On this day in engineering history, Bell
Aircraft Corporation and the United States Air Force (USAF) released pictures of
the X-14, Bell's
latest vertical take-off and landing (VTOL) airplane. Powered by two British-built
Armstrong-Siddely jet engines, the X-14 differed from other VTOL aircraft in
that it did not require ground-handling equipment for positioning during
takeoff. Even more importantly, the X-14 did not require a runway. Designed to
take-off vertically from a horizontal position, the X-14 hovered and then shifted
to forward flight, achieving a maximum speed of 172 mph and reaching a service
ceiling of 20,000 feet. The X-14's main competitor, Ryan Aeronautical Company's
X-13, could reach speeds of 350 mph, but took-off from a vertical position and
required special ground-handling equipment.
From the Model 65 to the X-14
Vertical take-off and landing (VTOL)
development began in earnest after World War II, when companies such as Rolls Royce
and Fairchild began designing jet engines with large thrust-to-weight (T/W)
ratios. During the 1950s, Bell Aircraft studied the feasibility of VTOL jet-fighters,
building an air test vehicle (ATV) with titling jet pods. Designated as the
Model 65, this ATV enabled Bell
engineers to collect data for the company's next VTOL project – the X-14. Although
the X-14 also used a vertical reaction-control system, this open-cockpit
monoplane differed from the Model 65 in that it used moveable exhaust ducts to
vector from powerful fuselage-mounted engines. As Time magazine explained to
its readers, the X-14's "two jet engines blow their gas through diverters
rather like Venetian blinds. The gas, deflected downwards, pushes the airplane
up."
Built by Beechcraft - Well, Not Quite
The Bell X-14 was built with parts from planes
made by Beech Aircraft (Beechcraft), a Kansas-based company which is best known
for its contributions to general aviation. The Beech Bonanza, a popular personal
aircraft, provided metal wings, a retractable landing gear, and ailerons –
moveable, hinged panels along the rear of each wing. The Beach T-34 Mentor, a
military trainer modeled after the Beech Bonanza, supplied the empennage – a tail
assembly that provides stability and controls both pitch and yaw. Powered by
two Armstrong-Siddley engines, the X-14 used jets of compressed air to maintain
its position during hovering. Once the X-14 got off the ground, however, the
thrust-diverter could be adjusted so that the engines pushed the airplane
forward.
Beyond the Wild Blue Yonder
Although Time magazine opined that Bell
Aircraft's latest VTOL "probably wastes thrust, reducing the weight that the
X-14 can carry", the experimental airplane had a bit part to play in the drama
of the Space Race. Neil Armstrong, the first man to walk on the Moon, would
pilot the X-14 as a lunar-landing trainer.
Resources:
http://www.globalsecurity.org/military/systems/aircraft/x-14.htm
http://pdf.aiaa.org/preview/1983/PV1983_2491.pdf
http://collections.nasm.si.edu/code/emuseum.asp?profile=objects&newstyle=single&quicksearch=A19571019000
http://en.wikipedia.org/wiki/X-13_Vertijet
http://en.wikipedia.org/wiki/VTOL
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Re: June 26, 1957 – The X-14 Experimental Aircraft
