The GAM-63 RASCAL was a supersonic air-to-surface missile that was developed by the Bell Aircraft Company. The RASCAL was the United States Air Force's first nuclear armed standoff missile. The RASCAL was initially designated the ASM-A-2, then re-designated the B-63 in 1951 and finally re-designated the GAM-63 in 1955. The name RASCAL was the acronym for RAdar SCAnning Link, the missile's guidance system.Jenkins, Dennis R. (1 July 2006). Little RASCAL: the first stand-off weapon. Airpower, p. 44 The RASCAL project was cancelled in September 1958.
Development During World War II, Nazi Germany air-launched 1,176 V-1 missiles from Heinkel He 111 bombers. The United States Army Air Forces (USAAF) studied this weapon system. Testing was conducted in the United States using B-17 bombers and the Republic-Ford JB-2, a locally produced copy of the V-1. Successful testing of this combination led to the release of requirements to the aerospace industry for an air-to-surface missile on 15 July 1945.Gibson, James N. (1996). Nuclear Weapons of the United States - An Illustrated History. Schiffer Publishing. .
On July 15, 1945, the USAAF published the military characteristics for an air-to-surface missile. The missile was to be launched from an aircraft at an altitude of , must operate at a speed of at least for a range of at least . The missile be able to strike within of the target 75 percent of the time. Guidance could be either remotely or self-contained.Bernard J. (1959). History of the Rascal Weapon System. Historical Division Office of Information Services Air Material Command, Wright-Patterson Air Force Base, Ohio This resulted in MX-767 Project Mastiff, which was to develop a nuclear armed air-to-surface drone or self-controlled air-to-surface missile. Northrop Corporation, Bell, and Republic Aviation were invited by the USAAF to submit proposals for Mastiff.Hansen, Chuck (1988). U.S. Nuclear Weapons - The Secret History. Aerofax, Arlington Texas. Bell was awarded a feasibility study contract by the USAAF on 1 April 1946. Bell studied the feasibility of developing a subsonic "pilot-less" bomber carrying a substantial payload over a distance of .Knaack, Marcelle Size (1988). The Air Force Aircraft and Missile Systems Volume II - Post-World War II Bombers 1945-1973. Office of Air Force History, USAF, Washington D.C. Rosenberg, Max (1988). Encyclopedia of U.S. Air Force and The National Guided Missile Program 1944-1950. USAF Historical Division Liaison Office, USAF, Washington D.C. pg. 76 After 18 months of study, Bell concluded that rocket propulsion was not capable of providing the performance needed to boost the missile the AAF wanted to a range of 300 miles. The range requirement was reduced to but other technical problems surfaced. The Rascal caught the attention of the journal Aviation Week in 1951 when it report “First practical application of the Bell X-1 supersonic research test plans as a military aircraft may be in an air-to-ground guided missile . . . which will probably be designated Rascal.
As a risk reduction measure the USAAF divided the program. Project MX-776 was divided into two sub projects as a risk reduction measure, MX-776A and MX-776B.
The MX-776A program developed the RTV-A-4 Shrike later re-designated the X-9 as a testbed for the later Rascal that would be developed under project MX-776B. MX-776A in itself was an ambitious program intended to not only develop aerodynamic, structural, guidance and propulsion information. The X-9 was also to develop the knowledge and skills required to check out and launch an air-to-ground missile. MX-776A was also to develop experience in training crews to maintain and deploy the new weapon. It was the intent of the Air Material Command that the Shrike could provide the USAF with a tactical weapon following the test program. The X-9 program was successful in that all essential goals were met. The X-9 program began using two rocket thrust chamber one built by Aerojet and the other by Solar. From flight of the 16th X-9 the rocket motor was a Bell XLR65-BA-1 The X-9 Shrike was flown with two different guidance systems. The first was a radio command guidance system manufactured by RCA's Federal Telecommunications Division. Later in the development program guidance was provided by a preset/radar command guidance system developed by Bell. The X-9 program also tested on three flights a warhead which dispersed chemical bomblets. The X-9 was one of the more successful of the early missile test programs resulting in the program being terminated well short of the originally intended number of flights. Twenty two X-9 missiles were launched between April 1949 and January 1953.
The intended mission for the RASCAL was the destruction of highly defended targets on routes to strategic targets. Only targets with well defined radar returns could be attacked by RASCAL.
Design In May 1947, the USAAF awarded the Bell Aircraft Company a contract for the construction of a supersonic air-to-surface missile compatible with the B-29 Superfortress, the B-36 bomber, and the B-50 Superfortress bomber. The missile was to have a range of ,Mark Wade, RASCAL, , retrieved on 6 December 2007.Aeronautical Systems Division History Office Website Development to Combat - Additional Technical Developments Chapter 7, , retrieved on 6 December 2007. Bell's development effort was led by Walter R. Dornberger. Rascal, was required to carry a 5,000 pound warhead a distance of 150 nautical miles at a speed of Mach 3.0 by July 1955. It was intended that the Rascal would be deployed on the B-50 and B-36.
