The Cadillac of the Constellation Line

Through the 1950s Douglas and Lockheed engaged in a rivalry to create the ultimate propliner as each company successively improved its product line to appeal to the rapidly expanding passenger market. Douglas' DC-6 led to the more powerful DC-7 and even with this aircraft, the design was pushed even further with the DC-7C. In addition to more power and fuselage stretch, the "Seven Seas" also had a constant-chord wing-root section added inboard of the engines. Not only did this move the loud radials five feet further away from the passenger cabin, it also increased the aspect ratio of the wing, reduced drag, and provided more space for internal fuel. The DC-7C could now outperform Lockheed's flagship propliner, the L-1049G Super Constellation, in terms of speed, range, and payload, allowing all-year round nonstop trans-Atlantic service. Not to be outdone, Lockheed briefly considered a turboprop Constellation, the L-1449, using the new Pratt & Whitney T34 engine (which was used on the Douglas C-133 Cargomaster). While military Constellations did flight test both the T34 installation and the Allison 501 turboprop (military versions of which were used on the C-130 Hercules and P-3 Orion), Pratt & Whitney balked at the use of the T34 as they felt Lockheed was pushing the engine too far. 

Scrapping the L-1449 out of the dispute with Pratt & Whitney, Lockheed took the new wing design it had developed for the turboprop L-1449 and grafted it on a stretched L-1049 Super Constellation fuselage to give birth to what many consider to be one of the ultimate piston engine airliners, the L-1649 Starliner. The wing was modified to accept the powerful Wright R-3350-18EA Turbo Compound radial engines which were originally developed to power the Navy's Lockheed P-2 Neptune patrol bomber. The 18-cylinder R-3350 instead of using a turbocharger for high altitude performance had power recovery turbines instead (PRTs)- one PRT collected the exhaust gases from six cylinders to deliver more power back to the engine crankshaft, providing a 500 horsepower boost. The same engines were used on the DC-7C as well. The long wing of the Starliner gave it the highest aspect ratio wing of any propliner, 12:1, and this translated to improved performance over the DC-7C. Nearly 2,000 gallons more of fuel could be carried compared to the Super Constellation. Like the DC-7C, the longer wing put the inboard engine nacelles further away from the passenger cabin. 

The Starliner made its first flight from Burbank on 10 October 1956. Amazingly, only three Starliners were used for a short 251-hour flight test program to get airworthiness approval on 19 March 1957. With a cost of $3 million per aircraft, TWA inaugurated L-1649 Starliner services on 1 June 1957, exactly one year to the day that the Douglas DC-7C was introduced into service. Though the DC-7C was faster, the Starliner had a longer range as well as a quiet and smooth ride thanks to increased sound insulation in the cabin and a flexible wing that dampened inflight turbulence. TWA marketed its Starliners as "Jetstream Starliners" and on marketing artwork, the wingspan of the Starliner was exaggerated to make the engines appear further from the fuselage than they were. In addition, artists cleverly depicted the Starliner without propellers, much to the ire of competing airlines that cried foul over the advertising campaign they called deceptive. TWA's famous inflight Ambassador Service was upgraded for the Starliners. The passenger seats were called "Siesta Sleeper Seats" that had pull out foot rests and a deep seatback recline that were nearly as comfortable as the sleeper berths which of course were still available on the Starliner's long routes. In the lounge area of each Starliner were cabin wall murals created specifically for TWA's aircraft by the artist Mario Zamparelli that showcased TWA's overseas destinations. 

The long range of the L-1649 Starliner allowed TWA to open up polar routes from the US West Coast to Europe. The inaugural TWA polar flight, Polar Flight 801, set a world record for the longest piston engine airliner flight on 2 October 1957 when flying westbound from London to San Francisco, encountered strong headwinds that resulted in a marathon 23-hour 19-minute nonstop flight. As impressive as the capabilities of the Starliner were, only TWA, Air France, and Lufthansa would be first-liner operators as few of the world's airlines had a route network and passenger traffic that made the Starliner economical. The Starliner only flew first line services for less than three years before getting displaced by the Boeing 707 and as a result of coming to market one year later than the Douglas DC-7C, only 44 Starliners were built compared to 121 DC-7Cs. When the final L-1649 Starliner was rolled out of the Burbank factory on 12 February 1958 for Lufthansa, it wasn't just the last Starliner but it was the end of the line for the Constellation family that stretched back to 1943. 

