Spin resistant aircraft configuration
A configuration and system for rendering an aircraft spin resistant is disclosed. Resistance of the aircraft to spinning is accomplished by constraining a stall cell to a wing region adjacent to the fuselage and distant from the wing tip. Wing features that facilitate this constraint include but are not limited to one or more cuffs, stall strips, vortex generators, wing twists, wing sweeps and horizontal stabilizers. Alone or in combination, aircraft configuration features embodied by the present invention render the aircraft spin resistant by constraining the stall cell, which allows control surfaces of the aircraft to remain operational to control the aircraft.
1. A configuration for an amphibious aircraft so as to be spin resistant, said amphibious aircraft comprising a fuselage including sponsons coupled to a lower portion of the fuselage comprising a hull, a T-tail configuration, and a high wing having a leading edge coupled to an upper portion of the fuselage wherein the high wing includes a first region adjacent to the fuselage and a second region adjacent to a wing tip, the first region being contiguous with the second region, and wherein at high angles of attack a stall cell and associated separated airflow is constrained using a discontinuity in the leading edge of the wing to remain within the first region and flow below the T-tail so as to remain apart from flight controls located within the second region and flight controls associated with the T-tail.
2. The configuration for an aircraft as defined in claim 1 , wherein the leading edge discontinuity includes a cuff operable to form an aerodynamic boundary between the first region and the second region.
3. The configuration for an aircraft as defined in claim 2 , wherein the cuff includes a delta vortex generator.
4. The configuration for an aircraft as defined in claim 1 , wherein the first region includes one or more stall strips associated with a leading edge of the wing.
5. The configuration for an aircraft as defined in claim 4 , wherein at least one of the one or more stall strips is coupled to the leading edge of the wing and angled downward as it extends toward the wing tip.
6. The configuration for an aircraft as defined in claim 5 , wherein at least one of the one or more stalls strips is coupled to and parallel with the leading edge of the wing.
7. The configuration for an aircraft as defined in claim 1 , wherein the second region includes vortex generators.
8. The configuration for an aircraft as defined in claim 1 , wherein the wing includes a wing twist such that a wing tip angle of incidence is less than a wing root angle of incidence.
9. The configuration for an aircraft as defined in claim 8 , wherein the wing twist of the first region is substantially different than the wing twist of the second region.
10. The configuration for an aircraft as defined in claim 1 , wherein the wing tip is swept forward.
11. The configuration for an aircraft as defined in claim 1 , wherein the T-tail includes swept tips.
12. The configuration for an aircraft as defined in claim 11 , wherein at high angles of attack the sponsons reduce an effective angle of attack of the wing near the fuselage.
13. A system for a spin resistant configuration in an amphibious aircraft, the system comprising:
a fuselage having a sponson associated with each side of a lower portion of the fuselage;
a T-tail having a span and wherein the span of the T-tail is optimized to maintain controllability during a stall;
a wing associated with the an upper portion of the the fuselage having a wing root and a wing tip and wherein the wing includes a first region near the wing root and a second region near the wing tip and wherein the first region and the second region are contiguous along a contiguous border; and
a leading edge discontinuity operable at high angles of attack to form an aerodynamic fence along the contiguous border isolating a stall cell and associated separated airflow to remain within the first region and flow below the T-tail apart from any control surfaces in the second region of the wing and and those associated with the T-tail.
14. The system for a spin resistant configuration in an aircraft according to claim 13 , wherein responsive to a stall cell being developed within the first region, control surfaces of the aircraft remain operational to control the aircraft.
15. The system for a spin resistant configuration in an aircraft according to claim 14 , wherein aircraft control surfaces are isolated from the stall cell.
16. The system for a spin resistant configuration in an aircraft according to claim 13 , further comprising a plurality of vortex generators associated with the second region.
17. The system for a spin resistant configuration in an aircraft according to claim 13 , further comprising one or more stall strips associated with a leading edge of the wing in the first region.
18. The system for a spin resistant configuration in an aircraft according to claim 17 , wherein one of the one or more stalls strips is coupled to the leading edge of the wing and angled downward as it extends toward the wingtip.
19. The system for a spin resistant configuration in an aircraft according to claim 17 , wherein one of the one or more stall strips is coupled to and parallel with the leading edge of the wing.
20. The system for a spin resistant configuration in an aircraft according to claim 13 , wherein the wing includes a wing twist such that a wing tip angle of incidence is less than a wing root angle of incidence.
21. The system for a spin resistant configuration in an aircraft according to claim 20 , wherein the wing twist of the first region is substantially different than the wing twist of the second region.
22. The system for a spin resistant configuration in an aircraft according to claim 13 , wherein the wing twist at the root is increased due to an effective angle of attack reduction due to each sponson.