On the Way to the Jet Age

«To put your life in danger from time to time. . . breeds a saneness in dealing with day-to-day trivialities, w

Nevil Shute, Slide Rule: The Autobiography of an Engineer

he last of the big airliners mounting recipro­cating engines on their wings were stretched versions of the airliners that had gone before. The DC-6 and the DC-7 were from the DC-4 model with various refinements to go along with the increase in length, breadth, and power. The Super Constellation was 19 feet longer than the original. With increased length came additional seating and with more seating came more revenue. Range was extended so that nonstop service was possible— not only coast-to-coast but transatlantic.

The DC-6 was launched in coast-to-coast service on April 27, 1947, with one stop en route for fuel. United advertised its service as ten hours total. (See Figure 19-1.) TWA’s Constellations could do about the same, advertised as ten hours, ten minutes.

Boeing, a late entry to the new postwar aircraft building party, in 1948 introduced the double-decked B-377 Stratocruiser, a four – engine landplane larger than either the DC-6 or

Constellation and designed with an emphasis on luxury reminiscent of the Pan Am Clippers. The airplane featured two decks with a cock­tail lounge with leather seating located below, accessible by a curved stairway, and with a honeymoon suite in the aft section. Take off per­formance in the Stratocruiser was marginal, with the DC-6 routinely outperforming it, but it was bigger and faster at 340 miles per hour than any other airliner. It was also expensive, costing over $1.5 million, and its high operation costs did not help matters. It had engine problems (the P&W Wasp Major had 112 spark plugs in 28 cylinders and delivered 3,500 horsepower) and the propel­lers had a tendency to go flying off on their own. Still, these airplanes were the ultimate in passen­ger comfort. New York to London was a pleasant affair of 12 hours duration, including cocktails, a five-course dinner, a good night’s sleep, and plenty of attention. But the Stratocruiser had the worst safety record of the postwar big planes; six were involved in fatal crashes with the loss of 108 passengers and 28 crew. United unloaded their Stratocruisers early; Northwest kept theirs for years. In the end, the airlines seemed glad to see them go. Figure 19-2 pictures the Boeing 377, the Constellation 049, and the DC-4.

The DC-7 proved to be the first true trans­atlantic airplane, flying either west or east with a full load. With it, Pan American regained its leadership position over TWA, which was flying the Super Constellation. The DC-7 had engines that were reaching the limits of reciprocating – engine power possibilities. With four Wright turbo-compound engines providing 3,250 horse­power, each weighing over 3,500 pounds, engine maintenance was a problem; American Airlines reported 10 engine failures a day on average. Westbound DC-7 service to the Pacific coast was advertised as nonstop, but with headwinds the advertised flying time of seven and one-half hours was often missed. Eastbound, American was able to adhere to its scheduled arrivals. The DC-7 made the first nonstop transatlantic cross­ing in 1957.

But the strain was showing; the limits of the reciprocating engine had been reached. It was time for the jet age.