GB1602338A - Rocket vehicles - Google Patents

Description

(54) ROCKET VEHICLES (71) We, BRISTOL AEROJET LIMITED, a Company organised under the laws of England, of Banwell, Weston-super-Mare, Avon, BS24 8PD, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to rocket vehicles of the kind shown as canards or of the kind having adjustable control fins of the kind known as canard fins, that is to say, fins which are intended, when the vehicle is travelling, to be located forward of the centre of gravity of the vehicle. In order to maintain pointing ability, it is necessary with such control fins to have tail fins.However, it has been found that when the control fins are adjusted to control roll of the rocket vehicle so that, where, for example, there are two fins which are located diametrically on opposite sides of the body of the vehicle, the fins are rotated in opposite directions, problems arise due to the incidence of the tip vortices produced by the adjustable fins on the tail fins. It has been found that under certain conditions of roll control the impact of the tip vortices on the tail fins may produce a force on these fins which acts in the opposite direction to the lift forces achieved by adjusting the control fins and thus the effect produced by the control fins is reduced and may, in fact, be reversed, and it is possible that a period of unpredictable flight may ensue.

According to the present invention, a rocket vehicle has a body, adjustable control fins forward of the rear end of the body, and a tail assembly comprising a sleeve and a plurality of tail fins secured to and projecting outwardly from the sleeve, the sleeve being rotatably mounted on the body of the rocket by having an inwardly facing circumferential surface running on a plurality of rollers or wheels each having its axis parallel with and offset from the axis of the vehicle and fixed in space relative to the vehicle.

Preferably each roller or wheel is mounted by a ball-bearing on an axle fixed to the body of the vehicle.

In a preferred arrangement there is a first ring of wheels and a second ring of wheels axially spaced from the first ring, the sleeve having two inwardly facing circumferential surfaces which run respectively on the rollers or wheels of the rings. There may be four wheels or rollers in each ring.

The invention may be carried into practice in various ways but one rocket vehicle, embodying the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a simplified and diagrammatic plan view of the rocket vehicle; Figure 2 is a fragmentary axial section of the tail portion of the vehicle to a larger scale; and Figure 3 is a transverse section on the line Ill-Ill in Figure 2.

The rocket vehicle shown in Figure 1 has a body 1 having a propulsion motor section 2, a pay-load section 3 and a control section 4 between the motor section 2 and the payload section 3. The control section 4 has adjustable canard control fins 5, 6 and at the rear of the motor section 2 there is a tail assembly comprising a sleeve 7 to which are secured four trapezoidal tail fins 8.

As can be seen in Figure 2, the sleeve 7 is formed with four ribs 9 each containing a longitudinal groove 11 in which the inner edge of a respective tail fin 8 is retained by means of screws 12. The sleeve is formed with a circumferential inwardly directed stiffening rib 13 intermediate its length and at each end there is secured a ring 14 of Lsection affording on its inner circumferential surfaces a track 15 which runs on four rollers 16 which are carried by the body of the rocket vehicle. These rollers 16 are carried by an integral mounting assembly 17 comprising a sleeve portion 18 with at each end pairs of circumferentially extending flanges 19 each formed with four lobes between which extend axles 21 on which the rollers are mounted by ball-bearings 20.The mounting assembly is secured by screws 22 to the rear end of the casing of the rocket motor section 2, thus forming a rearwardly extending portion surrounding the propulsion nozzle 23 which, as can be seen from Figure 2, is spaced inwardly from the inner surface of the mounting assembly 17 so that an insulating gap 24 is provided between them.

As can be seen in Figures 2 and 3, a considerable amount of space is available between the mounting assembly 17 and the sleeve 7 to which the tail fins 8 are secured, and this space is used to house ancillary equipment and wiring. Figures 2 and 3 show a break-up unit and transponder 25 located in part of this space, but it will be realised that this is given by way of example only.

Secured to the rear end of the mounting assembly is an antenna 26, and wiring from the antenna (not shown) is led through the space between the mounting assembly and the sleeve to the break-up unit and transponder.

In flight, the tail fins 8 maintain pointing ability for the vehicle while roll control is effected by the control fins 5 and 6. When these are rotated in opposite directions, tip vortices will be generated which will travel relatively straight backwards and will impinge on the tail fins 8. However, since the tail fins are free to rotate about the axis of the vehicle, they will be unable to exert any torque about this axis so that roll control will remain solely under the control of the control fins 5 and 6.

WHAT WE CLAIM IS: 1. A rocket vehicle having a body, adjustable control fins forward of the rear end of the body, and a tail assembly comprising a sleeve and a plurality of tail fins secured to and projecting outwardly from the sleeve, the sleeve being rotatably mounted on the body of the rocket by having an inwardly facing circumferential surface running on a plurality of rollers or wheels each having its axis parallel with and offset from the axis of the vehicle and fixed in space relative to the vehicle.

2. A rocket vehicle as claimed in Claim 1 in which each roller or wheel is mounted by a ball-bearing on an axle fixed to the body of the vehicle.

3. A rocket vehicle as claimed in Claim 1 or Claim 2 in which there is a first ring of wheels and a second ring of wheels axially spaced from the first ring, the sleeve having two inwardly facing circumferential surfaces which run respectively on the rollers or wheels of the rings.

4. A rocket vehicle as claimed in Claim 3 in which there are four wheels or rollers in each ring.

5. A rocket vehicle substantially as described herein with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. portion surrounding the propulsion nozzle 23 which, as can be seen from Figure 2, is spaced inwardly from the inner surface of the mounting assembly 17 so that an insulating gap 24 is provided between them. As can be seen in Figures 2 and 3, a considerable amount of space is available between the mounting assembly 17 and the sleeve 7 to which the tail fins 8 are secured, and this space is used to house ancillary equipment and wiring. Figures 2 and 3 show a break-up unit and transponder 25 located in part of this space, but it will be realised that this is given by way of example only. Secured to the rear end of the mounting assembly is an antenna 26, and wiring from the antenna (not shown) is led through the space between the mounting assembly and the sleeve to the break-up unit and transponder. In flight, the tail fins 8 maintain pointing ability for the vehicle while roll control is effected by the control fins 5 and 6. When these are rotated in opposite directions, tip vortices will be generated which will travel relatively straight backwards and will impinge on the tail fins 8. However, since the tail fins are free to rotate about the axis of the vehicle, they will be unable to exert any torque about this axis so that roll control will remain solely under the control of the control fins 5 and 6. WHAT WE CLAIM IS:

1. A rocket vehicle having a body, adjustable control fins forward of the rear end of the body, and a tail assembly comprising a sleeve and a plurality of tail fins secured to and projecting outwardly from the sleeve, the sleeve being rotatably mounted on the body of the rocket by having an inwardly facing circumferential surface running on a plurality of rollers or wheels each having its axis parallel with and offset from the axis of the vehicle and fixed in space relative to the vehicle.

2. A rocket vehicle as claimed in Claim 1 in which each roller or wheel is mounted by a ball-bearing on an axle fixed to the body of the vehicle.

3. A rocket vehicle as claimed in Claim 1 or Claim 2 in which there is a first ring of wheels and a second ring of wheels axially spaced from the first ring, the sleeve having two inwardly facing circumferential surfaces which run respectively on the rollers or wheels of the rings.

4. A rocket vehicle as claimed in Claim 3 in which there are four wheels or rollers in each ring.

5. A rocket vehicle substantially as described herein with reference to the accompanying drawings.