Thrust unit for a propulsion device and associated propulsion device

Thrust unit for a propulsion device, comprising:

• a thrust engine, arranged to generate a thrust stream, containing a nozzle defining a fluid ejection outlet,
• a deflector assembly comprising a pair of deflector elements movably mounted downstream of the fluid ejection nozzle in the thrust stream in order to deflect all or some of the thrust stream, wherein said deflector elements are arranged to be moved towards and away from each other between a closed configuration in which the deflector elements are in contact with each other and in a path of the thrust stream and an open configuration in which the deflector elements are away from each other and out of the path of the thrust stream,
• actuators arranged to cause the respective movements of said deflector elements, and
• a frame assembly including a frame and pivot links supported by the frame, the frame assembly surrounding the fluid ejection nozzle, the frame linked with each of the deflectors via the respective pivot links,
• wherein positions of the respective pivot links with respect to the fluid ejection outlet are determined by an arrangement of the frame in order that the actuators have a lower reaction time than the thrust engine to cause the deflector elements to be moved between the closed configuration and the open configuration,
• wherein:
• said deflector assembly contains link arms, wherein each link arm cooperates respectively and integrally with one of the deflector elements according to one of the respective pivot links,
• each actuator arranged to cause a rotational movement of one of the deflector elements contains a rudder bar,
• the thrust unit contains connecting rods cooperating respectively and integrally at a first end with the deflector elements and at a second end with the rudder bars of the actuators, wherein each of the connecting rods defines a thrust action point and is arranged to transmit the rotational movement from a respective rudder bar to a respective deflector element,
• the relative positioning of link pins of the pivot links in relation to the fluid ejection outlet is determined by distances D2 and D5 projected in a transverse plane of the thrust unit separating the thrust unit symmetrically into two halves along the direction of the thrust stream, where D2 consists of a vertical distance, when the thrust stream is oriented towards the ground, between one of the link pins and a force point of a resultant vector of the thrust force when the deflector element concerned is in the closed configuration, and D5 consists of a horizontal distance between said link pin and the force point, the distances D2 and D5 themselves being determined such that:
• D
• ⁢
• 2
• =
• R
• ⁢
• 1
• 2
• tan
• ⁢
• α1
• =
• Dn
• ·
• b
• 2
• tan
• ⁡
• (
• α
• ′
• -
• α
• )
• where Dn consists of the diameter of the ejection nozzle, b consists of a predetermined factor comprised between 1 and 1.3, α1 consists of a maximum angular difference between an angle of attack α′ of the deflector element in relation to an axis substantially parallel in the transverse plane to the fluid ejection direction in the open configuration and the angle of attack a of the deflector element in relation to an axis substantially parallel in the transverse plane to the fluid ejection direction in the closed configuration,
• D
• ⁢
• 5
• =
• C
• ⁢
• 4
• F
• ⁢
• 1
• =
• C
• ⁢
• 3
• -
• C
• ⁢
• 1
• F
• ⁢
• 1
• =
• (
• F
• ⁢
• 1
• ·
• D
• ⁢
• 2
• )
• -
• (
• C
• ⁢
• 2
• D
• ⁢
• 3
• )
• ·
• D
• ⁢
• 4
• F
• ⁢
• 1
• where C4 consists of a counter torque sought, i.e. a difference between a closing torque at the link pin and a torque of a mechanical system, F1 consists of a magnitude of the resultant horizontal vector of the thrust, C1 consists of the torque of the mechanical system at the point of the link pin, C2 consists of a predetermined servo-motor torque of the actuator, D3 consists of a predetermined length of the rudder bar, D4 consists of the distance between the link pin and the thrust action point, C3 consists of the closing torque at the link pin, wherein said distances D2 and D5 are chosen to minimize the value of the counter torque C4.