Airplane with unswept slotted cruise wing airfoil
Slotted cruise airfoil technology allows production of a substantially unswept wing that achieves the same cruise speed as today's conventional jet airplanes with higher sweep. This technology allows the wing boundary layer to negotiate a strong recovery gradient closer to the wing trailing edge. The result is about a cruise speed of Mach=0.78, but with a straight wing. It also means that for the same lift, the super velocities over the top of the wing can be lower. With very low sweep and this type of cruise pressure distribution, natural laminar flow will be obtained. In addition, heat is transferred from the leading edge of the wing and of the main flap to increase the extent of the natural laminar flow. The slotted cruise wing airfoil allows modularization of the wing and the body for a family of airplanes. The unsweeping of the wing significantly changes the manufacturing processes, reduces manufacturing costs and flow time from detail part fabrication to airplane delivery. The system architecture is all new for cost reduction. A high wing arrangement allows more freedom for installation of higher bypass ratio advanced geared fan engines. A low is wing in conjunction with aft body mounted engines will have a similar effect. Aerodynamic efficiency and engine fuel burn efficiency result in considerable lower emission of noise and greenhouse gases.
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This application claims the benefit of U.S. Provisional Application No. 60/028,853, filed Oct. 22, 1996.
FIELD OF THE INVENTIONThis invention relates to an aircraft configuration and, more particularly, to a commercial jet aircraft utilizing a slotted cruise airfoil and a wing with very low sweep compared to the sweep of more conventional jet aircraft, achieving the same cruise speed.
BACKGROUND OF THE INVENTIONThis invention relates to an aircraft configuration utilizing improved laminar flow. If laminar flow is achieved, aircraft drag, manufacturing aims, and operating costs are substantially reduced. U.S. Pat. No. 4,575,030, entitled, “Laminar Flow Control Airfoil” by L. B. Gratzer, and is assigned to the assignee of this invention. The Gratzer patent provides information on development which includes, among other techniques, suction surfaces and slots to promote natural laminar flow over a main box region of a wing.
SUMMARY OF THE INVENTIONAn aspect of the wing of this invention is that it incorporates a slotted cruise airfoil. Slotted cruise airfoil technology that we have developed allows us to produce an unswept, or substantially unswept, wing that achieves the same cruise speed as today's conventional airplanes with higher sweep.
This invention, this technology allows the wing boundary layer to negotiate a strong recovery gradient closer to the wing trailing edge. The result is about a cruise speed of Mach=0.78, but with a straight wing. It also means that for the same lift, the super velocities over the top of the wing can be lower. With very low sweep and this type of cruise pressure distribution, natural laminar flow can easily be obtained. Lower-surface Krueger flaps are installed to increase lift capability for low-speed operation and to protect the wing leading edge from bugs during takeoff and landing to prevent spoiling natural laminar flow.
In another aspect of the invention, heat is transferred from the leading edges of the wing and/or of the main flap to increase the extent of the natural laminar flow.
In still another aspect of this invention, a high wing arrangement allows more freedom for installation of higher bypass ratio engines. An advanced geared fan engine, by-pass ratio 12 or higher, is a possibility that could be easily installed under the high wing. The lower super velocities of the slotted cruise airfoil make the body shock problem associated with many high wing airplanes less of a concern here.
The slotted cruise wing airfoil and the straight wing allow us to modularize the wing and the body so that we can develop a family of airplanes by intermixing different bodies with different wings.
Another aspect of this invention is to reduce costs. The unsweeping of the wing significantly changes the manufacturing processes, reduces manufacturing costs and flow time from detail part fabrication to airplane delivery. The system architecture is all new rather than a major remodeling of a systems architecture from an exiting airplane. It is a top down approach geared towards the requirements of this airplane. Components from existing products will be used whenever they satisfy the requirements of this airplane. The payload systems allow for flexible interiors and extensive use of molded panels.
Still another aspect of this invention is that the expected fuel bum per seat for this type of an airplane is 20% to 30% less than on current jet airplanes, this can be associated with considerable reduction of emission of greenhouse gases.
There is very little difference in ditching capability between a low wing airplane and a high wing airplane. In both cases, the body provides the vast majority of the flotation. The wing provides some stability to prevent the ditched airplane from rolling over.
Another aspect of this invention is that a low wing version with aft mounted engines is also possible. It would feature many, if not most of the above advantages.
The illustrations on
On the prior art reference airplane,
On the ‘high wing’ example of the invention,
On the ‘low wing’ example of the invention, FIGS, 1c and 2c, an unswept wing 26 is attached to the bottom of the fuselage 27. Its structural box 28 is a single part, reaching from tip to tip. High bypass ratio engines 29 are attached to struts 30 at both sides of the aft fuselage 27. The main landing gear 31 is attached to the fuselage 27, of requiring additional space in the wing platform 26. Wing leading edge devices 20, spoilers 21 and ailerons 22 are of the same type and shape as on the previous airplane. The flaps 23 represent the ‘vane-main’ feature with the addition of a slot that is permanent for all flap positions and is a unique key to this invention. More detail is shown on
The embodiments of the whole airplane configurations are shown on
Of particular interest is the wing rear spar 39 shown in combination with the rear fragment of a wing 14 or 26. The components of the flap 23 are generally located aft of, and are structurally supported by, the wing rear spar 39.
In general, a slotted cruise trailing edge flap 23 formed in accordance with the application Ser. No. 08/735,233 has a single-slotted configuration during cruise,
The extension assembly 40 includes a support structure to which the flap assembly 23 is translatable and rotatably connected. The extension assembly 40 further includes an actuation mechanism that moves the flap assembly 23 relative to the support structure. In a stowed position, the vane element of flap 23 nests into the wing 14 or 26 such that the permanent single slot remains available to direct airflow from regions below the wing to regions above the wing. In an extended position, the vane and main elements of flap 23 form a double-slotted arrangement by rotating downward and translating rearward relative to the wing 14 or 26.
