Back Hiller 360 / UH-12 / OH-23
1947

Hiller OH-23

The Hiller UH-12, derived from the Model 360 two-seater of 1948 with a 180hp Franklin engine, occupies an important place in the history of the American helicopter industry in the fifties. Stanley Hiller Jr., who built the aircraft, was something of a whiz kid, in that he designed and built his first helicopter, the XH-44, in 1944 at the age of only 18. It was the first efficient American helicopter with coaxial, contra-rotating rotors. The later Hiller 360 leapt to fame in the summer of 1949 when it made the first transcontinental commercial flight. With an uprated engine and new UH-12A rotor blades, it was purchased by the US Army and Navy for battlefield evacuation and observation tasks, with the designation H-23 Raven, whilst the Navy ordered the same basic model as the HTE-1 for training.

Its successor, the H-23B, powered by a 200-210hp Franklin engine, was the first version used by the US Army as a trainer. A considerable number were built: 216 were assigned to the Primary Flying School at Fort Walters and another 237 were used for various tasks.

The UH-12B normally had skid or flotation gear, but a wheeled undercarriage was fitted to a batch ordered by the US Navy (the HTE-2). In 1955 a new variant, the UH-12C, appeared. It retained the 200hp Franklin engine, but had all-metal rotor blades and a "goldfish bowl" cockpit canopy. From 1956, 145 were delivered to the US Army as the H-23C. A purely military version, the OH-12D, flew on 3 April 1956 and 483 went to the US Army. The Franklin engine had been replaced by the more powerful 320hp Lycoming VO-540, and the transmission had also been changed to increase the service life of the helicopter.

The commonest version of this sturdy little helicopter was the UH-12E which had a more powerful engine. The US Army replaced nearly all the OH-23Ds by Hiller 12Es, designated OH-23G. In 1960 the Model E4 was developed from the Hiller 12E, with a longer cabin to seat four and an anhedral stabilizer on the tail boom. Twenty-two of these were acquired by the US Army as the OH-23F, for geodetic research.

The last civil variant, which appeared in 1963, was the Hiller 12L-4 which was also used as a test-bed for a PT6 turbine, but the project was taken no further.

Total sales of the Hiller 12E family exceeded 2000; more than 300 were exported. Operators of the Hiller included Argentina, Canada, Chile, Colombia, Great Britain, Guatemala, Japan, Morocco, Mexico, the Netherlands, Peru and Uruguay.

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

Hiller 360 / UH-12 / OH-23

Hiller Helicopters Inc. was formed in 1942 for the development and production of rotary-wing aircraft. Early work on the Hiller Model XH-44, UH-4 Commuter and the UH-5, which introduced a newly-developed 'Rotor-Matic' rotor control system, led to the Hiller Model 360 prototype. The company's first production helicopter followed and this, known as the Hiller UH-12 as Hiller had become part of United Helicopters, was of simple construction, incorporating a two-bladed main rotor and a two-bladed tail rotor on an upswept boom. The design was highly successful, being built extensively in two- and three-seat configurations for both civil and military use, and an early Model 12 was the first commercial helicopter to record a transcontinental flight across the United States. More than 2,000 were built before production ended in 1965, some 300 of this total being exported, and throughout this period the power and capability of the helicopter was steadily improved.

The commercial UH-12A to UH-12D became the OH-23A to OH-23D Raven respectively for service with the US Army, and the US Navy acquired UH-12As as HTE-1 and HTE-2. The UH-12E was basically a three-seat dual control version of the OH-23D and was built also as the military OH-23G. A lengthened-fuselage four-seat civil UH-12E4 was produced as the military OH-23F, and late civil versions with uprated powerplant included the UH-12E variants suffixed L3, L4, SL3 and SL4. OH-23s were exported to Argentina, Bolivia, Colombia, Chile, Cuba, Dominica, Guatemala, Guyana, Mexico, Morocco, the Netherlands, Paraguay, Switzerland, Thailand and Uruguay. The Canadian army acquired OH-23Gs which it operated with the designation CH-112 Nomad, and the Royal Navy used a number of ex-US Navy HTE-2s under the designation Hiller HT.Mk 2.

