Tag Archives: Prototype

19 April 1960

Grumman YA2F-1 Inruder Bu. No. 147864 (San Diego Air and Space Museum Archives)
Grumman YA2F-1 Intruder Bu. No. 147864 with landing gear extended during the first flight, 19 April 1960. (San Diego Air and Space Museum Archives)

19 April 1960: Grumman Aircraft Engineering Corporation test pilot Robert K. Smyth made the first flight of the prototype YA2F-1 Intruder, Bu. No. 147864, at the Grumman Peconic River Airport (CTO), Calverton, Long Island, New York. During the flight, Smyth climbed to 15,000 feet (4,572 meters). The landing gear remained extended during the flight. At one point, Smyth attempted to retract it, but a malfunction was indicated, so they remained down and locked. The first flight lasted one hour.

During follow-on flights, Bob Smyth and project test pilot Ernie von der Heyden (who flew the photo-chase plane during the first flight) alternated left and right seats.

Bu. No. 147864 was painted gray with U.S. Navy markings before being accepted by the Navy on 29 April 1960. The airplane was lost 31 May 1960.

Grumman test pilot Robert K. Smyth in the cockpit of the YA2F-1 prototype, Bu. No. 147864, 29 April 1960. With Program manager Bruce Tuttle and VP Larry Mead. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)
Grumman test pilot Robert K. Smyth in the cockpit of the YA2F-1 prototype, Bu. No. 147864, 29 April 1960. With Program manager Bruce Tuttle and VP Larry Mead. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

Eight Grumman YA2F-1 Intruders were built for the test program.  They were later redesignated A-6A Intruder.

The Grumman A-6A Intruder was a carrier-based, all-weather attack bomber powered by two turbojet engines. It was operated by a pilot and a bombardier/navigator, or “b/n,” in a side-by-side cockpit. The wings were slightly swept.

The A-6A was 54 feet, 9 inches (16.688 meters) long with a wing span of 53 feet, 0 inches (16.154 meters) and overall height of 16 feet, 2 inches (4.928 meters). The aircraft had an empty weight of 25,300 pounds (11,476 kilograms) and maximum takeoff weight of 53,700 pounds (24,358 kilograms).

 Grumman YA2F-1 Intruder, Bu. No. 147864, in Navy markings. (San Diego Air and Space Museum Archives)
Grumman YA2F-1 Intruder, Bu. No. 147864, in Navy markings. (San Diego Air and Space Museum Archives)

The prototypes were powered by two Pratt & Whitney J52-P-6 turbojet engines which had previously been used on the North American Aviation AGM-28 Hound Dog cruise missile. The J52 was a two-spool, axial-flow turbojet with a 12-stage compressor section (5 low- and 7 high-pressure stages) and 2-stage (1 high- and 1-low pressure stages). The engines were rated at 8,500 pounds of thrust (37.81 kilonewtons), each. The J52-P-6 was 2 feet, 6.2 inches (0.767 meters) in diameter and weighed 2,056 pounds (953 kilograms) The engine incorporated an exhaust nozzle that could be swiveled downward 23° to assist in short field takeoffs.

The A-6A had a cruise speed of 481 miles per hour (774 kilometers per hour), and a maximum speed of 646 miles per hour (1,040 kilometers per hour) at Sea Level. The service ceiling was 40,250 feet (12,268 meters), and the range was 1,350 miles (2,173 kilometers).

The initial production Intruders could carry 15,000 pounds (6,804 kilograms) of bombs on hardpoints under the wings.

The Intruder was a very successful combat aircraft with 693 built in attack, tanker and electronic warfare variants. They remained in service with the United States Navy until 1997.

Grumman YA2F-1 (A-6A) Intruder Bu. No. 147867, the third prototype, carrying thirty Mk. 82 low-drag bombs on multiple ejector racks under the wings and fuselage. (U.S. Navy)
Grumman YA2F-1 (A-6A) Intruder Bu. No. 147867, the third prototype, carrying thirty Mk. 82 low-drag 500-pound bombs on multiple ejector racks under the wings and fuselage. (U.S. Navy)

© 2017 Bryan R. Swopes

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19 April 1955

Lockheed XF-104 Starfighter 083-1002, serial number 53-7787, the second prototype, in flight near Edwards AFB. (Lockheed Martin/Code One Magazine)

19 April 1955¹: Lockheed test pilot Herman Richard (“Fish”) Salmon was flying the second prototype Lockheed XF-104 interceptor, 53-7787, conducting tests of the General Electric T171 Vulcan gun system.

At 47,000 feet (14,326 meters), Salmon fired two bursts from the T171. On the second burst, vibrations from the gun loosened the airplane’s ejection hatch, located beneath the cockpit, resulting in explosive decompression.