Physical factors limiting the performance of transonic cruise airfoils
In the following discussion, “airfoil” refers to the cross-sectional shape of a wing in planes that are substantially longitudinal and vertical, which plays a major role in determining the aerodynamic performance of said wing. “Transonic cruise” refers to operation of the wing at high subsonic speed such that the airflow past the wing contains local regions of supersonic flow. “Mach number” refers to the ratio of the flow speed to the speed of sound.
The performance of an airfoil in transonic cruise applications can be characterized by four basic measures:
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- 1) The airfoil thickness, usually expressed as the maximum-thickness ratio (maximum thickness divided by chord length). Thickness is beneficial because it provides the room needed for fuel and mechanical systems and because a wing structure with greater depth can be lighter for the same strength.
- 2) The speed or Mach number at the preferred operating condition The Mach number capability of the airfoil, modified by a factor related to the sweep angle of the wing, contributes directly to the cruise speed of the airplane.
- 3) The lift coefficient at the preferred operating condition. Increased lift coefficient is advantageous because it could allow increased weight (e.g. more fuel for longer range) or a higher cruise altitude.
- 4) The drag coefficient at the preferred operating condition and at other operating conditions that would be encountered in the mission of an airplane. Reducing the drag reduces fuel consumption and increases range.
Other measures such as the pitching-moment characteristics and the lift capability at low Mach numbers are also significant, but are less important than the basic four.
Together, the four basic performance measures define a level of performance that is often referred to as the “technology level” of an airfoil. The four basic performance measures impose conflicting requirements on the designer in the sense that design changes intended to improve one of the measures tend to penalize at least one of the other three. A good design therefore requires finding a favorable compromise between the four measures.
At any given technology level, it is generally possible to design a wide range of individual airfoils tailored to different preferred operating conditions and representing different trade-offs between the four basic performance measures. For example, one airfoil could have a higher operating Mach number than another, but at the expense of lower lift and higher drag. Given modern computational fluid dynamics tools, designing different airfoils at a given technology level is generally a straightforward task for a competent designer. On the other hand, improving the technology level, say by improving one of the basic performance measures without penalizing any of the other three, tends to be more difficult, and the more advanced the technology level one starts with, the more difficult the task becomes. Starting with an airfoil that is at a technology level representative of the current state of the art, it can be extremely difficult to find significant improvements.
The main factors that limit performance are associated with the physics of the flow over the upper surface of the airfoil. To understand these factors, it helps to look at a typical transonic cruise airfoil pressure distribution, plotted in terms of the pressure coefficient CP on a negative scale, as shown in
The lower curve 42 on the pressure-distribution plot represents the pressure on the lower surface 43, or high-pressure side, and the upper curve 44 represents pressure on the upper-surface 45. The vertical distance between the two curves indicates the pressure difference between the upper and lower surfaces, and the area between the two curves is proportional to the total lift generated by the airfoil. Note that near the leading edge there is a highly positive spike in the CP distribution 46 at what is called the “stagnation point” 47, where the oncoming flow first “attaches” to the airfoil surface, and the flow velocity outside the boundary layer is zero. Also, note that the upper- and lower-surface CP distributions come together at the trailing edge 48, defining a single value of CP 49 that is almost always slightly positive. This level of CP at the trailing edge, as will be seen later, has an important impact on the flow physics. Because the trailing-edge CP is dictated primarily by the overall airfoil thickness distribution, and the thickness is generally constrained by a number of structural and aerodynamic factors, trailing-edge CP is something over which the designer has relatively little control. Away from the leading-edge stagnation point and the trailing edge, the designer, by varying the airfoil shape, has much more control over the pressure distribution.
For a given airfoil thickness and Mach number, the problem of achieving a high technology level boils down to the problem of maximizing the lift consistent with a low drag level. Increasing the lift solely by increasing the lower-surface pressure is generally not possible without reducing airfoil thickness. Thus the designer's task is to reduce the upper-surface pressure so as to produce as much lift as possible, but to do so without causing a large increase in drag. In this regard, the pressure distribution shown in FIG. (7a) is typical of advanced design practice. The operating condition shown is close to the preferred operating condition that might be used for the early cruise portion of an airplane mission. The drag at this condition is reasonably low, but at higher Mach numbers and/or lift coefficients, the drag would increase rapidly.
Note that the upper-surface CP 44 over the front half of the airfoil is above the dotted line 41, indicating that the flow there is mildly supersonic. Just aft of midchord, this supersonic zone is terminated by a weak shock, indicated on the surface as a sudden increase in CP 50 to a value characteristic of subsonic flow. The CP distribution in the supersonic zone 51 is deliberately made almost flat, with only an extremely gradual pressure rise, in order to keep the shock from becoming stronger and causing increased drag at other operating conditions. The shock is followed by a gradual pressure increase 52, referred to as a “pressure recovery”, to a slightly-positive CP 49 at the trailing edge. The location of the shock and the pressure distribution in the recovery region are carefully tailored to strike a balance between increased lift and increased drag.
Trying to increase the lift will tend to move the airfoil away from this favorable balance and increase the drag. For example, one way of adding lift would be to move the shock 50 aft. This, however, would require a steeper recovery (because the immediate post-shock CP and the trailing-edge CP are both essentially fixed), which would cause the viscous boundary layer to grow thicker or even to separate from the surface, either of which would result in a significant drag increase. The other obvious way to increase lift would be to lower the pressure ahead of the shock even further (move the CP curve 51 upward over the forward part of the airfoil and increase the supersonic flow velocity there), but this would increase the pressure jump across the shock, which would result in an increase in the so-called shock drag. For single-element transonic airfoils at the current state of the art, this compromise between lift and drag has reached a high level of refinement, and it is unlikely that any large improvement in technology level remains to be made.
