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Brigadier General James Stewart (USAF Reserve), Kim Novak

... and Pye Wacket



1993, Columbia TriStar


Pye Wacket

Revenge of the Foo Fighters

In the fall of 1957, the Convair/Pomona division of General Dynamics obtained a study contract from the Air Force Air Proving Ground Center, Eglin Air Force Base, Florida, for a highly unusual vehicle called "Pye Wacket."

Convair/Pomona (later Hughes Missile Systems Company, and still later part of Raytheon specialized in sophisticated guided missile technology. Its later products would include the famous Stinger infrared-homing shoulder-launched surface-to-air missile and the Phalanx Close-In Weapon System anti-cruise missile ship defense system.

At the time the contract was initiated, the Air Force was looking for ways to defend its next-generation superbomber, the North American B-70 Valkyrie. Designed to fly at altitudes over 80,000 feet at cruising speeds of Mach 3 or more, the giant bomber would be required to penetrate the formidable air defense system that the Soviet Union was expected to have in place by the late 1960s. The Soviets were just fielding their first generation of surface-to-air missiles (SAMs) when Convair/Pomona began work on its new missile contract, and even dealing with those would be a very difficult problem.

When the B-70 program began in 1955, speed and altitude were seen as the aircraft's primary means of survival. A bomber flying at Mach 3 (about 2,000 mph) would cover ground at the rate of over 33 miles per minute and would transit radar and missile range envelopes so quickly that it would be difficult for defenses to acquire the bomber, prepare a SAM for launch and fire a round before the bomber began to approach the opposite edge of the missile's envelope. But as its development was delayed by technical problems and budget cuts, these advantages began to erode in the face of rapid advances in Soviet radar and missile technology. Air Force planners realized that since the angular B-70 had an enormous radar cross-section, Soviet surveillance radars would be able to detect it at great distances and alert SAM installations. An elaborate, powerful electronic countermeasures suite (the Westinghouse ALQ-24) was planned for the bomber, consisting of flush-mounted phased-array antennas built into the wing leading edges and boattail, as well as an infrared countermeasures system, but its effectiveness was questionable. By the fall of 1959 the B-70 was in a life-or-death funding battle with advocates of rival ballistic missile projects, who argued that no matter how high or fast the bomber flew, or how much ECM it poured into enemy receivers, it was vulnerable to nuclear-armed SAMs or air-to-air missiles launched from advanced interceptor aircraft in the MiG-25 Foxbat class. To keep the B-70 alive, some means of dealing with the anti-aircraft missile threat had to be devised. The B-70 Defensive Antimissile System (DAMS) was the result. It was easy to calculate that a SAM capable of hitting an aircraft like a B-70 would have to be traveling at speeds of considerably above Mach 4 to even catch the bomber in a tail-chase, and if such a missile was approaching from the bomber's forward hemisphere, the combined closing speeds would be even higher. The bomber could not take evasive action at Mach 3. A terminal DAMS would have to be extraordinarily fast, even more maneuverable --and like nothing that had ever been deployed before.

Soviet threats to US bombers as seen by SAC planners in 1959: SA-2 missile, TALL KING early warning radar, manned interceptors in the class of the experimental MiG Ye-152 armed with air-to-air missiles.


The B-70's designers considered three different missiles for the DAMS interceptor. A prime candidate was the Hughes XAIM-47A, left, a derivative of the Falcon series of air-to-air missiles used by many US interceptors. Very large, heavy and complex, the AIM-47A would use midcourse command guidance from the B-70 and an infrared terminal seeker. It was eventually selected as the armament of the Mach 3 Lockheed YF-12A. The other missile under consideration was of similar "cylindrical" layout and used similar guidance technology. The conventional-layout missiles were considered to be a better fit in the B-70's weapons bays than the lenticular concept, but their weight would cut over 700 miles from the bomber's range. Early North American studies reported that six defensive missiles would be adequate to protect a B-70 on a typical mission, but this number eventually grew to ten.

To solve this difficult problem, Convair abandoned traditional layouts and focused on a unique flying wing of circular planform and "lenticular" section. In addition to displaying unusual stability and high lift at extreme angles of attack, this "lenticular" shape would permit omnidirectional launch from a supersonic platform - ie, the interceptor would be capable of flying out forward, backward, or laterally from the bomber, saving crucial seconds in an attack. The initial test vehicle would be sixty inches in diameter and about a foot thick at the thickest point, and would be built from magnesium, weighing 425 pounds at launch and about 300 pounds after booster burnout. For testing, propulsion would be provided by three Thiokol M58A2 solid rocket motors derived from Falcon air-to-air missiles, giving the missile a total of over 14,000 pounds of thrust. Various means of control were studied in wind tunnel tests in the summer and fall of 1959 at Arnold Engineering Development Center, Tennessee, including flaps, vanes and conical "elevons" mounted at the "wingtips" of the disc. Eventually a rocket reaction control thruster system similar to the types used in space vehicles was selected due to its fast and effective response across the speed range. This consisted of a nitrogen pressure-fed hypergolic bipropellant system using six nozzles each producing 500 lb thrust (four pitch/roll nozzles and two yaw nozzles).

