Control system for rotor aircraft

In a rotor aircraft having a fuselage and a rotor mounted on a rotor head for tilting in fore and aft directions, an improved control system for controlling tilt of the rotor, an improved control system, comprising:

• a control stick mounted to the fuselage for fore and aft movement;
• a linkage assembly connected to the control stick and to the rotor head for tilting the rotor head in fore and aft directions in response to movement of the control stick;
• an adjusting member mounted between the control stick and the linkage assembly, the adjusting member being movable between first and second positions while keeping the control stick stationary to reposition at least portions of the linkage assembly relative to the control stick into gross and fine positions, the fine position of the linkage assembly desensitizing the control stick so that a selected fore and aft movement of the control stick causes less tilting movement of the rotor head than while in the gross position;
• wherein
• the control stick is pivotally mounted to the fuselage about a control stick pivot point and the linkage assembly comprises:
• a bell crank assembly pivotally mounted to the fuselage about a bell crank pivot point;
• an leg secured to the bell crank assembly at a control pivot point that is spaced from the control stick pivot point by a radius, the leg being connected with the control stick so that fore and aft movement of the control stick causes the control point to move a circumferential distance relative to the control stick pivot point at the same radius, thereby pivoting the bell crank assembly about the bell crank pivot point an amount proportional to the circumferential distance;
• and
• moving the adjusting member from the first to the second positions reduces the radius and thus the circumferential distance that the control point travels, causing the bell crank assembly to move less about the pivot point and thus tilt the rotor head less for a given movement of the control stick,
• a control point that rotates about the control stick pivot point while the control stick pivots between fore and aft positions;
• and wherein
• the adjusting member varies a radius between the control point and the control stick pivot point as the adjusting member moves between the first and second positions.

In a rotor aircraft having a fuselage and a rotor mounted on a rotor head for tilting in fore and aft directions, an improved control system for controlling tilt of the rotor, an improved control system, comprising:

• a control stick mounted to the fuselage for fore and aft movement;
• a linkage assembly connected to the control stick and to the rotor head for tilting the rotor head in fore and aft directions in response to movement of the control stick;
• and
• an adjusting member mounted between the control stick and the linkage assembly, the adjusting member being movable between first and second positions while keeping the control stick stationary to reposition at least portions of the linkage assembly relative to the control stick into gross and fine positions, the fine position of the linkage assembly desensitizing the control stick so that a selected fore and aft movement of the control stick causes less tilting movement of the rotor head than while in the gross position.

In a rotor aircraft having a fuselage and a rotor mounted on a rotor head for tilting in fore and aft directions, an improved control system for controlling tilt of the rotor, an improved control system, comprising:

• a control stick mounted to the fuselage for fore and aft movement;
• a linkage assembly connected to the control stick and to the rotor head for tilting the rotor head in fore and aft directions in response to movement of the control stick;
• an adjusting member mounted between the control stick and the linkage assembly, the adjusting member being movable between first and second positions while keeping the control stick stationary to reposition at least portions of the linkage assembly relative to the control stick into gross and fine positions, the fine position of the linkage assembly desensitizing the control stick so that a selected fore and aft movement of the control stick causes less tilting movement of the rotor head than while in the gross position;
• wherein the aircraft further comprises:
• a horizontal stabilizer mounted to an aft section of the fuselage, the horizontal stabilizer being tiltable in upward and downward positions;
• a horizontal stabilizer linkage connected between the horizontal stabilizer and the control stick so that fore and aft movement of the control stick tilts the horizontal stabilizer up and down;
• and wherein
• the horizontal stabilizer linkage is isolated from the adjusting member so that movement of the adjusting member between the first and second positions has no effect on an amount of tilt of the horizontal stabilizer relative to an amount of fore and aft movement of the control the control stick.

