.
Piasecki YH-21-PH Work-Horse 50-1231, first flight at Morton Grove, PA. (San Diego Air and Space Museum Archives)
11 April 1952: At the Piasecki Helicopter Corporation factory at Morton Grove, Pennsylvania, the first YH-21 tandem-rotor helicopter, serial number 50-1231, made it’s first flight. The test pilots were Leonard Joseph (“Len”) LaVassar and Martin P. (“Marty”) Johnson, both former U.S. Navy aviators.
The Piasecki Helicopter Corporation built 18 pre-production YH-21-PH helicopters, followed by three production variants, the H-21A, H-21B and H-21C.
The U.S. Air Force immediately ordered 32 H-21A helicopters for Search and Rescue operations. The Workhorse was well suited to cold weather operations and it was widely used in Alaska, Canada, and the Antarctic. Another 163 H-21B models were ordered as a troop transports. The U.S. Army ordered a similar H-21C variant.
Piasecki YH-21 Work Horse 50-1231, with rotors turning.
The YH-21 was a single-engine, tandem-rotor transport helicopter. It was normally operated by two pilots, with a flight mechanic (crew chief), and could carry up to 20 soldiers under ideal conditions.
With rotors turning, the YH-21’s overall length was 86 feet, 5 inches (26.340 meters). The fuselage was 52 feet, 6 inches (16.002 meters) long, and the helicopter had an overall height of 16 feet, 0 inches (4.877 meters). The rotors were 44 feet, 0 inches (13.411 meters) in diameter. The YH-21’s empty weight was approximately 8,117 pounds (3,682 kilograms) and maximum gross weight was 14,500 pounds (6,577 kilograms).
Piasecki H-21B Workhorse 51-3433 at Elmendorf Air Force Base, Alaska, circa 1960. (U.S. Air Force)
The forward rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right side.) The rear rotor turns the opposite direction. Normal operating speed for the main rotors was 233 to 258 r.p.m. (233–270 r.p.m. in autorotation.) The counter-rotating rotors cancelled out engine torque, eliminating any need for a tail rotor. The angle in the fuselage was intended to provide adequate vertical clearance between the intermeshing fore and aft rotor assemblies. (Later tandem rotor helicopters use raised pylons.)
Piasecki HH-21B 51-15855 supported X-15 flight operations at Edwards Air Force Base. (NASA)
The H-21 was powered by a single air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.875 liter) Wright Aeronautical Division Cyclone 9 863C9WD1 (R-1820-103) nine-cylinder radial, mounted inside the fuselage at midship, and drove the front and rear rotors in opposite directions through drive shafts and gear boxes. The Wright R-1820-103 engine was rated at 1,275 horsepower at 2,500 r.p.m., and 1,425 horsepower at 2,700 r.p.m., for takeoff. This direct-drive engine had a compression ratio of 6.80:1 and required 100/130 aviation gasoline. The engine was 4 feet, 0.50 inches (1.232 meters) long, 4 feet, 6.95 inches (1.396 meters) in diameter, and weighed 1,350 pounds (612 kilograms). Wright built 971 R-1820-103s from November 1950 through 1957.
Cutaway illustration of Piasecki H-21, showing internal arrangement. (U.S. Air Force)
The YH-21 could reach a maximum speed in level flight of 131 knots (151 miles per hour/243 kilometers per hour). Its Never Exceed limit (VNE) was 151 knots (174 miles per hour /280 kilometers per hour) (diving). The maximum Sea Level range was 397 nautical miles (457 statute miles/735 kilometers) at 125 knots (144 miles per hour/232 kilometers per hour). Its service ceiling was 19,200 feet (5,852 meters).
In 1955, Piasecki became Vertol and eventually Boeing Vertol. The company would continue to produce tandem rotor helicopters such as the H-46 Sea Knight and the CH-47 Chinook, which is still in production.
Piasecki CH-21B Workhorse, 51-15857, at the National Museum of the United States Air Force. (U.S. Air Force)
Prototype Northrop YT-38-5-NO Talon 58-1191 at Edwards AFB, 10 April 1959. (U.S. Air Force)
10 April 1959: Northrop test pilot Lewis A. Nelson made the first takeoff of the prototype YT-38-5-NO Talon, serial number 58-1191, at Edwards Air Force Base, California.
