FLETTNER   FL 282
KOLIBRI

 El Flettner Fl-282 (Hummingbird) fue diseñado desde el principio con dos plazas, así que, a expensas del alcance, se podía llevar un observador, con los beneficios obvios en las operaciones del ejército y de la armada. El observador se acomodaba en la parte trasera, detrás del rotor, mirando hacia atrás. El diseño le permitía a esta máquina volar con o sin pasajero sin necesidad de ponerle lastre o regular el trim. El diseño fue finalizado en julio de 1940 y se construyeron 30 prototipos y 15 máquinas de preproducción Los primeros tres prototipos eran de una sola plaza y tenían la cabina cubierta con plexiglás, pero las siguientes máquinas fueron construidas con los dos asientos al descubierto.

Estaba equipado con el mismo motor de los utilizados en las otras versiones, el Siemens-Halske Sh 14 A. Dependiendo de las fuentes este motor tenía una potencia de 150 ó160 hp. Este motor radial fue ubicado en el centro del fuselaje con un rotor con palas de madera. En la parte trasera del fuselaje, se proporciono de un estabilizador horizontal con propósitos de trimeado y una aleta y un estabilizador vertical bastante grande.

El Kolibri tenía un fuselaje construido de tubos soldados, bastante compacto. Se previó que se pudiera guardar en un área pequeña, como en un submarino U-Boat. Sin embargo no existen evidencias de que esto halla sucedido.

El Fl-282 fue el helicóptero mas desarrollado y el que mas horas de vuelo realizó de todos los helicópteros alemanes. Extremadamente maniobrable y muy estable, aún en condiciones de viento fuerte. Existieron dos máquinas que se las denominó Fl-282A, las cuales tenían una cabina parcialmente cerrada, se construyeron en 1941.

Durante 1942, se fabricó una versión mas desarrollada, el Fl-282B-1, este contaba con un fuselaje rediseñado que se fabricaba de una sola pieza y la cola se recubría completamente de tela. Esta aeronave, sin la protección de cabina, pesaba unas 110 libras menos, pero esta reducción fue adicionada en la parte trasera para poder llevar una bomba pequeña.

Para 1943, veinte Fl-282 habían sido construidos y se utilizaban rutinariamente en la protección de convoys y reconocimiento de barcos en el Báltico y en el Mediterráneo. El ejército alemán apreció la versión Fl-282B-2, con dos plazas, que se logró a expensas de rediseñar el tanque de combustible  y cambiarle la radio marina por una mas chica de corto alcance.

El pedido combinado del Ejército y la Marina alemana fue de 1000 aparatos, pero los bombardeos aliados sobre las fábricas de Flettner y BMW resultaron que no se pudiera lograr esa cifra. Solo se construyeron 25 Kolibris, pero sobrevivieron nada mas que 3 aparatos en condiciones operativas, el Fl-252 V15 y el V23 que lo tomaron los americanos y el tercero los rusos. El concepto del rotor interengranado fue usado en helicópteros de post guerra por Kaman por ejemplo.

Anton Flettner se radicó en USA y fue asesor de la Oficina Naval y continúo sus investigaciones hasta su muerte en 1962.

 The Flettner Fl-282 (Hummingbird) was designed from the outset as a two-seater, so that, at the expense of range, an observer could be carried, with obvious benefits in the roles of army and navy spotting and anti-submarine work. The observer was to be accommodated in a seat facing rearwards and positioned behind the rotor shafts, and the design provided for a permissible center of gravity travel which allowed the helicopter to fly with or without the observer without trim changes. The design was finalized by about July 1940 and work began on 30 prototypes and 15 pre-production machines at Flettner's Johannisthal and Bad Tolz factories. The first three Fl-282 prototypes were built as single-seaters and had enclosed Plexiglas-paneled cabins, but subsequent machines were built as open two-seaters.

The Fl-282 was powered by the same Siemens-Halske Sh 14A engine used on previous Flettner helicopters. Depending on the source the engine was rated at 150 or 160 horsepower. The radial engine was located in the center fuselage with a wooden bladed fan drawing in cooling air through openings in the fuselage underside.

At the rear end of the fuselage, a horizontal stabilizer was provided for trimming purposes and a fin and rudder of very generous area. This large area was necessary because much of it was ineffective due to the poor aerodynamic shape of the fuselage causing rearwards Row separation and turbulence. Steering of the Fl-282 was by a combination of the rudder and differential collective pitch change on the two rotors, but only the rudder could give steering during autorotation since collective pitch was then ineffective (another reason for the large rudder area).

