UH-1N
Bell flew the first twin-engined Huey in April 1965, calling it the Model 208. It was powered by two Continental Motors engines. The Canadian government provided the incentive for Bell to continue development of the Twin Huey using Pratt & Whitney Canada PT6 engines. The project attracted orders from the Canadian Forces, US Marine Corps, US Navy and USAF, but not the US Army.
The new aircraft was designated UH-1N Iroquois in US service and CUH-1N Twin Huey in Canadian Forces use. The Canadian designation was later changed to CH-135 Twin Huey. There was an HH-1N version produced for the USAF as a base rescue helicopter and for use by the 20th Special Operations Squadron in the counter-insurgency role using the call sign Green Hornet. Some Marine Corps UH-1Ns were converted to VH-1Ns as VIP transports, including six for Presidential use.
The UH-1N was widely produced and exported to a large number of countries and license-built by Agusta in Italy. Bell certified a civil version as the Model 212 in October 1970.
Read more about this topic: Bell UH-1 Iroquois Variants