Lockheed Chief Test Pilot Anthony W. LeVier (left) and Test Pilot Herman R. Salmon. An F-104 Starfighter is behind them. (Lockheed)
Lockheed Chief Test Pilot Anthony W. LeVier (left) and Test Pilot Herman R. Salmon. An F-104 Starfighter is behind them. (Lockheed Martin)

The Associated Press reported:

Test Pilot Leaps From New Jet

     INYOKERN, Calif., April 20 (AP)—Herman R. (Fish) Salmon, former racing pilot and now a top test pilot, bailed safely from one of the Air Force’s hot new F104 jet fighters over the Mojave dessert [sic] Tuesday.

He was  spotted on the desert after a two-hour search by military planes and brought to the Naval ordinance [sic] test station here for a physical examination. A preliminary checkup indicated he was not injured.

     Salmon, 41, was on a routine test flight when he hit the silk. Authorities gave no hint what happened to the supersecret plane to make the bailout necessary. The craft’s height at the time it was abandoned was not given. The plane’s top speed has been unofficially estimated at 1,200 m. p. h.

     Wreckage of the F104, one of two prototypes now being tested by Lockheed Aircraft Corp. for the Air Force, was found several miles south of the China Lake area.

     A Lockheed spokesman said Salmon, of Van Nuys, Calif., was spotted by a search plane and apparently picked up by a Navy helicopter and flown here. Salmon took off on the test flight from Palmdale, about 70 miles south of here.

Reno Evening Gazette, Volume LXXIX, Number 21, Wednesday, 20 April 1955, Page 24 at Columns 5–7.

Fish Salmon was wearing a David Clark Co. T-1 capstan-type partial-pressure suit and International Latex Corporation (I.L.C. Dover) K-1 helmet for protection in just such an emergency. The capstans are pneumatic tubes surrounded by fabric lacings, running along the arms, torso and legs. As the tubes inflated, the lacings pulled the fabric of the suit very tight and applied pressure to his body as a substitute for normal atmospheric pressure. The partial-pressure garment also enclosed his head, with a fiberglass helmet and a clear visor or face plate providing for vision.

Test pilot Herman R. Salmon with a prototype Lockheed XF-104 parked on Rogers Dry Lake. (Lockheed Martin)
Test pilot Herman R. (“Fish”) Salmon with a prototype Lockheed XF-104, parked on Rogers Dry Lake. (Lockheed Martin)

The sudden loss of cabin pressure and drop to subfreezing temperatures caused Salmon’s face plate to fog over. Inflating air bladders pushed his helmet high on his head.  The cockpit was filled with dust, fiberglass insulation and other debris. All this restricted his visibility, both inside and outside the airplane. The very tight pressure suit restricted his movements.

Fish Salmon cut the throttle, opened the speed brakes and began a descending turn to the left to reach a lower altitude. By the time he had reached 15,000 feet (4,572 meters) he had been unable to find a place on the desert floor to make an emergency landing. It was time to leave the crippled XF-104.

At 250 knots (288 miles per hour/463 kilometers per hour) the ejection seat fired Salmon out of the bottom of the cockpit. He had to open his parachute manually (the seat timer did not operate) and he made a safe landing.

The XF-104 had a downward-firing ejection seat, intended to avoid the airplane's tall vertical tail. Production aircraft used an upward-firing seat. (Lockheed)
The XF-104 had a downward-firing ejection seat, built by Stanley Aviation Inc. It was intended to avoid the airplane’s tall vertical tail. Later production aircraft used an upward-firing Martin-Baker seat. This airplane is the second prototype XF-104, 53-7787. (Lockheed Martin)

The prototype XF-104 impacted the desert approximately 73 miles (117 kilometers) east-northeast of Edwards Air Force Base. It was completely destroyed. Fish Salmon landed about 2 miles (3.2 kilometers) away. He was found two hours later and rescued by an Air Force helicopter.

Occasionally, a satisfied user thanked the researchers at the Aero Medical Laboratory. One of these was Lockheed test pilot Herman R. “Fish” Salmon. On April 14, 1955,¹ Salmon was flying the second XF-104 (53-7787) at 47,500 feet while wearing a T-1 suit, K-1 helmet, and strap-fastened boots. As he triggered the General Electric M61 Vulcan 20 mm cannon for a test firing, severe vibrations loosened the floor-mounted ejection hatch and the cockpit explosively depressurized at the same time as the engine flamed out. The suit inflated immediately. Repeated attempts to restart the engine failed, and Salmon ejected at 15,000 feet. Fish reported, “I landed in a field of rocks ranging from one foot to five feet in diameter. My right arm was injured and my head struck a rock. The K-1 helmet hard shell was cracked, but there was no injury to my head. It took me 10 to 15 minutes to get out of the suit with my injured arm. Rescue was effected [sic] by helicopter approximately two hour after escape.” Salmon reported that the K-1 helmet was excellent for rugged parachute landings, and his only complaint was that the visor may impair vision at extreme altitudes.”

