Convair XF-92A by Testors

1/72 scale
Kit. No. 941
Cost: $10.00
Decals: One version – U.S. Air Force experimental aircraft
Comments: Engraved panel lines; one-piece canopy; raised rivet detail on wings; no landing gear; includes display stand and four air-to-air missiles

History

The Convair XF-92 was an experimental design intended to test the feasibility of delta-winged jet aircraft by investigating its behavior at high and low subsonic speeds. It was the world’s first jet aircraft to fly using the radical delta-wing configuration pioneered by Germany’s Dr. Alexander Lippisch during the 1930s. It was developed by Convair and the U.S. Air Force, in close collaboration with Dr. Lippisch, who developed the Messerschmitt Me 163 Komet for Nazi Germany, and was later brought to the United States to continue his work after the war.

Lippisch’s work in the years immediately before the war led him to conclude, along with other aircraft designers, that traditional straight wings and relatively thick airfoils were not suitable for flight approaching the speed of sound. As a result, new swept-back wing shapes were proposed to reduce high drag and other problems which appeared at transonic speeds.

In addition to swept-back wing and tail-less aircraft like the Me 163, Lippisch proposed a triangular delta wing, so named because it resembled the Greek letter delta. This shape had several advantages. A delta wing combined a sharp angle which reduced drag, with a large surface area that increased lift. The wing could be built very thin, but was still very strong. During World War II, Lippisch built the P.13a, a delta wing glider to test the shape’s low-speed characteristics.

As the Allied armies advanced into Germany in the spring of 1945, reports about delta wing research were confiscated. Both Lippisch and his glider fell into Allied hands at the end of the war. In the United States, the NACA (National Advisory Committee for Aeronautics) wind tunnel research independently confirmed Lippisch’s earlier findings regarding the potential performance of a delta winged aircraft design at high speeds. Engineers at Consolidated-Vultee (later Convair), who were designing the XF-92 interceptor, were interested in the delta wing. Conferences with Lippisch convinced them that a delta wing would work.

The Consolidated-Vultee Model 7002 aircraft completed in 1948. It was initially built as a flying mock-up to investigate delta wing behavior at low and high subsonic speeds for the proposed XF-92 delta winged interceptor. Powered by a ramjet with small rockets inside the combustion chamber, it would have been a manned surface-to-air missile, with a short range, Mach 1.65 top speed, and a flight time at high altitude of 5.4 minutes. The XF-92’s engine was soon determined to be impractical, and the project was cancelled in 1948.

Despite the cancellation of the XF-92 project, work continued on the Model 7002 and it was prepared to fly powered by a Allison J-33-A-23 turbojet and later the J33-A-29 turbojet with afterburner. Its role remained that of a test vehicle for the delta wing configuration. The aircraft was delivered to Muroc Air Force Base, CA, on April 1, 1948. Its first flight, an inadvertent hop during a high-speed taxi test was made on June 9, 1948, by Consolidated-Vultee test pilot Sam Shannon. The official first flight was made on Sept. 18, and the Phase I testing began. This demonstrated that the aircraft was airworthy, and continued through August 1949. The Phase I flights were conducted by both Shannon and fellow company test pilot William Martin.

With the final flight on Aug. 26, 1949, the aircraft was turned over to the Air Force for Phase II testing by Maj. Charles E. “Chuck” Yeager, and given the Air Force designation XF-92A, and carried the serial number 46-692. Although the aircraft carried the designation of a prototype fighter, its role was now that of research aircraft. The Phase II flights were tests by Air Force pilots to see if the aircraft met the contract specifications. The first Phase II flight was made by Yeager on October 13, 1949 — just a day short of two years after his Mach 1 flight in the Bell X-1. The XF-92A tests were completed with a final flight on December 28, 1949, by Maj. Frank Everest.

The XF-92A Phase I and II tests were over, but it was flown occasionally over the next three years. Primarily, these were tests of the aircraft’s performance and its J33 engine by Yeager and Everest. The aircraft was also used for familiarization flights by other Air Force pilots. The XF-92A’s most unusual use was in the movie “Jet Pilot,” a 1957 film starring John Wayne and Janet Leigh, for which it was painted as a Soviet “MiG-23” fighter (although the real MiG-23 aircraft would not take its first flight until 10 years later). The Air Force completed its tests with the XF-92A in February 1953, and turned the aircraft over to the NACA.

Although the XF-92A was an experimental aircraft and was never armed because it never entered production, the Testors kit includes what appear to be early versions of the AIM-7 Sparrow missile — just why is a mystery.

