The Sikorsky S-64 was designed as an enlarged version of the prototype flying crane helicopter, the Sikorsky S-60. The S-64 had a six-blade main rotor and was powered by two 4,050 shaft horsepower (3,020 kW) Pratt & Whitney JFTD12A turboshaft engines. The prototype S-64 first flew on 9 May 1962 and was followed by two further examples for evaluation by the German armed forces.[2] The Germans did not place an order, but the United States Army placed an initial order for six S-64A helicopters (with the designation YCH-54A Tarhe). Seven S-64E variants were built by Sikorsky for the civil market. Originally a Sikorsky Aircraft product, the type certificate and manufacturing rights were purchased from them by Erickson Air-Crane in 1992. Since that time, Erickson Air-Crane has become the manufacturer and world's largest operator of S-64 Aircranes and has made over 1,350 changes to the airframe, instrumentation, and payload capabilities of the helicopter. The Aircrane can be fitted with a 2,650-gallon (~10,000 liter) fixed retardant tank to assist in the control of bush fires, and it has proven itself admirably in this role. The helicopter is capable of refilling 10,000 liters of water in 45 seconds from a water slide of only 18 inches or 46 cm thick. Erickson gives each of its S-64s an individual name, the best-known being "Elvis", used in fighting fires in Australia alongside "The Incredible Hulk", "Delilah" and "Isabelle". Other operators, such as Siller Brothers, have followed with their Sikorsky S-64E, Andy's Pride. The models which operate in Australia each summer are E and F models. The easiest way to determine which is which, the E model has a single wheel on each main undercarriage leg, while the F model has dual wheels. Specifications below are for the Model E. Model E "Delilah" Model F "Elvis" Model F "Isabelle"
