GAM-63 RASCAL

In March 1946, the United States Army Aviation (USAAF) began work on the Mastiff project - the development of a projectile with a nuclear warhead launched from a bomber. The effectiveness of this concept has already been proven by successful experimental launches of Republic JB-2 Loon airplanes from the Boeing B-29 Superfortress bombers . The developers set themselves the goal of creating a weapon that would allow bombers to attack well-defended targets, while remaining at the same time beyond the reach of air defense.

Initially, the technical requirements assumed the creation of a subsonic projectile with a rocket engine capable of flying 480 kilometers from a nuclear warhead on board. After examining the situation in detail, the developers from the Bell company came to the conclusion that the available level of technology does not allow creating a rocket with the required characteristics. In addition, subsonic speed was perceived as insufficient, given the prospect of the emergence of jet fighter-interceptors. As a result, the requirements were revised in favor of a rocket with a range of 160 km.

During the development of the project, the Bell engineers considered that the technical requirements for the rocket were close to the technical requirements for the experimental Bell X-1 rocket plane, the first manned aircraft that exceeded the speed of sound. The work on the X-1 was widely used in the work on the rocket. Since a number of questions arose during the creation of the rocket, which could not be resolved theoretically, a reduced prototype was created specifically for testing, which was designated RTV-A-4 (also known as X-9 "Shrike").

Rocket GAM-63 "Raskl" was performed on the aerodynamic configuration "duck" . Wingspan was 5.09 meters. The diameter of the cigar-shaped hull, structurally similar to the experimental aircraft X-1 was 1210 mm, most of it was occupied by fuel with an oxidizer. In front of the hull located control equipment and nuclear warheads . As such, the 120-kiloton W-5 was initially considered (based on the Mark-5 free-fall atomic bomb), but ultimately it was decided to install a 2-megaton thermonuclear W-27 warhead on the rocket.

The rocket was driven by a three-chamber liquid rocket engine XLR67-BA-1, working on kerosene and nitric acid (as an oxidizer). The maximum engine thrust was 46.4 kilonewtons. Three combustion chambers were located in a vertical plane: in the first two minutes of flight (the stage of acceleration) all three of them worked, then the upper and lower ones were turned off and the rocket continued to fly on one working nozzle. The rocket cruising speed exceeded M = 1.6 (up to M = 3 in a dive).

Fuel stock (aviation kerosene JP-4) was 235 liters, the stock of oxidant, steaming nitric acid , 600 liters. Fuel was stored in cylindrical tanks, selected for reasons of weight saving. The fuel supply was carried out by a turbo pump .

The missile guidance system was radio command, control was carried out from the aircraft carrier. The flight path of the rocket was set on the ground before departure. During the flight, the crew of the bomber loaded into the computer missiles amendments to the speed, force of the wind and other factors.

When a plane with a rocket reached a given starting point, the rocket’s automatics reset it and then start the engine. For such, a long cable was provided connecting the rocket with the bomber: in case of its failure, the engine could be started using a timer. The rocket was reset from a height of 12,000 meters. After the engine was activated, the rocket climbed to an altitude of 19,000 meters and entered the course towards the target. Small dimensions, high altitude and high speed, according to the developers, were to effectively protect the rocket from the threat of interception by the enemy.

Immediately after the launch of the rocket, the bomber turned around and went to the opposite course. The radar image of the target from the homing head of the missile was relayed to the bomber, from which the command was sent aboard the missile. 32 km from the target, the rocket went into a gentle peak. The accuracy of the hit was about 910 meters (QUO). For later models of the rocket, an inertial guidance system, insensitive to radio interference and reducing the deviation from the aiming point to 457 meters, was proposed.

Since the reliability of the rocket was considered to be very low, on additional demand, in the event of equipment failure, the rocket could simply be dropped like a normal atomic bomb.

As carriers were supposed to use the aircraft B-36D , DB-47 , DB-50 and B-29. The latter, however, was removed from service before the completion of the development of the rocket. Initially, B-36 was considered as the main carrier: Convair received an order for 12 retrofit kits to convert serial bombers into missile carriers, but in the end it was decided to abandon the B-36 missiles. As a result, within the framework of this program, only four serial B-36H received the name DB-36H were converted into carriers.

During the tests, which lasted from 1952 to 1957 , two experimental launches were performed from the DB-36H and thirty-eight from the DB-47. This experience has shown that the rocket suspension has almost no effect on the flight characteristics of the first, but violates the aerodynamics of the second. It was assumed that two combat squadrons would be formed from the DB-47 missile carriers, but as early as 1956, these plans were questioned.

Due to the constant delays of the program, the US Air Force began to lose interest in it. The reliability of the rocket, despite all efforts, remained very low - an analysis of experimental launches showed that out of 65 launches, only one was completely successful. The liquid-propellant rocket engine was capricious and difficult to maintain, using a highly toxic oxidizer. In addition, the program itself was already perceived as outdated: the appearance in the late 1950s of anti-aircraft missile systems and supersonic interceptor fighters (at speeds up to M = 2) made the rocket vulnerable to appropriate countermeasures. In addition, a radius of 160 km from the target could no longer be considered a safe distance for the aircraft carrier.

As a result, in August 1958, the RASCAL program was closed. Up to this point, 58 serial missiles and two DB-47E missile carriers were launched, but the missiles were never accepted for service. The military's attention shifted to the new AGM-28 “Hound Dog” cruise missile, a lighter one, using the usual turbojet engine and possessing almost ten times more radius of action.

At the time of the start of development, the GAM-63 RASCAL was an ambitious project that embodied all the best technical solutions of the time: air launch, supersonic flight speed, radio command guidance via a reticle. Unfortunately, it is this novelty and let down the project. Due to technical complexity, the development of the rocket was too long. As a result, when the first missile models were ready for adoption (relatively, because reliability remained extremely low), its technical characteristics did not meet the requirements of the time.

• Kuznetsov K., Dyakonov G. V-36 - America’s Last Argument? // Aviation and Time. - 2006. - № 3 . - p . 15 .

• http://www.airwar.ru/weapon/kr/gam63.html
• http://www.designation-systems.net/dusrm/app1/gam-63.html