Potential technology advantage of the slotted airfoil
The shape and resulting pressure distribution of a slotted transonic cruise airfoil are shown in FIGS. (6) and (7b). The airfoil 23 consists of two elements (a forward element 60 and an aft element 61) separated by a curved channel (62, the slot) through which air generally flows from the lower surface 84 to the upper surface 64. In this example, the slot lip (65, the trailing edge of the forward element) is just aft of 80 percent of the overall chord from the leading edge, and the overlap of the elements is about 3 percent of the overall chord. Pressure distributions are shown for both elements, so that the pressure distributions overlap where the airfoil elements overlap. As with the conventional airfoil, the upper curves 66,67 give the CP distributions on the upper surfaces 64,83, and the lower curves 68,69 give CP on the lower surfaces 84,70. Note that there are two stagnation points 71,72 and their corresponding high-pressure spikes 73,74, one on each element, where the oncoming flow attaches to the surface near each of the leading edges.
To begin the consideration of the flow physics, note that the preferred operating condition for the slotted airfoil shown is faster than that of the single-element airfoil (Mach 0.78 compared with 0.75), and that the lift coefficient is slightly higher, while both airfoils have the same effective thickness for structural purposes. At the slotted airfoil's operating condition, any single-element airfoil of the same thickness would have extremely high drag. The slotted airfoil's substantial advantage in technology level results from the fact that the final pressure recovery 75 is extremely far aft, beginning with a weak shock 76 at about 90 percent of the overall chord. Such a pressure distribution would be impossible on a single-element airfoil because boundary-layer separation would surely occur, preventing the shock from moving that far aft. The mechanism, loosely termed the “slot effect”, by which the slot prevents boundary-layer separation, combines several contributing factors:
-
- 1) The boundary layer on the upper surface 83 of the forward element is subjected to a weak shock 77 at the slot lip 65, but there is no post-shock pressure recovery on the forward element. This is possible because the aft element 61 induces an elevated “dumping velocity” at the trailing edge of the forward element (The trailing-edge CP 78 on the forward element is strongly negative, where on a single-element airfoil the trailing-edge CP is generally positive).
- 2) The upper- and lower-surface boundary layers on the forward element combine at the trailing edge 65 to form a wake that flows above the upper surface 64 of the aft element and that remains effectively distinct from the boundary layer that forms on the upper surface of the aft element. Over the of part of the aft element, this wake is subjected to a strong pressure rise 75,76, but vigorous turbulent mixing makes the wake very resistant to flow reversal.
- 3) The boundary layer on the upper surface 64 of the aft element has only a short distance over which to grow, starting at the stagnation point 72 near the leading edge of the aft element, so it is very thin when it encounters the final weak shock 76 and pressure recovery 75, and is able to remain attached. With regard to its pressure distribution and boundary-layer development, the aft element is, in effect, a separate airfoil in its own right, with a weak shock and pressure recovery beginning at about the mid-point of its own chord, for which we would expect attached flow to be possible.
The upper-surface pressure distribution of
One way of comparing the technology levels of airfoils is to plot the drag-rise curves (drag coefficient versus Mach number at constant lift coefficient), as shown in FIG. (8). Here the dashed curve 80 is for the single-element airfoil of
The pressure distribution on the lower surface also contributes to the technology level of the slotted airfoil of
The unsweeping of the wing significantly changes the manufacturing processes, reduces manufacturing costs and flow time from detail part fabrication to airplane delivery. Conventional commercial jet airplane wings are built with structural splices where the stringers and spars change direction, generally at the side of body. With an unswept wing, one of the spars has no changes in direction and no splice. Wing box structural stringers (skin panel stiffeners) are parallel to the straight spar and do not have splices. As with the spar and stringers, the wing structural skin does not require spanwise splicing although chord wise splicing will be used when the limits of raw material make single piece wing skins impractical. Building the wing as a single piece rather than a left wing a right wing and a wing stub eliminates the parts associated with splicing and the labor and flow time required to join the left and right wing to the wing stub. Significant reductions in the quantity of parts and manufacturing labor are a result of unsweeping the wing.
Unsweeping the wing 14 changes the wing relationship with the main landing gear 19. Conventional swept wing commercial jet airplanes integrate the landing gear into the portion of the wing aft of the rear spar 9. With the unswept high wing commercial jetliner configuration shown in
Structural design advantages of the unswept wing include higher loading of the front spar 82 and thereby unloading the rear spar 39 and aft part of the wing skins 83 and 84. This load redistribution results in the ability to increase the structural aspect ratio of the wing while maintaining the same stress levels. Utilizing a mid spar or spars may increase the wing aspect ratio further with out increasing stress levels.
The slotted cruise wing airfoil and the straight wing allow us to modularize the wing 14 and the body 15, so that we can develop a family of airplanes by intermixing different bodies with different wings.
Aspect Ratio is the ratio of (span)2 divided by wing area. Structural Aspect Ratio is the ratio of (structural span)2 divided by structural wing area.
While preferred embodiments of the invention have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims
1. A commercial jetplane capable of flying at a cruise speed of Mach=0.78 or above, comprising:
- a fuselage;
- a landing gear mounted on said fuselage;
- a single wing attached to said fuselage, said single wing being substantially unswept with a high aspect ratio, and including: a forward airfoil element having an upper surface and a lower surface; an aft airfoil element having an upper surface and a lower surface; an internal structure comprising at least two spars extending from one tip to an opposing tip of said single wing, with a rear one of the spars being straight and unswept in plan view; an airfoil structure having a slot that allows airflow from the forward airfoil element to the aft airfoil element, wherein during cruising flight of the airplane, said airfoil structure having said slot diverts some of the air flowing along the lower surface of the forward airfoil element to flow over the upper surface of the aft airfoil element, and where the lower surface of the forward airfoil element and the lower surface of the aft airfoil element are shaped to provide an efficient cross section for a main structural box of the single wing; and
- said wing and said fuselage being constructed of at least one of aluminum and graphite composite.
