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AS ULTRALIGHT WAVERIDER VEHICLES |
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A CONCEPTUAL STUDY
BY
GORDON J. ROSS
Waverider Should you wish to contact the
society or require general information please contact ASTRA
using the following Email address: Should you encounter any problems
with this Web
Page please
email: NB - Green numbers within brackets
refer to references. INTERPLANETARY
MEGASONIC FLEXWING (IMF). As with the Terrestrial Flexwing
described above, the Interplanetary version of the vehicle
consists of a nose section connected to four struts. In
common with its predecessor, the IMF has lift-generating
surfaces constructed from carbon matting, suspended from
four carbon/carbon struts. Where the two vehicle differ
noticeably, is in the number and orientation of the lifting
surfaces. Any combination of struts/surfaces
may be used to climb, turn, dive or slow down. The IMF, as
its name implies, is primarily intended for atmosphere
manoeuvring at Mach numbers in the range of
25-150. It has a much simpler geometry than
the Terrestrial Flexwing, but lacks the "survivability" of
its smaller, slower ancestor. Even with current
state-of-the-art, high-temperature composites, a vehicle of
this type may only survive two or three atmosphere
encounters. This "survivability factor" will vary with the
composition, pressure, and chemistry of the atmospheres
through which it will fly, but at interplanetary velocities,
it will be essentially an expendable "aero-shell", which is
sacrificed to achieve specified trajectories. The leading edges are shown in
Fig.2
and Fig.3
as being sharp. It would of course, be possible to have
rounded or tubular spars. Round sections would be much
stiffer for the same mass, and would permit the option of
internal cryogenic coolants for control of the thermal loads
in the solid airframe. Another method of passive heat
"dumping", would be to construct the "sails" from a matrix
which could be stretched longitudinally. By using sail out
hauls or tensioners, the material may be stretched, opening
the gaps between the "fibres" of the matting. Although the
sail area would remain the same, a percentage of the
boundary layer would bleed through to the leeward side of
the surface, carrying away heat, without other coolant being
required. It would be necessary, given a
transpirational sail membrane of this type, to have a
conical cloth shroud with zero porosity, fixed to the
airframe interior. This would protect the payload from
damaging plasma or corrosive chemicals, penetrating the
primary skin when cooling is in progress. Since at these enormous velocities,
the differences in performance between Nonweiler's original
Caret-Wing Waverider and optimised designs of the nineties
become less important, a caret-shaped IMF is shown in
Fig.3.
It would possess the same shape-changing abilities as the
Rogallo design, but with flat, ridged lower
cavities. Page
Six
Page
Four
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