By: Norm Goyer
The Douglas DF was manufactured in 1936 and 1937. Many of the wing, engine and tail parts were from the Douglas DC-2.
The year 2010 marks the 75th Anniversary of the Douglas DC-3, the aircraft that helped establish the airline industry as we know it today. World War II saw the same airplane with a new suit of camouflage clothes setting the benchmark for military twin-engine “fitzall” transports, The proud old girl is still earning her keep, what a great American airplane.
Before the DC-3 established her reign, there was the DC-2, the starting point for the infant airline industry. Douglas knew they had an outstanding wing and engine combo, a great tail design and a plan form that could be used to continue the line of famous Douglas seaplanes and flying boats. Douglas engineers took these elements and added a boat-shaped fuselage, no landing gear, and the DF series of airframes were developed. The first two airframes were labeled DF-151 (Douglas model number) and were promptly sold to Japan. They wanted to clone the latest American manufacturing methods. And indeed they did, Japan used these two DFs for both military and civilian transport after they did a bit of reverse engineering. The two were flown to Japan via the Bering Straits. The second pair of DF-195s, exact same airframe, were sold to Russia who needed dependable water based aircraft along their remote seaports. The two Russian Douglas airframes were disassembled and transported to Russia via ship. It is not known if any of the four airframes are still in existence, however, it is highly doubtful.
Douglas believed that there was a market for the DF, replacing obsolete four-engine seaplanes. The first two were sold to Japan.
Douglas only built four airframes; they didn’t really push the design because of their huge backorder for DC-3 transports. They also knew the era of Clipper type flying boats was grinding to an end. Airports were rapidly being constructed which had the strength and length to handle the four-engine transports which were on the design boards of almost every large company. Douglas engineers were working on the DC-4, Lockheed on the Constellation and Boeing on the Stratoliner. Douglas also knew that Consolidated had a far better twin engine military seaplane which had been designed just for search and rescue. Yes, we are talking about the outstanding Consolidated PBY series of Catalina twin engine seaplanes and flying boats. Some were built as only capable of operating from the water while others were amphibious (had retractable landing gear). So the rugged, great flying twin engine Douglas Flying Boat was discontinued. It was the last seaplane of any kind built by Douglas.
The second two DF 151s (DF-195) were sold to Russia who used them for many years.
But what had convinced Douglas engineers and the marketing department that there was indeed a market for a flying boat version of their great selling DC-2 transport design? It was Pan American Airways who also owned majority interests in a number of foreign airlines. Douglas viewed the airline as being a possible operator of a new series of aircraft, namely the new Douglas DF-151. It seems that Pan American had become the second customer for the Douglas DC-2 and had also bought two Dolphin amphibians for operation by a subsidiary. Douglas engineers reasoned that a large and efficient flying boat airliner could be built; the obvious customer was Pan American. The first studies were started in 1935, and the project was given the designation of DF for Douglas Flying boat. The new aircraft would allow the airline to retire their earlier flying boats yet still offer an airplane which had the capability of their four-engine aircraft with an even longer range. And, the fact that two engines are cheaper to operate than four was stressed by Douglas.
Poor sales and an increased military market caused Douglas to cease production. This was the last seaplane ever built by Douglas.
Specifications:
Span 95 ft 0 in
Length 69 ft 10.56 in
Height: 24 ft 6.25 in
Wing area: 1,295 sq.ft
Weight empty: 17,315 lb
Max T/O weight: 28,500 lb
Max speed: 178 mph at 6,800 ft
Cruise speed: 160 mph
Service ceiling: 9,842 ft
Initial climb: 800 ft
Range 1,500 miles