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Weapons of Mass Destruction (WMD)


GAM-63 Rascal

The "Rascal," originally designated as the XB-63, later GAM-63 [Guided Aircraft Missile], was an air-to-surface supersonic guided missile armed with a nuclear warhead. Its development was inaugurated in April 1946. The Rascal was designed for all-weather use in medium and heavy bomber operations against strategic targets. The Rascal was intended as a "stand off" weapon, to be launched from Strategic Air Command (SAC) bombers as far away as 90 miles, thus reducing the manned bomber crew's exposure to enemy defenses in the immediate target area. Launched from its carrier aircraft, the missile would continue toward its predetermined target controlled by a self-contained inertial guidance system. The terminal dive began about 20 miles from the target. During this final phase of flight, the Rascal's course could be altered by signals from the launching "director" aircraft.

In 1946 the Bell Aircraft Corporation was awarded a study contract for a rocket-propelled pilotless vehicle capable of carrying a nuclear warhead from a manned bomber to a priority target. It was at this date that the U.S. Air Force first appreciated that even the then-forthcoming generation of jet bombers might be unable to penetrate to a well-defended target in order to deliver free-falling weapons. Bell accordingly developed a test vehicle named Shrike, and this program was completed in 1953. This led to the Rascal missile, for which Bell — as prime contractor — was assigned responsibility for the missile, ground support eauipment, training aids and conversion of the B-47s of Strategic Air Command into the DB-47 configuration.

The Rascal program began with "Military Characteristics for a Pilotless Parasite Bomber," SAB-51-Bi, 14 December 1951, Directorate of Requirements: Hq. USAF, "Development Directive," No. 00-27-Al, 4 February 1952, ARDC; and Reorientation of Project MX-776, Contract W33-038ac14169," AF l-tter WCSGA/HDH/nrw, 4 March 1952.

The first launch of a guided Rascal took place in October 1953 from a DB-47 director aircraft; various successful powered flights were demonstrated during later tests. The AGAM-63 program was terminated in late 1958, shortly before the first Rascal-equipped SAC unit was to become operational, in favor of the more promising and longer range "Hound Dog" missile.

The Rascal Weapon System was designed to carry out air-to-surface bombing of strategic targets without exposing the bombardment airplane and aircrew to local target defenses. This mission is acconplished by combining a high-performance DB-47 bomber airplane with a relatively short-range, supersonic, GAM-63A missile. In operational employment, the system is based upon the ability of the missile to penetrate local defenses and to deliver a 2800-pound special warhead to a strategic target with little probability of being detected os intercepted. Thus, DB-47 strategic bombers as director aircraft armed with GAM-63A missiles need not approach the target closer than 90 nautical miles, the range of the missile.

An Air Force letter dated November 1953 established a maximum range requirement of 90 nautical miles for the Rascal missile. Based upon a missile range of 75 nautical miles, the GAM-63A will provide an airburst with a horizontal circular probable error (CEP) of less than 1500 feet and, excluding errors in weather prediction and target intelligence, a vertical standard deviation of less than 405 feet.

CEP is the limiting value, as the number of flights becomes large, of the radius of a right circular cylinder whose axis is a vertical line through the target and within which 50% of the detonations occur. Vertical standard deviation is the limiting value, as the number of flights becomes large, of the root mean-squared distance between the actual and intended detonation altitude.

In a typical maximum-range mission, the DB-47 director aircraft, carrying the GAM-63A missile, is navigated to a predetermined launch area by means of its MA-8 bombing-navigational system which constantly computes distance and course to the target. Immediately prior to launch, an automatic checkout system (ACS) checks items of the missile in sequence, while data regarding director aircraft velocity, heading, and changes in range-to-target fed into missile to serve as "initial condition" data for its non-emanating guidance system. At a preset distance from the target, the ACS, in conjunction with the MA-8 system, automatically released the GAM-63A on the proper heading for the target. Minimum launch altitude is 40,000 feet MSL; minimum launch velocity is Mach 0.78. After the missile cleared the launch gear of the DB-47, the rocket engine ignites. The GAM-63A accelerates to supersonic velocities in its climb to level flight altitude as programmed by a pressure sensing circuit.

From release to warhead detonation, the missile was controlled by a gravity-referenced inertial guilance system. The missile's range computer continuously computes ground range to target by double integration of a signal from a pitch-stabilized accelerometer. At a pre-established distance from the point of launch, the range-computing system places the GAM-63A in a 35° dive toward the target.

The terminal dive began about 20 miles from the target. During this final phase of flight, the Rascal’s course could be altered by signals from the launching “director” aircraft. At the initiation of terminal dive, a search radar mounted on the nose of the missile was automatically activated and scanned the area ahead of the GAM-63A over a 1500 sector. A radar image of the target and surrounding area is sent via a microwave relay link to the director aircraft. Here, the radar information, displayed on a plan position indicator, enables a guidance operator to monitor the progress of the flight and to ascertain errors in the missile's path to the target by the relative position of the target with the indicator cursors.

If the GAM-63A was headed off course, guidance commands in elevation and azimuth are computed and transmitted via the relay link to the missile's autopilot. This is accomplished as the operator manipulates a tracking stick to align cursors on the radar display in coincidence with the target. Displacement of the tracking stick determines the magnitude of the flight path corrections which are automatically computed, coded, and relayed to the missile's autopilot system. With the radar definition of the target area constantly improving as the GAM-63A approaches its objective, the required degree of accuracy in target acquisition is assured.

It is important to note that the guidance operator may, at any time after launch, initiate a command to energize the search radar in the missile. The relayed video information can be utilized to check and correct the flight path of the GAM-63A in relation to known checkpoirts. Also, the terminal dive can be initiated through the command link.

The B-47 aircraft was the only operational Rascal carrier. Installation of the GAM-63 system converts the aircraft to a DB-47, the weapon being accommodated on a pylon under the aircraft e.g. on the righthand side; theoretically a DB-47 could have two such pylons, the Rascal wing tips almost touching on the aircraft center-line.

Although accurate and effective, the Rascal was overtaken by rapid developments in the field of air-launched missiles, particularly the development of the more promising and longerranged Hound Dog missile. In late 1958, the GAM-63 program was terminated, shortly before the first Rascal-equipped SAC unit was to become operational.



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