In a rotor aircraft having a fuselage and a rotor mounted on a rotor head for tilting in fore and aft directions, an improved control system for controlling tilt of the rotor, an improved control system, comprising:

• a control stick mounted to the fuselage for fore and aft movement;
• a linkage assembly connected to the control stick and to the rotor head for tilting the rotor head in fore and aft directions in response to movement of the control stick;
• an adjusting member mounted between the control stick and the linkage assembly, the adjusting member being movable between first and second positions while keeping the control stick stationary to reposition at least portions of the linkage assembly relative to the control stick into gross and fine positions, the fine position of the linkage assembly desensitizing the control stick so that a selected fore and aft movement of the control stick causes less tilting movement of the rotor head than while in the gross position;
• wherein the aircraft further comprises:
• a wing extending from opposite sides of the fuselage;
• an aileron pivotally mounted to each wing for up and down tilting movement;
• an aileron linkage connected between the control stick and each of the ailerons for causing tilting movement of the ailerons in response to lateral movement of the control stick relative to the fuselage;
• and wherein
• the aileron linkages are isolated from the adjusting member so that movement of the adjusting member between the first and second positions has no effect on an amount of tilt of the ailerons relative to an amount of lateral movement of the control stick.

An aircraft, comprising:

• fuselage;
• a horizontal stabilizer pivotally mounted to an aft section of the fuselage for upward and downward tilting movement;
• a rotor head extending upward from the fuselage, the rotor heads being tiltable in fore and aft directions relative to the fuselage;
• a rotor mounted to the rotor head for rotation relative to the fuselage;
• a control stick pivotally mounted in a cockpit of the aircraft for fore and aft and side to side movement;
• a rotor linkage assembly connected between the control stick and the rotor head for tilting the rotor head fore and aft in response to the fore and aft movement of the control stick and tilting the rotor head laterally in response to lateral movement of the control stick;
• and
• a horizontal stabilizer linkage assembly pivotally connected between the control stick and the rotor head, the rotor linkage assembly and the horizontal stabilizer linkage assembly being connected with the control stick such that forward movement of the control stick from an aft position causes forward tilting of the rotor head and downward tilting of a trailing edge of the horizontal stabilizer.

An aircraft, comprising:

• a fuselage;
• a horizontal stabilizer pivotally mounted to an aft section of the fuselage for upward and downward tilting movement;
• rotor head extending upward from the fuselage, the rotor heads being tiltable in fore and aft directions relative to the fuselage;
• a rotor mounted to the rotor head for rotation relative to the fuselage;
• a control stick pivotally mounted in a cockpit of the aircraft for fore and aft and side to side movement;
• a rotor linkage assembly connected between the control stick and the rotor head for tilting the rotor head fore and aft in response to the fore and aft movement of the control stick and tilting the rotor head laterally in response to lateral movement of the control stick;
• a horizontal stabilizer linkage pivotally connected between the control stick and the rotor head, the rotor linkage assembly and the horizontal stabilizer linkage assembly being connected with the control stick such that forward movement of the control stick causes forward tilting of the rotor head and downward tilting of a trailing edge of the horizontal stabilizer;
• an adjusting member between the rotor linkage assembly and the control stick that moves the rotor linkage assembly between gross and fine positions relative to the control, such that movement of the rotor linkage to the fine position causes less fore and aft tilt of the rotor head when the control stick moves between full fore and aft positions than while in the gross position;
• and wherein
• the horizontal stabilizer linkage is isolated from movement of the rotor linkage assembly between the fine and gross positions, providing the same amount of horizontal stabilizer tilt for a given fore and aft movement of the control stick regardless of the fine and gross positions.

A rotor aircraft, comprising:

• a fuselage;
• a rotor mounted on a rotor head for tilting in fore and aft and lateral directions,
• a control stick mounted to the fuselage about a control stick pivot point for fore and aft and laterally movement;
• a rotor linkage assembly connected to the control stick and to the rotor head for tilting the rotor head in response to tilting movement of the control stick, the linkage assembly having a control point that rotates at a radius about the control stick pivot point;
• and
• an adjusting member mounted between the control stick and the linkage assembly, the adjusting member being movable to change the radius from the control point to the control stick pivot point, wherein the radius corresponds to the amount of tilt that the rotor head makes while moving between full aft and full forward positions with the control stick.

