Airlines and the Jet Age

In the 1930s, the NACA had conducted research on engine cowlings that improved cooling while reducing drag. This led to improvements in air­liner speed and economy, which in turn led to increased capacity and more acceptance by the traveling public; airliners were as fast as the fighters of the early Depression era. In World War II, the NACA shifted research focus to military needs, the most challenging being the turbojet,
and almost doubled potential top speeds. In civil aviation, postwar propeller-driven airliners could span the continent and the oceans, but at 300 mph. Initial attempts to install turbojets in straight winged airliners failed because of the fuel inefficiency of the jets and the increased drag at jet speeds; the loss of life in the mysterious crashes of three British jet-propelled Comets did not instill confidence. Practical airliners had to wait for more efficient engines and a better understanding of high subsonic speeds at high altitudes. NACA aeronautical research of the early 1950s helped provide the latter; the drive toward higher speed in military aircraft provided the impetus for the engine improvements. Boeing’s business gamble in funding the 367-80 demonstrator, which first flew in 1954, triggered the avalanche of jet airliner designs. Airlines began to buy the prospective aircraft by the dozens; because the Civil Aeronautics Board (CAB) mandated all ticket prices in the United States, an airline could not afford to be left behind if its competitors offered travel time significantly less than its propeller-driven fleet. Once passen­gers were exposed to the low vibration and noise levels of the turbine powerplants, compared to the dozens of reciprocating cylinders of the piston engines banging away combined with multiple noisy propellers, the outcome was further cemented. By the mid 1950s, the jet revolu­tion was imminent in the civil aviation world.

In late 1958, commercial transcontinental and transatlantic jet ser­vice began out of New York City, but it was not an easy start. Turbojet noise to ground bystanders during takeoff and landings was not a con­cern to the military; it was to the New York City airport authorities. "Organ pipe” sound suppressors were mandated, which reduced engine performance and cost the airlines money; even with them, special flight procedures were required to minimize residential noise footprints, requiring numerous flight demonstrations and even weight limitations for takeoffs. The 707 was larger than the newly redesigned British Comet and hence noisier; final approval to operate the 707 from Idlewild was given at the last minute, and the delay helped give the British aircraft "bragging rights” on transatlantic jet service.[1063]

Other jet characteristics were also a concern to operators and air traffic control (ATC) alike. Higher jet speeds would give the pilots less time to avoid potential collisions if they relied on visual detection alone. A high-profile midair collision between a DC-7 and Constellation over the Grand Canyon in 1956 highlighted this problem. Onboard colli­sion warning systems using either radar or infrared had been in devel­opment since 1954, but no choice had been made for mandatory use. Long-distance jet operations were fuel critical; early jet transatlantic flights frequently had to make unplanned landings en route to refuel. Jets could not endure lengthy waits in holding patterns; hence, ATC had to plan on integrating increasingly dense traffic around popular desti­nations, with some of the traffic traveling at significantly higher speeds and potentially requiring priority. A common solution to the traffic problems was to provide ground radar coverage across the country and to better automate the ATC sequencing of flight traffic. This was being introduced as the jet airliner was introduced; a no-survivors midair col­lision between a United Airlines DC-8 jetliner and a Constellation, this time over Staten Island, NY, was widely televised and emphasized the importance of ATC modernization.11

NACA research by Richard Whitcomb that led to the area rule had been used by Convair in reducing drag on the F-102 so it would go supersonic. It was also used to make the B-58 design more efficient so that it had a significant range at Mach 2, propelled by four afterburn­ing General Electric J79 turbojets. Convair had been busy with these military projects and was late in the jet airliner market. It decided that a smaller, medium-range airliner could carve out a niche. An initial design appeared as the Convair 880 but did not attract much interest. The decision was made to develop a larger aircraft, the Convair 990, which employed non-afterburning J79s with an added aft fan to reap the developing turbofan engines’ advantages of increased fuel efficiency and decreased sideline noise. Furthermore, the aircraft would employ Whitcomb’s area rule concepts (including so-called shock bodies on its [1064]

wings, something it shared with the Soviet Union’s Tupolev bombers) to allow it to efficiently cruise some 60-80 mph faster than the 707 and the DC-8, leading to a timesavings on long-haul routes. The aircraft had a higher cruise speed and some limited success in the marketplace, but the military-derived engine had poor fuel economics even with a fan and without an afterburner, was still very noisy, and generated enough black smoke on approach that casual observers often thought the aircraft was on fire (something it shared with its military counterpart, which gen­erated so much smoke that McDonnell F-4 Phantoms often had their position given away by an accusing finger of sooty smoke). The poten­tial trip timesavings was not adequate to compensate for those short­comings. The lesson the airline industry learned was that, in an age of regulated common airline ticket prices, any speed increase would have to be sufficiently great to produce a significant timesavings and justify a ticket surcharge. The latter was a double-edged sword, because one might lose market share to non-high-speed competitors.[1065]