GB1568250A - Aircraft - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO AIRCRAFT (71) We, HAWKER SIDDELEY AVIATION LIMITED, Richmond Road, Kingston-on Thames, Surrey KT2 5QS, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to aircraft wings of the type having both lift increasing flaps and lift decreasing spoilers.

Spoilers are used for modifying the airflow over a wing so as to reduce or destroy aerodynamic lift thus imparting a measure of attitude and/or lift control to the aircraft during both flight and landing.

Known arrangements of spoilers comprise small-chord spanwise surfaces pivotally mounted on top of each wing and symmetrically disposed about the aircraft longitudinal centre line. For lateral control, one or other of the port or starboard spoilers may be angularly raised modifying or destroying lift on the side raised to impart a rolling moment to the aircraft in similar manner to a conventional aileron. Additionally, both port and starboard spoilers may be raised simultaneously to provide direct and symmetrical lift control during flight. Similarly, during landing, symmetrical destruction of the wing lift significantly reduces the landing run.

Where an aircraft wing has a lift increasing flap which lies, when in an operative lift increasing position, aft of a spoiler so that a spanwise slot is defined between an aft region of the spoiler and a leading region of the flap, movement of the spoiler to decrease lift, thereby widening the slot, can produce an interaction characterised by a greater loss of lift than expected for a given movement of the spoiler followed by a smaller loss of lift than expected for subsequent movements.

In other words, the progression of lift loss with spoiler movement is non-linear; such a non-linear progression causes the aircraft to have undesirable flight control characteristics.

An object of the present invention is to provide a more linear progression of lift loss with spoiler movements so that the undesirable flight control characteristics are at least reduced.

According to the present invention an aircraft wing includes in combination a lift increasing flap movable from an inoperative position in which it conforms to the wing contour to an operative position in which it extends rearwardly and downwardly to increase lift, and a lift decreasing spoiler movable from an inoperative position in which it conforms to the wing contour to an operative position in which it extends upwardly to decrease lift, the flap and the spoiler being so arranged that when the flap is in an operative position and, at least when the spoiler is in an inoperative position, a primary spanwise slot is defined between an aft region of the spoiler and an upper leading region of the flap, the flap having an auxiliary spanwise slot through which air can be directed to flow over the upper leading region of the flap aft of the primary slot but sufficiently forward to effect flow improvements over a major chordwise portion of the flap.

Where the spoiler is of smaller span than the flap, the spanwise length of the auxiliary slot is the same as or less than the span of the spoiler, and the position of the auxiliary slot is such that its spanwise extremities do not extend beyond the spanwise extremities of the spoiler.

A preferred embodiment of the invention is described with reference to the accompanying drawings in which: Figure 1 depicts a starboard portion of an aircraft wing, Figure 2 is a chordwise section through an aft portion of the wing in the direction of arrows II-II of Figure 1 with a lift increasing flap in an operative position, Figure 3 is a similar section to Figure 2 but with the lift increasing flap in an inoperative position, and Figure 4 is a graphical comparison of linear and non-linear lift loss plotted against spoiler angular movement.

in the drawings, an aircraft wing 1 has forward region 2, an aft region 3 and a tip region 4. Its aft region 3 includes a fixed spanwise structure 5, a lift increasing flap 6 carried, by means not shown, upon the fixed structure 5, and a lift decreasing spoiler 7 also carried by the fixed structure 5.

The flap 6 is movble from an inoperative position, shown in Figure 3, in which it conforms to the wing contour, to an operative position, shown in Figures 1 and 2, in which it extends rearwards and downwards to increase wing lift.

The spoiler 7 is pivoted about a spanwise axis 8 and is movable from an inoperative position, shown in Figures 1, 2 and 3, to an operative position shown in broken outline at 7a in Figure 2. Such pivotal movement is effected by a jack 9 extending between the fixed structure 5 and the spoiler 7.

