An aircraft includes a processor, an airframe, a pitch attitude flight control surface coupled with the airframe, a nose wheel coupled with the airframe, main wheels coupled with the airframe, and a brake system coupled with the main wheels. The processor is programmed to determine that the aircraft has entered a braking segment of a landing phase of a flight of the aircraft while the aircraft is on a ground surface and to command the pitch attitude flight control surface with a nose up command during the braking segment in response to determining that the aircraft has entered the braking segment. The nose up command causes the pitch attitude flight control surface to generate a downforce that increases traction between the main wheels and the ground surface due to a weight shift from the nose wheel to the main wheels and directly due to the downforce on the main wheels.

An aircraft includes a processor, an airframe, a pitch attitude flight control surface coupled with the airframe, a nose wheel coupled with the airframe, main wheels coupled with the airframe, and a brake system coupled with the main wheels. The processor is programmed to determine that the aircraft has entered a braking segment of a landing phase of a flight of the aircraft while the aircraft is on a ground surface and to command the pitch attitude flight control surface with a nose up command during the braking segment in response to determining that the aircraft has entered the braking segment. The nose up command causes the pitch attitude flight control surface to generate a downforce that increases traction between the main wheels and the ground surface due to a weight shift from the nose wheel to the main wheels and directly due to the downforce on the main wheels.

A gear element includes a support (3) on which first rollers (10a) and second rollers (10b), which are intended for engaging with the teeth of a neighboring gear element (2), are alternately mounted. Each roller (10a, 10b) is mounted for rotation about its longitudinal axis (X′) via rotary guide means (20) cooperating with end portions of the rollers (10a, 10b). The rotary guide means (20) of the first rollers (10a) and the rotary guide means (20) of the second rollers (10b) are staggered in the vicinity of an outer periphery of the support (3).

A gear element includes a support (3) on which first rollers (10a) and second rollers (10b), which are intended for engaging with the teeth of a neighboring gear element (2), are alternately mounted. Each roller (10a, 10b) is mounted for rotation about its longitudinal axis (X′) via rotary guide means (20) cooperating with end portions of the rollers (10a, 10b). The rotary guide means (20) of the first rollers (10a) and the rotary guide means (20) of the second rollers (10b) are staggered in the vicinity of an outer periphery of the support (3).

An aircraft having a fuselage and a front landing gear; both sides of the rear bottom of the fuselage are fixedly connected with the rear landing gear; one end of the front landing gear is rotatably connected to the front bottom of the fuselage. When the front landing gear rotates to the first position, the second position and the third position, the connecting line between the end of the front landing gear away from the fuselage and the end of the rear landing gear away from the fuselage intersects with the plane, where the fuselage is located, on the side close to the front of the fuselage, parallel to and intersect on the side close to the rear of the fuselage.

An aircraft having a fuselage and a front landing gear; both sides of the rear bottom of the fuselage are fixedly connected with the rear landing gear; one end of the front landing gear is rotatably connected to the front bottom of the fuselage. When the front landing gear rotates to the first position, the second position and the third position, the connecting line between the end of the front landing gear away from the fuselage and the end of the rear landing gear away from the fuselage intersects with the plane, where the fuselage is located, on the side close to the front of the fuselage, parallel to and intersect on the side close to the rear of the fuselage.

A wear amount estimation device estimates plural kinds of wear energy depending on each of an internal pressure of aircraft tires, a load acting on the aircraft tires, a velocity of an aircraft, a slip angle caused in the aircraft tires, and a braking force of the aircraft, in accordance with each of these elements and wear energy EFR of the aircraft tires in a state of a free rolling run The wear amount estimation device estimates the wear amount wear of the aircraft tires in accordance with each of the calculated wear energy and a wear resistance R indicating a relationship between predetermined wear energy and a predetermined wear amount.

A wear amount estimation device estimates plural kinds of wear energy depending on each of an internal pressure of aircraft tires, a load acting on the aircraft tires, a velocity of an aircraft, a slip angle caused in the aircraft tires, and a braking force of the aircraft, in accordance with each of these elements and wear energy EFR of the aircraft tires in a state of a free rolling run The wear amount estimation device estimates the wear amount wear of the aircraft tires in accordance with each of the calculated wear energy and a wear resistance R indicating a relationship between predetermined wear energy and a predetermined wear amount.

A packaged bearing unit is disclosed including an outer surface for receiving an aircraft landing gear wheel and an inner surface for receiving an axle. The unit may include first and second spaced-apart sets of tapered roller bearings, held between inner and outer raceways. There may be a bearing setting spacer which can be used when setting and pre-loading the bearings. The bearing unit may be a sealed unit which includes a pre-set amount of lubricant (grease) for lubricating the bearings. One or more sensors may be retained in a void between the sets of bearings. The bearing unit may remain fixed to the axle when the wheel is removed. The bearing unit may be serviced less frequently than the wheels, and may thus have a longer lifetime, possibly comparable with the lifetime of the major components of the landing gear.

A packaged bearing unit is disclosed including an outer surface for receiving an aircraft landing gear wheel and an inner surface for receiving an axle. The unit may include first and second spaced-apart sets of tapered roller bearings, held between inner and outer raceways. There may be a bearing setting spacer which can be used when setting and pre-loading the bearings. The bearing unit may be a sealed unit which includes a pre-set amount of lubricant (grease) for lubricating the bearings. One or more sensors may be retained in a void between the sets of bearings. The bearing unit may remain fixed to the axle when the wheel is removed. The bearing unit may be serviced less frequently than the wheels, and may thus have a longer lifetime, possibly comparable with the lifetime of the major components of the landing gear.