At the height of UH-12/OH-23 production Hiller was taken over by the Fairchild Corporation, but in 1973 a new company, Hiller Aviation, acquired design rights and production tooling for the UH-12E, and for some years provided support for the world-wide fleet of UH-12 variants. In April 1984 Hiller became a subsidiary of Rogerson Aircraft of Port Angeles, Washington. Renamed Hiller Helicopters and later Rogerson Helicopters, the company, now known as Rogerson Hiller, relaunched the piston-engined UH-12E in 1991 as the Hauler, and a number have been exported. The company is also proposing the Allison turbine-powered UH-12ET development for the US Army's NHT (New Training Helicopter) requirement.

D.Donald "The Complete Encyclopedia of World Aircraft", 1997

360

Two-seat helicopter based on UH-5 of all-metal construction with fixed tricycle u/c, fully enclosed cabin and rear fuselage, overhead mounted control stick attached to Hiller rotor control, powered by one 175hp Franklin 6V4-178-B32 engine. Prot. N68940.

UH-12

Developed 360 with framed 'bubble'-type cabin, no fuselage structure round engine, skid u/c and 175hp Franklin 6V4-178-B33 engine. 1015kg TOGW.

UH-12A Raven

 

Production two-seat UH-12 with collective pitch ballast system and wooden rotor blades for civil and military customers. 1082kg TOGW.

UH-12B

UH-12A with skid/wheel u/c, 200hp Franklin 6V4-200-C33 engine and 1128kg TOGW.

UH-12B

UH-12B for USN with wheel u/c. Also HT Mk.1 for Royal Navy.

UH-12C

UH-12B with moulded bubble canopy, 3 seats and metal rotor blades.

UH-12D

 

Military UH-12C with 250hp Textron Lycoming VO-435-A1C engine, new transmission system, 1240kg TOGW. Prot. FF 3 Apr. 1956.

UH-12E

 

UH-12D with 305hp Textron Lycoming VO-540-A 1 A engine. OH-23G is 3-seat dual control trainer.

UH-12EL

 

UH-12E retro-fitted with Ham-Standard rotor stability augmentation system, stainless steel rotor blades and 1400kg TOGW.

UH-12E3

 

Revised designation for Hiller Aircraft Corp. production UH-12E with 3 seats.

UH-12E3T

 

Revised designation for Hiller Aircraft Corp. 3-seat UH-12ET.

UH-12E4

UH-12E with inverted rear tail planes and lengthened cabin to accommodate pilot plus rear bench seat for 3 pax.

UH-12ET

 

UH-12E fitted with Soloy conversion to 400shp Allison 250-C20B turboshaft.

UH-12E4T

 

UH-12E4 fitted with Soloy conversion to 400shp Allison 250-C20B turboshaft.

UH-12E5

UH-12E4 fitted with five seats and 340hp Textron Lycoming VO-540 piston engine. Prot. flown but design not further developed.

UH-12E5T

 

Proposed turbine-powered UH-12E5 with Allison 250-C20B. Not built.

UH-12J-3

 

Unofficial designation for Soloy-converted UH-12E.

UH-12SL

 

UH-12E with supercharged Textron Lycoming TIVO-540 engine and 'L' series rotor head with gyro-controlled stability augmentation system.

UH-12L

 

UH-12SL with unsupercharged VO-540 engine.

UH-12SL4

UH-12L with E4 four-seat cabin.

*     *     *
Stanley Hiller Jr designed the Model 360 which has enjoyed considerable commercial success since its first flight in 1948. It was derived from the UH-5 which had proved very unstable during trials and had subsequently been fitted with a new stability system patented as the Hiller 'Rotormatic'. It entailed fitting the two-blade rotor with two small paddles which acted as a control rotor and were also connected to a hanging stick. This servo 'paddle control' system tilts the rotor head and actuates the cyclic pitch control.

