since its introduction three decades ago
the helicopter has been a valuable
national asset
more recently the tilt rotor aircraft
has demonstrated it can do almost
everything the helicopter does and more
including flying like a fixed-wing plane
once airborne
as our airports and air space become
more congested and the demand for
short-range commuter flights grows the
appeal of rotorcraft is becoming greater
but current systems are too noisy burn
too much fuel and require expensive
maintenance
it is problems like these which nasa's
ames research center in mountain view
california is studying
here engineers use wind tunnels to carry
out aerodynamic tests similar to those
done on conventional planes and
automobiles
a rotor blade section is mounted in
front of a sophisticated instrument
called a laser velocimeter or lv
once setup is complete air along with a
fine oil mist is blown through the
tunnel
tiny oil particles reflect light back
into the air
allowing researchers to determine how
fast air flows around any area of the
blade being tested
related work is underway at the ames
outdoor aerodynamic research facility
in this particular study engineers are
investigating how certain aerodynamic
characteristics of rotor systems
influence overall performance according
to the chief of the rotary wing
aeromechanics branch at ames ten percent
of a rotor system's total energy is
wasted because downward forces generated
by the spinning blades push other parts
of the aircraft towards the ground bill
warnbrook
consequently the rotor system has to
work 10
harder
to develop an equivalent amount of lift
say to lift
a crew and useful cargo complementing
these experimental studies are computer
simulations when a blade rotates it is
constantly colliding with tornado-like
pockets of turbulence created by other
blades in front of it the result is less
efficiency and greater noise
simulations like these cut costs by
allowing researchers to study
aerodynamic problems before building the
final aircraft
nasa's rotorcraft research an approach
aimed at improving the performance of
future transport systems