The Boeing 707 is usually seen as having been the catalyst for the ‘jet age.’ This basic narrow-body quadjet was the American producer’s first jet airliner. The 707 helped convey air journey to the plenty following its launch within the late-1950s, and was recognized for its long-range capabilities. Nonetheless, a shorter-range variant was additionally developed, promoting over 150 models: the lesser-known Boeing 720.
The start of the jet age
The world’s first jet airliner was the De Havilland Comet, which first flew commercially in 1952. Nonetheless, it was not till the top of this decade that jetliners skilled widespread reputation. Certainly, the identical could be stated of economic aviation itself. On the finish of the 1950s, two American quadjet airliners had been launched that might go on to revolutionize the airline business, each technologically and socially. These had been the Boeing 707 and the Douglas DC-8.
Pan Am launched the 707 commercially in October 1958. Delta and United did the honors for the DC-Eight lower than a yr later, in September 1959. The 2 plane marked the arrival of widespread business air journey, significantly within the long-haul market. It’s no coincidence that 1958 was the primary yr that extra transatlantic passengers flew than took the boat.
Evaluating the Boeing 707 and Douglas DC-8
When it comes to specs, there was not a lot to separate the 2 plane. Each sorts had 4 Pratt & Whitney JT3D turbofan engines, and a capability of 140-150 passengers (relying on the precise configuration). Nonetheless, evaluating the 707-4320B and DC-8-62 models, the 707 simply had the sting by way of cruising pace (607mph / 977km/h vs. 578mph / 930km/h). It additionally benefitted from an extended operational vary (9,900km / 5,350 NM vs. 9,650km / 5,200 NM).
Nonetheless, the story by way of the 2 airliners’ business success has a larger distinction. Whereas Boeing offered 1,010 707s, Douglas might solely shift simply over half of this determine, promoting a complete of 556 models. Amongst Boeing’s 1,010 707s had been 154 examples of a shorter variant – this was often called the Boeing 720.
The Boeing 720
The Boeing 720 is, up to now, the corporate’s solely passenger jetliner that doesn’t comply with the ‘7×7’ naming pattern. Boeing designed the 720 as a lighter model of the 707, which might enable it to supply larger versatility by way of serving airports with shorter runways.
It was round 2.7 meters (9 ft) shorter than the unique 707-120, with a considerably decreased vary. The unique 720 had a variety of 5,200 km (2,800 NM), utilizing Pratt & Whitney JT3C turbofan engines. Nonetheless, a later variant, often called the 720B, might fly barely additional following the implementation of improved JT3D engines. The plane had a two-class capability of 131-137 passengers, or 156 in a one-class configuration.
Profitable regardless of decrease gross sales
Though the 154 720s that Boeing offered solely represented round 15% of complete 707 gross sales, the sort nonetheless proved worthwhile for Boeing. The rationale for this was that, as a spinoff of an present plane reasonably than a brand new mission altogether, it had comparatively low improvement prices. Following its business launch with United in July 1960, the 720 loved a service life that spanned greater than half a century.
Throughout this time, the 720 was greater than only a passenger airliner. For instance, 1984 noticed a 720 partake within the FAA and NASA’s ‘Controlled Impact Demonstration’ program. On this take a look at, a remote-controlled 720 was intentionally crashed to check security expertise comparable to fire-retardant gas.
Engine producer Pratt & Whitney Canada operated the ultimate 720 as a testbed plane. This made its ultimate flight in September 2010, bringing greater than 50 years of various service to an finish for the sort. PWC changed the 720 with a 747SP – as a shortened variant, that is to the 747 what the 720 was to the 707. Two years later, the previous PWC 720 flew to Trenton, Ontario, the place it could be displayed on the Nationwide Air Pressure Museum of Canada. A number of different examples of the 720 have additionally been preserved around the globe.