J.Herris Siemens-Schuckert Aircraft of WWI (A Centennial Perspective on Great War Airplanes 12)

SSW Guided Missiles

   Guided missiles are not the kind of 'aircraft' one normally associates with WWI, but SSW built and tested them and they are included here for their interest. In October 1914 Dr. Wilhelm von Siemens proposed remotely-controlled glide bombs, an air to surface missile. Work began that month and by January 1915 small models were under test.
   Scale model glide-bombs were launched from towers, balloons, and a track built on the roof of the Siemens airship shed at Biesdorf in addition to launches from airships and airplanes. Initially the gliders' servo-controls were powered by batteries, but these heavy cells were soon replaced by propeller-driven dynamos that generated electricity. Guidance commands were transmitted from airships to the glide bombs by thin wires that unraveled from a spool after the glider was launched. After guidance commands the rudder returned to neutral but the elevator remained in the last position commanded. Many flight tests with gliders from 92 to 265 pounds weight were made from autumn 1915 to spring 1917.
   Ships are difficult to hit with conventional bombs due to their ability to maneuver quickly after bombs are released, so they were a natural target for guided missiles. In mid-1916 torpedoes were chosen over bombs for the missile warhead because torpedoes allowed the maximum stand-off distance between the ship and the attacking aircraft. By autumn 1916 a method had been developed and tested to eject the torpedo just before the glider struck the water.
   The size of the gliders was then increased significantly since torpedoes were to be carried, and night tests commenced. A flare was added to the glider so it could be seen in the dark and guided to its target. SSW conducted these tests throughout 1917. After more than 75 tests at Biesdorf, Zeppelins were provided to test larger, heavier gliders from higher altitude. From summer 1917 gliders weighing 660 pounds (300 kg) were launched from airship Z.XII in Hannover. In Autumn gliders of 1,100 pounds (500 kg) and 2,200 pounds (1,000 kg) were tested from Zeppelin L.35 at Juterbog and PL 25 at Potsdam.
   After the older airships were dismantled L.35 was seldom available for the glider tests, and when a glider collapsed while suspended below L.35 in April 1918, further tests were suspended until the reason could be determined and fixed. Tests resumed in summer and the last test launch of a torpedo glider was made August 2, 1918. L.35 released the 1,000 kg biplane torpedo glider from 4,000 feet altitude at a target 4.6 miles (7.4 km) away. At an altitude of about 200 feet above the target and just after being commanded to turn into the target, the 5-mile long wire broke and the glider spun and crashed.
   Meanwhile, SSW had designed monoplane torpedo gliders that would fit under the wings of bombers. However, the Armistice intervened before any of these could be test-launched and work on the torpedo-glider project was ended in December 1918.