radio-controlled model aircraft flying
is one of america's most popular hobbies
the people who fly these small-scale
versions of their favorite planes have
many reasons why they are interested
some like the excitement of flying some
like building them
and some just enjoy the camaraderie
engineers at nasa's dryden flight
research center in california
use radio control aircraft for another
reason research
they know that meaningful data can be
obtained from radio controlled aircraft
they are using a 15 percent model of
dry-in zone f-18
high alpha research vehicle that has
been built as a proof-of-concept
platform to conduct aerodynamic research
the model was made at dryden almost
exclusively from standard rc model
industry equipment
like this aeron servo but a number of
modifications had to be made in order to
meet research specifications
the fuselage made of fiberglass comes
from an off-the-shelf model kit
the wings and tail surfaces are made out
of a styrofoam core and sheeted with
balsa wood
entirely new engine inlets and exhaust
stucks were made in order to more
accurately represent
the true f-18 inlet configuration
this included functional boundary layer
diverters
stress carrying bulkheads made of a
special laminate of end grain balsa wood
and fiberglass
had to be installed to handle the
stresses encountered by the model in
flight
some parts like the stabilator pivot
mechanism were made by hand
other types of material used were
plywood carbon fiber and balsa wood
the model's thrust comes from two
commercially available ducted fan units
that are 85 percent efficient in
converting horsepower to thrust
two model airplane engines power the fan
units producing 11 pounds of static
thrust each
the plane has been tracked on radar at
160 knots a speed which should be
increased with the installation of
liquid propane fuel mini turbo jets
thrust vectoring vanes have been added
to the model to make it true to the real
aircraft but are not operational
however an operational system has been
designed for a future project
the plane is fully instrumented to
measure air speed angle of attack
side slip and control surface positions
three axis rate gyros measure the rate
of rotation
and three accelerometers measure the
g-forces experienced by the model in
flight
it took six months to build at a cost of
approximately twenty five thousand
dollars
these modifications make it truly
capable performing as a flight research
vehicle
like its full-scale big brother rc
subscale models like this have a unique
quality that allows researchers to
gather aerodynamic data
which is difficult and expensive to
obtain in wind tunnels
models like this are especially suited
for getting aerodynamic data
like performing parameter identification
studies and for confirming the basic
airworthiness of unique
aircraft configurations research and
advanced control theory can also be done
by using existing technology
a flight control computer can be
installed that would allow the aircraft
to gather data at specific flight
conditions
radio-controlled model aircraft flying
is a great hobby but for nasa's dryden
flight research center
they are just another innovative tool in
advancing their frontiers of flight
research
you