Advanced Technology Tactical Transport
(ATTT)
The Model 133-4.62 Advanced Technology Tactical
Transport (ATTT) proof-of-concept demonstrator is a 62%
scaled version of an airplane designed to challenging STOL
and long range requirements. The ATTT was developed and
test flown by Scaled Composites, Inc. under contract to
DARPA. The initial flight test program consisted of 51 flights
with the original cruciform tail configuration, measuring
and refining performance, stability and control, and handling
qualities. The results of the fabrication and test program
were presented in a comprehensive report to DARPA .
In an effort to improve the aft loading capability
of the aircraft and to correct aerodynamic deficiencies
discovered during the test program, the ATTT aircraft was
modified with a twin-boom tail whose general configuration
was similar to that of the Rockwell OV-10 Bronco. This modified
configuration is shown in the accompanying photograph. Pratt
and Whitney of Canada PT6A-135A turboprop engines were attached
to the twin booms in a tractor configuration. A simple fully
mechanical flight control system was installed, with full
control available from both seats. The Scaled-designed landing
gear is actuated using electric motors.
The M-133 demonstrator used a unique flap
system to enable its STOL performance. The high lift configuration
consists of eight Fowler-type flaps, each of 43% chord.
The flap system was designed to allow the initial takeoff
roll to be performed with the flaps extended, but at low
deflections to minimize takeoff drag. As rotation speed
was neared, the flaps were quickly rotated to the maximum
lift position via a separate pilot action. The ATTT was
a key program for Scaled. It demonstrated our ability to
perform a challenging aerodynamic and structural design,
and to build, test, and deliver what amounted to two different
manned research airplanes, including all design and flight
test data, to DARPA for less than 3 million dollars, including
all recurring and nonrecurring costs.
The ATTT is currently in storage at the Air
Force Flight Test Center Museum, at Edwards Air Force Base.
Click here to
return to the projects list.