With the flap 6 in its operative position and the spoiler 7 in or near to its inoperative position, a primary spanwise slot 12 is formed between a trailing edge 10 of the spoiler 7 and an upper leading edge 11 of the flap 6; the flap 6 is thus of the slotted type in which the depth of the slot 12 is chosen to allow a desired airflow to pass from the underside of the wing, through the slot 12, to flow over the upper surface of the flap 6 and thereby improve the airflow over it. In other words, the lift increasing characteristics of the flap are enhanced.

However, when the spoiler 7 is moved to an operative position, for example that referenced 7a in Figure 2, the slot 12 becomes deeper, deviating from its chosen depth, so that the quantity of air flowing through it also changes. This change has a pronounced effect upon the lift characteristics of the flap.

To reduce this effect the flap 6 is accordingly provided with a spanwise auxiliary slot 13 extending through the thickness of the flap with an inlet 14 on a lower region and an exit 15 on an upper leading region of the flap. The exit 15 lies aft of the primary slot 12 when the flap 6 is in an operative position but is sufficiently near to the leading edge of the flap that air flowing from the exit effects flow improvement over a major chordwise portion of the flap.

When the flap 6 is in its inoperative position, as shown in Figure 3, the spoiler 7 is arranged to lie above an upper surface ofthe flap to close the exit 15 of the auxiliary slot. A closure member 16, carried by and extending aft of the structure 5, is provided to close the inlet 14.

The auxiliary slot 13 is of a finite spanwise length chosen to be less than the span of the spoiler 7. However its spanwise length may approach the span of the spoiler 7 provided its spanwise extremities do not extend inboard or outboard beyond the extremities of the spoiler.

Figure 4 graphically illustrates the rise of lift loss in progression with spoiler angular movement. The graph A illustrates the characteristics of a wing including a spoiler 7 and a flap 6 with no auxiliary slot 13; as can be seen there is a sharp lift loss associated with initial spoiler angular movement followed by a relatively gradual lift loss as spoiler angular movement increases. The graph is distinctly non linear.

The graph B illustrates the characteristics of a wing including a spoiler 7, and a flap 6 in which an auxiliary slot 13 is incorporated; as can be seen there is an approximately linear relationship between lift loss and spoiler angular movement.

WHAT WE CLAIM IS: 1. An aircraft wing including in combination a lift increasing flap movable from an inoperative position in which it conforms to the wing contour to an operative position in which it extends rearwardly and downwardly to increase lift, and a lift decreasing spoiler movable from an inoperative position in which it conforms to the wing contour to an operative position in which it extends upwardly to decrease lift, the flap and spoiler being so arranged that when the flap is in an operative position and at least when the spoiler is in an inoperative position, a primary spanwise slot is defined between an aft region of the spoiler and an upper leading region of the flap, the flap having an auxiliary spanwise slot through which air can be directed to flow over the upper leading region of the flap aft of the primary slot but sufficiently forward to effect flow improvement over a major chordwise portion of the flap.

2. An aircraft wing according to claim 1 wherein the spanwise length of the auxiliary slot is the same as or less than the span of the spoiler, and the position of the auxiliary slot is such that its spanwise extremities do not extend beyond the spanwise extremities of the spoiler.

3. An aircraft wing according to claim 1 or claim 2 wherein the spoiler is arranged to lie above the flap when the latter is in the inoperative position to cover an exit region of the auxiliary slot.

4. An aircraft wing according to any one of the previous claims wherein an inlet region of the auxiliary slot is covered by a closure member when the flap is in an inoperative position.

5. An aircraft wing substantially as described with reference to Figures 1, 2 and 3 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   forward region 2, an aft region 3 and a tip region 4. Its aft region 3 includes a fixed spanwise structure 5, a lift increasing flap 6 carried, by means not shown, upon the fixed structure 5, and a lift decreasing spoiler 7 also carried by the fixed structure 5.

   The flap 6 is movble from an inoperative position, shown in Figure 3, in which it conforms to the wing contour, to an operative position, shown in Figures 1 and 2, in which it extends rearwards and downwards to increase wing lift.

