Hiller UH-12

Hiller UH-12
United States Navy HTE-2
Type:	Light training and observation helicopter
Design country:	United States
Manufacturer:	Hiller Aircraft Company
Commissioning:	1948
Number of pieces:	over 2000

The Hiller UH-12 was a two- to four-seater light observation and training helicopter , almost all versions of which were also used by the United States Army , u. a. in the Korean War . Total production was over 2000 units, making it Hiller's most commercially successful helicopter before it was acquired by Fairchild . The design, areas of application and range of services can be compared with that of the Bell 47 .

history

In 1946, Hiller developed the lightweight Hiller 360 , which made the first commercial transcontinental flight of a helicopter over the USA in 1949 . The 131 kW Franklin engine, which was actually too weak, was then replaced by a 147 kW engine in 1950, and new rotor blades were used at the same time. This model has now been named UH-12A by Hiller (now United Helicopters ) . Orders from the US military came quickly : The US Army used the UH-12A as the H-23A Raven , and the Navy as the HTE-1 school helicopter . Hiller pushed the development forward quickly and installed the Franklin 6V4-200-C33 engine with 147 or 154.4 kW. The resulting version UH-12B was optionally available with a skid landing gear or floating bodies. The US Army ordered more than half of the production; After the UH-12A was successfully used as a school helicopter in the Navy, the UH-12B should now serve the same purpose in the Army. A total of 216 H-23B went to the Primary Helicopter School at Fort Wolters. The Navy also ordered the new model: It was called the HTE-2 and was given a four-wheel chassis instead of the runners or floats. The UH-12C model, released in 1955, underwent extensive changes . The Franklin engine was retained, but the main rotor was practically redesigned and the helicopter was given the well-known Plexiglas cabin, which was jokingly called the “fishbowl” because of its bulbous shape, but offered excellent all-round visibility. From 1956 a total of 145 units went to the Army as H-23C . The prototype of the new UH-12 generation, the " D ", flew on April 3, 1956 . This version was specially developed 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 was reinforced. 483 pieces of this version went to the Army ( H-23D ).

The Army had developed its own versions; therefore the UH-12E was the OH-23G here . This model had an even more powerful engine than the UH-12D ( Lycoming VO-540 with 305 hp) and was the most popular version of the UH-12 series. The names of both the Army and Hiller now changed: the Army had introduced the letters OH for "Observation Helicopter" and Hiller, who had renamed "United Helicopters" to "Hiller Aircraft Corporation", replaced UH the whole word Hiller .

In 1960 the last variant used by the military appeared: The Hiller 12E4 . The cabin had been lengthened by 64 cm and the helicopter could now accommodate four people. The Army used it for geodetic survey work and owned 22 copies, which it designated as OH-23F .

The last development stage in the UH-12 series was the Hiller 12LE from 1963 , a civil version. This variant and some of the older models were produced and sold until the end of the 1960s. Attempts have been made, a Pratt & Whitney Canada PT6 - turbine powered the 12LE to use, but this project was abandoned.

Military users

US Army H-23D

 Egypt Argentina Biafra Bolivia Chile Germany
 
 
 
 
 

• army

 Dominican Republic France Guatemala Indonesia Switzerland Israel
 
 
 
 
 

Israeli OH-23, Jerusalem 1952

 Japan Canada Colombia Morocco Mexico Netherlands Paraguay Peru Sri Lanka Thailand Uruguay
 
 
 
 
 
 
 
 
 
 

• United States Army
• United States Navy

 United Kingdom : Royal Navy United States
 

production

As part of the Mutual Defense Aid Program (MDAP), the Hiller UH-12 was also delivered to allied countries.

Acceptance of the UH-12 by the USAF, US Army and US Navy (only until 1959):

version	1950	1951	1952	1953	1954	1955	1956	1957	1958	1959	TOTAL
YH-23	1										1
HTE-1 US Navy	1	15th									16
HTE-2 US Navy			35								35
H-23A US Army	5	89	2								96
H-23B USAF					20th						20th
H-23B US Army			158	80	45	25th					308
H-23B MDAP					20th						20th
H-23C US Army						1	78	65			144
H-23C MDAP									1		1
H-23D US Army								5	73	20th	98
TOTAL	7th	104	195	80	85	26th	78	70	74	20th	739

Technical specifications

Parameter	H-23D Raven
Construction year	1956
Manufacturer	Hiller Aircraft Corporation (still United Helicopters)
crew	1-3
Rotor diameter	10.80 m
Hull length	8.53 m
Length over all	12.40 m
height	2.98 m
Preparation mass	807 kg
Takeoff mass	1270 kg
Top speed	154 km / h
Max. Hover altitude with ground effect	3290 m
Service ceiling	4940 m
Range	360 km
Engine	1 × Lycoming VO-540-1B with 235.3 kW (320 PS)

H-23C of the US Army in the helicopter museum Bückeburg

See also

• List of helicopter types

Web links

Commons : H-23 Raven  - album with pictures, videos and audio files

Individual evidence

1. ↑ Statistical Digest of the USAF 1948, p. 16; 1949, p. 164 f .; 1951, p. 158; 1952, p. 158; 1953, p. 185 f .; 1954, pp. 70 f .; 1955, p. 80 f .; 1956, p. 91 f .; 1957, p. 97 f .; 1958, p. 72; 1959, p. 68

Remarks

1. ↑ The civil name "UH-12" used below stands for United Helicopters; The Hiller Aircraft Corporation operated under this name in the 1950s. It should not be confused with the military designation UH (Utility Helicopter, e.g. Bell UH-1 ) given by the US Army , which was only introduced in 1962 (previously HU). The correct military designation of the UH-12 was H-23 and OH-23 (US Army) or HTE-1 and HTE-2 (US Navy). Conversely, the widespread opinion that H-23 stands for "Hiller Model 23" is also wrong, since the army had assigned the H (for helicopter) and the code number 23. The H-23 was the "United Helicopters Model 12" when it was launched; after the renaming from "United Helicopters" to "Hiller Aircraft Corporation", the following models were called "Hiller 12".