what if an aircraft could fly without
the rear vertical stabilizer and rudder
what would be the advantages better yet
how could it be done the x31
International test team is helping
explore these possibilities at NASA's
Dryden Flight Research Center Edwards
California x31 team members previously
demonstrated supersonic quasi tailless
capabilities in March of 1994 quasi
tailless is a state of simulated reduced
tail or tail as flight through
destabilizing feedback to the ship's
rudder and ailerons closed-loop
stability and control is then completely
provided by the x31 s unique thrust
vectoring system this work has captured
the interests of the joint advanced
strike technology or jest program group
members from the US Navy Marine Corps
and Air Force have joined together
technology for the next generation of
fighter aircraft the benefits are
decreased weight and drag this will
increase range and make future aircraft
smaller resulting in less expensive more
affordable strike fighter aircraft the
x31 team at NASA Dryden was chosen
because the x31
is capable of gathering this data now
not three to five years in the future
the x31 test team and jest will conduct
a two phase flight experiment to include
simulated power approach and ground
attack maneuvers at low altitude for
multiple levels of destabilization phase
one emphasis will be on validating the
simulation model for tail thus flight
test maneuvers will be conducted at
20,000 feet and 8,000 feet and lower in
both cruise and power approach
configurations at Mach numbers point
three four point six and point eight the
levels of D augmented stability from the
rudder and ailerons planned to be varied
a minimum of between 100 percent tail
off to full tail during this test phase
of roughly 10 to 12 sorties the power
approach tailless flight was initiated
by the IT o test team September 1st
phase two testing will demonstrate the
operational viability
of tailless flight through quasi
tailless testing simulated ground attack
maneuvers and precision approaches will
be flown the objective will be to
provide flight validated data supporting
future tailless designs eight to ten
test flights under these conditions
should meet those objectives upon
completion the x31 test team will
analyze the test data and provide a
final report and briefing of their
accomplishments in quasi tailless
research to the Jass program managers in
washington d.c the IT o test team at
nasa dryden continues to plan for a
reduced tail tailless x31 flight
programme during calendar year 1995
the x31 international test team
demonstrated supersonic quasi tailless
capabilities in march 1994 quasi
tailless is a state of simulated reduced
tail or tail thus flight through
destabilizing feedback to the ship's
rudder and ailerons at this point the
x31 s thrust vectoring system provides
closed-loop stability and control
tailless flight would decrease aircraft
weight and drag increasing their range
this would lead to smaller aircraft in
the future resulting in less expensive
more affordable strike fighter aircraft
the x31 project at nasa dryden was
chosen because the aircraft can provide
immediate test results the x31 test team
and the joint advanced strike technology
team from the US Air Force Navy and
Marine Corps will conduct a two phased
flight experiment to gather this data
phase one emphasis will be on validating
the simulation model for tailless flight
test maneuvers will be conducted at
20,000 and 8,000 feet and lower in both
cruise and power approach configurations
this test phase began September 1st 1994
phase two testing will demonstrate the
operational viability of tailless flight
through quasi Taylors testing simulated
ground attack maneuvers and precision
approaches will be flown upon completion
the x31 test team will analyze the data
and provide a final report to the Jazz
program managers in Washington DC from
NASA's Dryden Flight Research Center
Edwards California I'm Roger Williams