What the shape of Boeing’s 7J7 tells us about the 797

Back in the 1980s, Boeing found a small twin-aisle aircraft offers some unexpected benefits.

The sixth in a series focusing on Boeing’s road to developing its next all-new commercial airplane.

As it pondered a response to the arrival of the Airbus A320 and revamped MD-80, Boeing considered a radical departure from the shape of its airliners. In the mid-1980s it was searching for a 150-seat successor for the 737, it gave serious consideration to the 7J7, an aircraft powered by two tail-mounted unducted fan engines and filled to the brim with advanced technology for its day. Boeing would eventually soften on the effort in late 1987, shelving the development in favor of the Next Generation 737 five years later. The 7J7’s bears few technical attributes in common with Boeing’s coming 7K7 New Mid-Market Airplane (NMA), but its alphabetical predecessor shares a contemporary lesson for designs separated by three decades.

As aircraft get stretched for added capacity or crammed with more passengers traveling with more carry-on luggage, turnaround times have slowed. In 2001, Boeing estimated that since 1970 boarding times have risen by 50%, to as low as nine passengers a minute. And that was before ancillary bag fees further increased the number of passengers hauling bags aboard.

Related: Boeing’s quest for NMA steers it away from its history

As it fine tuned the 7J7, Boeing paid particular attention to the speed with which it could get passengers on and off the aircraft, comparing the relative benefits of a single or twin-aisle design. In the late fall of 1985, Boeing enlisted 371 people to test the boarding and deplaning speeds with different cabin layouts, according to historical product development studies reviewed by The Air Current. The company timed passenger flows, varying the amount of luggage brought aboard, the size of the aisle, entry door width and most importantly, the number of aisles.

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