This projected "helicrane' was also to have side-by-side contra-rotating rotors at the extremities of outriggers. The two engines, originally of 1600hp, and later of 2000hp each, were located at the centre of the transverse beam and operated the rotors through gear and shafting. The rotors were synchronized and could work on one engine alone.
The version with two 1600hp engines was planned to lift 2 metric tons, the version with two 2000hp engines 7 tons.
Although development work on this helicopter had been virtually completed, only a few portions of the body had actually been built at the Breguet factories in France by the time World War II ended.
P.Lambermont "Helicopters and Autogyros of the World", 1958
The Fa 284 was probably the world's first helicopter design for the specific role of a flying crane. The machine was extremely large and ambitious and was to employ once again Focke's side-by-side layout of twin rotors. Much of the fuselage was of open framework construction with tail surfaces at the rear. A central two-seat enclosed cockpit afforded a good view, through the forward open framework, of the suspended load below. Extending sidewards from the front of the fuselage were the two outrigger structures for the rotors, and housed in each outrigger was a 1,600hp BMW 801 engine with a main undercarriage member immediately below.
Although some parts of the Fa 284 may have been manufactured, the design was abandoned (probably late in 1943) for an adaptation of the Fa 223, which would have kept the production of new parts to a minimum.
The plan was to build a four-rotor helicopter by combining two Fa 223s with the fuselages in line and joined by a new centre section. There is a possibility that the designation Fa 284 was transferred to the twin Fa 223, but, although the centre section was manufactured at Laupheim, a complete machine did not materialize.
J.R.Smith, Antony L. Kay "German Aircraft of the Second World War", 1972
The largest helicopter designed during World War II was this twin-rotor Focke-Achgelis Fa.284, a huge fiying crane intended to haul such loads as armored vehicles and trucks. Some work on the Fa.284 was carried out by Breguet, the pioneer helicopter company in France, during the German occupation. In the face of wartime difficulties the project was eventually dropped, but not before considerable design work and some airframe construction had been accomplished. The diameter of each rotor was 17.8m. Initially the machine was to have two BMW 1200kW engines, later raised to 1500kW.
Technical data for Fl 284
Number of seats: 2, engines: 2 x BMW 801 rated 1600hp, rotor diameter: 18m, length: 13.72m, weight fully loaded: 12000kg, empty weight: 8165kg, cruising speed: 208km/h, absolute ceiling: 6340m, range: 400km