US3712564A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Slotted diffuser system for reducing aircraft induced drag
Assignee: Individual
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Filing: 1970-11-13
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Granted: 1973-01-23
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Expires: 1990-11-13
Abstract
Abstract A wing assembly for increasing lift and reducing drag is disclosed comprising (1) an inboard conventional primary wing panel, and (2) an outboard secondary wing panel which is aftswept and comprised of a cascade of airfoil elements. The inboard panel is provided with a constant lift distribution which is dropped sharply at the knee or juncture with the outer panel, shedding a substantially concentrated vortex at the knee rather than at the wing tip. The sweep of the outer panel deflects the flow carrying this vorticity outboard, and its cascade airfoil elements then operate in the upflow outboard thereof. The cascade elements of the outer panel are stacked vertically above to the rear, so that the vorticity shed from each element generates a spanwash providing an incremental lift and thrust on the next element aft and above, which, in turn, because of its sweep deflects the vorticity underneath outboard, providing a greater effective span. The cascade splits the vortex into a vertical stack of vortex sheets, which laminate into an expanded size, slowly turning vortex core. The energy and corresponding induced drag of the vortex pair shed from this improved wing assembly is less because the vortex cores are (a) expanded, and (b) displaced outboard.
Inventors
- 👤 S Rethorst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:02
CPC Classifications
B; B64; B64C; B64C23/00; B64C23/06; Y; Y02; Y02T; Y02T50/00; Y02T50/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
146 words
An aircraft wing comprising a primary solid portion and a secondary slotted portion, said secondary portion trailing said primary portion including a cascade of airfoil-shaped elements extending aft and swept outboard of the primary solid portion so as to be parallel to, along side of, outboard of, and in close proximity to any residual vorticity shed from said primary solid portion, and having a negative or lesser angle of attack than the inboard primary solid portion such that when the said primary portion of the wing is operating at a positive amgle of attack, the vector sum of the upwash generated by the residual inboard vorticity and the free stream flight velocity provides a resultant upflow giving a positive angle of attack on the outboard secondary portions, thereby providing a force normal to the resultant velocity which has both a lift and a forward thrust component.
Claim 2
Dependent Claim
146 words
An aircraft wing comprising a primary solid portion and a secondary slotted portion, said secondary portion trailing said primary portion including a cascade of airfoil-shaped elements extending aft and swept outboard of the primary solid portion so as to be parallel to, along side of, outboard of, and in close proximity to any residual vorticity shed from said primary solid portion, and having a negative or lesser angle of attack than the inboard primary solid portion such that when the said primary portion of the wing is operating at a positive amgle of attack, the vector sum of the upwash generated by the residual inboard vorticity and the free stream flight velocity provides a resultant upflow giving a positive angle of attack on the outboard secondary portions, thereby providing a force normal to the resultant velocity which has both a lift and a forward thrust component.
Claim 3
Dependent Claim
188 words
An aircraft wing comprising an inboard solid portion and an outboard slotted portion, said outboard portion comprising a plurality of airfoil-shaped elements with the aft ends of said elements swept outboard in a direction beyond said inboard portion, said elements having leading and trailing edges, said leading edges being rounder, thicker, and having a larger radius than said trailing edges which have a thinner, sharper, and lesser radius, said elements having upper and lower surfaces, said upper and lower surfaces being smoothly faired from said leading edges to said trailing edges, said elements being disposed with their centroids stacked vertically above to the rear, said inboard solid portion and said outboard slotted portion being joined in a smoothly faired juncture region, said juncture region having a sharp decrease in angle of attack, or washout, so as to shed the lifting vorticity inboard from the wing tip, the aft sweep of the outboard slotted portion then deflecting the air flow outboard, transporting outward the shed wing tip vortex, said vortex generating an upflow for said outboard slotted wing portion, providing a lift force with a reduced induced drag component.
Claim 4
Dependent Claim
188 words
An aircraft wing comprising an inboard solid portion and an outboard slotted portion, said outboard portion comprising a plurality of airfoil-shaped elements with the aft ends of said elements swept outboard in a direction beyond said inboard portion, said elements having leading and trailing edges, said leading edges being rounder, thicker, and having a larger radius than said trailing edges which have a thinner, sharper, and lesser radius, said elements having upper and lower surfaces, said upper and lower surfaces being smoothly faired from said leading edges to said trailing edges, said elements being disposed with their centroids stacked vertically above to the rear, said inboard solid portion and said outboard slotted portion being joined in a smoothly faired juncture region, said juncture region having a sharp decrease in angle of attack, or washout, so as to shed the lifting vorticity inboard from the wing tip, the aft sweep of the outboard slotted portion then deflecting the air flow outboard, transporting outward the shed wing tip vortex, said vortex generating an upflow for said outboard slotted wing portion, providing a lift force with a reduced induced drag component.
Claim 5
Dependent Claim
84 words
An aircraft as in claim 2 said solid portion having center of lift forward of the aircraft center of gravity, said slotted portion having center of lift aft of the aircraft center of gravity, said aft portion inCluding a cascade of airfoil-shaped elements with the aft ends of said elements swept outboard towards the trailing edge of said wing, the inboard edge of said elements being displaced down and being reflexed in providing passages from the upper to the lower surface of said wing.
Claim 6
Dependent Claim
34 words
An aircraft as in Claim 2 said solid portion having center of lift forward of the aircraft center of gravity, said slotted portion having center of lift aft of the aircraft center of gravity.
Claim 7
Dependent Claim
54 words
An aircraft wing as in claim 2, said slotted portion including a cascade of airfoil-shaped elements with the aft ends of said elements swept outboard towards the trailing edge of said wing, said elements having chord lengths substantially less than the chord of the wing itself, thereby providing lower Reynolds number and laminar flow.
Claim 8
Dependent Claim
38 words
An aircraft wing as in claim 2, said slotted portion including a cascade of airfoil-shaped elements, said elements having chord lengths substantially less than the chord of the wing itself, thereby providing lower Reynolds number and laminar flow.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-23 | 1976-07-24 | 1977-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-23 | 1980-07-24 | 1981-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-23 | 1984-07-24 | 1985-01-23 | $7700.00 | Window Closed / Lapsed |