Focke-Achgelis Fa 330
|Fa 330 Bachstelze|
|An Fa 330 on display at the Hubschraubermuseum|
The Focke-Achgelis Fa 330 Bachstelze (English: Wagtail) was a type of rotary-wing kite, known as a rotor kite. They were towed behind German U-boats during World War II to allow a lookout to see further.
Because of their low profile in the water, submarines could not see more than a few miles over the ocean. To solve this, the German admiralty considered a number of different options, including a folding seaplane (Arado Ar 231). In the end, they chose the Fa 330, a simple, single-seat autogyro kite with a three-bladed rotor.
The Fa 330 could be deployed to the deck of the submarine by two people and was tethered to the U-boat by a 150 m (500 ft) cable. The airflow on the rotors as the boat motored along on the surface would spin them up. The kite would then be deployed behind the U-boat with its observer-pilot aboard, raising him approximately 120 meters above the surface and allowing him to see much farther — about 25 nautical miles (46 km), compared to the 5 nautical miles (9 km) visible from the conning tower of the U-boat. If the U-boat captain were forced to abandon it on the surface, the tether would be released and the Fa 330 descend slowly to the water.
When not in use, the Fa 330 was stowed in two watertight compartments aft of the conning tower. Recovering, dismantling, and stowing the Fa 330 took approximately 20 minutes and was a difficult operation.
Focke-Achgelis proposed a powered version of the Fa 330, the Fa 336, but the design never made it to the hardware phase.
As Allied air cover in other theatres of the war was considered too much of a threat, only U-boats operating in the far southern parts of the Atlantic and the Indian Ocean used the Fa 330. Despite its advantages, the use of the Fa 330 resulted in only a single sinking when U-177 used one to spot, intercept and sink the Greek steamer Efthalia Mari on 6 August 1943.
The Allies came into possession of an Fa 330 in May 1944 when they captured the U-852 intact. After the war, the British government did successful experiments towing Fa 330s behind ships and jeeps, but the development of the helicopter quickly occupied the attention of the military.
U-boats that deployed Fa 330 kites included at least U-177, U-181, and U-852. Otto Giese wrote, "Our boat was rigged with a Bachstelze. This was a small, single, piloted helicopter attached to a long steel cable and lifted into the air by the speed of the boat while the cable was gradually reeled out. From his position aloft, the pilot had a 360-degree view and could report any vessels.":183–184
Legacy and influence
In February 2013, Aviation Week and Space Technology reported that L-3 Communications was testing its Valkyrie, an unpowered, tethered autogyro that weighs 210 lb (95 kg), which is intended to serve as a cheap alternative to a shipborne helicopter. Valkyrie is designed to hover as high as 5,000 feet (1,524 meters) but is envisioned to operate typically at 500 to 1,000 feet (152 to 305 meters), offering a 28- to 39-mile (45- to 63-kilometer) field of view. L-3 stated that naval vessels could easily be retrofitted with this system.
- 100150 – On static display at the Le musée de l'Air et de l'Espace in Paris. This airframe was restored using parts from Wk. Nr. 100115 or Wk. Nr. 100145.
- 100042 – On static display at the Deutsches Museum in Munich.
- 100345 – On static display at the Deutsches Technikmuseum in Berlin.
- 100406 – On static display at the Hubschraubermuseum Bückeburg in Bückeburg.
- 100143 – On static display at the Imperial War Museum Duxford in Duxford.
- 100503 – On static display at the RAF Museum Cosford in Cosford.
- 100509 – On static display at the Science Museum at Wroughton in Swindon.
- 100545 – On static display at the Fleet Air Arm Museum in Ilchester.
- 100549 – Awaiting restoration at the Lashenden Air Warfare Museum in Ashford.
- 60133 – On static display at the Steven F. Udvar-Hazy Center in Chantilly, Virginia.
- 100463 – On static display at the National Museum of the United States Air Force in Dayton, Ohio.
