Jet Aircraft Development

The Navy's first radar-equipped jet, the twin-engine Douglas F3D Skyknight, which first flew on March 23, 1948, was a straight-winged, two-seat, carrier-based night fighter whose relatively large size earned it the unofficial nickname of 'Willie the Whale.' Only 268 were built, but they served actively over Korea and Vietnam, the last not being retired until 1978. On November 2, 1952, an F3D-2 scored the first jet victory over another jet at night when it destroyed a North Korean Yak-15, and Skyknights accounted for more victories over enemy aircraft over Korea than any other single Navy type.

American jet fighter development inevitably included some intriguing dead ends. The earliest was the Northrop XP-79B Flying Ram (January 1996 Aviation History, p.10), a flying wing whose pilot was supposed to fly from a prone position and supplement his four 50-caliber wing guns by slicing off the wings or tail surfaces of enemy aircraft with the reinforced leading edge of his own wings. The XP-79's first flight, on September 12, 1945, was also its last. After 15 minutes, the plane suddenly fell into a spin, and when test pilot Harry Crosby tried to bail out, he got caught in the slipstream and his parachute failed to open. Northrop turned its attention to flying-wing bombers rather than continue with the Flying Ram.

More conventional-looking, save for its unusually hefty size, was the Curtiss XP-87 Blackhawk, one of the few four-engine fighter aircraft ever built (November 1991 Aviation Heritage, P. 8). Originally intended as a ground attack plane, its role changed in midstream to that of an all-weather interceptor by the time it made its first flight on March 5, 1948. The USAF had planned to order 88 Blackhawks despite a 'buffeting' problem that was never eliminated, but the deal fell through on October 10, when the superior Northrop XF-89 was chosen over the XP-87. That final disappointment, after an investment of 38 months and $11 million, marked the ignominious end for the illustrious Curtiss Aeroplane Division, which was taken over by North American shortly thereafter.

On the other side of the scale was McDonnell's XF-85 Goblin (January 1995 Aviation History, P. 18), a tubby little parasite fighter that was intended to provide protection for American bombers by stowing away in their bomb bays until needed, launching and returning by means of a retractable trapeze bar. During flight testing on August 23, 1948, test pilot Edwin F. Schoch found himself unable to hook up due to the turbulence caused by the Boeing EB-29B under which he was trying to 'land.' After 10 minutes of trying, Schoch collided with the trapeze, smashing his canopy, and was fortunate to bring the Goblin down for a belly landing. Four subsequent attempts were more successful, but there was an equal number of failures, and in late 1949 the Goblin project was canceled.

On October 14, 1947, Air Force Captain Charles E. Yeager, flying in a rocket-powered Bell XS-1 research plane over Muroc Dry Lake, became the first man to officially pass through the sound barrier when he hit a speed of 700 mph (Mach 1.06). Although great effort and sacrifice were expended to build a jet airplane capable of sustaining level flight above Mach 1 during the 1940s, it would not be until late 1952 that a Soviet I-350M (the precursor of the MiG-19) achieved that goal. The USAF would match the feat on May 25, 1953, when George Welch reached the sound barrier over Edwards Air Force Base in a descendant of the F-86 Sabre, the YF-1OOA Super Sabre.

If any major power felt left behind at the onset of the jet age, it was the Soviet Union. The first turbojet-powered flight to be conducted in Soviet air space was made on August 5, 1945, when Colonel Andrei G. Kotchetkov test-flew a captured Me-262 near Moscow.

Soviet work in turbojet engines had begun in the 1920s with the experiments of Arkhip Lyulka and his assistants I.F. Kozlov and P.S. Shevchenko, on the VRD-1, an axial-flow engine with an eight-stage compressor and a projected thrust capability of 1,323 pounds. The German invasion on June 22, 1941, postponed Lyulka's experiments, but they resumed at the end of 1942, and by the end of 1944 he had developed the TR-1, a more advanced power plant capable of producing 2,866 pounds of thrust. In February 1945, Soviet forces advancing into Germany discovered the first BMW 003 and Junkers Jumo 004 turbojets. So Josef Stalin, perceiving Western advances in military aircraft as a potential threat to Soviet security, placed maximum priority on the development of Soviet turbojet fighters and bombers.

