Lockheed YF-12A Interceptor by Testors/Italeri

1/72 scale
Kit No. 697
Retail: $99.00 (Out of production, aftermarket)
Decals: Two versions by Scalemaster
Comments: Detailed cockpit, raised panel lines, internal weapons bay with two AIM-47 missiles, detailed exterior surface, option for open or closed canopies, optional position landing gear but no display stand

History

The YF-12A was a direct descendant of the Central Intelligence Agency-funded A-12 reconnaissance aircraft program. The A-12, more commonly known as the SR-71, remains the fastest, highest-flying reconnaissance aircraft in the world, designed in the late 1950’s by the Lockheed Corporation. The A-12 program proved concepts of Mach 3-plus flight at altitudes exceeding 80,000 feet, while its variant, the YF-12A, successfully proved itself as an interceptor and also provided the supreme “look-down-shoot-down” capability unmatched then or today.

The origin of the YF-12A arguably has its roots in the “U-2 Incident” of May 1, 1960, when Major Francis Gary Powers was shot down near Sverdlovsk, Russia while conducting a reconnaissance flight over the Soviet Union for the CIA. U-2’s had operated with impunity over the Soviet Union since 1956, flying at altitudes of up to 70,000 feet and collecting sensitive data on Soviet military and space installations. Photo-intelligence gathered by U-2’s had revealed intel about the Soviet space program and confirmed that the Russians were actually significantly behind the U.S. in their development of a fleet of long-range strategic bombers. After Powers was shot down and subjected to a show trial in Moscow in what was a major international incident and embarrassment for the United States, overflights of the Soviet Union ceased, but other world conflicts continued to highlight the need for valid, accurate reconnaissance information.

In the wake of the U-2 incident, a higher and faster flying aircraft was needed to outrun the increasingly powerful surface-to-air missiles being developed by the Soviet Union. Efforts were begun to design aircraft with much lower radar signatures, thereby reducing the ability of Soviet radars to target them. This was the birth of stealth technology. Lockheed’s A-12 design was selected over a Convair design called KINGFISH, and in August 1959 Project OXCART began. By the end of January 1960, Lockheed had proven that the A-12 design did in fact have a reduced radar signature, and they were authorized to begin production.

The Air Force contracted with Lockheed to develop three interceptor versions of A-12 on October 31, 1960. Kelly Johnson realized the A-12 airframe, powerplant and flight characteristics had the potential to outperform the Air Force’s existing and proposed air-defense interceptors. He had begun discussions with Air Defense Command General Hal Estes in March 1960. Estes wanted to incorporate the AN/ASG-18 radar system developed by Hughes Aircraft, which had been successfully tested on a specially modified Convair YB-58 Hustler. General Estes also wanted to complete testing and use of the Hughes GAR-9 missile, another element of the B-58 test bed. Johnson was directed to equip an A-12 variant with the Hughes missile and radar system.

The YF-12A design was not only a sibling of the A-12 but it was manufactured at the same time as the original aircraft in a walled-off section of the famous “Skunk Works” manufacturing facility at Burbank, California. Flying for the first time on August 7, 1963 from the ultra-secret CIA flight test and training facility at Groom Lake, Nevada — a complex deep within the U.S. nuclear test range north of Las Vegas — the YF-12A began a program of flight testing which continued until November 7, 1979. During that period, the YF-12A established numerous speed and altitude records including an absolute sustained altitude of 80,258 feet and 15/25 kilometer closed circuit speed of 2, 070.1 mph (Mach 2.69).

YF-12A Configuration

The YF-12A had many of the same characteristics as the A-12 with some significant differences:

• The YF-12A had its forward fuselage chines cut back to accommodate the 40-inch radar dish of the AN/ASG-18.
  The camera and surveillance equipment bays were redesigned into three missile bays (forward left, right and right rear). Design computations of airflow around the missile bay doors opening at Mach speeds indicated significant directional stability degradation. This destabilizing force would multiply as Mach increased.
• Designers added a folding ventral centerline fin on the fuselage and smaller ventral fins on each engine nacelle to provide more directional stability at Mach speeds. The large ventral fin dropped well below landing gear clearance so it was designed to deploy only in flight, and retract when the landing gear were lowered for landing.
• The pilot’s seat was raised for better visibility, and a Radar Systems Operator (RSO) seat was installed behind the pilot’s compartment in the forward fuselage. On the A-12, this location (the “Q-Bay”) held sensitive camera equipment.

In addition, the right-front bay was composed entirely of flight-test equipment and radar equipment controlling the AN/ASG-18. An Airborne Observation (AO) panel was installed containing a bank of lights that designated “on/off” status of the cockpit instruments. A 35mm color camera snapped pictures every 0.8 seconds, capturing instrument status. At times, disagreement occurred between test engineers and pilots on instrument readouts, and if the AO was activated or not. Flight Test engineers solved the problem by including in the camera view an on/off switch for the AO camera itself and a clock, quelling any disputes on instrument readings.

