AP 118 · No. 10 Section II · Aircraft Plate 52 / 109

Plate 52 of 109 · Second World War · U-boat observation rotor kite

Focke-Achgelis Fa 330 Bachstelze

Fa 330 A-1 Bachstelze, painted as Werknummer 100503, a Focke-Achgelis Fa 330 A-1 Bachstelze rotor kite built by Weser Flugzeugbau to be carried in pieces aboard a Type IX U-boat and towed behind it on a cable to lift a lookout high above the conning tower, one of the kites brought to Britain after the war and now kept by the RAF Museum, painted as it is shown at RAF Museum Midlands, Cosford: pale blue-green overall, tubes, skids, mast, tail surfaces and rotor blades alike, a black Balkenkreuz with a narrow white border on each side of the fin and smaller crosses on top of the tailplane near the tips, a black leather seat with a tan webbing harness, a black instrument box at the nose, a small grey-green pack hung on the mast behind the seat and a red release handle under the rotor head; it is shown standing on its skids with the 24 ft three-blade rotor at rest, one blade over the tail and two forward, the blade droop is estimated and the rotor-head linkages are simplified.

3D model

Turn it over

A procedural model built in Blender from published dimensions, drawings and photographs, painted as Werknummer 100503, a Focke-Achgelis Fa 330 A-1 Bachstelze rotor kite built by Weser Flugzeugbau to be carried in pieces aboard a Type IX U-boat and towed behind it on a cable to lift a lookout high above the conning tower, one of the kites brought to Britain after the war and now kept by the RAF Museum, painted as it is shown at RAF Museum Midlands, Cosford: pale blue-green overall, tubes, skids, mast, tail surfaces and rotor blades alike, a black Balkenkreuz with a narrow white border on each side of the fin and smaller crosses on top of the tailplane near the tips, a black leather seat with a tan webbing harness, a black instrument box at the nose, a small grey-green pack hung on the mast behind the seat and a red release handle under the rotor head; it is shown standing on its skids with the 24 ft three-blade rotor at rest, one blade over the tail and two forward, the blade droop is estimated and the rotor-head linkages are simplified. Drag to orbit, scroll or pinch to zoom · download .glb (217 KB)

Data plate

Specification

First flight, number built and top speed are for the whole family (); engine, crew and dimensions are for the Fa 330 A-1 Bachstelze modelled here.

History

The Fa 330

A U-boat’s lookouts stood barely five metres above the sea, and on a clear day they could see the masts of a ship only a few miles off. In the open spaces of the South Atlantic and the Indian Ocean, where the long-range Type IX boats hunted far from Allied air cover, the German navy wanted a way to look further. It asked Focke-Achgelis, Henrich Focke’s helicopter firm, for a rotor kite that a submarine could carry and tow aloft. The Fa 330 Bachstelze (“wagtail”) flew in 1942. It had no engine: like an autogiro, its three-blade rotor was turned by the air flowing up through it, and the forward speed of the U-boat on the surface was enough to lift it.

It was little more than a steel-tube keel carrying a seat, a mast with the rotor head on top, a pair of skids and a fabric-covered tail. It came apart into a few pieces that were stowed in watertight tubes in the U-boat’s conning tower, and a trained crew could put it together on the after deck in a few minutes. The pilot flew it with a control column and rudder pedals while a winch paid out the cable, and from a few hundred feet up he could see many times further than the men on the bridge, reporting by telephone through a line in the cable. If the boat had to dive in a hurry, he could pull a lever that cast off the rotor and opened a parachute to bring him and the frame down into the sea. About 200 were built under contract by Weser Flugzeugbau at Hoykenkamp near Bremen.

Only a handful of boats used them, among them U-177, U-181 and U-852 on long patrols to the Indian Ocean in 1943 and 1944. U-177’s kite is said to have spotted the Greek steamer Efthalia Mari, which the boat then sank, but the kites were slow to recover, and a boat that had to dive with its observer still aloft would leave him behind; once Allied aircraft reached the far oceans the idea was dropped. Several were taken to Britain after the war, and the Airborne Forces Experimental Establishment at Beaulieu towed them behind vehicles and ships in trials in 1948 and 1949. At least fifteen survive, three of them in British museums.

This airframe

Fa 330 A-1 Werknummer 100503

100503The airframe modelled

The RAF Museum believes its Fa 330 is Werknummer 100503, one of the kites taken for evaluation in 1945; it may have been among those tested at Beaulieu in 1948 and 1949. In the early 1960s it was one of three Fa 330s stored in the Aero Club barn at the Royal Aircraft Establishment, Farnborough, and in September 1967 it passed, incomplete, to the RAF Museum’s store at Henlow, recorded under a number that was not its own. It was given the maintenance serial 8469M in February 1976, hung above the main entrance at Hendon for the ‘Wings of the Eagle’ display of German aviation in 1975 and 1976, and had moved to the Aerospace Museum at Cosford by 1980, where it is still shown. The model shows it as displayed there: pale blue-green overall, a black Balkenkreuz with a narrow white border on each side of the fin and smaller crosses on top of the tailplane near the tips, a black leather seat with a tan webbing harness, a small grey-green pack on the mast behind the seat and a red release handle under the rotor head. It stands on its skids with the rotor at rest, one blade over the tail and two forward; the droop of the blades is estimated and the rotor-head linkages are simplified.

See it at Royal Air Force Museum Midlands

Where to see one

In the gazetteer

The gazetteer records the Fa 330 in 4 UK collections. The airframe modelled here is marked.

Every airframe and serial All 109 plates

Profiles and models are procedural interpretations built in Blender from published dimensions, three-view drawings and photographs of each airframe. Treat the museum aircraft as the reference.