Base drag reducing device
AssigneeRafael-Armament Development Authority Ltd.
InventorsHanan Rom, Zvi Weinberg
Life of this patent
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Abstract
A device for reducing base drag on cylindrical rear truncated objects moving in a fluid, caused by the shedding of vortices at the base of the object. The device consists of ring shaped winglets attached to the rear of the object which may be sub-divided into a plurality of hinged partial winglets. The parameters of distance of winglet from cylinder shaped object, winglet circumference, angle, profile and chord length may be varied automatically for optimum drag-reducing capability.
Claims6
A device for reducing base drag in a truncated cylindrical projectile having a base radius R and moving in a fluid, said device comprising:
- a ringlet shaped body having a first end and a second end, said body formed of at least one substantially continuous winglet, said substantially continuous winglet having an outer surface and an inner surface, said outer surface and said inner surface being cooperatingly configured for redistributing lateral vorticity and said inner surface extending along a taper such that said inner surface joins said outer surface at said respective first and second ends, such that said first end has a diameter greater than the diameter of said second end;
- and
- a mounting means connecting said ringlet shaped body near to the base of the projectile such that the first end of said ringlet shaped body is positioned approximately 0.05 R from said base of said projectile so that at least a portion of the ringlet is within a vortex ring caused by the projectile.
Dependencies are inferred from the claim text.