FR2665763A1 - BOOT AND BOOT PROPELLANT THUS OBTAINED. - Google Patents

Abstract

A sabot (3) for use on a projectile launched from a cannon is configured to define a chamber (14) for a booster propellant (20) for the projectile as it exits the barrel of the barrel.

Description

1. The present invention relates to a hoof booster for

  shells and other projectiles and more specifically, a sabot for launched projectiles

by a cannon.

  It is often advantageous to impart a boost to a projectile after it has left the barrel so that it propagates at a faster speed.

  higher than that which would be conferred by the single tube.

  We know how to use a hoof on a projectile launched by a cannon, because it allows the use of a

  projectile of a lower caliber, which while maintaining

  the possibility of controlling the projectile inside

  laughter of the tube, during the launch, allows to obtain

  higher mouth speed.

  Another advantage of having a hoof on a pro-

  jectile is that it makes it possible to reduce the thickness of the walls of the projectile in certain zones to carry it, 2. for example, typically 5 mm to 1 mm Without shoe, a wall of 1 mm for the projectile he would not allow it to support the launch forces, and the projectile would be crushed However, with an appropriate shoe, the thickness of the rear walls of the projectile can be reduced

  up to 1 mm This is due to the fact that hooves are

  required in this way, as described in UK patent application No. 8630208, absorb

  a fairly large proportion of the accelerating forces

  protection of the thinner walls of the pro-

  jectiles, against excessive acceleration forces in the tube by transmission of part of the force

  to the anterior portion of the projectile.

  According to one aspect of the present invention, a shoe is provided for use on a launched projectile.

  by a barrel and configured so as to define a cham-

  propellant bre which is intended to keep the propellant

  sister as an adjunct for launching the projectile then

as it comes out of the barrel tube.

  Preferably, the propellant chamber is configured so that the propellant is ignited by gas from the main charge of the barrel during

  launch and a suitable delay mechanism The cham-

  propellant bre can be annular and the shoe can

  be configured so that the pressure of the developing gases

  sword during launch keep the hoof on the pro-

  jectile The projectile may have a shoulder

  tre which abuts the hoof during the launch.

  Alternatively, a separate bracelet can be used

  re against which the shoe abuts during launching, the bracelet being sufficiently solid when subjected

  to longitudinal compression, but which may extend

  relatively easy in the radial direction to be rejected after launch The bracelet can be made of a polytetrafluoroethylene (PTFE) 3- band.

with metallic reinforcement.

  Preferably, the hoof and the projectile defi-

  together converge / divergent nozzle.

  The shoe may have a multitude of extending blades

  longitudinally which stabilize it when it is rejected and which keep the fins of the

  projectile both before and during the rejection of the hoof.

  In addition, it is important that the propellant cannot agglomerate at the rear of the hoof during launch,

  and a solid propellant can be used

  quent, the propellant can be wedged against the walls of the

  shoe, or can be attached by an adhesive to the walls.

  In practice, a molten propellant can

  be poured centrifugally on the interior walls

  hoof laughter, and then solidify preferably-

  this, the shoe is arranged so that the propellant al-

  lume just before the hoof and projectile reach

  hinder the end of the barrel tube The shoe can include

  a full combustion plug.

  The present invention will be well understood when

  of the following description made in conjunction with

  attached drawings in which: Figure 1 is a sectional diagram of a projectile and a booster booster according to the present invention; Figure 2 is a view of a section taken along the axis CC 1 of Figure 1; Figure 3 is a sectional view taken along the axis DD 1 of Figure 1;

  Figure 4 is a longitudinal sectional view

  the end, nose side, of another embodiment

  tion of the present invention; Figure 5 is a simplified diagram of part of a bracelet of Figure 4; FIG. 6 is a graph of the pressure as a function of the distance from the rear of the tube for a projectile according to the present invention;

  Figure 7 is a graph of the pressure

  dull acting on the shoe in the general direction of arrow A in Figure 1 as a function of the distance from the rear of the tube; and Figure 8 is a graph of the speed of the

  projectile as a function of distance from the lan-

  cement, which indicates the possibilities of adding a sa-

bot according to the present invention.

  In connection with FIGS. 1, 2 and 3, we have represented

  felt in broad outline a projectile in 1, the pro-

  jectile comprising a generally cylindrical body 2 and a conical nose 4 The nose ends at the rear with a

  undercut part which defines an annular shoulder

area 6.

  Projectile 1 is surrounded by a general sabot

  generally cylindrical 3, comprising four longitudi-

  nales 5, an anterior conical zone 9 which abuts against

  a shoulder 6, a cylindrical zone 10, a conical zone

  than posterior 11, a tail area 12 and a hat

  13 The shoulder 6, the body 2 of the projectile, the conical zone

  that before 9 and the cylindrical zone 10 of the shoe 3 defined-

  feels an annular propellant chamber 14 which is seg-

  mented by the four blades 5 and contains during use

  sation a propulseur 20 To make the figure clearer, only a vane 5 has been represented in FIG. 1 so as to

  allow the view of the thruster chamber The au-

  bes 5 have small holes 38 for balancing the

  gas pressure to ensure uniform combustion

  me when igniting the propellant.

