AIR & SPACE MAGAZINE

The Cult of the Sonic Cruiser

The airliner that never took off.

September 2015

For nearly two years, from five months before the 9/11 attacks until 15 months afterward, Boeing appeared to be convinced that the classic engines-under-sweptback-wing airliner shape, which it had invented in the early 1950s, was old hat. Instead, Boeing relentlessly incanted the praises of the Sonic Cruiser, a tail-first airplane with two vertical fins and a cranked-delta wing. It would fly at Mach 0.98, 15 percent faster than most jets but only half as fast as Concorde.

Before it was announced, on March 29, 2001, only a few potential customers knew about the Sonic Cruiser, and they had been sworn to silence. Boeing stalled media requests for briefings until the Paris airshow in June, where all would be revealed.

Or not. The Paris event was more revival than briefing. Futurologist John Naisbitt led with a 25-minute sermon. Naisbitt had just sold his houses in Telluride, Colorado, and Cambridge, Massachusetts, and moved to a flat in Vienna. He had visited a German beerhouse in Seoul. “We are living in the time of the parenthesis, a great and yeasty time,” he concluded. “Make uncertainty your friend.”

I barely had time to wonder what the bleeping bleep that “yeasty” bleep had to do with aviation when Alan Mulally, Boeing’s commercial airplanes boss, launched into some holy-rolling tub-thumping: “Can it be done? Absolutely! Can we do it economically? Absolutely! Is it the right thing to do for the travelers of the world? Absolutely!”

On its face, the Sonic Cruiser was a dumber-than-dirt idea. The industry’s shared, consistent experience of supersonic flight was that you did not want to cruise at Mach 0.98; cruising at a faster speed would actually reduce drag. Boeing knew this, and admitted that the Sonic Cruiser would need to have bigger engines and burn more fuel than a classic subsonic jet, but the company argued that passengers would pay the premium fare necessary. How much more would they pay? No one knew. Boeing had done no studies or surveys, because that would have blown the secret project’s cover.

Boeing had been having a tough few years. It had spent most of 2000 pushing warmed-over versions of the 767 and 747, with no success, and was losing ground to Airbus. It seemed to me that Sonic Cruiser was either a desperate gamble or a public diversion. But the irrepressible Mulally would not be stopped. In July he told unions that it was “a 100 percent go.”

The story got weirder. In an online NASA presentation from late 2000, I found a Boeing design that looked exactly like the Sonic Cruiser, except it was skinnier, sharp-nosed, and described as a supersonic transport. Chief engineer Walt Gillette dismissed the resemblance as superficial, but his boss’ boss, Boeing president Harry Stonecipher, had a dangerous habit of saying what he was actually thinking. Designing the Sonic Cruiser as though it were a faster-than-sound aircraft “was the secret to coming up with something that we liked,” he told me. “Before, everybody tried to take a subsonic aircraft and speed it up, and ran into all sorts of trouble.”

This was an era when U.S.-Russia relations were happy, and in the late 1990s Boeing was working with Sukhoi on a supersonic business jet. The Sonic Cruiser’s supersonic ancestor never got a designation and looked nothing like any prior U.S. design, but with its aft-set, compound-sweep wing, it looked a good deal like Sukhoi’s supercruisers, descended from the company’s T-4 supersonic bomber. The airplane that was supposed to save the U.S. industry’s bacon had more Russian DNA than a Romanov family reunion.

“Don’t believe everything you read in the newspaper,” Gillette told Boeing’s own magazine in July 2002. “We are talking with very senior people at the airlines, and there is a lot of interest.”

I didn’t believe the newspapers, but I did set a lot of store by the views of Airbus’ marketing guru, Adam Brown, who had told me five months earlier that he had written the Sonic Cruiser off completely. Post-9/11, the airlines lost interest in speed; they cared about nothing except operating cost. Brown was proven right in December, and in the following month Boeing started talking about the new, 0.85-Mach 7-“E for effiency”-7. Today, that’s called the 787.