Four design teams took up the challenge; two of them delivered prototypes for flight testing a bare six months after the Me-262's first trials. The first to fly–by the outcome of a coin toss–was Artem Mikoyan and Mikhail Gurevich's MiG-9, which took off on April 24, 1946, with MiG test pilot Alexei Grinchik in the cockpit. It was followed by the Yakovlev Yak-15, flown by Mikhail I. Ivanov.

Developed by Yevgeny Adler of the Yakovlev design collective, the Yak-15 represented a remarkable shortcut to satisfy Stalin's crash program, being essentially the airframe of a piston engine Yak-3U fighter with a duralumin main wing spar in place of the original wooden one and a 1,984-lb.s.t. Jumo 004B turbojet engine slung beneath the fuselage. Fire protection aft of the engine was provided by a stainless steel sheath under the rear fuselage and a steel roller in place of the rubber tail wheel. The racket made by the aircraft during takeoff and landing was described as 'horrendous.' In late spring 1947, however, a version with tricycle landing gear, the Yak-15U (U standing for Usovershenstovanny, or 'improved'), was introduced. It was later refined into the Yak-17, which also introduced wingtip fuel tanks to compensate for the sacrifice in fuselage fuel capacity to accommodate the nose wheel. In general, the early Yaks were pleasant to fly and were ideal interim fighters for the first generation of Soviet pilots to make the transition from piston- to jet-powered flight.

The MiG-9, in contrast, was a completely original design, a midwing monoplane with two BMW 003 jets mounted side by side within a semimonocoque fuselage. Similar in performance to the Gloster Meteor, the MiG-9 had a better thrust-to-weight ratio, but higher wing loading, than the Yak-15. Despite some hair-raising experiences during its early test flights, the MiG-9 was described by its pilots as being easier to fly than the Yak-15, but its modest performance (a maximum speed of 566 mph at 16,400 feet) was recognized as being good only until the lessons learned from its construction could be applied to creating something better.

Coming later than the Yak-15 and MiG-9 were Pavel O. Sukhoi's Su-11 and Semyon A. Lavochkin's La-150. Although it had an oval-section fuselage and numerous other original characteristics, the twin-jet Su-11, which first flew on August 18, 1946, was dismissed out of hand by its evaluators as a 'warmed over Me-262' because of its superficial resemblance to the German jet.

First flown in September, the La-150 had a single Jumo 004B engine and was of pod-and-boom configuration. The La-150 was heavier than the Yak-15, and its performance was handicapped further by a substantial wetted area, on top of which its shoulder-mounted wing produced an excessive dihedral effect and its tail boom tended to oscillate dangerously. It was quickly abandoned.

As had been the case with the Americans, British jet engines and German research into sweptwing configuration radically accelerated Soviet jet development. In 1946, the British government allowed the export of Rolls-Royce Derwent and Nene engines as well as technical drawings to the USSR, which the Russians promptly placed in license production as the RD-500 and RD-45, respectively. Renewed efforts were then made to take advantage of these new developments. Yakovlev simply stuck the RD-500 in a final refinement of the basic Yak-15 formula, the straight-winged Yak-23, which featured the first ejector seat in a Soviet fighter and entered service in 1948. Mikoyan and Gurevich, on the other hand, built an original sweptwing fighter around one of the imported British Nenes, the I-310, which first flew on December 17, 1947. Production using the RD-45 engine quickly followed, under the designation of MiG-15.

Forgotten by posterity are the MiG-15's contemporary rivals. The prototype Yak-30, which looked similar to the MiG-15, performed well enough, but did not fly until September 1948, by which time the MiG-15 was about to go into production. Lavochkin's shoulder-wing La-15 did get a small production contract.