A method for controlling forward and rearward tilt of a rotor head that supports a rotor that rotates relative to a fuselage, comprising:

• (a) pivotally mounting a control stick in the fuselage for fore and aft movement;
• (b) connecting a rotor linkage between the control stick and the rotor head, the rotor linkage having a fine position and a gross position;
• (c) placing the rotor linkage in the gross position and moving the control stick from a full aft to a full forward position, thereby tilting the rotor head a gross amount in fore and aft directions;
• and
• (d) placing the rotor linkage in the fine position and moving the control stick from the full aft to the full forward position, thereby tilting the rotor head a fine amount that is much less than the gross amount.

A method for controlling forward and rearward tilt of a rotor head that supports a rotor that rotates relative to a fuselage, comprising:

• (a) pivotally mounting a control stick in the fuselage for fore and aft movement;
• (b) connecting a rotor linkage between the control stick and the rotor head, the rotor linkage having a fine position and a gross position;
• (c) placing the rotor linkage in the gross position and moving the control stick from a full aft to a full forward position, thereby tilting the rotor head a gross amount in fore and aft directions;
• (d) placing the rotor linkage in the fine position and moving the control stick from the full aft to the full forward position, thereby tilting the rotor head a fine amount that is much less than the gross amount;
• wherein:
• step (a) comprises mounting the control stick about a control stick pivot point;
• and
• step (b) comprises providing the rotor linkage with a control point that rotates about the pivot point at a first radius while in the gross position and at a second and smaller radius while in the fine position.

A method for controlling forward and rearward tilt of a rotor head that supports a rotor that rotates relative to a fuselage, comprising:

• (a) pivotally mounting a control stick in the fuselage for fore and aft movement;
• (b) connecting a rotor linkage between the control stick and the rotor head, the rotor linkage having a fine position and a gross position;
• (c) placing the rotor linkage in the gross position and moving the control stick from a full aft to a full forward position, thereby tilting the rotor head a gross amount in fore and aft directions;
• placing the rotor linkage in the fine position and moving the control stick from the full aft to the full forward position, thereby tilting the rotor head a fine amount that is much less than the gross amount;
• wherein the aircraft has a horizontal stabilizer located at an aft end of the fuselage, and wherein the method further comprises:
• connecting a horizontal stabilizer linkage between the control stick and the horizontal stabilizer step (c) comprises tilting a trailing edge of the horizontal stabilizer fully downward in response to the full forward movement of the control stick and fully upward in response to the full aft movement of the control stick;
• and
• step (d) comprises tilting the trailing edge of the horizontal stabilizer fully downward and fully upward the same amount as in step (c).

A method for controlling forward and rearward tilt of a rotor head that supports a rotor that rotates relative to a fuselage, comprising:

• (a) pivotally mounting a control stick in the fuselage for fore and aft movement;
• (b) connecting a rotor linkage between the control stick and the rotor head, the rotor linkage having a fine position and a gross position;
• (c) placing the rotor linkage in the gross position and moving the control stick from a full aft to a full forward position, thereby tilting the rotor head a gross amount in fore and aft directions;
• (d) placing the rotor linkage in the fine position and moving the control stick from the full aft to the full forward position, thereby tilting the rotor head a fine amount that is much less than the gross amount;
• while the rotor linkage is in the gross position, moving the control stick from a full starboard position to a full port position, and thereby causing tilting of the rotor head from a full starboard position to a full port position;
• and
• while the rotor linkage is in the fine position, moving the control stick from the full starboard position to the full port position, and thereby causing tilting of the rotor head from the full starboard position to the full port position.