Focke Achgelis FA330A-1 (100545)
Similar to gyrocopters, but un-powered, these rotor kites, were developed so that U-Boat commanders could search for shipping at much greater heights than a periscope at sea level. This was necessary as U-Boats in the Atlantic were being forced to keep their distance due to increasingly effective allied tactics.
With the U-Boat surfaced and motoring at speed the rotors of the tethered rotor kite would spin fast enough to generate lift in the airflow. With the U Boat sill travelling forwards, the kite could now be flown (controlled by a winch) to a height of up to 120m (394 ft) above the surface. This allowed the kite pilot to see up to 25 miles. A German test pilot said of his experience flying one, “it was like sitting in an open chair in the sky with a clear view upwards and as far as the eye could see was ocean”
The kites handled well, however, in an emergency the pilot could pull a lever jettisoning the rotors and allowing him to parachute to safety. The Kite could be winched down within 3 minutes but if the U-Boat needed to dive quickly the winch cable would be cut. When not in use the Kite was folded up and taken inside the U-boat.
Large IX – D2 U-Boats were designed to take two Kites and carried three crew trained as pilots. As Allied equipment and tactics improved, holding air superiority in the North Atlantic, only two of these large U-Boats were deployed in South Atlanticwaters. Little is known about the use of their Bachstelzes Kites as both U-Boats were lost in the winter of 1943. Rotor kites achieved greater use in the Indian Ocean but there is only one recorded sinking resulting directly from the use of a Bachstelze, the Greek steamer EFTHALIA MARI.
Over 200 were built and many were captured and test flown by the Allies. However, fewer that 12 are know to exist today.
The Museums aircraft
Probably one of the comparatively large numbers captured by the allies at the end of the war and brought back to the UK for evaluation. Although the Museum machine was acquired in 1994 little is known of its earlier history.
Bachstelze is German for Water Wagtail. The Wagtail is a small bird that is often seen by streams and ponds. Dainty and agile, they have long tails which they wag frequently.
Single Seat Submarine Borne Spotter
Manufacturer: Focke Achgelis
Rotor Diameter: 7.30 m (23 ft 11 in)
Length: 4.47 m (14 ft 8 in)
Height: 1.67 m (5 ft 6 in)
Weight: Empty weight: 68 kg (150 lb)
Max Speed: 40 km/h (25 mph; 22 kn) on tow