The MiG-15 was a distressing surprise to the West, for it not only advanced Soviet jet technology faster than anyone had expected, but it also gave the Soviets a fighter that could outperform anything in the West except for the F-86 Sabre. During the fighting over Korea between 1950 and 1953, the MiG proved capable of outmaneuvering and outclimbing the Sabre, while the Sabre could outdive the MiG. In combat, however, the MiG-15 revealed one fatal weakness–an unstable gun platform, especially in a dive, where it had a tendency to snake. Soviet pilots who flew the MiG-15 over Korea found that to be a serious handicap, which was even more grievous for its less experienced North Korean and Chinese pilots. The problem was recognized by the MiG team, which remedied it by lengthening the fuselage and completely redesigning the wing to create the MiG-17, one of the outstanding jet fighters of the 1950s–and even of the 1960s. This was only the beginning for Mikoyan and Gurevich, whose wartime products had previously been known only for their mediocrity. The jet age was to make MiG a household word.

The Soviet Yak-15 and its progeny were almost unique in the history of jet aviation, but not quite. Sweden also tried, with less success, to enter the jet age by adapting a jet engine to a piston-engine airframe. Recognizing the unprecedented challenge that the Cold War would present to her policy of strict neutrality, Sweden embarked on a crash program to modernize her air defenses. On November 9, 1945, the Swedish government instructed the Svenska Aeroplan Ante Bolaget (Saab) to adapt its twin-boom, piston-engine 21A fighter to use the British de Havilland Goblin turbojet. The result, the Saab 2IR, retained some 50 percent of the 21A's original design when its prototype took off on March 10, 1947, with Ake Sunde at the controls.

Although its configuration resembled the de Havilland Vampire's, the Saab 21R's handling characteristics did not. Its maximum speed of 497 mph, which was about 100 mph faster than the 21A's, coincided with the stress factors for which the 21A had been aerodynamically intended, and pilots who exceeded that speed found the controls to be excessively heavy. An additional problem was the plane's fuel capacity, because it allowed a flying time of only 40 minutes. By the time the first Saab 21R entered service early in 1950, its production order had been halved from 120 to 60.

In October 1945, the Saab design team had tentatively laid out Project R-1001 for a pod-and-boom turbojet fighter whose corpulent appearance led the team's leader, Lars Brising, to dub it the Tunnan ('Barrel'). At the end of the year, the project was affected by two new developments. First, it was learned that de Havilland was working on a more powerful engine than the Goblin, called the Ghost. Second, a Saab engineer came back from a visit to Switzerland with a wealth of Luftwaffe reports on its experiments with wing sweepback.

By January 1946, a revised design incorporating the Ghost engine and a 25-degree wing sweepback had been finalized, and the first prototype, designated the Saab 29, was flown by British test pilot Wing Cmdr. A.R. Moore, RAF, on September 1, 1948. Such was the Swedish government's sense of urgency that large-scale production was requested before the new fighter was flight tested, and the first Saab 29A was delivered to fighter squadron F13 just 32 months later, on May 10, 1951. Fortunately, despite its hasty gestation, the 29 proved to be an excellent airplane. Just as the mediocre MiG-9 and the outstanding MiG-15 turned the Soviet design team of Mikoyan and Gurevich into one of the great success stories of the jet age, so did the unsuccessful 21R and first-rate 29A Tunnan sire a proud line of fighting Saabs, with names like Lansen, Draken and Viggen.

France, recovering from a devastating German occupation, was understandably late in entering the jet age, although the Rateau firm had been experimenting with jet turbines as early as 1939. During the occupation, the Societé Nationale de Constructions Aéronautiques de Sud-Ouest (SNCASO) began clandestinely to design a jet test-bed called the SO 6000 Triton. Wind tunnel tests with models were conducted in 1944, and following the liberation, construction of five prototypes began early in 1945.

