CIVIL TILTROTOR:  NATIONAL INITIATIVE

NASA FACT SHEET
JULY 1989

A revolutionary aircraft is emerging that combines the
advantages of the helicopter and the airplane.  It is called the
"tiltrotor," because of its unique ability to take off like a
helicopter using engines mounted on the tips of the wings.
 Once the aircraft lifts off vertically, the pilot rotates the
engines forward and flies the aircraft like a conventional
airplane.  

The concept, including flight tests of the XV-15 tiltrotor
research aircraft, has been thoroughly researched at NASA's
Ames Research Center, Mountain View, California.

The success of the XV-15 program has led to the development
of the world's first operational tiltrotor, the V-22 Osprey,
designed for use in the military.  The success of the XV-15,
which first flew May 3, 1977, and the development of the V-
22, which first flew March 9, 1989, will lead to the
commercial development of tiltrotors.  A civil tiltrotor will
change commercial aviation much as did the advent of the jet
age.

A national initiative, directed by Congress, has resulted in a
NASA/NAVY/FAA/Industry agreement to use Navy flight-test
data to speed up the FAA certification of the V-22 for
commercial use.  The potential for tilt-rotor technology is
great, primarily because of the ability to deliver passengers,
for example, city center to city center, avoiding long drives to
airports through clogged freeways.

Commercial air travel has increased to the point where
crowding of our airports rivals and often contributes to the
crowding of our highways.  Removing short-haul passengers
from overcrowded airports to metropolitan and suburban
vertiports will allow better use of the airport's facilities and
provide for faster and more convenient service to the short-
distance commuter.

The success of the XV-15 program encouraged the military and
industry to select the tilt-rotor concept for an aircraft to
replace the aging helicopters now used for troop transport.
The combination of full helicopter capability with the cruise
efficiency of a turboprop airplane will provide larger troop
transports, longer range, and twice the speed using half the
fuel of conventional helicopters.  Additionally, vibration and
noise levels are greatly reduced, improving the ride qualities
and enhancing crew and troop performance.  The low noise
level is achieved because tiltrotors do not require a tail rotor,
and the large proprotors are turning much more slowly than
conventional propellers.

The V-22, designed and built by Bell Helicopter (builder of the
XV-15) and Boeing Helicopter, can carry 24 troops, and a crew
of 4, and can operate from the Navy's small Helicopter Attack
Carriers.  The V-22 is capable of carrying troops 2100 miles
(West Coast to Hawaii) against a 20-kt. head wind.  This makes
it deployable anywhere in the world without depending on large
transport aircraft and/or transport ships.

Only at the NASA Ames Research Center does a "full-circle" of
research tools exist, which enables this Center to conduct
research from drawing board to flight tests.  Starting with
computer-aided design, progressing through computational
fluid dynamic investigations, to aircraft and subsystem
simulation, the technology data base is established that
permits full-scale hardware to be designed, built, and tested
in the wind tunnel and/or in flight.