Hiller OH-23 Raven
The Hiller UH -12 [A 1] was a 2 -4- seater easier observation and training helicopter that was used in almost all versions even in the United States Army, including in the Korean War. Total production amounted to about 2,000 units, which before the takeover made him the most commercially successful of Hiller helicopters by Fairchild. Construction, uses and power spectrum can be compared with that of the Bell 47.
History
1946 was developed in the light Hiller Hiller 360, with the possible in 1949 the first commercial transcontinental flight of a helicopter over the United States. The really weak to 131 kW Franklin engine was then replaced in 1950 by a 147 -kW engine, at the same time new rotor blades were used. This model was developed by Hiller (now United Helicopters ) now designated UH -12A. It quickly came orders from the U.S. military concluded: In the U.S. Army UH -12A was used as H -23A Raven, in the Navy as a training helicopter HTE -1. Hiller drove the development progressing rapidly and built the Franklin 6V4 -200 -C33 engine with a 147 or 154.4 kW. The resulting version of UH -12B was optionally available with skid landing gear or floats. The U.S. Army has ordered more than half of the production; after the UH -12A has been used successfully in the Navy as a training helicopter, the UH -12B should now serve the same purpose in the Army. A total of 216 H -23B went to Primary Helicopter School at Fort Wolters. The Navy ordered the new model: it was called HTE -2 and got instead of skids, or floats a four-wheel chassis. Major changes experienced in 1955 published model UH- 12C. The Franklin engine was retained, but the main rotor was virtually redesigned and the helicopter got the known plexiglass cabin that was called because of their bulbous shape jokingly " fishbowl ", but excellent visibility bot. In 1956 a total of 145 units were as H- 23C to the Army. Already on April 3, 1956 flew the prototype of the new UH -12 generation, the "D". This version was developed specifically for the military. The Franklin engine had to give way to the much more powerful Lycoming VO -435 engine with 250 hp and the transmission has been strengthened. 483 pieces of this version went to the Army (H- 23D ).
In the Army they had developed their own versions; Therefore, the UH- 12E was the OH - 23G here. This model had an even stronger machine than the UH- 12D ( Lycoming VO -540 with 305 hp ) and was the most produced version of the UH -12 series. Both the Army and at Hiller now changed the names: The Army had the initials OH for "Observation Helicopter " ( observation helicopter ) introduced and Hiller, who had renamed from "United Helicopters " to " Hiller Aircraft Corporation ," UH replaced by the whole word Hiller.
1960 appeared the last used by the military variant: The Hiller 12E4. The cabin had been extended by 64 cm and the helicopter could now accommodate 4 persons. The Army used them for geodetic surveying and had 22 copies, which she described as OH - 23F.
The final stage of evolution in the UH -12 series was from 1963, the Hiller 12LE, a civilian version. Produced and sold was this variant and even some of the older models until the end of the 1960s. Attempts have been made to use a Pratt & Whitney Canada PT6 turbine drive as the 12LE, but this project was abandoned.
Military user
- Army
- United States Army
- United States Navy