The RASCAL design used the X-9's canard aerodynamic configuration and a rocket engine derived from the X-9's rocket-propulsion system. The RASCAL was larger than the X-9 with a fuselage that was longer and larger in diameter. The RASCAL's flight controls included forward and rear surfaces. Forward surfaces include fixed horizontal stabilizers and movable dorsal and ventral surfaces. Rear surfaces include wings with ailerons and fixed dorsal and ventral stabilizers. The aft lower stabilizer could be folded for ground handling.
The RASCAL was powered by a XLR67-BA-1 rocket engine also developed by Bell. The XLR-67 provided National Museum of the United States Air Force Website. BELL XGAM-63 RASCAL retrieved on 26 December 2007. of thrust using three vertical in-line thrust chambers. All three thrust chambers of the XLR67 were operated during the missile's boost phase which could last up to two minutes. At the conclusion of the boost phase the upper and lower chambers of the XLR-67 were shut down and thrust was sustained by the center chamber alone. Fuel for the XLR-67 included of white fuming nitric acid oxidizer and of JP-4 jet fuel. The oxidizer was stored in a series of tube bundles instead of a spherical storage tank. It is believed this configuration was chosen because it weighed less than a spherical tank of the same volume.Emresman, C.M. and Boorady Fredrick A. (2007). Bell Aircraft Company from a Modest Beginning to a Major Aerospace Innovator. 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 8–11 July 2007, Cincinnati, OH Propellant was provided to the thrust chambers by a turbine driven propellant pump. A gas generator powered the propellant pump. The propellants were glow plug ignited. Bell contracted with Purdue University for the glow plug ignition system. Aerojet provided the pump drive assemblies.
The RASCAL guidance system was developed jointly by Bell, Federal Communications/Radio Corporation of America (RCA) and Texas Instruments. The initial version of the control system provided an accuracy or circular error probable (CEP) of . Adequate for a missile equipped with a nuclear weapon.
The bomber carrying the missile was modified with an additional antenna and equipment at the bombardier's position needed to guide the RASCAL. During the flight to the launch point, the bombardier transferred wind and navigation data periodically to the missile. Prior to launch the bombardier tuned a video relay receiver, altitude phasing, and adjusted the terminal guidance tracking indicator. Missile control surfaces were also checked to make sure they were functional.
Prior to the bomber taking off, the RASCAL was pre-programmed for a given flight path. Navigation to the intended launch point 90 miles from the target was determined by the DB-47E's MA-8 navigation system. Before launch the MA-8 fed the aircraft's velocity and heading to the missile. Following launch an inertial system guided the missile during launch, climb and mid-course phases of its flight. During the terminal dive a command guidance control system was used where the RASCAL was remotely controlled by the bombardier in the launching bomber. After launch, a lanyard connecting the RASCAL to the bomber was used to start the missile's rocket engine. In the event the lanyard failed an automatic timer would count down and start the engine. The RASCAL was air-launched above . Terminal guidance was by radar imaging of the target which was transmitted back to the bomber. As the missile approached the target the detail in the radar video transmitted from the missile improved. The missile began a terminal dive about from the target.National Museum of the Air Force Website YDB-47E, , retrieved on 22 November 2007. The command guidance system did not send a directional signal and was not encrypted which made it susceptible to detection and jamming.
The guidance system developed by Bell for the GAM-63A version of the RASCAL produced a CEP of . The accuracy claims of the inertial guidance system have been questioned by sources., It was possible to drop the RASCAL as a gravity bomb if a system malfunction occurred in flight. In such case the missile would be used to attack a less heavily defended target.
The RASCAL's forward section was interchangeable for different targets. Using this capability the RASCAL could be equipped with nuclear, biological, chemical, blast, or incendiary warheads. The requirements for biological and chemical warheads were dropped at the end of 1953. On 5 December 1949, requirements for the RASCAL called for a nuclear warhead weighing between and . The RASCAL warhead compartment accommodated a cylinder in diameter and in length. The USAF also wanted the ability to use the RASCAL as a standard gravity bomb if the missile could not be readied for launch.
In January 1950, Bell began to study what nuclear warheads were available for RASCAL. The W-5 nuclear warhead was initially considered. On 20 August 1950 the Special Weapons Development Board (SWDB) authorized a W-5/RASCAL integration effort. The Atomic Energy Commission (AEC) was responsible for developing the fuzing system for the RASCAL warhead. No provision was made for surface burst at this time. In April 1952 fuze development was shifted to Bell which resulted because it was USAF policy to make airframe contractors responsible for nuclear weapons fuzing since this system needed to be integrated with the missile's guidance system. Bell developed two complete fuzing systems, airburst or surface burst. Then in March 1956 the W-5/RASCAL program was canceled.
In July 1955, the W-27 nuclear warhead was considered as a replacement for the W-5 for the RASCAL.Federation of American Scientists Website, Complete List of all U.S. Nuclear Weapons, , retrieved on 8 December 2007. USAF requirements for the W-27 called for a 2,800 lb (1,300 kg) nuclear warhead with either electronic countermeasures equipment, infrared countermeasures equipment, or extra fuel to increase the range of the RASCAL. A design for the adaption kit between the W-27 and the RASCAL was completed in January 1957 before the RASCAL was canceled.