Dressing for Altitude: U.S. Aviation Pressure Suits—Wiley Post to Space Shuttle, by Dennis R., Jenkins, National Aeronautics and Space Administration SP–2011–595, Washington, D.C., 2012, Chapter 4 at Page 141.

Lockheed's Chief Test Pilot, Anthony W. ("Tony") LeVier, is wearing a David Clark Co. T-1 capstan-type partial-pressure suit and K-1 helmet. The first prototype XF-104, 53-7786, is behind him. (U.S. Air Force)
Lockheed’s Chief Test Pilot, Anthony W. (“Tony”) LeVier, is wearing a David Clark Co. T-1 capstan-type partial-pressure suit and International Latex Corporation K-1 helmet. The first prototype XF-104, 53-7786, is behind him. (Jet Pilot Overseas)

There were two Lockheed XF-104 prototypes. Initial flight testing was performed with 083-1001 (USAF serial number 53-7786). The second prototype, 083-1002 (53-7787) was the armament test aircraft. Both were single-seat, single-engine supersonic interceptors. The XF-104 was 49 feet, 2 inches (14.986 meters) long with a wingspan of 21 feet, 11 inches (6.680 meters) and overall height of 13 feet, 6 inches (4.115 meters). The prototypes had an empty weight of 11,500 pounds (5,216 kilograms) and maximum takeoff weight of 15,700 pounds (7,121 kilograms).

The production aircraft was planned for a General Electric J79 turbojet but that engine would not be ready soon enough, so both prototypes were designed to use a Buick-built J65-B-3, a licensed version of the British Armstrong Siddeley Sapphire turbojet engine. XF-104 53-7787 had been built with an afterburning Wright J65-W-7 turbojet, rated at 7,800 pounds of thrust, and 10,200 pounds of thrust with afterburner.

The XF-104 had a maximum speed of 1,324 miles per hour (2,131 kilometers per hour), a range of 800 miles (1,287 kilometers) and a service ceiling of 50,500 feet (15,392 meters).

The General Electric T171 Vulcan was a prototype 6-barrelled 20 mm “Gatling Gun” automatic cannon. The barrels were rotated at high speed by a hydraulic drive. The gun is capable of firing 6,000 rounds per minute. The initial production version was designated M61. The cannon system was installed in a weapons bay on the left side of the F-104, between the cockpit and engine intakes.

The first prototype Lockheed XF-104, 53-7786, was also destroyed, 11 July 1957 when the vertical fin was ripped off by uncontrollable flutter. The pilot, William C. Park, safely ejected.

¹ Reliable sources give the date of this incident as both 14 April and 19 April. Contemporary news reports, published Wednesday, 20 April 1955, say that the accident took place “yesterday” and “Tuesday,” suggesting that the correct date is 19 April.

© 2017, Bryan R. Swopes

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18 April 1952

Consolidated-Vultee YB-60-1-CF 49-2676. (U.S. Air Force)
Consolidated-Vultee YB-60-1-CF 49-2676. (U.S. Air Force)

18 April 1952: Piloted by Chief Test Pilot Beryl A. Erickson, and Arthur S. Witchell, the prototype Consolidated-Vultee YB-60-1-CF, serial number 49-2676, made its first takeoff at Carswell Air Force Base, Fort Worth, Texas.

As a proposed competitor to Boeing’s B-52 Stratofortress, the YB-60 (originally designated B-36G) was developed from a B-36F fuselage by adding swept wings and tail surfaces and powered by eight turbojet engines. Its bomb load was expected to be nearly double that of the B-52 and it would have been much cheaper to produce since it was based on an existing operational bomber.

Test pilot Beryl A. Erickson waves from the cockpit of the YB-60. (Convair, via Jet Pilot Overseas.)
Test pilot Beryl A. Erickson waves from the cockpit of the YB-60. (Jet Pilot Overseas.)

The Associated Press reported:

New Jet ‘Rides Like Cadillac’, Crew Says After Test Flight

     FORT WORTH, April 18 (AP)—The all-jet YB-60 bomber “rides like a Cadillac” and “touched at fighter speed,” crew members said Friday after the ultra-secret global bomber completed its first test flight.

   “I came back with very little perspiration, B.A. Erickson, chief test pilot for Consolidated Vultee Aircraft Corp. said. “That’s the answer to any pilot.”

  Erickson tried the YB-60’s performance and capabilities only “modestly,” he said. The flight was made at a moderate altitude—”a couple of Texas miles,” Erickson said.

Rides Like Cadillac

     “The YB-60 rode like a Cadillac with no noise like a B-36—no prop noise or vibration,” Arthur S. Witchell Jr., the co-pilot, said.

