UH-1E
In 1962 the US Marines held a competition to choose a new assault support helicopter to replace the Cessna O-1 and Kaman OH-43D helicopter. The winner was the UH-1B which was already then in service with the US Army.
The UH-1B was developed into a special model, designated UH-1E, to meet Marine Corps requirements. The major changes included the use of all-aluminum construction for corrosion resistance (earlier UH-1s had some magnesium components), special avionics that were compatible with Marine Corps ground frequencies, a rotor brake to stop the rotor quickly on shutdown for shipboard use and a roof-mounted rescue hoist.
The UH-1E was first flown on 7 October 1963 and deliveries commenced 21 February 1964, with 192 aircraft completed. Due to production line realities at Bell the UH-1E was produced in two different versions, both with the same UH-1E designation. The first 34 built were essentially UH-1B airframes with the Lycoming T53-L-11 of 1,100 shp (820 kW). Because Bell was switching Army production to the UH-1C the UH-1E production line was converted to commonality with the “C”. This meant the later “Echo” Hueys were completed with the “Charlie” style tailboom including the larger fin, the 540 rotor system and a gross weight of 8,500 lb (3,900 kg).
The Marines used the UH-1E as both a gunship and troop transport. Many were upgraded to the Lycoming T53-L-13 engine which produced 1,400 shp (1,000 kW), making these “Echos” similar to the Army “Mike” models. At least 126 UH-1Es survived their Vietnam service and were still in use more than a decade later.
There was a Marine Corps training version of the UH-1E, which was based on the UH-1C variant and was designated TH-1E. Twenty were delivered in 1965.
Read more about this topic: Bell UH-1 Iroquois Variants