Entrepreneurship

5 Things You Likely Never Knew About Boeing’s 747

Last Saturday marked the 50th anniversary of the 747 jumbo jet era; back when Pan Am ferried American tourists to and from Europe and iPhones were still just a twinkle in Steve Jobs’ eye. But Boeing’s big gamble on the world’s first twin-aisle commercial aircraft not only went on to pay off handsomely, it led to a revolution in the way the whole world traveled and shipped air freight.

Thus, to mark the anniversary of the 747’s February 9, 1969, inaugural test flight, here are five things you might not have known about the world’s first jumbo jet.

The 747 was so large Boeing had to build a new factory just to put it into production.

Its six-story high tail was simply too big for any existing factory, says veteran aviation author Jay Spenser, who along with the late 747 engineering lead Joe Sutter, co-authored Sutter’s memoir: “747: Creating the World’s First Jumbo Jet and Other Adventures From a Life in Aviation”

So, Boeing chose Paine Field, a former World War II airbase some 30 miles North of Seattle, as the new factory’s site. Thus, in 1966, Boeing began construction on a 200 million-cubic-foot 747 assembly plant in Everett, Wa. This facility, since expanded to include 767, 777 and 787 production, remains the world’s largest building by volume.

“On its September 30, 1968 rollout, the first 747 prototype looked ready to fly but was in fact just 80 percent complete,” Spenser told me. “This deliberately premature unveiling served to reassure skittish bankers that their large loans had resulted in a real airplane.”

A losing bid on the Air Force’s C-5 program led Boeing to a new understanding of the 747’s need for powerful and fuel-efficient, high-bypass turbofan engines.

What Sutter learned from Boeing’s competition with the Lockheed Corporation to secure a contract for the C-5 transport serendipitously paved the way for stronger, more fuel-efficient turbofan engines. Such engines were exactly what was needed for the next generation of wide-body aircraft like the 747.

These high-bypass-ratio turbofan engines would soon replace the low-bypass fanjets that were then powering the world’s existing commercial jetliners, as Sutter and Spenser note in “747.”

As the authors explain, “a [turbojet] engine works by compressing air, mixing in fuel, and feeding the fuel into combustion chambers where it ignites. The exploding exhaust gases vent to the rear past curved metal blades on rows of turbine discs. This hot, high-pressure efflux pushes on those curved blades, spinning the turbines on a central shaft running the length of the engine.

It’s rotational energy that powers the compressor at the front of the engine, they note. This energy, in turn, pushes more air through the engine, continuing a cycle of continuous combustion.

In contrast, a turbofan adds a fan unit at the front, the authors note. This is a wide compressor that passes only some of the air it pressurizes through the engine’s core, they write. The rest of the air passes around the core in a nozzle-shaped path through the engine. This ultimately produces net thrust.

But it was the turbofans that revolutionized commercial aviation propulsion by offering three things over existing turbojets: They accelerated a larger volume of air to a lower velocity so that takeoff acceleration is improved. They used less fuel. And they were much quieter than the old turbojets.

The 747 was arguably inadvertently responsible for the demise of supersonic transports (SSTs) like the Concorde.

The 747 was envisioned as only an interim intercontinental subsonic substitute before being replaced by SSTs.

In the late sixties, the next generation of SSTs was thought to be close to taking over the global aviation market. Once passenger SSTs were flying globally, Boeing was planning on primarily marketing the 747 as a cargo freighter. After all, less than a month after the first 747 test flight, an Anglo/French supersonic transport consortium was testing the Concorde which made its first test flight in Paris on March 2, 1969.

But it was the 747 that was the big hit of the 1969 Paris Air Show. Ironically, at the time, even Boeing had some supersonic skin in the game. After all, it’s not for nothing that Seattle’s former NBA franchise was named the Supersonics.

Even so, as Sutter notes in “747,” an SST requires lots of fuel to plow through the kinds of aerodynamic shockwaves generated by flight faster than sound.

The Concorde also had range and capacity problems. It could barely accommodate 100 passengers and its range limited it to crossing the North Atlantic. By contrast, the fledgling U.S. SST program, designated as a Boeing 2707, was being designed to carry 270 passengers across the Pacific at three times the speed of sound.

But as noted in “747,” an internal Boeing study noted that the planned B2707’s economics were shaky. Even a 5% increase in the price of fuel would make it unprofitable for the airlines. Thus, in the Spring of 1971, Congress cut funding for the joint NASA/Boeing SST initiative.

The 747 was initially envisaged as a single-aisle double-decker aircraft.

Boeing’s C-5 proposal had called for a double-decker aircraft, with a cargo deck below and a troop deck on top. Thus, Boeing designers thought a similar twin deck configuration might work for the new 747. Boeing was also leaning towards this design at the urging of Pan Am CEO Juan Trippe — who like the 747’s primary launch customer — had long dreamed of an aerial ocean liner of the skies.

But Boeing soon realized there were problems inherent to any double-decker design.

Today’s 747 configuration — with a shortened upper deck and cockpit on top of a twin-aisle main passenger cabin — is both the result of a large cargo-loading design option in the 747’s front-end as well as aerodynamic concerns.

There were also safety concerns with a double-decker since Federal regulations dictated that all airliners be able to do an emergency evacuation within 90 seconds. That’s harder with a twin deck aircraft.

Ironically, the 747’s wide-body design only emerged when Boeing realized that it could accommodate an almost equal number of passengers by using today’s classic dual-aisle, 10-across passenger seating configuration.

But Boeing may have been right to be cautious about a twin-deck design. With this week’s Airbus announcement that it’s discontinuing production of its A380 double-decker superjumbo, Sutter’s words at the end of “747” sound particularly prescient, since he expressed surprise that Airbus had opted for such a design.

The test pilots marveled at how well the 747 handled turbulence from the very first flight.

“As we flew out, we realized the airplane was very responsive and performing very successfully,” Brien Wygle, the First Officer on that first initial flight told me. “We commented that it seemed to handle the turbulence that we encountered very well.”

It probably handled turbulence better than other aircraft at the time, says Wygle, because it was larger and heavier and those same air currents would have less effect.

And in the end, as Spenser points out, the 747 transformed air travel because its operating costs per seat was 30 percent lower than competing airliners. Thus, he says, via lower ticket prices, it opened up air travel to the masses.

Without the 747, there would likely have been no extended range Boeing 767s, 777s, and 787s; no Airbus A330s, 340s, or 380s. For when Wygle touched down on that cold February day, he might not have realized it, but the world had already begun to shrink.

 

 

 

This article originally appeared on Forbes

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