   The spoiler 7 is pivoted about a spanwise axis 8 and is movable from an inoperative position, shown in Figures 1, 2 and 3, to an operative position shown in broken outline at 7a in Figure 2. Such pivotal movement is effected by a jack 9 extending between the fixed structure 5 and the spoiler 7.

   With the flap 6 in its operative position and the spoiler 7 in or near to its inoperative position, a primary spanwise slot 12 is formed between a trailing edge 10 of the spoiler 7 and an upper leading edge 11 of the flap 6; the flap 6 is thus of the slotted type in which the depth of the slot 12 is chosen to allow a desired airflow to pass from the underside of the wing, through the slot 12, to flow over the upper surface of the flap 6 and thereby improve the airflow over it. In other words, the lift increasing characteristics of the flap are enhanced.

   However, when the spoiler 7 is moved to an operative position, for example that referenced 7a in Figure 2, the slot 12 becomes deeper, deviating from its chosen depth, so that the quantity of air flowing through it also changes. This change has a pronounced effect upon the lift characteristics of the flap.

   To reduce this effect the flap 6 is accordingly provided with a spanwise auxiliary slot 13 extending through the thickness of the flap with an inlet 14 on a lower region and an exit

   15 on an upper leading region of the flap. The exit 15 lies aft of the primary slot 12 when the flap 6 is in an operative position but is sufficiently near to the leading edge of the flap that air flowing from the exit effects flow improvement over a major chordwise portion of the flap.

   When the flap 6 is in its inoperative position, as shown in Figure 3, the spoiler 7 is arranged to lie above an upper surface ofthe flap to close the exit 15 of the auxiliary slot. A closure member 16, carried by and extending aft of the structure 5, is provided to close the inlet 14.

   The auxiliary slot 13 is of a finite spanwise length chosen to be less than the span of the spoiler 7. However its spanwise length may approach the span of the spoiler 7 provided its spanwise extremities do not extend inboard or outboard beyond the extremities of the spoiler.

   Figure 4 graphically illustrates the rise of lift loss in progression with spoiler angular movement. The graph A illustrates the characteristics of a wing including a spoiler 7 and a flap 6 with no auxiliary slot 13; as can be seen there is a sharp lift loss associated with initial spoiler angular movement followed by a relatively gradual lift loss as spoiler angular movement increases. The graph is distinctly non linear.

   The graph B illustrates the characteristics of a wing including a spoiler 7, and a flap 6 in which an auxiliary slot 13 is incorporated; as can be seen there is an approximately linear relationship between lift loss and spoiler angular movement.

   WHAT WE CLAIM IS: 1. An aircraft wing including in combination a lift increasing flap movable from an inoperative position in which it conforms to the wing contour to an operative position in which it extends rearwardly and downwardly to increase lift, and a lift decreasing spoiler movable from an inoperative position in which it conforms to the wing contour to an operative position in which it extends upwardly to decrease lift, the flap and spoiler being so arranged that when the flap is in an operative position and at least when the spoiler is in an inoperative position, a primary spanwise slot is defined between an aft region of the spoiler and an upper leading region of the flap, the flap having an auxiliary spanwise slot through which air can be directed to flow over the upper leading region of the flap aft of the primary slot but sufficiently forward to effect flow improvement over a major chordwise portion of the flap.
2. 2. An aircraft wing according to claim 1 wherein the spanwise length of the auxiliary slot is the same as or less than the span of the spoiler, and the position of the auxiliary slot is such that its spanwise extremities do not extend beyond the spanwise extremities of the spoiler.
3. 3. An aircraft wing according to claim 1 or claim 2 wherein the spoiler is arranged to lie above the flap when the latter is in the inoperative position to cover an exit region of the auxiliary slot.
4. 4. An aircraft wing according to any one of the previous claims wherein an inlet region of the auxiliary slot is covered by a closure member when the flap is in an inoperative position.
5. 5. An aircraft wing substantially as described with reference to Figures 1, 2 and 3 of the accompanying drawings.