September 1959 AEDC report on preliminary supersonic wind tunnel tests of lenticular missile shapes. This study focused on the aerodynamics of simple discs of three different profiles at speeds up to Mach 5.

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March 1960 AEDC Report on wind tunnel tests of Pye Wacket lenticular configurations at supersonic speeds. By this time, a subtle wedge-shaped cross-section had been selected. This test series investigated different control surface configurations at various Mach numbers and angles of attack and bank.

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A wedge-profile, 60-inch diameter configuration with a rocket thruster attitude control system was proposed in for flight testing in a 1961 Convair document prepared for the Air Proving Ground Center at Eglin AFB, Florida.

The Lenticular Defense Missile was designed to maneuver with extreme violence, being slammed by its thrusters into bank attitudes that would produce tremendous accelerations and fantastic rates of turn. Preliminary reports refer to typical accelerations of 60 gs, with rates over 250 gs being possible at Mach 3 and above. Early plans envisioned that the operational version of the disc-shaped missile would be 48 inches in diameter, carry a 50 pound warhead, and achieve speeds of Mach 6 or more, depending on the direction of the target. The engagement with a threat missile or aircraft up to 15 miles away would be over in a matter of seconds as the little saucer closed on its prey at speeds of thousands of feet per second. Anti-missile missiles were often compared to bullets hitting bullets. In reality, bullets moved like molasses compared with the velocities the lenticular missile could reach.

The characteristics of the LDM missile evolved considerably over time, and later Air Force documents reported that

The device was found to be stable up through Mach 6, although the control surfaces were proving to be harder to define than expected. The missile was 70 inches in diameter, 9 inches deep, and weighed 510 pounds. A maximum speed of 4,500 mph (Mach 6.5) was provided by two solid rocket motors that provided 10,200 lbf. An infrared seeker was installed in the nose with a jettisonable cover to protect it at launch. The range was approximately 72 nautical miles.

USAF illustration shows configuration of the production Lenticular Defense Missile. It would have followed a trajectory downloaded to its guidance computer by the B-70's defensive weapons system just before launch, then used an infrared seeker for terminal homing on the target. The missile would have been deployed from the bomber's weapons bay by a unique form of rotary launcher. This would have consisted of vertically-oriented concentric threaded rods that would pass through corresponding threaded tubes through the missile's axis. The inner threaded shaft would rotate to translate the missile downward to a point just above the weapon bay door. The outer shaft would rotate the missile to the proper launch azimuth, the weapon bay door would open, and the missile would be ejected into the airstream by a "percussion ejector." Once clear of the B-70, the Pye Wacket's rocket engines would ignite and it would head for the target. Two stacks of five missiles would be carried in the B-70's weapons bay.

information and diagram courtesy Dennis Jenkins

Convair also noted that the lenticular configuration could be applicable to a strike missile to be launched from manned bombers on low-altitude penetration runs. Able to fly laterally and make supersonic terminal maneuvers, the missile could attack SAM sites or other targets close to the bomber's flight path with good probability of evading defenses.

Unfortunately, the little disc-shaped missile could not fend off critics of the B-70 bomber program. The B-70 was essentially cancelled in December 1959, partially revived in mid-1960, then finally killed as a weapon system in March 1961, when Defense Secretary Robert McNamara directed that the three prototypes already under construction were to be used only as supersonic technology demonstrators. Senate and Air Force supporters of the program fought the Kennedy administration decision for another year, attempting to force McNamara to permit production of a limited number of improved B-70s - RS-70s - for special strike or reconnaissance missions. The Pye Wacket missile may have helped to bolster the proponents' arguments that the B-70 actually was capable of surviving in the Soviet air defense environment.

Presumably the Lenticular Defense Missile project died in 1962 with the final demise of the military aspects of the B-70 program, but information from Air Force history offices hints that an early Pye Wacket test vehicle actually was flown at least once circa 1959, and a full-scale vehicle may have undergone rocket sled testing at the track facility at Hurricane Mesa, in southern Utah in this time frame as well. Hopefully more information will surface soon.

