of the Sparrow was later used to inform the design of the Vympel R-27, particularly the servomechanisms and movable wings. UK British Aerospace (BAe) licensed the AIM-7E2 technology in the 1970s, producing the Skyflash missile. Skyflash used a Marconi XJ521 monopulse seeker together with improvements to the electronics. It was powered by the Aerojet Mk52 mod 2 rocket engine (later by the Rocketdyne Mk38 mod 4). Skyflash entered service with the Royal Air Force (RAF) on their Phantom FG.1/FGR.2 in 1978, and later on the Tornado F3. Skyflash was also exported to Sweden for use on their Viggen fighters. An upgraded version with active radar seeker, called Active Sky Flash was proposed by BAe and Thomson-CSF, but did not receive funding because the RAF opted for other missiles. Design The Sparrow has four major sections: guidance section, warhead, control, and rocket motor (currently the Hercules MK-58 solid-propellant rocket motor). It has a cylindrical body with four wings at mid-body and four tail fins. Although the external dimensions of the Sparrow remained relatively unchanged from model to model, the internal components of newer missiles represent major improvements, with vastly increased capabilities. The warhead is of the continuous-rod type. As with other semi-active radar guided missiles, the missile does not generate radar signals, but instead homes in on reflected continuous-wave signals from the launch platform's radar. The receiver also senses the guidance radar to enable comparisons that enhance the missile's resistance to passive jamming. Principle of guidance The launching aircraft will illuminate the target with its radar. In radars of the 1950s these were single target tracking devices using a nutating horn as part of the antenna. This caused the beam to be swept in a small cone. Signal processing would be applied to determine the direction of maximum illumination and so develop a signal to steer the antenna toward the target. The missile detects the reflected signal from the target with a high gain antenna in a similar fashion and steers the entire missile toward closure with the target. The missile guidance also samples a portion of the illuminating signal via rearward pointing waveguides. The comparison of these two signals enabled logic circuits to determine the true target reflection signal, even if the target were to eject radar-reflecting chaff. Operators See also AIM-9 Sidewinder AIM-54 Phoenix R-27 Brazo List of missiles Sparoair Super 530 Notes References Footnotes Bibliography McCarthy Jr., Donald