I've just found these you-tube videos featuring a Hyper DC-3 with the R-2000 engines ( DC4) you can clearly see the slightly longer prop-shaft and different shape air intake.
https://www.youtube.com/watch?v=_-NAFZtBDM0
https://www.youtube.com/watch?v=jM9P10ECqoA
You hear very little about the
Hiper DC3 not to be confused with the Super DC3 with a different wing, tail and wheel spats.
Any Pruners out there that may have flown the Hiper or can provide details? Happpy to hear from you.
I know that Avianca operated Hipers in Colombia, which I believe were fitted with DC4 engines, but otherwise do not know in what other features it differed from the standard version. These planes were faster and presumably, because of the extra power, better suited to Colombia's rugged terrain and weather than the stock DC3.
Avianca lost many DC3s during the 50s and 60s quite a few with hired American pilots falling foul to notorious weather and high ground. Ernest Gann, in his book
Fate is the Hunter, gives a poignant long list of airmen that met with such fate at a time when aviation was still young.