An aircraft having a frame assembly that supports a compressor having an outer shell that defines front and rear nozzle ports with rotatable nozzles for selectable vertical or horizontal thrust. The inner shell and the outer shell define an intake gap therebetween such as an annulus. A first fan unit within the inner shell and is configured to exhaust air through the front nozzle ports. A second fan unit within the outer shell intakes air through the intake gap and exhausts air through the rear nozzle ports. The fan units are preferably connected to one another via a drive shaft that is surrounded by a streamlining tube. The fan units each include a plurality of fans having stators therebetween. The stators have a plurality of stator arms with a wing structure pivotally attached to the trailing edge for angling air flow from a front to a rear fan.

A center biased actuator having an outer cylinder, a slave cylinder linearly transposed within the outer cylinder, a rod assembly with a piston linearly transposed within the slave cylinder and a rod extending from the outer cylinder, one or more first dynamic seals arranged to act on a sidewall of the rod to inhibit hydraulic fluid leaking from the outer cylinder, one or more second dynamic seals arranged to act on a sidewall of the slave cylinder or an inner surface of the outer cylinder to inhibit hydraulic fluid leaking from the outer cylinder, and a gas chamber comprising a sealed expandable chamber containing gas. The expandable chamber is arranged to act on hydraulic fluid within the center biased actuator to bias the center biased actuator to assume an intermediate condition which lies between a compressed condition and an extended condition.

A center biased actuator having an outer cylinder, a slave cylinder linearly transposed within the outer cylinder, a rod assembly with a piston linearly transposed within the slave cylinder and a rod extending from the outer cylinder, one or more first dynamic seals arranged to act on a sidewall of the rod to inhibit hydraulic fluid leaking from the outer cylinder, one or more second dynamic seals arranged to act on a sidewall of the slave cylinder or an inner surface of the outer cylinder to inhibit hydraulic fluid leaking from the outer cylinder, and a gas chamber comprising a sealed expandable chamber containing gas. The expandable chamber is arranged to act on hydraulic fluid within the center biased actuator to bias the center biased actuator to assume an intermediate condition which lies between a compressed condition and an extended condition.

Systems and methods for a bi-stable valve are provided. The bi-stable valve may comprise a housing including an input port, a first output port, and a second output port, a spool disposed within the housing and configured to translate in response to a first magnetic force, wherein the spool is further configured to selectively enable fluid communication between the input port and each of the first output port and the second output port in response to translating the spool between a first position and a second position, a spring disposed within the housing and coupled to the spool, an electromagnet coupled to the housing and configured to apply the first magnetic force to the spool, and a permanent magnet configured to apply a second magnetic force to the spool.

Systems and methods for a bi-stable valve are provided. The bi-stable valve may comprise a housing including an input port, a first output port, and a second output port, a spool disposed within the housing and configured to translate in response to a first magnetic force, wherein the spool is further configured to selectively enable fluid communication between the input port and each of the first output port and the second output port in response to translating the spool between a first position and a second position, a spring disposed within the housing and coupled to the spool, an electromagnet coupled to the housing and configured to apply the first magnetic force to the spool, and a permanent magnet configured to apply a second magnetic force to the spool.

A trailing link landing gear (6) has a main arm (20) which extends from a proximal end (22) attachable to an aircraft (2) to a distal end (24), and a trailing arm (30) which extends from a pivotable connection at the distal end (24) of the main arm (20) to one or more wheels (39). A shock absorber (40) extends between the main arm (20) and the trailing arm (30). An adjustment member (50) mounted to one of the arms can be moved to move an end of the shock absorber (40) and thereby change the angle that the trailing arm (30) makes with the main arm (20). This, in turn, changes the height of the landing gear (6) and in doing so changes the angle of attack (10) of an aircraft (2) including the landing gear (6).

A trailing link landing gear (6) has a main arm (20) which extends from a proximal end (22) attachable to an aircraft (2) to a distal end (24), and a trailing arm (30) which extends from a pivotable connection at the distal end (24) of the main arm (20) to one or more wheels (39). A shock absorber (40) extends between the main arm (20) and the trailing arm (30). An adjustment member (50) mounted to one of the arms can be moved to move an end of the shock absorber (40) and thereby change the angle that the trailing arm (30) makes with the main arm (20). This, in turn, changes the height of the landing gear (6) and in doing so changes the angle of attack (10) of an aircraft (2) including the landing gear (6).

Disclosed herein are shock absorbing foot pieces configured to be attached to an apparatus and to absorb the weight of the attached apparatus and any impact caused by the normal usage of the apparatus. In one or more embodiments, the shock absorbing foot pieces comprise multiple elements including a biasing spring and that are configured as a unitary piece.

Disclosed herein are shock absorbing foot pieces configured to be attached to an apparatus and to absorb the weight of the attached apparatus and any impact caused by the normal usage of the apparatus. In one or more embodiments, the shock absorbing foot pieces comprise multiple elements including a biasing spring and that are configured as a unitary piece.

An aircraft landing gear 2 is disclosed having a first arm 6a configured to have one or more wheels 8a mounted at one end, the first arm 6a being configured for mounting to a pivot 10a. The landing gear 2 includes a second arm 6b configured to have one or more wheels 8b mounted at one end, the second arm 6b being configured for mounting to a pivot 10b. The landing gear 2 further includes a first link 18a pivotally coupled to the first arm 6a, a second link 18b pivotally coupled to the second arm 6b; and a main link 20 pivotally coupled to each of the first and second links 18a, 18b and to a shock absorber 22 arranged to provide a biasing force via (i) the main linkage 20 and the first link 18a which opposes rotation of the first arm 6a about the pivot 10a and (ii) the main linkage 20 and the second link 18b which opposes rotation of the second arm 6b about the pivot 10b.