Changes

== Development ==

== Development ==

Earlier helicopters such as the Sikorsky R-4 and the Bell 47 had used piston engines. By the early 1950s turbine engines were being used in fixed wing aircraft and a turbine engine that could turn it's trust into shaft power had been developed, called the turboshaft engine.A major advantage to using a turboshaft engine in a helicopter is that they have a higher power to weight ratio, provide more power for the equivalent size and require less maintenence. the first bell helicopter to use a turboshaft engine was a modifyed version if the Bell 47, designated the XH-13F and first flown in October 1954.

Earlier helicopters such as the Sikorsky R-4 and the Bell 47 had used piston engines. By the early 1950s turbine engines were being used in fixed wing aircraft and a turbine engine that could turn it's trust into shaft power had been developed, called the turboshaft engine. A major advantage to using a turboshaft engine in a helicopter is that they have a higher power to weight ratio, provide more power for the equivalent size and require less maintenance. the first bell helicopter to use a turboshaft engine was a modified version if the Bell 47, designated the XH-13F and first flown in October 1954.