One interesting side note from TWA's operation of the Starliner came about due to reliability issues with the R-3350 Turbo Compound engines. While they were some of the most powerful piston engines ever flown, they were a maintenance nightmare compounded by the intricate plumbing work of the three power recovery turbines. In fact, TWA mechanics joked that PRT actually stood for "Parts Recovery Turbine". To minimize the disruption caused by engine failures, TWA acquired a military surplus Fairchild C-82 Packet transport that had a Westinghouse J34 engine in a dorsal nacelle as a jet booster. Nicknamed "Ontos" (the Greek word for "thing"), the C-82 could carry whole R-3350 Turbo Compound engines and a maintenance team to outlying stations where a Starliner might be stranded. Even though the Starliner would be phased out of TWA service, the airline kept Ontos in service to carry spare jet engines for the Boeing 707 and even the Boeing 747, finally retiring the odd bird in January 1972. 

Source: From Props to Jets: Commercial Aviation's Transition to the Jet Age 1952-1962 by Craig Kodera, Mike Machat, and Jon Proctor. Specialty Press, 2010, p77-85. 

The Holy Grail of Nonstop Transcontinental Service

The growth of US postwar air travel didn't reach a point until the 1950s that justified nonstop transcontinental services even though aircraft theoretically capable of such flights were already in airline use at the end of the Second World War. During the course of the war, Douglas DC-4s and Lockheed Constellations seconded to the US Army Air Forces routinely made trans-Atlantic crossings safely. But the exigencies of war are far removed from market demand and in the second half of the 1940s traffic demand simply wasn't there and what passengers did travel transcontinentally were few in number and used existing multistop services. In fact, many airlines believed that passengers preferred enroute stops to stretch their legs. But more significantly, federal regulations prohibited flights more than 8 hours without a backup crew aboard and to the airlines, that increased labor costs on long distance flights. It was more economical to change crews enroute. Of course, TWA and Pan American operated their trans-Atlantic services with backup crews, but this was a matter of obvious necessity.

As air travel numbers experienced major growth in the early 1950s, American Airlines was the first out of the gate with an announcement that it would begin nonstop transcontinental services between New York and Los Angeles once it had taken delivery of its Douglas DC-7 propliners. Eager to upstage American Airlines and its iconic head, C.R. Smith, Howard Hughes had TWA launch its own transcontinental nonstop service on the same route using its new Lockheed L-1049 Super Constellations. On 19 October 1953, Trans World Airlines' "Ambassador Service" Flight 2 departed Los Angeles for New York Idlewild and just barely got into New York under the federal eight hour crew limit at 7 hours, 55 minutes. The westbound Ambassador Service flight had to deal with prevailing winds at altitude and thus couldn't make the flight nonstop within 8 hours- a 15 minute technical stop was scheduled enroute at Chicago Midway to allow for a crew change but no local passenger traffic.

The following month American Airlines inaugurated its own nonstop "Mercury Service" DC-7 flights between Los Angeles and New York Idlewild on 29 November. As the DC-7 had a higher cruising speed than the Super Constellation, the eastbound LA-New York run was made easily in 7 hours, 15 minutes (a fact not lost upon American's marketing department, hence the name "Mercury Service"), but the westbound run from New York to LA couldn't be made within 8 hours. Despite over a dozen modifications to the DC-7s made by American's engineers which included tweaks of the Wright R-3350 radial engines to squeeze every bit of horsepower out of the engines, the DC-7s still couldn't beat the prevailing winds. American's pilot union repeatedly pointed this fact out, but C.R. Smith's influence in Washington left the issue unaddressed by federal regulators. In the following year, federal regulators adjusted the time limit to allow the flight to be made legally and American's DC-7s blocked in at 8 hours, 15 minutes on a westbound nonstop.

Although TWA had reached an agreement with its Super Constellation pilots for overtime pay on the westbound nonstops to eliminate the technical stop for a crew change in Chicago, no such agreement existed with American and following deadlocked negotiations, American's pilots striked on 31 July 1954. C.R. Smith was furious but had no choice to accept an agreement for overtime pay on the westbound Mercury nonstops that exceeded 8 hours. After a punishing 24-day strike, American's pilots returned to work under new rules for transcontinental flights in excess of 8 hours.

Arriving late to the transcontinental battle was United Air Lines. United took delivery of its DC-7s six months after American Airlines but didn't inaugurate nonstop services until 1 June 1954 on it's "Red Carpet" services between San Francisco and New York Idlewild. United's nonstops were eastbound only and rather unusually, westbound nonstops weren't added by the airline until 1955, nearly a year later after the Red Carpet services started.

