It took less than ten seconds for the 19-ton Curtiss-Wright Transport to leave the ground once the locks were pulled to start its maiden ight. This is but one of the many pertinent results that came out of the ship's first test flight. It isn't every day of the year that its possible to look into the report of such a flight test and the following paragraphs taken from the Curtiss-Wright report are aimed at giving a summarized picture of what went on while the transport was put through its paces.
Eddie Allen has been in charge of the flight testing being assisted by Dean Smith and Willis Wells of Curtiss-Wright's St Louis plant.
"The new airliner, technically nown as the CW-20, was loaded to 7,000 pounds gross weight at a CG of 24% of the MAC for the first flight. The wind was 20 mph and the airport (St Louis) pressure altitude was 310 feet. Most of the ests were conducted at 4,000 feet.
"Power used in take-off was 1150 hp per engine, which corresponds to a take-off loading of 11.75 lbs/hp. This is a higher loading than it will maintain when maximum takeoff gross weight and power are later used.
"The flaps were set for take-off at 15°, or about one quarter of their full travel. This angle was decided upon as a result of simulated takeoff tests and seemed to be a comfortable compromise. During the flight the flaps were raised and lowered several times and operated perfectly. Longitudinal trim was practically unaltered when flaps were moved, and the airplane seemed quite as readily controllable with flaps in any position. At one time, with the airplane flying at low speed and power, the flaps were retracted at full retraction rate with practically no loss of altitude. The landing gear and tail wheel were raised a short time after takeoff and lowered just before landing. The retracting mechanism safety latches, and position indicators seemed to act promptly and positively.
"Preliminary tests were made of air control effectiveness and stability. The use of power controls made handling easier, despite the fact that surface tab balances were set in their least effective positions to avoid any possibility of overbalance. The power controls were used during most of the test.
"Tests were made with various rpm and bmep readings. Changes in throttle setting seemed to have but minor effect on longitudinal trim even when flaps were used. With a outside air temperature of 50° F, at no time during the flight and including the takeoff period, did any cylinder head exceed 380° F. Without cowling changes, it now seems perfectly feasible to hold the maximum temperature for cruising to a constant value of 400° F, under any air conditions.
"While the airplane was only maneuvered gently and not flown at high speed, there were no skin wrinkles in evidence and no tendency of any part to vibrate or flutter was noted. No difficulties of any kind were experienced with power plant operation, brake operation, instrument vibration, hydraulic system, electrical system or other units where difficulty is frequently experienced on the first flight."
The new Curtiss-Wright Substratosphere transport is one of the largest airliners to have been built having a wing span of 108', and being 75' long and being 19' 2" in height. Her two 1700-hp Wright Double Row Cyclone engines, equipped with two three-bladed, 15-foot Curtiss Electric, controllable pitch, "full-feathering" propellers, provide her with a cruising [speed] of 210 mph and a maximum speed of 243 mph.
This article was originally published in the May, 1940, issue of Aviation magazine, vol 39, no 5, p 58.
The photo is not credited.