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US 5,871,173 AGranted
Drag-producing aerodynamic device
AssigneeGEC-Marconi Limited
InventorsStephen J Frank, David Hawkins
Life of this patent
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Abstract
It is known to use a rigid cone to provide stability to a body being towed by an aircraft. However, such cones are useful over a limited range of speeds. The invention provides a drag-producing aerodynamic device in which the cross-sectional area of the structure producing drag is variable. The cross-sectional area of the structure producing drag decreases as the towing speed, and hence the dynamic air pressure acting on the structure producing drag, increases and vice versa.
Claims12
An aerodynamic device for producing a variable drag during towing to provide stability to a towed body, said device comprising:
- a) a sleeve extending along a longitudinal axis and mounted on the body for longitudinal movement along said axis;
- b) resilient means mounted on the body and resiliently bearing against, and resiliently resisting the longitudinal movement of, the sleeve with a restoring force;
- and
- c) a plurality of drag-producing blades having a first set of end portions pivotably mounted on the sleeve and arranged about said axis, and a second set of free end portions arranged about a circular locus whose diameter changes uniformly and symmetrically in response to a variable pressure exerted on said free end portions during towing, said blades being operative in unison to move the sleeve to an equilibrium position in which the pressure exerted on said free end portions counterbalances the restoring force of the resilient means.
1 more element
Dependencies are inferred from the claim text.