“This is the Queen Mary coming in gracefully,” Erickson said.

     The YB-60, an eight-jet bomber sometimes called a jet version of the B-36, was in the air one hour and six minutes. Erickson said it “touched at fighter speed.”

The plane is about the same size as the B-36, Erickson said. “Most any B-36 pilot would feel right at home,” he said.

Higher Speed Tests

     Witchell said tests would probably be made soon at higher speeds and higher altitudes.

The plane took off with a deep roar, with a shrill, whining overtone. Several thousand spectators, including Air Force personnel from Carswell Air Force Base, home of the B-36, lined the left side of the Carswell runway and stood on rooftops.

     The spectators were able to distinguish little more than the YB-60’s extreme, almost-triangular swept-back shape.

     The YB-60 made a rendezvous in the air with a B-25 Air Force camera plane from which highly secret photographs were taken.

Valley Morning Star, Volume XLII, No. 271, Saturday 19 April 1952, Page 1 at Columns 3 and 4.

Consolidated-Vultee YB-60 (Jet Pilot Overseas)
Consolidated-Vultee YB-60 49-2676. (Jet Pilot Overseas)

The YB-60’s first flight was three days after that of the Boeing YB-52 Stratofortress. In testing, it was 100 miles per hour (161 kilometers) slower than the B-52 prototype, despite using the same engines. A second B-60 prototype was cancelled before completion, and after 66 flight hours the YB-60 test program was cancelled. Both airframes were scrapped in 1954, with the second prototype never having flown.

The Convair YB-60 was 171 feet (52.121 meters) long with a wingspan of 206 feet (62.789 meters) and overall height of 60 feet, 6 inches (18.440 meters). The wings were swept at a 37° angle. It had an empty weight of 153,016 pounds (69,407 kilograms) and gross weight of 300,000 pounds (136,078 kilograms).

The prototype jet bomber 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 were rated at 8,700 pounds of thrust (38.70 kilonewtons), each. 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). These were the same engines used in the YB-52, and were similarly mounted in four 2-engine nacelles below the wings.

Right profile of the first prototype YB-60. Note the tail landing gear strut. (Jet Pilot Overseas)
Right profile of the first prototype YB-60. Note the tail landing gear strut. (Jet Pilot Overseas)

Maximum speed was 0.77 Mach (508 miles per hour, 818 kilometers per hour) at 39,250 feet (11,963 meters) and the combat ceiling was 44,650 feet (13,609 meters). The YB-60 could reach 30,000 feet (9,144 meters) in just over 28 minutes. Takeoff required 6,710 feet (2,045 meters) and 8,131 feet (2478 meters) were required to clear a 50-foot (15.24 meters) obstacle. Maximum range was 8,000 miles (12,875 kilometers) but the combat radius was 2,920 miles (4,699 kilometers) with a 10,000 pound (4,536 kilograms) bomb load.

The maximum bomb load was 72,000 pounds (32,659 kilograms). Defensive armament consisted of two M24A1 20 mm autocannon in a remote-controlled tail turret. The second YB-60 retained the upper forward and lower aft retractable gun turrets of the B-36, adding eight more 20 mm cannon.

Chief Test Pilot Beryl Arthur Erickson. (Convair)
Chief Test Pilot Beryl Arthur Erickson. (Convair)

© 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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15 April 1952

The Boeing YB-52 Stratofortress, 49-231, takes off from Boeing Field at 11:09 a.m., 15 April 1952. (Robert F. Dorr Collection)
The Boeing YB-52 Stratofortress, 49-231, takes off from Boeing Field at 11:09 a.m., 15 April 1952. (Robert F. Dorr Collection)

15 April 1952: At 11:09 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, test pilot, after the first flight of the Boeing XB-52 Stratofortress prototype, 2 October 1952. (LIFE via Jet Pilot Overseas)
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 at the time. Johnston radioed that the airplane performed exactly as the engineers had predicted.

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, would have been the first to fly, but it was damaged during ground testing.

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 to 35° and mounted high on the fuselage (“shoulder-mounted”). The eight turbojet engines were in in two-engine nacelles mounted on pylons, below and ahead 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)
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 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 were rated at 8,700 pounds of thrust (38.70 kilonewtons), each. 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.

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 55 years old and has flown more than 21,000 flight hours.

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.

Captain William Magruder (standing) Boeing Chief Test Pilot Alvin M. Johnston (center) and Lieutenant Colonel Guy M. Townsend with the Boeing YB-52 Stratofortress 49-231. (Boeing)
Left to right: Captain William Magruder, Boeing Chief Test Pilot Alvin M. Johnston and Lieutenant Colonel Guy M. Townsend with the Boeing YB-52 Stratofortress, 49-231. (Boeing)

© 2017, Bryan R. Swopes

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