It received its FAA (Federal Aviation Administration) approval in October 1948 and a year later a production model designated Model 12 made the first transcontinental helicopter flight across the USA. At that time it still had an open cockpit, and the 178hp Franklin 6V4-178-B33 was in an open engine bay.

Models 12A, B and C were powered by a 200hp 6V4-200-C33 or a 210hp 6V-335-B Franklin piston engine. The 12C was the first version with a goldfish bowl canopy.

The Korean War gave an added impetus to improvements and when the Hiller 12E appeared in 1959 it came either as the L3 with a 305hp Lycoming VO-540-C2A or as the SL3 with a supercharged 315hp TIVO-540-A2A engine.

The 12E has been used for the usual range of civil work, like fire-fighting, crop and forestry control, and as a private and business transport.

A Model E4 was built with a longer fuselage to take a bench for three passengers and it introduced stabilized tail surfaces. All new helicopters now have these features and they can be retrofitted on Model 12Es. A turbine-powered retrofit kit is available as the UH-12E4. This engine pack was jointly developed with Soloy Conversions of Chehalis, Washington who began work on it in 1976.

The Model 12 has the usual equipment for helicopter safety and civil work, but can also be fitted with a night-lighting kit, a 454kg capacity cargo hook, twin heavy duty cargo racks, and auxiliary fuel tanks. Equipped with extra tanks the 12E has a maximum range of 676km. Production of both the 12E and 12E-4 is running at about five a month and with over 2200 helicopters built since the introduction of the Model E there is a world-wide maintenance service.

Bill Gunston "The Illustrated Encyclopedia of Commercial Aircraft", 1980

*     *     *

FACTS AND FIGURES

- An early UH-12 was the first commercial helicopter to log a transcontinental flight across the United States.

- Over 1,600 UH-12s went to the US Army and were used in Korea and Vietnam.

- As a flying ambulance, the UH-12 can carry two stretcher cases.

- UH-12s were exported to at least 18 countries, many via the Mutual Defense Aid Program.

- The Hiller UH-12 was the US Army's primary trainer until 1965.

- UH-12s were manufactured by Hiller in Palo Alto, near San Francisco, California.


Technical data for Hiller OH-23D "Raven"

Engine: 1 x Avco Lycoming VO-540-A1B 6-cylinder pistone engine, rated at 241kW, main rotor diameter: 10.82m, length: 8.53m, height: 2.97m, take-off weight: 1225kg, empty weight: 824kg, max speed: 153km/h, cruising speed: 132km/h, service ceiling: 4025m, range: 330km

Comments1-20 21-40
Barry McHenry, e-mail, 24.02.2012reply

Initial training in the OH-23 and after returning from Vietnam I flew about 1,000 hours as an instructor pilot at Ft. Wolters.

Peter Boitel-Gill, e-mail, 23.03.2013reply

Bought first 12E in 1976 for spraying in UK, followed by about ten more up till 1993. Also three 12E4's. 12E had Lycoming 540 and could carry 70 Imp gallons. When EU banned aerial application in UK, sold 612Es to Greek operator. Great little helicopter. Happy days...

peter hiller, e-mail, 11.07.2010reply

very good

Bennie J. Shields, e-mail, 02.10.2012reply

Fresh out of college in 1966, I got hired to train Army officers to fly helicopters. Most of the 93 pilots I trained were trained in the Hiller H-23.

omer mehic, e-mail, 16.02.2010reply

I like flying this machine in Serbia. It is pleasure

fred peck, e-mail, 25.01.2010reply

Check out the wed site Alohaaeroscouts.org to see how this brids were used in Veitnam.

moses, e-mail, 24.01.2010reply

Memories of maneuvering at Fort Wolters so as to get a OH-23 with doors, rather than a 13 or 55, or a helicopter without doors.