A private venture by Northrop, the Talon was designed by a team led by Edgar Schmued, famous for his work on the North American Aviation P-51 Mustang, F-86 Sabre and the F-100 Super Sabre. The Talon is a twin-engine advanced trainer capable of supersonic speeds. More than 5,500 hours of wind tunnel testing was performed before the airplane’s final configuration was determined.
After testing, the two YT-38s were modified to the YT-38A configuration. The modified aircraft was accepted by the United States Air Force and ordered into production as the T-38A Talon.
The T-38 was the world’s first supersonic flight trainer. The Northrop T-38A Talon is a pressurized, two-place, twin-engine, jet trainer. Its fuselage is very aerodynamically clean and uses the “area-rule” (“coked”) to improve its supersonic capability. It is 46 feet, 4.5 inches (14.135 meters) long with a wingspan of 25 feet, 3 inches (7.696 meters) and overall height of 12 feet, 10.5 inches (3.924 meters). The one-piece wing has an area of 170 square feet (15.79 square meters). The leading edge is swept 32º. The airplane’s empty weight is 7,200 pounds (3,266 kilograms) and maximum takeoff weight is approximately 12,700 pounds (5,761 kilograms).
Northrop YT-38-5-NO 58-1191 in flight over Edwards AFB, 10 April 1959. (U.S. Air Force)
The T-38A is powered by two General Electric J85-GE-5 turbojet engines. The J85 is a single-shaft axial-flow turbojet engine with an 8-stage compressor section and 2-stage turbine. The J85-GE-5 is rated at 2,680 pounds of thrust (11.921 kilonewtons), and 3,850 pounds (17.126 kilonewtons) with afterburner. It is 108.1 inches (2.746 meters) long, 22.0 inches (0.559 meters) in diameter and weighs 584 pounds (265 kilograms).
The T-38A has a maximum speed of Mach 1.08 (822 miles per hour/1,323 kilometers per hour) at Sea Level, and Mach 1.3 (882 miles per hour/1,419 kilometers per hour) at 30,000 feet (9,144 meters). It has a rate of climb of 33,600 feet per minute (171 meters per second) and a service ceiling of 55,000 feet (16,764 meters). Its range is 1,140 miles (1,835 kilometers).
Northrop YT-38-5-NO Talon 58-1191. (Northrop)
Between 1959 and 1972, 1,187 T-38s were built at Northrop’s Hawthorne, California factory. As of 2014, 546 T-38s remained in the U.S. Air Force active inventory. The U.S. Navy has 10, and NASA operates 15.
Northrop YT-38-5-NO Talon 58-1191. (Northrop)58-1191 and sister ship 58-1192 were converted to YT-38As. (Northrop)Lewis A. Nelson. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Lewis Albert Nelson was born 13 September 1920 at San Diego, California, the second of three children of George Walter Nelson, an electrician, and Edith Clarissa Merrill Nelson. He grew up in Santa Cruz, California.
Nelson first flew in a Piper J-3 Cub as a teenager. While attending a junior college in 1939, he was accepted into the Civilian Pilot Training Program and continued while at San Jose State College, San Jose, California.
Nelson enlisted as an aviation cadet in the U.S. Army Air Corps at Moffett Field, California, 12 January 1942. He was 5 feet, 7 inches (1.702 meters) tall and weighed 154 pounds (69.9 kilograms). He served until 1947. He was twice awarded the Distinguished Flying Cross.
After leaving the Air Corps, Nelson studied aeronautical engineering at the University of Southern California (USC) in Los Angeles, graduating in 1949. He later earned a master’s degree from the University of California, Los Angeles (UCLA).
Lew Nelson worked as an aeronautical engineer for the National Advisory Commission on Aeronautics (NACA), and joined the Northrop Corporation as a test pilot in 1950. In 1952 he was promoted to Chief Experimental Test Pilot. Nelson made the first flights of a number of Northrop aircraft, such as the F-89 Scorpion, N-156 and F-5. Nelson retired from Northrop in 1986.
He married Elaine M. Miller, Clark County, Nevada, 28 April 1979.
Lewis Albert Nelson died at Menifee, California, 15 January 2015, at the age of 94 years. His remains were buried at sea.