Data from 
- Crew: 1
- Length: 4.42 m (14 ft 6 in)
- Empty weight: 68 kg (150 lb)
- Main rotor diameter: 7.32 m (24 ft 0 in)
- Main rotor area: 42 m2 (450 sq ft) 3-bladed rotor
- Maximum speed: 40 km/h (25 mph; 22 kn) on tow
- Minimum control speed: 27 km/h (17 mph; 15 kn) on tow
- Petite, Bob (April 2015). "Vertical Rewind: Spoils of War". Vertical Magazine. Archived from the original on 25 April 2015. Retrieved 25 April 2015.
- Ford, Roger (2013). Germany's Secret Weapons of World War II. London, United Kingdom: Amber Books. p. 224. ISBN 9781909160569.
- Helgason, Guðmundur. "Efthalia Mari (Steam merchant) - Ships hit by U-boats - uboat.net". German U-boats of WWII - uboat.net. Retrieved 26 August 2011.
- Focke-Achgelis Fa 330A-1 "Bachstelze" — Smithsonian Institution National Air and Space Museum article at the Internet Archive. Retrieved 3 May 2012.
- Giese, O., 1994, Shooting the War, Annapolis: United States Naval Institute, ISBN 1557503079
- Osborne, Tony, "The autogyro returns," Aviation Week and space Technology, February 25, 2013, p.26
- "100032 at Egeskov Castle Jun 2014". EuroDemobbed. June 2014. Retrieved 1 October 2016.
- "Focke-Achgelis Fa 330-A-0 Bachstelze". Musée Air & Espace (in French). Retrieved 1 October 2016.
- "Focke-Achgelis Fa 330 "Bachstelze", 1942". Deutsches Museum. Retrieved 1 October 2016.
- "Munich - Deutsches Museum, Germany". EuroDemobbed. Retrieved 1 October 2016.
- "Flugzeuge und Flugkörper in der Luftfahrtausstellung des Deutschen Technikmuseums" (PDF). Stiftung Deutsches Technikmuseum Berlin (in German). December 2015. Retrieved 1 October 2016.
- "Berlin - Deutsches Technikmuseum, Germany". EuroDemobbed. Retrieved 1 October 2016.
- "Gyrocopters". Hubschrauber Museum. Retrieved 1 October 2016.
- "Aircraft Database". LPH2O. LPH2O.com. Retrieved 1 October 2016.
- "Focke Achgelis Fa-330". Imperial War Museums. IWM. Retrieved 1 October 2016.
- Wilberg, Thomas. "Focke Achgelis FA 330 Bachstelze". The Virtual Aviation Museum. Thomas Wilberg. Retrieved 1 October 2016.
- "Focke Achgelis FA330". Royal Air Force Museum. Trustees of the Royal Air Force Museum. Retrieved 1 October 2016.
- "An Fa-330 at Wroughton". Robroy. July 2004. Retrieved 1 October 2016.
- "Focke Achgelis FA330A-1 (100545)". Royal Navy Fleet Air Arm Museum. Fleet Air Arm Museum. Retrieved 1 October 2016.
- Matthews, Trevor. "EXHIBITS". LASHENDEN AIR WARFARE MUSEUM. Lashenden Air Warfare Museum. Retrieved 1 October 2016.
- "Focke-Achgelis Fa 330A-1 Bachstelze (Water Wagtail)". Smithsonian National Air and Space Museum. Retrieved 1 October 2016.
- "Focke-Achgelis Fa 330 Sandpiper". National Museum of the US Air Force. 16 April 2015. Retrieved 1 October 2016.
- "AIRCRAFT, DRONES AND MISSILES AT THE NATIONAL MUSEUM OF THE U.S. AIR FORCE" (PDF). National Museum of the US Air Force. June 2016. Retrieved 1 October 2016.
- Green, William (2010). Aircraft of the Third Reich. Vol.1 (1st ed.). London: Aerospace Publishing Limited. p. 338. ISBN 978 1 900732 06 2.
|Wikimedia Commons has media related to Focke-Achgelis Fa 330.|
- The FA 330 at NASM
- Helgason, Guðmundur. "The Bachstelze". German U-boats of WWII - uboat.net.
- "German Submarine-Borne Observation Rotor-Kite", Allied Intelligence Report
- Video of the assembly and operation of a Focke-Achgelis Fa 330 aboard a German U-boat on YouTube