Bell's "Huey" Helicopter, officially known as the Model 204, formed the basis for one of the most successful series of helicopters ever built.  Flown for the first time in October 1956, it was designated the XH-40, then HU-1 by the US Army (who called it the Huey), before a designation change to the HU-1A Iroquis.  The HU-1B introduced a more powerful engine and the HU-1C had a new rotor system.  Later still teh HU- designation was changed to UH-.

The turbine engine was one of the keys to the Huey's success. Mounted on the cabin roof just behind the gearbox, it left the cabin unecumberd and provided the performance required by the US Army.  The engine was upgraded to a 1100HP engine that became standard.  The larger engined allowed for the helicopter to be armed with rocket pods and machine guns carried on the cabin's sides.

The UH-1C, which flew in 1965, used a new rotor system with 'door hinges' and wider blades.  This provided more lift, enabliing the fuel load to be increased and improving the machine's manuervability and speed.  Variants fo the UH-1C wer used by the US Air Force, Navy and Marine Corps in the training, rescue and assault roles.

Bell UH-1C "Huey" Helicopter

Type:	Single -engined mulit-role utility helicopter
Poweplant:	one 1100-hp Lycoming T53 turboshaft engine
Maximum Speed:	148mph (238 km/h) at sea level
Initial Climb Rate:	1400 fpm (427 m/min)
Range:	381 miles (515 km) with auxiliary fuel
Service Ceiling:	11,500ft (3505 m)
Weights:	5060 lbs (2300 kg) empty; Maximum Takeoff 9480 lbs (4309 kg)
Dimensions:	Rotor Diameter:  44ft (13.41 m) Length:   42ft 7in (12.98 m) Height:  12ft 7in (3.84 m) Rotor Disc Area: 1520 sq ft (141.26 m2)