Patent US5850400A successfully refreshed from Google Patents.
US4301736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Supersonic, low drag tubular projectile
Assignee: United States Department of the Army
•
Filing: 1979-03-13
•
Granted: 1981-11-24
•
Expires: 1999-03-13
Abstract
Abstract A hollow tubular projectile is disclosed having about 30 percent less mass than conventional ammunition projectiles and considerably less drag, as a result of precise aerodynamic design details.
Inventors
- 👤 Abraham Flatau
- 👤 Joseph Huerta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:17
CPC Classifications
F; F42; F42B; F42B10/00; F42B10/32; F42B10/34
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
181 words
An elongate tubular projectile having a longitudinal center axis, consisting of: a cylindrical center throat portion having a wall thickness defined by concentric inner and outer spaced-apart surfaces, a forward compression section adjoining said throat portion and formed by two converging conical surfaces intersecting each other to form a sharp leading edge and enclosing a V-shaped leading edge angle, the bisector of which in the longitudinal cross-section is substantially parallel to said longitudinal center axis, and an aft diffusion section adjoining said throat portion and formed by two converging conical surfaces forming a V-shaped trailing edge, said aft diffusion section having a smooth constant expansion angle and a smooth transition from said adjoining throat portion to said trailing edge, said throat portion having constant diameter throughout the length of said inner surface, said sharp leading edge defines a circular inlet having a predetermined first cross-sectional area for inlet airflow, said throat portion diameter defines a constant second cross-sectional area for airflow through said throat portion and the ratio of said second area to said first area is not less than 0.6.
Claim 2
Dependent Claim
181 words
An elongate tubular projectile having a longitudinal center axis, consisting of: a cylindrical center throat portion having a wall thickness defined by concentric inner and outer spaced-apart surfaces, a forward compression section adjoining said throat portion and formed by two converging conical surfaces intersecting each other to form a sharp leading edge and enclosing a V-shaped leading edge angle, the bisector of which in the longitudinal cross-section is substantially parallel to said longitudinal center axis, and an aft diffusion section adjoining said throat portion and formed by two converging conical surfaces forming a V-shaped trailing edge, said aft diffusion section having a smooth constant expansion angle and a smooth transition from said adjoining throat portion to said trailing edge, said throat portion having constant diameter throughout the length of said inner surface, said sharp leading edge defines a circular inlet having a predetermined first cross-sectional area for inlet airflow, said throat portion diameter defines a constant second cross-sectional area for airflow through said throat portion and the ratio of said second area to said first area is not less than 0.6.
Claim 3
Dependent Claim
30 words
The structure set forth in claim 1 above, wherein: said length of said throat portion is within a range from 0.5 to 2.5 times said diameter of said throat portion.
Claim 4
Dependent Claim
22 words
The structure of claim 2 above wherein: the distance between said first and second areas is greater than said throat portion diameter.
Claim 5
Dependent Claim
32 words
The structure of claim 1, further including: an external conical surface on said aft diffusion section extending in a constant slope from said throat portion outer surface to said trailing edge lip.
Claim 6
Dependent Claim
27 words
The structure of claim 1 above, wherein: said aft section extends a distance along said center longitudinal axis at least as long as said forward compression section.
Claim 7
Dependent Claim
23 words
The structure in claim 1 wherein: said length of said throat section is at least one half said diameter of said throat section.
Claim 8
Dependent Claim
15 words
The structure in claim 1 wherein: said leading edge angle does not exceed 15° total.
Claim 9
Dependent Claim
16 words
The structure in claim 1 wherein: said trailing edge includes a flat annular planar bearing surface.
Claim 10
Dependent Claim
26 words
The structure in claims 1 above, further including: force transmitting means adapted to make snug, force transmitting contact with said throat portion and said aft section.
Claim 11
Dependent Claim
29 words
The structure in claim 1 above, further including: a rotating band affixed to said projectile adapted to engage rifling within a gun bore and impart rotation to said projectile.
Claim 12
Dependent Claim
27 words
The structure in claim 6 above, further including: force transmitting means adapted to make tight nestling engagement with said aft section for transmitting forward propulsion force thereto.
Claim 13
Dependent Claim
26 words
The structure in claim 11 above, wherein: said force transmitting means includes a plurality of protruberances adapted to engage said aft section in force-transmitting relationship therewith.
References Cited (Backward Citations)
DE245458C
Cited
DE308434C
Cited
US1149679A
Cited
FR22432E
Cited
FR844987A
Cited
CH470648A
Cited
US4164904A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-23 | 1985-05-25 | 1985-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-23 | 1989-05-25 | 1989-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-23 | 1993-05-25 | 1993-11-24 | $7700.00 | Window Closed / Lapsed |