2. The airplane of claim 1 wherein said airfoil structure having a slot produces natural laminar flow over the aft airfoil element of said single wing.
3. The airplane of claim 1 wherein said airfoil structure having said slot produces natural laminar flow over the forward airfoil element of said single wing.
4. The airplane of claim 1 wherein heat is transferred from a leading edge of at least one of said wing and main flap to increase the extent of said natural laminar flow.
5. An airplane of claim 1 which comprises a “T”-tail type empennage.
6. The airplane of claim 1 which comprises a “V”-tail type empennage.
7. The airplane of claim 1 which comprises a low tail type empennage.
8. The airplane of claim 7, wherein at least two high bypass ratio engines are attached to the airframe.
9. The airplane of claim 8 wherein said high bypass engines are geared fan engines or unducted fans which are energy efficient with reduced fuel consumption, noise and greenhouse gas emissions.
10. The airplane of claim 1 wherein the reduced rotation angle also decreases the aft body upsweep and reduces drag.
11. An airplane of claim 1 wherein said single wing is attached to the top of said fuselage and the engines are attached below the wing.
12. An airplane of claim 1 wherein said single wing is attached to the bottom of said fuselage and said engines are attached to the aft end of the fuselage.
13. An aircraft, comprising:
- a fuselage;
- at least one wing attached to the fuselage, the wing having an upper surface, a lower surface, and an internal structure including at least one spar;
- a trailing edge device carried by the wing, the trailing edge device having an upper surface and a lower surface, the upper surface of the trailing edge device being recessed away from an aft-extended contour of the wing upper surface in a thickness direction along its entire length when in a neutral, undeflected, undeployed position, at least one of the at least one wing and the trailing edge device having a spanwise slot that allows airflow from the at least one wing to the trailing edge device, the slot having an aft-facing exit opening at an offset between the upper surfaces of the at least one wing and the trailing edge device, the offset being in the thickness direction, wherein during cruising flight of the aircraft, the slot diverts some of the air flowing along the lower surface of the at least one wing through the slot to flow over the upper surface of the trailing edge device, the lower surface of the at least one wing and the lower surface of the trailing edge device being shaped to provide an efficient cross section for a main structural box of the at least one wing; and
- landing gear depending from the fuselage.
14. The aircraft of claim 13 wherein the at least one wing is at least approximately unswept.
15. The aircraft of claim 13 wherein the slot is configured to remain open at all flight conditions.
16. The aircraft of claim 13 wherein the at least one wing is configured to operate at a cruise Mach number of 0.78 or higher.
17. The aircraft of claim 13 wherein the at least one spar includes a forward spar and an aft spar forming portions of opposing sides of a wing box.
18. The aircraft of claim 13 wherein the at least one wing includes a forward spar and an aft spar and wherein at least one of the forward and aft spars is at least approximately unswept.
19. The aircraft of claim 13 wherein the at least one spar extends in an at least generally straight line from one side of the fuselage to the other.
20. The aircraft of claim 13 wherein the at least one wing includes a single wing having a common structure extending from a first side of the fuselage to a second side of the fuselage.
21. The aircraft of claim 13 wherein the at least one wing includes a single wing having a unitary structure extending from a first side of the fuselage to a second side of the fuselage.
22. The aircraft of claim 13 wherein the at least one wing includes a structure extending from a first side of the fuselage to a second side of the fuselage without a splice.
23. The aircraft of claim 13 wherein the slot extends over less than an entire span of the at least one wing.
24. The aircraft of claim 13 wherein the wing includes an aileron, and wherein the slot extends spanwise through a region of the at least one wing containing the aileron.
25. The aircraft of claim 13 wherein the at least one wing includes a single wing extending from a first tip on a first side of the fuselage to a second tip on a second side of the fuselage, and wherein the at least one wing further includes forward and aft spars, the forward spar extending from a first position at least proximate to the first tip to a second position at least proximate to the second tip, the aft spar extending from a third position at least proximate to the first tip to a fourth position at least proximate to the second tip.
26. The aircraft of claim 13 wherein the slot is a first slot, and wherein the trailing edge device is movable relative to the at least one wing to form a second slot forward of the first slot and divert additional air from the lower surface of the wing to the upper surface of the trailing edge device.
27. The aircraft of claim 13 wherein at least one of the upper surface and lower surface of at least one of the wing and the trailing edge device includes a composite material.
28. The aircraft of claim 13, further comprising a propulsion system depending from at least one of the at least one wing and the fuselage.
29. The aircraft of claim 13, further comprising an empennage aft of the at least one wing.
30. The aircraft of claim 13 wherein the slot is configured to divert air sufficient to increase a critical Mach number of the aircraft.
31. The aircraft of claim 13 wherein the slot is configured to divert air sufficient to increase a maximum cruise speed of the aircraft.
32. An aircraft, comprising:
- a fuselage,
- at least one wing attached to the fuselage, the at least one wing including: a forward airfoil element having an upper surface and a lower surface; at least one spar positioned within the forward airfoil element and extending in an at least generally straight line from one side of the fuselage to the other; an aft airfoil element having an upper surface and a lower surface, the aft airfoil element being coupled to the forward airfoil element, the aft airfoil element having a leading edge spaced apart from a portion of the forward airfoil element with a slot positioned between the portion of the forward airfoil element and the leading edge of the aft airfoil element, the slot being configured to be open during cruise flight to divert some of the air flowing along the lower surface of the forward airfoil element to flow over the upper surface of the aft airfoil element;
- a propulsion system depending from at least one of the at least one wing and the fuselage; and
- landing gear depending from the fuselage.