Ron Hartleroad Army National Guard, e-mail, 21.10.2009reply

I am currently refurbishing an OH-23 at my job here in Lexington,OK. It has been on a pole since 1975. It is still in pretty good condition. I can send pictures of the in progress or completed version if anyone wants. 10 /21 /2009

Joseph Hood, e-mail, 01.06.2009reply

Appreciate if somebody could provide the supplier list of UH-12.

Major General S. Muhammad Azam ( Retired, e-mail, 17.05.2009reply

I was busy compiling the history of Pakistan Army Aviation and discovered that Hiller-23 was the first helicopter learned by Pakistan Army Aviators while undergoing flying training at Ft Wolters in 1957 to 1960 /64.I would appreciate if some one could post pictures of that time especially if Pakistan Army pilots could be seen.Probably Mr Gammons( 02-05-08 )could offer some help.

jerry, e-mail, 13.05.2009reply

I recognize this helicopter from the early James Bond movies, "Goldfinger" and "From Russia with Love". As far as I know, these appearances (possibly the same machine) in two back-to-back films of the series are the only examples of the UH-12 in popular culture.

Jock Williams Yogi 13, e-mail, 23.04.2009reply

The Canadian Army had a number of these machines, and as a former Army officer undergoing RCAF pilot training I had a number of friends who flew them -pretty dangerously in some instances as I now recognize!
Without mentioning any names, Wally Johnson, Gary Flath, and Rusty Willet all took me on some hair-raising rides -and I fell in love with helicopters -although I learned not to mention it -or I would have been a helo driver rather than a fighter pilot in short order.
Years later I became a Kiowa driver voluntarily -and very happily -but that was when fighters were no longer an option.
One of the guys I flew with then was nicknamed "Happy Harry the Hiller Killer" -I guess you can imagine what HIS record included!
The Hiller served Canada well for many years.

Jock Williams Yogi 13

john steelman, e-mail, 30.03.2009reply

anyone know where i can get some -4 blades for a uh-12d hiller

Shauna, e-mail, 21.01.2009reply

As a community project, a group has gotten together to try to renovate the entrance to the old Fort Wolters base. Two helicopters used to act as 'guardians' of the base at the entrance. One was an OH-23 (by Fairchild Hiller), the other a TH-55A (by Hughes). Does anyone know if /where /how I could get my hands on replicas or just shells of these kinds of aircrafts?

MIke Cress Sr, e-mail, 28.11.2008reply

I trained on both the H-23 and H-13 as a MOS 67Q. I loved the simplicity of the aircraft.

ted, e-mail, 11.09.2008reply

I JUST PURCHASED A OH23 /12C AND WAS TOLD THAT THE CURRENT DOORS WITH THE SLIDING SIDE WINDOWS ALSO WITH VENTS WERE ONLY LEGAL ON THE 12E MODELS AND NOT ON 12C. COULD YOU HELP ME OUT WITH THIS QUESTION. THANK YOU TED

Gordon McCoy, e-mail, 20.08.2008reply

Soloed in that aircraft a Ft. wolters in the Warrent Officer Flight Program back in '68.. Been in love with rotorcaft ever since... Recently retired from the Airlines as a Airbus A-320 Cpt. Owe my love of flying and "war stories" to you, the Hiller builders! Gordon McCoy, Annapolis, MD

perry francis, e-mail, 17.08.2008reply

Is it true that a Hiller 12E with a Soloy conversion has landed on top of Mt. McKinley? Does anyone have documentation as to this? Thanks in advance if someone has this information.

vance gammons, e-mail, 02.05.2008reply

The OH-23 was the machine at Ft Wolters, Tx when our army flight class went thru basic , Jan - Mar 1959. We had a few B's & D's but mostly C's. The next time I flew one was 1968 at Cu Chi while assigned to the 1st Bde, 25th Inf Div.They were strong ,rugged machines.

Mohamed elbadry, e-mail, 03.04.2007reply

I need a more details for the UH-12E3

1-20 21-40
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