A. Scott Crossfield was the NACA pilot selected for the XF-92A research flights. His introduction to the aircraft, during a taxi across the lakebed, was memorable. He recalled years later, “Nobody wanted to fly the XF-92. There was no lineup of pilots for that airplane. It was a miserable flying beast.” Before the taxi, Everest briefed Crossfield, who recalled, “He told me, ‘Keep the nose up so it will slow down. Because it will roll a long ways.’ Well, I let the nose come down on the nose wheel. I couldn’t get it back up. It didn’t have enough tail power to do it. So that airplane was rolling like mad towards the edge of the lakebed…. I saw a county road off to the left. And I managed to get that thing turned and head up that country road. Burned out the brakes. Just melted them right there. Rolled up that county road about 100 yards. And fortunately no damage to the airplane. Came out pretty well, except the brakes were all burned out.” The road was later named “Crossfield Pike.”

Crossfield flew a total of 25 flights in the XF-92A between April 9, 1953 and Oct. 14, 1953. The initial 13 flights were for data on static longitudinal stability; dynamic stability; directional control; longitudinal and lateral stability and control, and low speed stability and control. These were followed by 10 flights to test different wing fence configurations. The wing fences were designed to control the tendency of swept wing aircraft to pitch up at low speeds and in turns. The initial six flights were made at speeds under Mach 1. The last four were for data on low-speed lateral and directional control with the wing fences. On one flight, the modified wing fences buckled during the test. The XF-92A undertook two low-speed lateral and directional control flights without the wing fences. These were both made on Oct. 14, 1953. When the XF-92A landed on the lakebed after the second flight, its nose gear collapsed. Crossfield was unharmed, but the XF-92A never flew again. The Air Force subsequently donated the XF-92A to the University of the South in Sewanee, TN. The aircraft was transferred to the Air Force Museum in 1969, where it is now on display.

The XF-92A proved that a delta-wing aircraft was practical, but, as Crossfield noted, the aircraft itself had shortcomings. It had severe pitch up problems, which often exceeded 6 gs, and once exceeded 8gs. Convair (the new name for Consolidated-Vultee) corrected the problems, and incorporated the lessons learned from the experimental XF-92A program into the subsequent development of the F-102 and F-106 interceptors, the XF2Y-1 Sea Dart jet-powered seaplane fighter, and the B-58 strategic bomber. Only one XF-92A was built.

The original Hawk kit of the XF-92A from the 1950’s.

Specifications

Span: 31 ft. 3 in.
Length: 42 ft. 5 in.
Height: 17 ft. 8 in.
Weight: 8,500 empty; 14,608 lbs. maximum
Armament: None
Engines: Allison J33-A-29 of 7,500 lbs. thrust with afterburner
Crew: One
Cost: $6,048,928

Performance:
Maximum speed: 715 mph/624 knots
Cruising speed: 654 mph/569 knots
Service ceiling: 40,000 ft.

The Kit

The Convair XF-92A Dart, released by Testors in 1995, is a re-box of the Hawk kit of the same name, initially released under their label back in 1952.  It is injection molded in gray and consists of 23 parts, including two parts for a display stand, and has no landing gear. It appears this kit was intended to be an in-flight display model only, most likely for the purpose of adorning an aerospace executive’s desk. Incredibly, given its age, the kit bears engraved panel lines, but in truth it is not particularly detailed. The fuselage is smooth (with the left and right fuselage interiors bearing the single word “Hawk”) and features the lion’s share of the kit’s few engraved panel lines, with the delta wings bearing raised rivet detail.

There is no cockpit to speak of, with a pilot’s head protruding above the cockpit area on the two fuselage halves. There is a small one-piece canopy, an intake splitter for the open nose, and no attempt at all to provide any detail for the rear exhaust nozzle, which is left open. Although the XF-92A never entered production, four air-to-air missiles are included in the kit, and appear to be a crude, early form of the AIM-7 Sparrow. The point of this appears to be to indulge modelers’ desire for underwing stores, as there is no evidence that the XF-92A was ever armed — although it could have been used as a test bed for the first Sparrow I missile (a primitive version of what ultimately became the AIM-7), which according to the Directory of U.S. Rockets and Missiles, made its first recorded interception in 1952, but did not enter even limited production until 1954, the year after the XF-92 program ended.

Testors’ main contributions to this updated re-issue are new box art, consisting of a photo of the finished kit, which admittedly looks more professional than the original art on the old Hawk box, and the provision of Scale Master decals, which are in perfect register, have good realistic color, and a nice semi-gloss finish. As this was an experimental aircraft that never entered production, there is not a great deal of available information on which to base any attempt to detail the kit any further. It is nonetheless of historic interest because of its seminal role in the development of the delta winged F-102 and F-106 interceptors.

An overhead view of the Model 7002, irreverently referred to by test pilots as “Seven Balls Two” — an indication of the less than high regard in which they held it.

References

• Armstrong Flight Research Center, NASA (www.nasa.gov)
• National Museum of the United States Air Force (www.nationalmuseum.af.mil)