This July 1961 report, issued months after the cancellation of the B-70 weapon system, may represent part of a last-ditch effort to save the bomber program, or at least to establish the usefulness of the lenticular configuration for other types of missions. To be launched from a rocket sled moving at high velocity, the Pye Wacket Feasibility Test Vehicle would prove out the control system of the lenticular rocket at supersonic speeds and low altitude. This report actually may reflect the results of flight tests that were conducted two years earlier.

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Pye Wacket was just one of a family of lenticular aerodynamic vehicles being studied by many contractors in the late 1950s and early 1960s, as this 1962 weapons encyclopedia entry indicates. "Lenticular Rocket" was apparently a 1960 General Dynamics- Astronautics/USAF study for a maneuvering ICBM warhead.


How Did It Get Its Name?

The lenticular missile program evidently gained its odd name from a film that hit theaters in 1958 - "Bell, Book And Candle," starring James Stewart, Kim Novak, Jack Lemmon, Ernie Kovacks and Elsa Lanchester. In the movie, Novak plays a sophisticated Manhattan witch who seduces a rather clueless Stewart into a whirlwind affair with the aid of a love spell cast by her "familiar," the supernaturally agile Siamese cat Pye Wacket. The film was based on a Broadway play by John Van Druten, who had reached into antiquity to select an authentic familiar name from Elizabethan witch lore.

Matthew Hopkins, the so-called "Witch-finder General" who was active in Essex, England in the 1640s. Hopkins is said to have specialized in persecuting pet-owning old women, claiming that the animals were demon-posessed familiars. One of these, a cat named Pyewacket, was of particular interest to Hopkins. He allegedly commented that it was a name no mortal could have invented.
Kim Novak with Pye Wacket.

Convair's reason for this strange name choice may be explained by the fact that James Stewart , in addition to being a much-loved veteran actor, was a decorated combat veteran who had flown many bomber missions in Convair (Consolidated) B-24s with the 8th Air Force in Europe in WWII. By 1958, Stewart was a Reserve Air Force colonel who had become a darling of Strategic Air Command's chief, General Curtis LeMay, for his portrayal of a Convair B-36 pilot in the 1955 film "Strategic Air Command." In fact, according to James H Farmer, writing in Meyers Jacobsen's epic B-36 history, Colonel Stewart was so popular with LeMay that the actor was allegedly slated to assume the number three staff officer position in SAC should he be reactivated in wartime. When Stewart came up for promotion in February 1959, LeMay insisted that the actor deserved to be made a brigadier general based on his role in the B-36 film. In July 1959 Stewart got the star. Additionally, Stewart occasionally appeared in Convair's own publicity films to promote Convair's aircraft, such as the B-58 supersonic bomber.

"It's a wonderful bomber." Brigadier General James Stewart, Deputy Director of Information Services, Office of the Secretary of the Air Force, at controls of Convair B-58 Hustler supersonic bomber, left; explaining virtues of the B-58's delta wing, right.


Scenes from General Dynamics Convair Division promotional film Champion of Champions (1962)

Pye Wacket in perspective

This manmade disc, designed a decade into the flying saucer era, was virtually an embodyment of what some early Air Force UFO investigators thought a UFO would turn out to be - a disc-shaped guided missile of extreme performance - essentially a "Foo Fighter." Like the World War II "Foo Fighters," Pye Wacket was small, fast, unmanned and highly maneuverable. As was suspected of the 1946 Swedish Ghost Rockets and the 1948 Green Fireballs, it was constructed of magnesium. It proved that the disc configuration had some aerodynamic advantages - at least for an uninhabited vehicle flying at supersonic speeds - and in fact was intended to have levels of maneuverability beyond almost any other vehicle that flew by aerodynamic means. In Pye Wacket, operational technology had finally begun to catch up with the level of performance that witnesses attributed to "flying saucers."


Jacobs, Horace and Eunice Engelke Whitney, Missiles and Space Projects Guide. New York: Plenum Press, 1962

Jacobsen, Meyers K, Convair B-36: A Comprehensive History of America's "Big Stick." Atgen, PA: Schiffer Publishing Ltd, 1997

Jenkins, Dennis and Tony Landis, North American XB-70A Valkyrie. North Branch, MN: Specialty Press, 2002

Price, Alfred, The History of US Electronic Warfare, Vol II. The Association of Old Crows, 1989

Remak, Jeanette and Joe Ventolo Jr, XB-70 Valkyrie: The Ride to Valhalla. Osceola, WI: MBI Publishing Co, 1999