33. The aircraft of claim 32 wherein the at least one wing is configured for a subsonic cruise speed of at least Mach 0.78.
34. The aircraft of claim 32 wherein the at least one wing has an at least approximately unswept leading edge.
35. The aircraft of claim 32 wherein the at least one spar is at least approximately unswept.
36. The aircraft of claim 32 wherein the slot is configured to divert air sufficient to increase a critical Mach number of the aircraft.
37. The aircraft of claim 32 wherein the slot is configured to divert air sufficient to increase a maximum cruise speed of the aircraft.
38. The aircraft of claim 32 wherein the at least one wing includes a single wing having a unitary structure extending from a first side of the fuselage to a second side of the fuselage.
39. The aircraft of claim 32 wherein the slot extends over less than an entire span of the at least one wing.
40. The aircraft of claim 32 wherein the at least one wing, includes an aileron, and wherein the slot extends spanwise through a region of the at least one wing containing the aileron.
41. An aircraft system, comprising:
- at least one wing having an upper surface shaped to include at least one transonic region during cruise flight; and
- a flap assembly that includes a forward airfoil element having an upper surface portion and a lower surface portion, and an aft airfoil element coupled to the forward airfoil element, the aft airfoil element having an upper surface portion and a lower surface portion, at least a part of the aft airfoil element being spaced apart from a part of the forward airfoil element by a fixed first slot, the first slot being configured to be open during cruise flight to divert some of the air flowing along the lower surface portion of the wing to flow over the upper surface portion of the aft airfoil element, the first slot having an aft-facing exit opening at an offset between the upper surface of the wing and the upper surface portion of the aft airfoil element, the offset being in the thickness direction, and wherein the forward airfoil element and the aft airfoil element are movable as a unit relative to the at least one wing to open a second slot between the forward airfoil element and the at least one wing, the forward and aft airfoil elements having a fixed angular relationship with each other when the second slot is open and when the second slot is closed.
42. The aircraft system of claim 41 wherein the at least one wing is shaped to be efficient at a transonic condition.
43. The aircraft system of claim 41, further comprising:
- a fuselage coupled to the at least one wing,
- a propulsion system depending from at least one of the at least one wing and the fuselage; and
- landing gear depending from at least one of the at least one wing and the fuselage.
44. The aircraft system of claim 41 wherein the at least one wing is at least approximately unswept.
45. The aircraft system of claim 41 wherein the at least one wing overlaps the trailing edge assembly by three percent of a combined chord length of the at least one wing and the flap assembly when the flap assembly is stowed.
46. The aircraft system of claim 41 wherein the slot extends over less than an entire span of the at least one wing.
47. The aircraft system of claim 41 wherein the at least one wing includes an aileron, and wherein the slot extends spanwise through a region of the at least one wing containing the aileron.
48. The aircraft system of claim 41 wherein the slot is configured to divert air sufficient to increase a critical Mach number of the aircraft.
49. The aircraft system of claim 41 wherein the slot is configured to divert air sufficient to increase a maximum cruise speed of the aircraft.
50. An aircraft system, comprising:
- at least one wing having a leading edge, an upper surface, and a lower surface, the upper surface being shaped to include at least one transonic region during cruise flight; and
- a trailing edge device carried by the at least one wing, the trailing edge device having an upper surface and a lower surface, the upper surface of the trailing edge device being recessed away from an aft-extended contour of the at least one wing upper surface in a thickness direction along its entire length when in a neutral, undeflected position, at least one of the at least one wing and the trailing edge device having a spanwise slot, the slot having an aft-facing exit opening at an offset between the upper surfaces of the at least one wing and the trailing edge device, the offset being in the thickness direction, the slot being configured to be open during cruise flight to divert some of the air flowing along the lower surface of the at least one wing to flow over the upper surface of the trailing edge device, the slot being positioned to increase a Mach number at which the at least one wing undergoes transonic drag rise by about 0.03 compared with a wing having generally similar shape without the slot, the Mach number corresponding to a component of flow travelling generally normal to the leading edge of the at least one wing.
51. The aircraft system of claim 50, further comprising:
- a fuselage coupled to the at least one wing;
- a propulsion system depending from at least one of the at least one wing and the fuselage; and
- landing gear depending from at least one of the at least one wing and the fuselage.
52. The aircraft system of claim 50 wherein the at least one wing is shaped to be efficient at a transonic condition.
53. The aircraft system of claim 50 wherein the at least one wing is at least approximately unswept.
54. The aircraft system of claim 50 wherein the slot is configured to remain open at all flight conditions.
55. The aircraft system of claim 50 wherein the at least one wing includes at least one spar that is at least approximately unswept.
56. The aircraft system of claim 50 wherein the slot extends over less than an entire span of the at least one wing.
57. The aircraft system of claim 50 wherein the at least one wing includes an aileron, and wherein the slot extends spanwise through a region of the at least one wing containing the aileron.
58. The aircraft system of claim 50 wherein the slot is a first slot and wherein the trailing edge device includes a forward portion and an aft portion, the forward portion and the aft portion being movable as a unit relative to the at least one wing to form a second slot forward of the first slot and divert additional air from the lower surface of the at least one wing to the upper surface of the trailing edge device.
59. The aircraft system of claim 50 wherein the at least one wing overlaps the trailing edge device by a distance at least approximately equal to three percent of a combined chord length of the at least one wing and the trailing edge device.
