The Germans experimented with glide weapons as far back as the First World War, in the form of “glide torpedoes” designed for the Imperial German Navy by Siemens-Schukert? Werke (SSW). These were very ingenious weapons, featuring a “wire guidance” system that allowed an operator to control their flight through wires trailing behind them, and an airframe that split open to release the torpedo. Both biplane and monoplane glide torpedoes were developed, with weights of up to a tonne. While some test drops were performed from Zeppelins and captive tests were performed with bombers, these weapons were not used in combat during the war. Glide torpedoes were developed for the Third Reich in the late 1930s by the Blohm und Voss company. The sketchy information available indicates that they were unguided after launch, and saw little or no combat.
Blohm und Voss also experimented with a “glide torpedo” that was actually a very primitive attempt to build the equivalent of a modern “sea skimmer” antiship missile. This weapon, designated the “BV-143”, was designed to glide down to wavetop height, where it would use a mechanical “feeler” arm about two meters long to gauge its altitude over the waves. On contact with the waves, the feeler arm would fire the weapon’s liquid fuel rocket engine to keep the weapon at altitude until it struck the target ship above the waterline. BV-143 prototypes were launched four times, and to no surprise all of them went into the water. Sea skimmers would have to wait for better technology.
- Blohm und Voss also developed a true glide bomb named “Hagelkorn (Hailstone)”, designed by Dr. Richard Vogt. This was a streamlined bomb with a cruciform tail and long slender wings, with the wings made of steel cores supporting an airfoil of form-cast concrete! This unusual construction was apparently intended to help separation of the weapon from the carrier aircraft. When the Hagelkorn was attached to the carrier aircraft’s stores rack or pylon, stubs were fitted between the aircraft and the tips of the Hagelkorn’s long stiff wings to cause a slight bend. The spring tension provided by the concrete-stiffened wings ensured clean separation.
The initial version of the Hagelkorn was the “BV-226”, which had a spindle-shaped body 3.53 meters (11 feet 7 inches) long, with long slender wings spanning 6.4 meters (21 feet), and a cruciform tail. The front half of the body contained a warhead, while the rear half contained the guidance system. The long wings gave the Hagelkorn a glide ratio of 25:1, meaning it flew 25 meters or feet for every meter or foot it dropped, and so had potentially long standoff range. The BV-226 quickly led to the “BV-246”, which was similar but had a twin-tailfin configuration.
The Hagelkorn had a gyroscopic stabilization system, and it appears that at least at first that was its only guidance scheme. The weapon was simply released to glide off in the direction of the target. This was obviously not very accurate, particularly for a long-range weapon, and the Germans worked hard to develop a reliable, accurate, and jam-resistant means of providing precision guidance for the Hagelkorn, particularly against targets outside of visual range.
Designing a guided weapon that could deal with countermeasures was difficult, particularly because the British were extremely clever at electronically outfoxing the Germans, so much so that some Germans refused to believe the British could be so far ahead of them. Experiments were performed with infrared and radio guidance schemes, but the Luftwaffe was not enthusiastic about the Hagelkorn, and though over 1,100 of the weapons were built starting in late 1943, the project was cancelled in early 1944. Test drops of the weapon were performed by He-111 bombers and FW-190 fighters, but the Hagelkorn saw little or no combat action.
The BV-246 was revived a year later in small-scale tests where it was fitted with a passive radar seeker, or “Radieschen”, to home in on emissions from Allied radar stations. Ten of these weapons were tested, and though two proved extremely accurate, the other eight failed. There was no time left for the Reich to field such a weapon in any case.
