Berliner-Joyce Helicopter 1924
In 1922, Henry ordered a surplus Nieuport 23 fighter fuselage and mounted a Bentley 220 hp engine to the front. He attached a spar mid-way up the fuselage to form the bottom of a truss extending from the sides of the aircraft. The trusses each supported one of the two counter-rotating lifting rotors, which the engine powered through a series of geared shafts. The two rotors could tilt slightly in opposite directions to control yaw.
A variable-pitch tail rotor, 76 cm (30 in) in diameter, mounted horizontally in front of the vertical stabilizer, maintained pitch control while hovering. To initiate forward flight, the pilot pushed forward on the stick to increase the pitch of the horizontal tail rotor, which dropped the nose and inclined the lifting propellers slightly to initiate forward flight. The flight controls also connected to elevators and an enlarged rudder on the tail of the fuselage, which helped maintain control at higher forward speeds. Two sets of five 91 cm (36 in) x 20 cm (8 in) louvers, located below each rotor, opened and closed differentially to provide roll control by presenting a flat surface, which reacted against the rotor downwash.
In the fall of 1923, Henry decided to mount a set of triplane wings onto the aircraft to allow for a safe glide in case of an engine failure. With the new design, he found he could marginally control the helicopter in a hover and in forward flight at speeds up to 64 kph (40 mph). However, Henry discovered that the helicopter did not have adequate thrust to climb out of ground effect. The roll-control louvers were the weak-point of the control system and lateral handling was poor.
On February 23, 1924, the helicopter recorded its best performance when it reached a height of 4.57 m (15 ft) during a one minute, thirty-five second flight. Many observers felt that the airframe was simply too heavy, including an Army engineer sent to observe the tests from McCook Field.
It was successfully demonstrated to the US Army in 1924, with several free flights at College Park, Md. Airport.
After Emile and Henry completed the testing of their triplane model, the younger Berliner offered it to the Smithsonian Institution. This aircraft is the oldest intact helicopter in the world and was on loan to the College Park Aviation Museum since 1998, appropriately located on the site of the Berliner's original testing ground.
Wingspan: 11.58 m (38 ft)
Rotor Diameter: 4.57 m (15 ft)
Length: 5.49 m (18 ft)
Height: 2.06 m (6 ft 9 in)
Weight: Empty, 748 kg (1,650 lb)
Gross, 870 kg (1,918 lb)
Engine: Bentley BR-2 Rotary, 220 hp