Hiller UH-12 by Special Hobby

1/72 scale
Kit No. SH72017
Retail: $40.00 and up (Aftermarket, Out of Production)
Decals: Three Versions – U.S. Army, Air National Guard, Fleet Air Arm
Comments: Short run kit with resin detail parts, vacuform canopy

History

First flown in 1948, the Hiller UH-12 was used extensively by the U.S. military in a variety of roles such as training, utility, observation, and especially in medical evacuation of casualties during the Korean War. The UH-12 was given the designation OH-23 Raven in the US Army and HTE-1 and HTE-2 in the US Navy. The Royal Navy bought over 20 US Navy HTE-2s and used them as primary trainers under the designation Hiller HT Mk 1. These were later joined by another 21 UH-12E variants which were given the designation Hiller HT Mk 2.

The UH-12 was broadly similar to the contemporary Bell Model 47 helicopter — suggesting a dragonfly, with a framed plexiglas cockpit featuring a sloped windshield and removable forward-hinged doors on each side; exposed engine and drive system; and a two-blade main rotor made of wood. Hiller had wanted metal main rotor blades, but ran into snags, though the tail rotor was made of metal. It differed in having three-across seating instead of twin seats; fixed tricycle landing gear, all with single wheels, the main gear on tripod mountings; and having the two-blade tail rotor mounted on an upraised “stinger” tailboom, enhancing its insectlike appearance.

At the outset, the tail rotor was on the left, with a matching tailplane on the right, and a rod for a tail rotor guard under the tailboom. It was powered by a 130 kW (175 HP) Franklin 6V4-178-B33 flat-six air-cooled engine; drive to the tail rotor was fed through a strut that also held up the tailboom. One innovative feature was an overhead control stick, linked directly to the Rotormatic paddles. The UH-12 was noted for its stability, but it came at a price: there was a noticeable lag in control response, one pilot saying with a bit of exaggeration that one could eat a sandwich before the machine responded to a control adjustment.

The UH-12 led to the “UH-12A”, introduced in 1950; it featured improved rotor blades and max take-off weight increased by about 7%. With the beginning of the Korean War in June 1950, the military became interested in using helicopters for medical evacuation. In September 1950, the Army began tests of a UH-12A with enclosed side-mounted litter carriers and fitted with military radios, giving the type the designation “YH-23”. The type went into production as the H-23A “Raven”, with the Navy also ordering a number of dual-control trainers with the designation “HTE-1”.

At first, the H-23 proved unsatisfactory in combat service, its performance and reliability leaving something to be desired, the H-23 being well overshadowed by the Bell Model 47 in the war theater. Part of the problem was that Bell understood military requirements better than the Hiller company, indeed better than the Army; although the Army had made no strong demands on Bell for field service support, Bell made sure a corps of service people were in Korea to keep their helicopters flying. The Army didn’t encourage the Hiller company to do so, and company staff didn’t think of it until the problem became obvious.

Hiller engineers focused on fixing the problems, resulting in 1951 in the UH-12B (a.k.a. H-23B) for the US Army — featuring a 200 hp Franklin 6V4-200-C33 engine , option for skid or float landing gear, and a more robust airframe, with the maximum takeoff weight raised by 4%. The Army found the H-23B more satisfactory than the H-23A and was enthusiastic about it. A batch of trainers with four-wheel landing gear replacing the skids was built for the US Navy as the HTE-2.

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 U.S. Army as the H-23C. A purely military version, the OH-12D, flew on April 3, 1956 and 483 went to the U.S. 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 Kit

Released in 1998, Special Hobby’s UH-12 helicopter is injection molded in grey plastic and consists of 23 plastic parts, four vacuform parts, and 13 resin detail parts (for the engine, cockpit floor and rear bulkhead, main instrument panel, tailskid wheels, control yokes and other parts). There are two vacuform canopies provided, both the original, relatively flat canopy, and the bulbous, “goldfish bowl” canopy by which the type is more well known.

The heart of this diminutive kit is the resin engine, and the engine assembly is fairly complex with a series of support struts (all of which must be crafted from scratch) and two mufflers. In fact, multiple struts must be scratch-built to complete the kit. While many of the parts are quite small, the instruction sheet has relatively large illustrations and is very clearly laid out; still, it will require careful study to effectively build the kit.

Markings

The kit decals are manufactured by Cartograf and provide three versions. The first is for a Hiller OH-23 of the California Air National Guard, circa 1962. This helicopter is painted in overall olive drab with a yellow band on the rear boom and black rotor blades. The second version is for a Hiller UH-12C of the U.S. Army, and is painted in a scheme of white and signal red. No unit information or date is provided, and its rotor blades are white with a black center section. The final version if for a Hiller HTE-2 (the designation given by the British Royal Navy) with No. 705 Squadron of the Fleet Air Arm. It is painted in a scheme of insignia yellow with black rotor blades.

Conclusion

This is a detailed kit for fairly experienced modelers, given the need for scratchbuilding a number of critical parts. Highly recommended for its historical interest.

References

https://airvectors.net/
https://aviastar.org/