60. An aircraft system, comprising:
- at least one wing, the at least one wing having an upper surface and a lower surface;
- an internal structure including at least one spar; and
- an airfoil structure including a trailing edge device carried by the at least one wing, the trailing edge device having an upper surface and a lower surface, the upper surface of the trailing edge device being recessed away from an aft-extended contour of the at least one wing upper surface in a thickness direction along its entire length when in a neutral, undeflected, undeployed position, at least one of the at least one wing and the trailing edge device having a spanwise slot that allows airflow from the at least one wing to the trailing edge device, wherein during cruising flight of the at least one wing, the airfoil structure diverts some of the air flowing along the lower surface of the at least one wing through the slot to flow over the upper surface of the trailing edge device.
61. The aircraft system of claim 60 wherein the slot extends over less than an entire span of the at least one wing.
62. The aircraft system of claim 60 wherein the at least one wing includes an aileron, and wherein the slot extends spanwise through a region of the at least one wing containing the aileron.
63. A method for manufacturing an aircraft system, comprising coupling a trailing edge device to an aircraft wing, with the aircraft wing overlapping the trailing edge device by a distance at least approximately equal to three percent of a combined chord length of the aircraft wing and the trailing edge device, and with a spanwise slot positioned between at least part of the aircraft wing and at least part of the trailing edge device, the slot being configured to be open during cruise flight to divert some of the air flowing along a lower surface of the aircraft wing to flow over an upper surface of the trailing edge device, the upper surface of the trailing edge device being recessed away from an aft-extended contour of the aircraft wing upper surface in a thickness direction along its entire length when in a neutral, undeflected, undeployed position, the slot having an aft-facing exit opening at an offset between an upper surface of the aircraft wing and the upper surface of the trailing edge device, the offset being in the thickness direction.
64. The method of claim 63, further comprising:
- attaching the aircraft wing to a fuselage;
- connecting a propulsion system to at least one of the aircraft wing and the fuselage; and
- coupling landing gear to at least one of the aircraft wing and the fuselage.
65. The method of claim 63 wherein coupling a trailing edge device to an aircraft wing includes coupling the trailing edge device to an at least approximately unswept aircraft wing.
66. The method of claim 63, further comprising configuring the slot to remain open at all flight conditions.
67. The method of claim 63, further comprising supporting the aircraft wing with at least one spar that is at least approximately unswept.
68. The method of claim 63, further comprising positioning the slot to extend over less than an entire span of the aircraft wing.
69. The method of claim 63, further comprising attaching an aileron to the aircraft wing and positioning the slot to extend spanwise through a region of the aircraft wing containing the aileron.
70. A method for manufacturing an aircraft system, comprising:
- coupling a trailing edge device to an aircraft wing; and
- positioning a slot between at least part of the aircraft wing and at least part of the trailing edge device to increase a Mach number at which the aircraft wing undergoes transonic drag rise by about 0.03 compared with an aircraft wing having a generally similar shape without the slot, the Mach number corresponding to a component of flow travelling generally normal to the leading edge of the aircraft wing, the slot being configured to be open during cruise flight to divert some of the air flowing along a lower surface of the aircraft wing to flow over an upper surface of the trailing edge device.
71. The method of claim 70, further comprising:
- attaching the aircraft wing to a fuselage;
- connecting a propulsion system to at least one of the aircraft wing and the fuselage; and
- coupling landing gear to at least one of the aircraft wing and the fuselage.
72. The method of claim 70 wherein coupling a trailing edge device to an aircraft wing includes coupling a trailing edge device to an at least approximately unswept wing.
73. The method of claim 70, further comprising configuring the slot to remain open at all flight conditions.
74. The method of claim 70, further comprising supporting the aircraft wing with at least one spar that is at least approximately unswept.
75. The method of claim 70, further comprising positioning the slot to extend over less than an entire span of the aircraft wing.
76. The method of claim 70, further comprising attaching ailerons to the wing and positioning the slot to extend spanwise through a region of the wing containing the ailerons.
1724456 | August 1929 | Crook |
1770575 | July 1930 | Ksoll |
