GB2152450A

GB2152450A - Improvements in or relating to rotary winged aircraft

Info

Publication number: GB2152450A
Application number: GB08400476A
Authority: GB
Inventors: Kenneth Horatio Wallis
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-01-10
Filing date: 1984-01-10
Publication date: 1985-08-07
Also published as: GB2152450B

Abstract

A rotor brake system for a rotary winged aircraft, such as an autogyro, wherein the brake control lever 1 is located on the control column 3 in such a manner that when actuated to the ON position shown the lever is objectionally obtrusive but when actuated to the OFF position the control column hand-grip is structurally clean. The lever further provides a geometric lock for the rotor brake system. <IMAGE>

Description

SPECIFICATION Improvements relating to rotary winged aircraft It is usual for rotary winged aircraft to incorporate some form of brake to act upon the rotary system, to slow and stop the rotors after landing.

Such a rotor brake is described in part of my G.B. Patent No 925,302, filed on 15 November 1961.

In that example the rotor brake is applied by the pilot pulling down on a hand lever attached to the rotor head. The brake operating only as long as the lever is pulled. It is purposely not provided with a means of retaining the brake in the "ON"position, because of the risk of damage and danger which might result if the pilot omitted to release the brake before attempting to start the rotors and take-off.

In the case of aircraft for military use and certain other roles, it is of importance that the rotors be brought quickly to rest, particularly, in the case of an autogyro aircraft, since the pilot can taxi quickly into suitable concealment with the rotors stopped fore and aft.

It is the object of this invention to provide a brake lever, conveniently placed in the pilot's cockpit such that he can immediately select the lever to "ON" upon landing, and then leaving his hands free for other tasks, the rotors will be brought to rest at a pre-determined frictional load. Means are provided to prevent inadvertent take-off attempts with the brake "ON".

According to the invention, the risk of damage to the aircraft by an attempt to start the rotors with the brake "ON" is reduced by fitting the rotor brake lever on a fulcrum axis situated just below the hand-grip, and at the rear, of the pilot's control column.

When the rotor brake lever is in the "ON" position it is approximately vertically above its fulcrum axis and in line with the hand-grip, such that, when the pilot grips the hand-grip the presence of the rotor brake is uncomfortable and readily apparent.

To release the brake lever it is moved through approximately 1800 to the downward position, where it rests unobtrusively below the hand-grip.

In a preferred form of the invention the hand lever is connected to the rotor head brake system by a suitable flexible inner and outer cable, such as a Bowden cable.

Movement of the hand lever from the downward to the upward position exerts an increasing pull on the inner cable, applying the brake progressively.

As the lever reaches the upright and fully "ON" position the axes of the cable under tension, and the fulcrum axis of the lever, intersect. A further small movement to a suitable stop results in a geometric lock and the brake lever will remain in the "ON" position until selected "OFF".

That part of the lever facing the pilot in the "ON" position may be suitably annotated, using "Dayglo" (Registered Trade Mark) red and/or indication that the rotor brake is "ON". When the brake lever is down and "OFF" a green indicator may be displayed.

According to the invention we provide a brake for rotors of rotary winged aircraft comprising, in part, a brake lever having its fulcrum axis approximately vertically below and in line with the handgrip of a pilots control column so that the brake lever when in the "ON" position interferes with the pilots control column grip making it uncomfortable and the presence of the brake lever readily apparent.

The invention will now be described, by way of example only, in conjunction with the accompanying illustration in which, Figure 1 shows the hand brake in the "OFF" position and Figure 2 shows the hand brake in the "ON" position.

Referring to figure 1 a rotor brake lever (1) is pivoted on a bracket (2) rigidly attached to a control column (3) in a convenient position below the control column hand grip (4). A bifurcated connector link (5) is pivotally attached to the rotor brake lever at its bifurcated end and pivotally attached to an inner cable (6), of such as a Bowden cable, at its other end. A sleeve, or outer cable (7) in which the inner cable slides is rigidly attached by a clamp (8) at a convenient point on the control column (3). In this configuration the hand brake is unobtrusively below the hand grip and does not impede the pilots grip.

Referring now to figure 2 wherein the same numerals represent like parts, the hand brake (1) is shown in the "ON" position and the inner cable has been pulled through the outer cable or sleeve to apply the rotor brake, not shown. As can be seen from the illustration the hand brake impedes the pilots grip on the hand grip (4) and an immediate indication is transmitted to the pilot that the rotor brake is in the on position and must be released before any attempt to start the rotor.

In the brake system described, a simple mechanical system of application, and a geometric lock, is employed, but it is to be understood that the invention is not confined to this system. Hydraulic or other means of application, and another means of locking in the "ON" position, might be used in conjunction with the control column mounted lever described.

1. A hand brake for rotors of rotary winged aircraft comprising in part, a brake lever having its fulcrum axis approximately vertically below and in line with the hand-grip of a pilots control column so that the brake lever when in the "ON" position interferes with the pilots control column hand-grip making it uncomfortable and the presence of the brake lever readily apparent.

