Hiper DC-3
The conversion from a standard DC-3 using P&W R-1830s to Hiper DC-3 sporting P&W R-2000s was engineered and performed by an outfit in Alabama called HAYES Aviation in the 1950s. The first Hiper DC-3s coming out from Hayes were owned by PANAGRA Airways N49550, N28335 and N54311 and operated mainly out of the Quito, Ecuador Int. airport at 9,200 ft AMSL and there was a marked improvement in engine-out operation. Avianca also ordered some of these conversions in the 1950s and little known the USAF also had several Hiper C-47 Puffin Dragons and EC-47s operating in Viet Nam. The most tell-tale characteristic was an extension of the crankshaft some 10" long.