1785620 | December 1930 | Frise |
1913169 | June 1933 | Martin |
2086085 | July 1937 | Lachmann et al. |
2138952 | December 1938 | Blume |
2169416 | August 1939 | Griswold |
2207453 | July 1940 | Blume |
2282516 | May 1942 | Hans et al. |
2289704 | July 1942 | Grant |
2319383 | May 1943 | Zap |
2444293 | June 1943 | Holt |
2347230 | April 1944 | Zuck |
2383102 | August 1945 | Zap |
2387492 | October 1945 | Blaylock et al. |
2406475 | August 1946 | Rogers |
2421694 | June 1947 | Hawkins |
2422296 | June 1947 | Flader et al. |
2458900 | January 1949 | Erny |
2502315 | March 1950 | Earhart |
2518854 | August 1950 | Badenoch |
2549760 | April 1951 | Adams |
2555862 | June 1951 | Romani |
2563453 | August 1951 | Briend |
2652812 | September 1953 | Fenzl |
2665084 | January 1954 | Feeney et al. |
2665085 | January 1954 | Crocombe et al. |
2743887 | May 1956 | Fiedler |
2864239 | December 1958 | Taylor |
2891740 | June 1959 | Campbell |
2892312 | June 1959 | Allen et al. |
2920844 | January 1960 | Marshall et al. |
2938680 | May 1960 | Greene et al. |
2990144 | June 1961 | Hougland |
2990145 | June 1961 | Hougland |
3102607 | September 1963 | Roberts |
3112089 | November 1963 | Dornier |
3136504 | June 1964 | Carr |
3203647 | August 1965 | Alvarez-Calderon |
3362659 | January 1968 | Razak |
3375998 | April 1968 | Alvarez-Calderon |
3447763 | June 1969 | Allcock |
3486720 | December 1969 | Seglem et al. |
3493196 | February 1970 | McCall |
3504870 | April 1970 | Cole et al. |
3528632 | September 1970 | Miles et al. |
3539133 | November 1970 | Robertson |
3556439 | January 1971 | Autry et al. |
3583660 | June 1971 | Hurkamp et al. |
3589648 | June 1971 | Gorham et al. |
3642234 | February 1972 | Kamber et al. |
3653611 | April 1972 | Trupp et al. |
3677504 | July 1972 | Schwarzler et al. |
3704828 | December 1972 | Studer et al. |
3704843 | December 1972 | Jenny |
3743219 | July 1973 | Gorges |
3767140 | October 1973 | Johnson |
3776491 | December 1973 | Oulton |
3790106 | February 1974 | Sweeney et al. |
3794276 | February 1974 | Maltby et al. |
3831886 | August 1974 | Burdges et al. |
3836099 | September 1974 | O'Neill et al. |
3837601 | September 1974 | Cole |
3853289 | December 1974 | Nevermann et al. |
3862730 | January 1975 | Heiney |
3874617 | April 1975 | Johnson |
3887147 | June 1975 | Grieb |
3897029 | July 1975 | Calderon et al. |
3904152 | September 1975 | Hill |
3910530 | October 1975 | James et al. |
3917192 | November 1975 | Alvarez-Calderon et al. |
3941334 | March 2, 1976 | Cole |
3941341 | March 2, 1976 | Brogdon, Jr. |
3968946 | July 13, 1976 | Cole |
3985319 | October 12, 1976 | Dean et al. |
3987983 | October 26, 1976 | Cole |
3992979 | November 23, 1976 | Smith |
3994451 | November 30, 1976 | Cole |
4015787 | April 5, 1977 | Maieli et al. |
4049219 | September 20, 1977 | Dean et al. |
4117996 | October 3, 1978 | Sherman |
4120470 | October 17, 1978 | Whitener |
4131253 | December 26, 1978 | Zapel |
4146200 | March 27, 1979 | Borzachillo |
4171787 | October 23, 1979 | Zapel |
4172575 | October 30, 1979 | Cole |
4189120 | February 19, 1980 | Wang |
4189121 | February 19, 1980 | Harper et al. |
4189122 | February 19, 1980 | Miller |
4200253 | April 29, 1980 | Rowarth |
4240255 | December 23, 1980 | Benilan |
4248395 | February 3, 1981 | Cole |
4262868 | April 21, 1981 | Dean |
4275942 | June 30, 1981 | Steidl |
4283029 | August 11, 1981 | Rudolph |
4285482 | August 25, 1981 | Lewis |
4293110 | October 6, 1981 | Middleton |
4312486 | January 26, 1982 | McKinney |
4351502 | September 28, 1982 | Statkus |
4353517 | October 12, 1982 | Rudolph |
4358077 | November 9, 1982 | Coronel |
4365774 | December 28, 1982 | Coronel |
4368937 | January 18, 1983 | Palombo |
4384693 | May 24, 1983 | Pauly et al. |
4395008 | July 26, 1983 | Sharrock et al. |
4427168 | January 24, 1984 | McKinney |
4441675 | April 10, 1984 | Boehringer et al. |
4444368 | April 24, 1984 | Andrews |
4461449 | July 24, 1984 | Turner |
4471925 | September 18, 1984 | Kunz et al. |
4471927 | September 18, 1984 | Rudolph |
4475702 | October 9, 1984 | Cole |
4485992 | December 4, 1984 | Rao |
4496121 | January 29, 1985 | Berlin |
4498646 | February 12, 1985 | Proksch |
4533096 | August 6, 1985 | Baker et al. |
4575030 | March 11, 1986 | Gratzer |
4576347 | March 18, 1986 | Opsahl |
4605187 | August 12, 1986 | Stephenson |
4637573 | January 20, 1987 | Perin et al. |
4650140 | March 17, 1987 | Cole |
4700911 | October 20, 1987 | Zimmer |
4702441 | October 27, 1987 | Wang |
4702442 | October 27, 1987 | Weiland et al. |
4706913 | November 17, 1987 | Cole |
4717097 | January 5, 1988 | Sepstrup |
4729528 | March 8, 1988 | Borzachillo |
4763862 | August 16, 1988 | Steinhauer et al. |
4784355 | November 15, 1988 | Brine |
4786013 | November 22, 1988 | Pohl |
4834326 | May 30, 1989 | Stache |
4856735 | August 15, 1989 | Lotz et al. |
4899284 | February 6, 1990 | Lewis |
4962902 | October 16, 1990 | Fortes |
5046688 | September 10, 1991 | Woods |
5074495 | December 24, 1991 | Raymond |
5082208 | January 21, 1992 | Matich |
5088665 | February 18, 1992 | Vijgen |
5094411 | March 10, 1992 | Rao |
