A method of assisting the piloting of an aircraft. A collective pitch margin of a main rotor is determined by applying a recursive algorithm using a main relationship that supplies said collective pitch margin at each current calculation instant as a function of the quotient of a limiting power margin divided by a denominator, the denominator being equal to the product of a first term multiplied by a second term, the first term being a function of the current collective pitch at said current calculation instant and of the collective pitch limit at a previous calculation instant prior to said current calculation instant, said second term being a function at least of a predetermined coefficient for reducing said power margin of the power plant.

A passive elastic teeter bearing for an aircraft rotor, including, rotatably arranged on an rotational axis of said rotor, a teeter beam, configured for attaching the rotor which has rotor blades, with the teeter beam being configured for performing a teetering motion, and having two pairs of first lugs arranged at opposite ends thereof at a distance with respect to the rotational axis; and a hub piece located below the teeter beam, the hub piece having two arms that extend outwardly in a radial direction, each having a second lug arranged at a distance with respect to said rotational axis. Each second lug is located between the two lugs of a respective pair of first lugs, and respective connecting pins pass through the first and second lugs on either side of the rotational axis. A pair of elastic bushings are arranged on each connecting pin between a first one of the first lugs and the second lug and between a second one of said first lugs and the second lug, respectively.

A parking system for a propulsor teeter of an aircraft is disclosed. The system includes a propulsor including a hub. The hub is mechanically connected to a rotor, wherein the hub is configured to rotate about a rotational axis. A teeter mechanism is connected to the hub, wherein the teeter mechanism is configured to permit a propulsor plane of the propulsor to pivot with respect to a point of intersection between the propulsor plane and the rotational axis of the propulsor. A locking mechanism is configured to selectively lock the teeter mechanism while the aircraft is in flight, wherein selectively locking the teeter mechanism restricts the pivoting of the propulsor plane.

A parking system for a propulsor teeter of an aircraft is disclosed. The system includes a propulsor including a hub. The hub is mechanically connected to a rotor, wherein the hub is configured to rotate about a rotational axis. A teeter mechanism is connected to the hub, wherein the teeter mechanism is configured to permit a propulsor plane of the propulsor to pivot with respect to a point of intersection between the propulsor plane and the rotational axis of the propulsor. A locking mechanism is configured to selectively lock the teeter mechanism while the aircraft is in flight, wherein selectively locking the teeter mechanism restricts the pivoting of the propulsor plane.

A method of assisting a pilot in order to minimize the risks of an aircraft rolling over on the ground, the aircraft having a main rotor and a yaw movement control rotor (4), together with lateral cyclic pitch control means for the main rotor and yaw movement control means for the yaw movement control rotor. At least one measurement is taken relating to left forces exerted on a left side undercarriage and to right forces exerted on a right side undercarriage in order to evaluate asymmetry, if any, between the left and right forces, and then a recommended position (26) is determined for at least one of the yaw and lateral cyclic pitch control means in order to make the left and right forces more symmetrical. Each recommended position is displayed on a display unit.

A rotor arm assembly for use in a rotor craft rotor hub system includes a pitch shaft and a plurality of discrete bearings coupled to the pitch shaft. The plurality of bearings are elastomeric bearings configured to facilitate movement of the rotor arm assembly about a plurality of degrees of freedom. A respective one of the plurality of bearings is configured to accommodate a single degree of freedom.

A rotor arm assembly for use in a rotor craft rotor hub system includes a pitch shaft and a plurality of discrete bearings coupled to the pitch shaft. The plurality of bearings are elastomeric bearings configured to facilitate movement of the rotor arm assembly about a plurality of degrees of freedom. A respective one of the plurality of bearings is configured to accommodate a single degree of freedom.

A cylindrical elastomeric bearing including a plurality of elastomeric layers arranged about a central bore. The elastomeric layers are characterized by a middle portion having a first thickness and two outer portions having a second thickness, the second thickness being greater than the first thickness, the one or more elastomeric layers being tapered between the middle portion and the outer portions. One or more shim layers, each of the plurality of shim layers being arranged between two of the plurality of elastomeric layers. The shim layers are shaped to fit with the elastomer layers.

A cylindrical elastomeric bearing including a plurality of elastomeric layers arranged about a central bore. The elastomeric layers are characterized by a middle portion having a first thickness and two outer portions having a second thickness, the second thickness being greater than the first thickness, the one or more elastomeric layers being tapered between the middle portion and the outer portions. One or more shim layers, each of the plurality of shim layers being arranged between two of the plurality of elastomeric layers. The shim layers are shaped to fit with the elastomer layers.

A blade pitch actuation mechanism comprising a rotating race member in which is formed a race configured to receive a trunnion pin attached to a blade, whereby the race defines a cam profile such that rotation of the race member causes the trunnion pin received in the race to rotate as it slides over the cam profile.