Apparatus for twisting a wing to increase lift on aircraft and other vehicles
AssigneeUtah State University
InventorWarren F. Phillips
Life of this patent
Estimating the term…
Abstract
A method and apparatus for varying the twist of a wing such that induced drag is minimized or reduced during cruise and lift is maximized or increased at least during takeoff and landings. In addition, variations in the twist may produce yawing and rolling moments. The twist amount is varied pursuant to the operating conditions, including those parameters used to determine the lift coefficient. The twist for reducing induced drag and/or improving lift may be employed by geometric or aerodynamic twist, including full span control surfaces used to provide roll control, high-lift and reduced induced drag. The twist may also be employed by twisting just a portion of the wing or the entire wing, either geometrically or aerodynamically.
Claims42
A vehicle comprising;
- a wing;
- a twistable portion on the wing;
- and
- a control system for implementing a first twist distribution and a second twist distribution in the twistable portion of the wing;
- wherein the control system is able to vary twist amount for the first and second twist distributions to implement a twist distribution based, at least in part, upon an equation, the equation being
- ω
-
- (
- θ
- )
- =
- F
-
- (
- π
- /
- 2
- )
- -
- F
-
- (
- θ
- )
- F
-
- (
- π
- /
- 2
- )
- -
- F
-
- (
- 0
- )
- where
- F
-
- (
- θ
- )
- =
- ∑
- n
- =
- 1
- ∞
-
- w
- n
- [
- 4
-
- b
- C
- ~
- L
- ,
- αC
-
- (
- θ
- )
- +
- n
- sin
-
- (
- θ
- )
- ]
-
- sin
-
- (
- n
-
-
- θ
- )
- w
- n
- =
- 1
- 2
-
- π
-
- ∫
- θ
- =
- 0
- π
-
- c
-
- (
- θ
- )
-
- C
- ~
- Ld
-
- (
- θ
- )
- bC
- L
-
- sin
-
- (
- n
-
-
- θ
- )
-
- ⅆ
- θ
- and where
- ω(θ) is the twist distribution
- b is a wingspan,
- {tilde over (C)}L,α is an airfoil section lift slope,
- c(θ) is a local airfoil section chord length at θ,
- θ is equal to cos−1(−2z/b) where z is a spanwise coordinate and
- b is a wingspan,
- {tilde over (C)}Ld(θ) is a target airfoil section lift coefficient distribution that is to be produced over the wingspan, and
- CL is a lift coefficient of the wing.
A system for twisting a wing of a vehicle, said system comprising:
- means for determining an amount of twist to be applied to at least a portion of the wing for the purpose of improving lift generated by the wing;
- and means for applying a twist to said at least a portion of said wing, wherein the twist amount is based, at least in part, by an equation, the equation being
- Ω=[F(π/2)−F(0)]CL
- where
- F
-
- (
- θ
- )
- =
- ∑
- n
- =
- 1
- ∞
-
- w
- n
- [
- 4
-
- b
- C
- ~
- L
- ,
- αC
-
- (
- θ
- )
- +
- n
- sin
-
- (
- θ
- )
- ]
-
- sin
-
- (
- n
-
-
- θ
- )
- w
- n
- =
- 1
- 2
-
- π
-
- ∫
- θ
- =
- 0
- π
-
- c
-
- (
- θ
- )
-
- C
- ~
- Ld
-
- (
- θ
- )
- bC
- L
-
- sin
-
- (
- n
-
-
- θ
- )
-
- ⅆ
- θ
- and where
- Ω is the twist amount,
- b is a wingspan,
- {tilde over (C)}L,α is an airfoil section lift slope,
- c(θ) is a local airfoil section chord length at θ,
- θ is equal to cos−1(−2z/b) where z is a spanwise coordinate and
- b is a wingspan,
- {tilde over (C)}Ld(θ) is a target airfoil section lift coefficient distribution that is to be produced over the wingspan, and
- CL is a lift coefficient of the wing.
A system for twisting a wing of a vehicle, said system comprising:
- a control system for implementing a twist distribution in the wing of the vehicle;
- wherein the control system is able to vary a twist amount to implement the twist distribution to thereby generate improved lift during operation of the vehicle, wherein the twist distribution is based, at least in part, on an equation, the equation being
- ω
-
- (
- θ
- )
- =
- F
-
- (
- π
- /
- 2
- )
- -
- F
-
- (
- θ
- )
- F
-
- (
- π
- /
- 2
- )
- -
- F
-
- (
- 0
- )
- where
- F
-
- (
- θ
- )
- =
- ∑
- n
- =
- 1
- ∞
-
- w
- n
- [
- 4
-
- b
- C
- ~
- L
- ,
- αC
-
- (
- θ
- )
- +
- n
- sin
-
- (
- θ
- )
- ]
-
- sin
-
- (
- n
-
-
- θ
- )
- w
- n
- =
- 1
- 2
-
- π
-
- ∫
- θ
- =
- 0
- π
-
- c
-
- (
- θ
- )
-
- C
- ~
- Ld
-
- (
- θ
- )
- bC
- L
-
- sin
-
- (
- n
-
-
- θ
- )
-
- ⅆ
- θ
- and where
- ω(θ) is the twist distribution
- b is a wingspan,
- {tilde over (C)}Lα is an airfoil section lift slope,
- c(θ) is a local airfoil section chord length at θ,
- θ is equal to cos−1(−2z/b) where z is a spanwise coordinate and
- b is a wingspan,
- {tilde over (C)}Ld(θ) is a target airfoil section lift coefficient distribution that is to be produced over the wingspan, and
- CL is a lift coefficient of the wing.
Dependencies are inferred from the claim text.