Three missile bays were configured to hold one each of the Hughes Aircraft GAR-9 Super Falcon radar-guided, air-to-air missile, initially designed for the XF-108 Rapier program, which was cancelled in September 1959. The follow-on YF-12B design would allow for missile launches from all four bays. Ultimately the GAR-9 would become known as the AIM-47 missile. Some of the AIM-47 technology would later be used by Hughes Aircraft to develop the AIM-54 Phoenix missile carried by the Navy’s F-14 Tomcat.

Hughes Aircraft supplied the AN/ASG-18 pulse-Doppler radar system, which had also been designed for the XF-108 Rapier. It was the first integrated pulse-Doppler radar system designed in the United States, with a capability of look-down, lock-down operations exceeding 100 miles. The radar utilized a liquid-cooled transmitter train of two traveling wave-tube amplifiers in tandem to provide needed gain, and analog circuits to generate and process high-pulse, repetition-frequency wave forms. The system contained 41 separate units, weighing almost 1,400 pounds, housed in the nose and in what would otherwise have been the fourth missile-bay area. It used an on-board, solid-state digital computer for navigation and firing solutions; an analog attack-steering computer, and an infrared search and track system capable of being connected to the radar.

The interceptor mission profile of the YF-12A was for an aircraft able to reach and destroy potential attackers at considerable distance from U.S. shores. The high speed and range of the YF-12A coupled with its Hughes AN/ASG-18 radar and AIM-47A nuclear-armed missiles led to a high probability of success in its designated mission. As 1980 approached, it became overwhelmingly clear that the real nuclear threat lay with ICBM’s (Intercontinental Ballistic Missiles), not high-flying bombers. Resulting changes in Air Force needs in the 1980’s brought an end to the long range interceptor requirement, and the YF-12A program was cancelled, going the way of the Canadian CF-105 Arrow and America’s own XF-108 Rapier, both of which were terminated in 1959.

The YF-12A was then used by NASA at the Dryden Test Center at Edwards Air Force Base. The YF-12A’s high sustainable airspeed allowed the aircraft to extensively probe speed, altitude and temperature regimes once limited to only a few seconds in other test aircraft. The sole remaining YF-12A — only 3 were built — is on display at the U.S. Air Force Museum at Wright-Patterson AFB outside Dayton, Ohio. It was delivered on November 7, 1979, ending the magnificent career of a fantastically advanced trio of aircraft.

The Kit

Testors/Italeri’s YF-12A interceptor is injection molded in black plastic and consists of 72 parts including 5 clear parts for the canopy and windows for the aircrew. One thing immediately obvious upon opening the box is that the kit is dominated by two large parts for the upper and lower halves of the rear fuselage and wings, which bear a significant amount of engraved detail representing the corrugations and various grill-like areas to be found on the airframe.

The corrugations on the wing sheet metal prevented it from curling at high speeds and temperatures, which would have compromised the integrity of the fasteners holding the aircraft together. The grill-like areas helped control bleed air flows in and out of each nacelle and were a major factor in preventing the YF-12’s advanced Pratt 7 Whitney J58 engines from overheating. The temperatures on the wing surface could get up to 525 degrees Fahrenheit at sustained cruising speeds. The large, conical inlet spikes had to be positioned precisely so as not to set up a shockwave in the duct that could choke off the vital airflow.

The cockpit consists of a tub with raised detail representing side panel instrumentation, two instrument panels bearing raised detail (with a paint guide for both), two detailed ejection seats in a tandem arrangement, with separate parts for a control yoke and ejection handles to be cemented to each seat.

The kit provides a rudimentary internal weapons bay (it is not fully enclosed) but more importantly includes two AIM-47 air-to-air nuclear missiles. Thankfully a paint guide for these weapons is provided. The kit features separately mounted elevators and parts for detailed jet exhausts, two per engine. The weapons bay, like the cockpit, can be depicted open or closed. Modelers will also have a choice of depicting the kit in flight or with its landing gear deployed, although no display stand is provided for the in-flight option.

Markings

The decals are by Scalemaster and are fully in register with realistic colors and what appears to be a satisfactory semi-gloss finish that should give modelers no trouble.

The kit provides decals for two of the three versions of the YF-12A that were built. All markings are for U.S. Air Force aircraft. The first version is for the second YF-12A, 06935, in its early days in 1963 at the time of its maiden flight. This version is easily distinguished by a mostly Titanium paint scheme, with the leading and trailing edges of the airframe and the cone-shaped air inlet spikes painted Flat Black. The exceptions are the vertical tail surfaces, both dorsal and ventral, which are both Titanium.

The second set of decals is for both the second and third aircraft in the series, representing the YF-12A as it appeared in the years 1965-1979. The paint scheme is one of overall Flat Black for both aircraft. The second aircraft, 06935, bears a marking for NASA on its twin vertical tails. The third aircraft, 06936, looks largely identical to 06935 but for the NASA markings and the different serials on the engine nacelles. For some reason, there are no markings representing the first YF-12A.

Conclusion

This is a fascinating kit representing the interceptor version of the reconnaissance platform that we know today as the SR-71. Highly recommended for its historical value.

References

• Kit instructions
• https://www.nationalmuseum.af.mil
• https://www.aahs-online.org/pubs/journals/files/551002.pdf