Jetrader - November/December 2010 - 22

aviation history

Douglas & the DC-1.-3
By Bill Bath

Douglas C-39 transport, the military version of the DC-2.

Santa Monica, Calif., 3 July 1933—a twinengine airplane, its streamlined aluminum skin gleaming in the midday sun, was lifting off from Clover Field when not yet 200 feet up there was a pronounced drop in the sound of two Wright Cyclone engines at take-off power. A few seconds later there was silence as the second engine quit. Douglas chief test pilot, Carl Cover, nosed the aircraft over to level ﬂight and the engines started up as if nothing untoward had occurred. Resuming the climb, the engines again quit, and once more Cover nosed over to level ﬂight and the engines restarted; the saw-tooth ﬂight proﬁle continued until 1,500 feet when the pilot slowly turned back toward the runway for a smooth landing. The engines were removed by Wright technicians and for ﬁve days were stripped down, reassembled and tested. They ran perfectly on the test stand with no indication of the problem that caused the engines to shut down. Finally they took a close look at the carburetors and discovered they had been installed back to front so that the ﬂoats shut off the fuel when in a nose-up position. A

respected builder of navy torpedo aircraft, it was Donald Douglas’ ﬁrst commercial airplane, with the DC-1 denoting Douglas Commercial One. It was not the forerunner of the modern piston power airliner—that honor belongs to the Boeing 247 on 22 May 1933 with a record 19 hours, 30 minutes from San Francisco International to Newark, N.J., on its inaugural ﬂight. It was operated by Boeing Air Transport, part of United Aircraft and Transportation Corp. As a result, it originally had the Pratt & Whitney 550 hp Wasp radial engine and a 10-passenger cabin. The ﬁnal “D” version, with a more powerful Wasp engine, still had 10 seats but also had NACA engine cowlings and variable pitch propellers. The main wing spar passed through the cabin at ﬂoor level, requiring passengers and the stewardess to step over it when walking down the aisle. Boeing Air Transport with its Boeing 247D order eventually morphed into United Airlines for a total combined order of 70 aircraft at a unit price of $65,000 and a proviso that no other airline could receive delivery until these had been delivered.

Early Plans for DC-1
Locked out of the order book, Jack Frye, TWA vice president, sent a one-page letter to other airframe and engine manufacturers together with a one-page speciﬁcations sheet for a more competitive airliner. Brieﬂy, it had to be a tri-motored, all-metal airplane; carry 12 passengers 1,060 miles with a 79 percent power setting of 146 mph; and have a top speed of 185 mph and landing speed of 65 mph. More importantly, it had to be capable of taking off safely and climbing under full control on any two of the three engines from all TWA airports (Windslow, Ariz., was the highest at 4,500 feet). Its minimum service ceiling was to be 21,000 feet and 10,000 feet on two engines. Chief Douglas engineer James “Dutch” Kindelberger, (of “P-51 Mustang fame,” Jetrader August 2007), knowing that both Pratt & Whitney and Wright-Aeronautical had more powerful engines under development, concluded that the new design had to be a twin-engine aircraft. His assistant Arthur Raymond proposed they use the strong multicellular structure wing design

22 The ofﬁcial publication of the International Society of Transport Aircraft Trading

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