THE
FDL-5 PROJECT
During the early 1960s, the USAF Flight Dynamics Laboratory (FDL)
devised new and unconventional shapes for hypersonic vehicles. The
shapes - FDL-5, FDL-6, FDL-7 and FDL-8 - were designed with the
intention of sustained hypersonic flight (both gliding and powered)
and re-entry. Even at hypersonic speeds, they were capable of lift-to-drag
ratios as high as 3:1. The tail and fin arrangements were all different,
but they all shared one characteristic: The were all 75 degree triangles.
In the late 1960s, Lockheed and the USAF Flight Dynamics Laboratory
built a full-scale mockup of a hypersonic research vehicle using
the FDL-5 shape. This configuration used a stabilization technique
called "compression sharing" anf featured flip-out wings to reduce
its landing speed and retractable farings in front of the split
windshield. Fuel for initial acceleration was to be carried in two
conformal tanks that fitted around its nose like a collar.
The USAF FDL projects paved way for future projects involving
orbital, transatmospheric and hypersonic flight. These projects
include the Transatmospheric Vehicle (TAV) and the Maneuvering Re-entry
Research Vehicle (MRRV).