5094412 | March 10, 1992 | Narramore |
5100082 | March 31, 1992 | Archung |
5114100 | May 19, 1992 | Rudolph |
5129597 | July 14, 1992 | Manthey |
5158252 | October 27, 1992 | Sakurai |
5167383 | December 1, 1992 | Nozaki |
5203619 | April 20, 1993 | Welsch |
5207400 | May 4, 1993 | Jennings |
5244269 | September 14, 1993 | Harriehausen |
5259293 | November 9, 1993 | Brunner |
5351914 | October 4, 1994 | Nagao |
5441218 | August 15, 1995 | Mueller |
5474265 | December 12, 1995 | Capbern |
5535852 | July 16, 1996 | Bishop |
5544847 | August 13, 1996 | Bliesner |
5600220 | February 4, 1997 | Thoraval |
5609020 | March 11, 1997 | Jackson |
5680124 | October 21, 1997 | Bedell et al. |
5686907 | November 11, 1997 | Bedell et al. |
5735485 | April 7, 1998 | Ciprian et al. |
5740991 | April 21, 1998 | Gleine et al. |
5743490 | April 28, 1998 | Gillingham |
5788190 | August 4, 1998 | Siers |
5875998 | March 2, 1999 | Gleine |
5921506 | July 13, 1999 | Appa |
5927656 | July 27, 1999 | Hinkleman |
5934615 | August 10, 1999 | Treichler |
5984230 | November 16, 1999 | Orazi |
6015117 | January 18, 2000 | Broadbent |
6045204 | April 4, 2000 | Frazier |
6073624 | June 13, 2000 | Laurent |
6076767 | June 20, 2000 | Farley et al. |
6076776 | June 20, 2000 | Breitbach |
6109567 | August 29, 2000 | Munoz |
6161801 | December 19, 2000 | Kelm |
6213433 | April 10, 2001 | Gruensfelder |
6293497 | September 25, 2001 | Kelley-Wickemeyer et al. |
6328265 | December 11, 2001 | Dizdarevic |
6349798 | February 26, 2002 | McKay |
6364254 | April 2, 2002 | May |
6375126 | April 23, 2002 | Sakurai |
6443394 | September 3, 2002 | Weisend |
6484969 | November 26, 2002 | Sprenger |
6499577 | December 31, 2002 | Kitamoto et al. |
6536714 | March 25, 2003 | Gleine et al. |
6547183 | April 15, 2003 | Farnsworth |
6554229 | April 29, 2003 | Lam |
6591169 | July 8, 2003 | Jones |
6598829 | July 29, 2003 | Kamstra |
6598834 | July 29, 2003 | Nettle |
6601801 | August 5, 2003 | Prow |
6622972 | September 23, 2003 | Urnes, Sr. et al. |
6625982 | September 30, 2003 | Van Den Bossche |
6644599 | November 11, 2003 | Perez |
6651930 | November 25, 2003 | Gautier et al. |
6796534 | September 28, 2004 | Beyer |
6799739 | October 5, 2004 | Jones |
20020046087 | April 18, 2002 | Hey |
20030132860 | July 17, 2003 | Feyereisen |
20040004162 | January 8, 2004 | Beyer |
20040059474 | March 25, 2004 | Boorman |
20050011994 | January 20, 2005 | Sakurai et al. |
20050017126 | January 27, 2005 | McLean et al. |
0 103 038 | March 1984 | EP |
230061 | July 1987 | EP |
0 947 421 | October 1999 | EP |
705155 | June 1931 | FR |
56121 | September 1952 | FR |
57 988 | September 1953 | FR |
58273 | November 1953 | FR |
1181991 | February 1970 | GB |
2 144 688 | March 1985 | GB |
WO-9105699 | May 1991 | WO |
- Petrov, A.V., “Certain Types of Separated Flow over Slotted Wings,” Fluid Mechanics—Soviet Research, vol. 7, No. 5, Sep.-Oct. 1978.
- TU 1-44 Canard, 1 pg, date unknown.
- U.S. Appl. No. 10/454,417, Neal V. Huynh.
- International Search Report, PCT/US03/19724/ Sep. 11, 2003, 5 pages.
- Moog, Component Maintenance Manual, May 1994 (2 pages).
- Drella, Mark, “Design and Optimization Method for Multi-Element Airfoils,” MIT Department of Aeronautics and Astronautics, pp. 7 and 9, figures 3, 7, and 8.
- * The High Speed Frontier, Chapter 2: The High-Speed Airfoil Program, “Supercritical” Airfoils, 1957-1978 (4 pages) http://www.hq.nasa.gov/office/pao/History/SP-445/ch2-5.
- * Junkers JU 52/3M (2 pages) http://www.wpafb.af.mil/museum/outdoor/od16 [Accessed Aug. 7, 2003].
- * Whitcomb, Richard T., “Review of NASA Supercritical Airfoils,” National Aeornautics and Space Administration, Aug. 1974 (pp. 8-18).
- * Drella, Mark, “Design and Optimization Method for Multi-Element Airfoils,” MIT Department of Aeornautics and Astronautics, Copyright 1993, American Institute of Aeronautics and Astronautics, Inc. (pp. 1-11).
- Hansen, H., “Application of Mini-Trailing-Edge Devices in the Awiator Project,” Airbus Deutschland, EGAG, Hunefeldstr. 1-5, D-28199 Bremen, Germany, 9 pages.
- Drela, M., “Optimization Techniques In Airfoil Design,” MIT Aero & Astro, 29 pages.
- European Supplementary Search Report for European Patent Application No. EP97947269, search completed May 19, 2000, 1 page.
- International Search Report for International Application No. PCT/US97/19048, mailed Feb. 23, 1998, 3 pages.
- Whitcomb, Richard T., “Review of NASA Supercritical Airfoils,” National Aeronautics and Space Administration, Aug. 1974 (pp. 8-18).
- Drella, Mark, “Design and Optimization Method for Multi-Elements Airfoils,” MIT Department of Aeronautics and Astronautics, pp. 7 and 9, figures 3, 7, and 8.
Type: Grant
Filed: Oct 22, 1997
Date of Patent: Jun 25, 2013
Assignee: The Boeing Company (Chicago, IL)
Inventors: Robert H. Kelley-Wickemeyer (Renton, WA), Peter Z. Anast (Sammamish, WA), James Douglas McLean (Seattle, WA), Hilda Seidel (Renton, WA)
Primary Examiner: Rob Swiatek
Application Number: 10/671,435
International Classification: B64C 3/14 (20060101); B64C 3/18 (20060101); B64C 3/28 (20060101); B64C 3/50 (20060101);