The Kolibri had a fuselage constructed of welded steel tubing that was sized so that it could be stowed with rotor blades and landing gear removed in a compact area, 5.9 feet in diameter by 18 feet long, built as a pressure tank for carriage on a U-boat. However there is no evidence that any Fl-282 was deployed on a German submarine. The undercarriage was of the non-retractable tricycle type with the nosewheel connected to the rudder pedals for steering.

The Fl-282 was more highly developed and flew more hours than any other German helicopter, and very extensive tests and measurements were made of all flight aspects. Most of this test work was done by Flettner's chief pilot, Hans E. Fuisting, who also undertook blind lying and trained many of the 50 pilots who learned to fly the Fl-282.

Extremely maneuverable and very stable, even in gusty conditions, the machine could be flown hands-off in forward flight above 60 km/h (37 mph) for indefinite periods.The first two Fl-282 helicopters had all metal streamlined fuselages with streamline fairings around the rotor masts, and a fully enclosed plexiglass paneled single seat cockpit. The tails were mostly fabric covered. These two machines were designated Fl-282A. Test flying began in 1941 and was conducted by Flettner's (chief Test Pilot, Hans Fuisting.

The German Army also appreciated the usefulness of the helicopter and ordered a two seat version of the Kolibri, known as the Fl-282B-2. It was similar to the navy ships, but a rear facing seat was fitted in the fuselage behind,the engine. Space for the extra seat and passenger was obtained by remodeling the standard fuel tank and special naval radio equipment. A 25 liter cylindrical fuel tank was mounted an the outside of the fuselage, adjacent to the pilot's cockpit and the long range naval radio was replaced with a smaller and lighter short range radio.

The Fl-282B had a maximum speed of 93 mph. at sea level. Range was 166 miles as B single seater at 71 mph., or 106 miles as a two seater at 68 mph.. Gross weight was 2205 pounds, with useful load of 529 pounds. Maximum rate of climb was 300 feet per minute. with a hover ceiling of 985 feet and a service ceiling of 10,800 feet. The Fl-282B-2 was used for such military tasks as directing artillery fire and guiding tanks over rough terrain. Beginning in 1944, the army began to implement a program to provide a helicopter to each independent artillery brigade.

During 1942, a more productionized version, the Fl-282B-1 was developed. The fuselage was redesigned to use only flat wrapped (no multi-contour) sheet metal covering over the engine compartment, and the aft fuselage became fabric covered. The tail surfaces were redesigned to simplify construction and became entirely fabric covered. The streamline rotor mast fairings were eliminated. This was still a single seater, but now the pilot sat completely in the open. An exception was the third ship which had a nose similar to the first two, but the upper cockpit panels were deleted making it a semi-enclosed cockpit. The airframe weight was reduced by 110 pounds when compared to the Fl-282A, but some of this reduction was added back with the addition of a small bomb bay, a rubber life raft, and mooring gear for shipboard use.

By 1943, twenty Fl-282s had been built and they were routinely being used by the Kriegsmarine for convoy protection and reconnaissance from ships in the Aegean, Baltic, and Mediterranean Seas. The helicopter was found to be especially valuable at dawn and dusk when pilots of fixed wing aircraft did not have good visual contact in the poor light. During the day observation was especially favorable in the Mediterranean where the clear water allowed the helicopter crews to 'see' submarines as deep as 130 feet.

A combined Army-Navy order for 1,000 Fl-282s was given to Flettner and BMW in 1944. Tooling up was begun, but heavy aerial bombardment of the Flettner and BMW factories resulted in none of these machines being built. Only a total of 25 Kolibris had been manufactured by Flettner at war's end. Luft-Transportstaffel 40 based at Ainring in April 1945, had at least three Fl-282s (and also three Focke Achgelis Fa-223s) at its disposal. during the last few months of the war and this unit made many flights into and out of besieged and encircled towns transporting dispatches, mail, and key personnel. It was possibly one of this unit's Fl-282s that flew Gauleiter Hanke out of besieged Breslau just before the capture of that city.

After the war, only three Fl-282s were discovered by the Allies in a serviceable condition for testing, the Fl-252 V15 and V23 being taken to the USA and a third machine to the USSR. Examples, known to have survived are the Fl-282 (c/n 28368) at the Cranfleld Institute of Technology, and the Fl-282 V23 at the United States Air Force Museum, Dayton, Ohio.

Thanks to germanvtol.com

Characteristics
Características

Information
Información

Characteristics
Características

Information
Información

1 Bramo
Sh 14a
7 cil.

 1 / 1-2 some models

 150 - 160 HP

1675 Lb

Ft

2205 Lb

985 Ft

Kts

10800 Ft

95 Kts

95 NM

Dimensions / Dimensiones

21,52 ft
6,56 m

39,30 ft each
11,96 m each

7,21 ft
2,20 m

NA