2. A hand brake as claimed in Claim 1 wherein said brake lever is rotatable through approximately 1800 to a downward position where it rests unobtrusively below the hand-grip when the rotor brake is "OFF".

3. A hand brake as claimed in Claim 1 having a

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements relating to rotary winged aircraft It is usual for rotary winged aircraft to incorporate some form of brake to act upon the rotary system, to slow and stop the rotors after landing. Such a rotor brake is described in part of my G.B. Patent No 925,302, filed on 15 November 1961. In that example the rotor brake is applied by the pilot pulling down on a hand lever attached to the rotor head. The brake operating only as long as the lever is pulled. It is purposely not provided with a means of retaining the brake in the "ON"position, because of the risk of damage and danger which might result if the pilot omitted to release the brake before attempting to start the rotors and take-off. In the case of aircraft for military use and certain other roles, it is of importance that the rotors be brought quickly to rest, particularly, in the case of an autogyro aircraft, since the pilot can taxi quickly into suitable concealment with the rotors stopped fore and aft. It is the object of this invention to provide a brake lever, conveniently placed in the pilot's cockpit such that he can immediately select the lever to "ON" upon landing, and then leaving his hands free for other tasks, the rotors will be brought to rest at a pre-determined frictional load. Means are provided to prevent inadvertent take-off attempts with the brake "ON". According to the invention, the risk of damage to the aircraft by an attempt to start the rotors with the brake "ON" is reduced by fitting the rotor brake lever on a fulcrum axis situated just below the hand-grip, and at the rear, of the pilot's control column. When the rotor brake lever is in the "ON" position it is approximately vertically above its fulcrum axis and in line with the hand-grip, such that, when the pilot grips the hand-grip the presence of the rotor brake is uncomfortable and readily apparent. To release the brake lever it is moved through approximately 1800 to the downward position, where it rests unobtrusively below the hand-grip. In a preferred form of the invention the hand lever is connected to the rotor head brake system by a suitable flexible inner and outer cable, such as a Bowden cable. Movement of the hand lever from the downward to the upward position exerts an increasing pull on the inner cable, applying the brake progressively. As the lever reaches the upright and fully "ON" position the axes of the cable under tension, and the fulcrum axis of the lever, intersect. A further small movement to a suitable stop results in a geometric lock and the brake lever will remain in the "ON" position until selected "OFF". That part of the lever facing the pilot in the "ON" position may be suitably annotated, using "Dayglo" (Registered Trade Mark) red and/or indication that the rotor brake is "ON". When the brake lever is down and "OFF" a green indicator may be displayed. According to the invention we provide a brake for rotors of rotary winged aircraft comprising, in part, a brake lever having its fulcrum axis approximately vertically below and in line with the handgrip of a pilots control column so that the brake lever when in the "ON" position interferes with the pilots control column grip making it uncomfortable and the presence of the brake lever readily apparent. The invention will now be described, by way of example only, in conjunction with the accompanying illustration in which, Figure 1 shows the hand brake in the "OFF" position and Figure 2 shows the hand brake in the "ON" position. Referring to figure 1 a rotor brake lever (1) is pivoted on a bracket (2) rigidly attached to a control column (3) in a convenient position below the control column hand grip (4). A bifurcated connector link (5) is pivotally attached to the rotor brake lever at its bifurcated end and pivotally attached to an inner cable (6), of such as a Bowden cable, at its other end. A sleeve, or outer cable (7) in which the inner cable slides is rigidly attached by a clamp (8) at a convenient point on the control column (3). In this configuration the hand brake is unobtrusively below the hand grip and does not impede the pilots grip. Referring now to figure 2 wherein the same numerals represent like parts, the hand brake (1) is shown in the "ON" position and the inner cable has been pulled through the outer cable or sleeve to apply the rotor brake, not shown. As can be seen from the illustration the hand brake impedes the pilots grip on the hand grip (4) and an immediate indication is transmitted to the pilot that the rotor brake is in the on position and must be released before any attempt to start the rotor. In the brake system described, a simple mechanical system of application, and a geometric lock, is employed, but it is to be understood that the invention is not confined to this system. Hydraulic or other means of application, and another means of locking in the "ON" position, might be used in conjunction with the control column mounted lever described. CLAIMS

3. A hand brake as claimed in Claim 1 having a flexible inner and outer cable forming at least part of a connecting system between the brake lever and rotor head brake system.

4. A hand brake as claimed in Claim 3 wherein movement of the brake lever from the downward position to the upward position exerts an increasing pull on the inner cable for progressive application of rotor brake.

5. A hand brake as claimed in Claims 1 to 4 wherein the geometry of the brake lever causes the lever to lock in the "ON" position until selected to "OFF".

6. A hand brake for rotors of rotary winged aircraft substantially as herein described in conjunction with the accompanying drawings.