Seating two crewmen side by side within a corpulent fuselage, the S0-6000 was to have been powered by a Rateau SRA-1 axial-flow engine with 16-stage compressor and two-stage turbine embodying the bypass principle. At the time the airplane was completed, however, the SRA-1 was still not fully developed, so the modified prototype, SO-6000J No.1, used a German-built 1,984-lb.s.t. Junkers Jumo 004B-2 engine when it made its first flight on November 11, 1946. Subsequent Triton prototypes were built around the British Rolls-Royce Nene engines and were designated SO-6000N. The fourth airplane in the series crashed in 1949, but much was learned from the Tritons, and S0-6000N No. 3 survives at the Musée de l'Air et l'Espace at le Bourget.

The only operational French combat jet aircraft to fly before 1950 was the product of Marcel Bloch, a World War I pilot who had manufactured aircraft prior to World War II and had spent the war in a Nazi prison camp. Bloch survived his captivity, then suddenly changed his religion from Judaism to Catholicism and changed his name to Marcel Dassault. In 1946, he embarked on a private venture to rebuild his aircraft firm and, on June 29, 1948, succeeded in obtaining a French government grant to build three prototypes of a new jet fighter design.

On February 29, 1949, Dassault's straight-winged creation, the M.D.450 Ouragan ('Hurricane') took to the air, and promptly earned a contract for 150 more. As with McDonnell, MiG and Saab, Dassault's first jet was to be the forerunner of a dynasty of great aircraft, such as the Mystère and the Mirage.

A second noted French designer would create a jet fighter in the 1940s, but not for France. Emile Dewoitine lent his aeronautical experience to the Fabrica Militar de Aviones (FMA) to produce Argentina's first indigenously-built turbojet-powered aircraft, the I.Ae.27 Pulqui ('Arrow'). Powered by a Rolls Royce Derwent 5 engine generating 3,600 lb. of thrust, the all-metal, straight-winged Pulqui was armed with four 20mm cannons and was intended as a single-seat interceptor capable of operating from short, rustic runways. The prototype was first flight-tested on August 9, 1947, but its maximum speed of 447 mph and initial climb rate of 4,921 feet per minute were far below international standards of the time. As a result of that disappointing performance, FMA abandoned further development of the Pulqui jet fighter, turning its attention to the production of less sophisticated but more economically feasible aircraft types.

January 1950 ushered in a new decade and one more belated newcomer to the jet age: Canada. On January 19, the first prototype of a two-seat, radar-equipped interceptor, designed to defend Canada–and the United States–from the possibility of a Soviet bombing attack via the Arctic Circle, made its inaugural flight. Built by A.V. Roe Canada, a newly established branch of Britain's Avro firm, the first CF-100 was powered by two Rolls-Royce Avon engines, pending the completion of the indigenously designed Orendas that had originally been intended for it. Variously known as the Canuck and, more popularly, as the 'Clunk' (a reference to the sound made by the landing gear as it retracted into place), the CF-100 had the distinction of being NATO's first operational all-weather fighter and the first straight-winged jet to exceed the speed of sound.

While the development of fighter aircraft seemed to dominate the scene prior to 1950, the bombers they were designed to intercept would not come into full stride until the 1950s. Two straight-wing medium bombers, the Soviet Ilyushin Il-28 and the English Electric Canberra, entered service in the late 1940s and went on to remarkably long careers. In strategic bombing, the United States took the lead with the Boeing B-47, which had six jet engines slung under its sweptback wings and which would be the progenitor of one of the most influential designs in civil airliners, the Boeing 707. Without a doubt, however, the most original bomber of the 1940s was the Northrop XB-49, a giant jet-powered flying wing whose futuristic design failed to find favor in the Air Force.

The late 1940s had not established the definitive configuration for jet aircraft, but they had seen the genesis of its most fundamental elements. The decades to follow would see those fundamentals refined and expanded, as man's quest to fly greater loads farther, higher and faster applied itself to the jet age.

This article was written by Jon Guttman and originally published in the January 1998 issue of Aviation History. For more great articles subscribe to Aviation History magazine today!