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Dash 80

The story of the prototype 707.

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(Continued from page 3)

In the early 1960s, Dash 80 was used to test some modification that would later show up in the 727.  These tests led in turn to a long stint with NASA and Boeing testing wings that can generate enough lift for the airplane to remain airborne at extremely low speeds.  Dash 80 had averaged 612 mph during a transcontinental speed record flight in 1957.  Now it was creeping around Seattle skies at 80 mph and landing at 92 mph.  Dismayed commuter airline pilots had to S-turn their Douglas DC-3s on final approach to Boeing Field to avoid overrunning what appeared to be a 707.  To preserve control at such ridiculously low speeds, Dash 80 sprouted a lush profusion of leading- and trailing-edge devices on its wings.  Their appearance alone was enough to make test pilots blanch.

Gannett continued to fly Dash 80 throughout the low-speed tests, but Johnston and Loesch had moved on and were replaced by S. Lewis Wallick, recently retired from Boeing, and Thomas Edmonds, who is still a test pilot there.  In test of leading-edge slats for the wing, engineers experimented with the curve of the slats by applying the file and fiberglass to the devices between flights.  Leading-edge symmetry is critical—without it, an airplane tends to roll uncontrollably in a stall.  This imprecise shaping of the wing made for occasional imbalance and some very sporty flying.  Edmonds recalls a day when one flight was enough: “We stalled, rolled over to about 90 degrees to the horizon, did a split-S, and ended up headed in the opposite direction.  We looked around, kind of startled, and decided there was no point in doing any more stalls that day.”

Dash 80 wore its high-lift wings to the end of its career, and Boeing and NASA engineers tested a series of design ideas that depended on solid control at slow speeds.  The aging airplane was landed on grass, dusty lake beds, soft earth, and even mud, using a landing gear system being considered for what would become the Air Force’s enormous C-5A Galaxy transport.  The landing gear spread the weight of the aircraft over 20 tires instead of Dash 80’s 10.  The tires’ flotation allowed the airplane to land on dust-covered mud only marginally more supportive than yogurt.

In 1965, with a long needle-like sensing unit, a comical face painted on its nose in honor of its 11th anniversary, and computer-mediated controls, it imitated the landing characteristics of a series of supersonic designs for NASA.  A second set of controls enabled the copilot to take over and fly the airplane normally, a precaution that allowed the computer to crash without the airplane following suit.  Dash 80 also tested scores of cockpit instruments and controls, some of which later showed up in the video display cockpits of the 757 and 767.  But this was the stuff of swan songs.

On January 22, 1970, after completing the last of a series of flights designed to test an automatic landing system for the space shuttle, Dash 80 went into retirement.  Its logbook showed 1,691 flights over 16 years for a total of 2,349 hours and 46 minutes, but it was not quite closed.  In 1972 Boeing returned Dash 80 to nearly original condition for a reenactment of the record-setting cross-country flight.  It ended in Washington, D.C., where Boeing presented the grand old 707 prototype to the National Air and Space Museum.

After the ceremonies, Wallick and Edmonds ferried it west to Davis-Monthan Air Force Base in the preserving climate of the Arizona desert.  For the past 15 years it has sat patiently at an aircraft storage depot, awaiting a slot at the Museum.  The paint scheme Boeing once described as “an eye-catching blend of canary yellow, chocolate brown, and silver” has faded, but Dash 80’s legend and legacy are likely to endure at least as long as its tired aluminum can hold together.

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