It should be noted, though, that although these services were operated by Lockheed Super Constellations and Douglas DC-7s, on 3 February 1948 TWA inadvertently operated the first eastbound nonstop when TWA Flight 12, operated by a Lockheed L-049 Constellation, had its regular stops in Kansas City and Chicago Midway canceled due to winter weather and the flight had to continue on to New York, arriving after covering 2,470 miles in 6 hours, 55 minutes.

Source: From Props to Jets: Commercial Aviation's Transition to the Jet Age 1952-1962 by Craig Kodera, Mike Machat, and Jon Proctor. Specialty Press, 2010, p46-47.

Scandanavian Airlines System Pioneers Polar Commercial Routes

Only seven weeks after being established on 1 August 1946, Scandinavian Airlines System (SAS) inaugurated its first long-haul services across the Atlantic with Douglas DC-4s from Stockholm to New York La Guardia via Copenhagen, Prestwick, and Gander for a flying time of 25 hours. The New York services quickly become profitable for SAS and despite an expansion of its international network to South America and Asia in the years that followed, the US market remained SAS's most profitable overseas destination. Wishing to expand its network to the US West Coast (San Francisco and Los Angeles), SAS didn't want to put its DC-4s on a long transcontinental run across the United States after a trans-Atlantic crossing.

Route planners decided the best "short cut" was a polar flight on the Great Circle Route from Scandinavia to California. But it was 1947 and the most advanced aircraft in the SAS fleet, the Douglas DC-4, didn't have the range. Even more problematic, no airline had ever operated in the polar regions, so in that year SAS set out on a series of trial flights to gain polar operating experience as well as refine polar navigational techniques. Since magnetic compasses didn't work in the regions around the North Magnetic Pole, SAS worked with US avionics manufacturer Bendix to create a precision gyro compass to replace the traditional magnetic compass. During the summer months, the sun would prevent use of a sextant for stellar navigation, so the airline worked with another US avionics company to develop a solar compass that used polarized light to determine the direction of the sun. The airline also developed its own polar charts that laid down a grid over the polar region with the Greenwich meridian as the starting point.

Having created the navigational aids, SAS then set about establishing radio stations across Norway, Greenland and Northern Canada since the only existing radio stations in the region were for military use only. In 1952 sixty trial flights were conducted using the new Douglas DC-6 between Copenhagen and Sondre Stromfjord in Greenland. In December of that year SAS took delivery of its first long-range DC-6B in Long Beach, christened "Arild Viking" and flew it from Long Beach to Copenhagen via Edmonton and Thule. The trip took 28 hours and was the first commercial flight over the Arctic.

With all the pieces in place, all that awaited were route authorities from the United States. The first rights granted were only to Seattle, but persistence on the part of the Los Angeles Chamber of Commerce gained SAS its prized rights to that city. Specially provisioned with Arctic survival equipment, the SAS DC-6B "Helge Viking" departed Copenhagen for Los Angeles on 15 November 1954 via Sondre Stromfjord and Winnipeg. Taking off from Los Angeles and headed in the opposite direction was the DC-6B "Leif Viking".

On 24 February 1957 SAS made its first flight over the North Pole with services between Copenhagen and Tokyo via Anchorage, saving 18 hours and 2,400 miles over previous routings that passed via the Mediterranean and South Asia. That same year, SAS introduced the Douglas DC-7C on its polar routes and the flying time between Copenhagen and Tokyo was cut from 50 hours to 32 hours. By this time, however, SAS's monopoly on the polar routes was over as Canadian Pacific, TWA, Pan American, and BOAC introduced services using the "short cut" over the Arctic region.

Pure jets were introduced by SAS on the polar routes with the Douglas DC-8-33 in 1960, then the DC-8-62 in 1967 and the DC-8-63 in 1968. In 1974, widebody service arrived on SAS polar services with the introduction of the Douglas DC-10. With the liberalization of travel markets, deregulation in the United States, the end of the Cold War (which opened up Russian airspace) and open skies agreements, the polar routes have diminished in importance for SAS but there is still nonstop service between Copenhagen and Tokyo taking only 11 hours.

Source: Aircraft, January 2010, Vol. 43, No. 1. "Polar Pioneers- How SAS pioneered airline services over the inhospitable polar regions" by Roy Allen, p62-66.