  The rear conical zone 11 and the tail zone 12 of the shoe 3, with the body 2 of the projectile, define a convergent / divergent nozzle 15, which 5. allows the gases of the propellant to escape from the chamber

  14 during combustion of the propellant, hence the development

  pement of the thrust The nozzle 15 also allows the passage of gases produced by the combustion of the main charge, so that they enter the chamber 14 of the propellant. In the cap 13 is a plug 16 with full combustion which, during its combustion, allows - the entry of hot gases from the main charge

  in chamber 14 in order to ignite the propellant 20 which it-

contains it.

  Rear of shoe 3 is fitted with fins

  deployable 17 The function of these fins is replaced

  created by that of the fins 18 of the projectile when the shoe 3 emerges from the projectile 1 after launching in the known manner On the shoe is a sliding shutter 19 which forms a seal against the gases between the

  barrel tube and hoof / projectile combination.

  Before executing the projected combination

  tile / sabot, chamber 14 is filled with solid propellant

  of 20 It is desirable to avoid agglomeration of the propellant in the rear part of the hoof, as a result of

  the initial acceleration of the projectile during the launcher

  ment In connection with FIGS. 2 and 3, the propellant 20 can be introduced into the chamber 14 as follows, for example: 1 The shoe can be rotated at very high speed and a propellant at the molten state can be introduced and poured centrifugally on

  the inner walls of the shoe 3 When cooling

  ment, the propellant 20 solidifies on the shoe.

  2 A solid block of propellant is brought to occupy the space 23 between the successive blades 5 and is linked to the shoe to prevent any relative movement. This connection can be an adhesive connection or be of a 6.

any other suitable type.

  In all cases, the interior wall of the shoe can be grooved, ribbed or have another configuration so that the projectile is wedged and that there is reduction of the risk of a relative movement. In each case, the propellant 20 does not preferably fill the entire chamber 14, but

  defines an annular air gap 24 between the pro-

  blower 20 and projectile 1 so as to allow the gases from the main charge to travel through the

  length of the chamber 14, from where the ignition of the propellant

  so that it burns evenly between the interior

  laughing and outside This function is assisted by

  the orifices 38 for balancing the pressure of the gases.

  The air gap 24 allows the pressure and temperature of each segment 23 between the blades 5 to reach equilibrium with the neighboring segments, ensuring that the developed thrust is generally uniform in

the circumferential sense.

  The projectile / sabot combination is launched by

  a cannon (not shown), the main charge of which

  applies pressure to the cap 13 and causes the acceleration

  projectile and hoof in the tube The pro-

  pressure potential wires are shown in figure

  res 6 and 7 The main charge also ignites the plug 16 so that the propellant 20 of the chamber 14 is ignited by the hot gases of the main charge, then

  that the projectile / sabot combination comes out of the barrel tube.

  In this way, maximum use is made of

  booster booster capacities, i.e. those

  These are used after the projectile has reached the maximum speed that can be obtained inside the barrel tube. The deployable fins 17 then come out of a 7. hop in the known manner, and stabilize the projectile until complete combustion of the hoof booster

  In this way, the propellant provides a boost to the projection.

tile 1 just after launch.

  In FIG. 8, two speed profiles have been represented, 25 and 26. Profile 25 is typical of a

  standard shell launched by a cannon and has two pha-

  ses Phase 1 concerns acceleration in the tube

  of the gun and phase 2 deceleration during the race.

  Profile 26 is the result of a projectile launched with

  a booster from a barrel of the same cali-

  bre It presents the same phase 1, phase 2 being a

  new acceleration due to the boost and the pha-

  se 3 slower deceleration after rejection of the sa-

bot.

  The anterior conical zone 9 of the hoof is now

  held against shoulder 6 using different

  your methods at different stages, for example: 1 Before the projectile is loaded into the barrel, the shoe is held in position against the shoulder 6

  by a shear stud or alternatively by an adjustment

  rubbing friction The rear part of the shoe can be held by the equivalent of a rolled cartridge

on the back of the shoe 3.

  2 After placement in the barrel tube, the firing pressure acting on the cap 13 and the combination

  projectile / sabot causes the sharing of forces

  be the base 39 of the projectile and the posterior conical zone

  re 12 of shoe 3 The force acting on the conical zone

  posterior 12 is transmitted through the

  ties 10 and 9 to the shoulder 6, hence the maintenance of the po-

  linear position of the hoof relative to the projectile.

  3 After complete combustion of the plug 16, the gas pressure inside the propellant chamber, and 8. consequently, acting on the internal surface of the anterior conical zone 9 in the gap 30 varies as shown in the figure 7 The initial peak 31 is due to the peak of the gases coming from the main charge, and the subsequent flat zone 32 illustrates the booster effect The pressure also maintains the

shoe 3 against shoulder 6.

  In all figures 6, 7 and 8, x indicates

  the approximate length of the barrel tube.

  During the combustion of the propellant, the internal forces exerted on the conical zone 9 of the shoe

  decrease to the point where the outside air pressure

  laughing acting on zone 9 is greater than pressure

  internal which holds the shoe 3 against the shoulder 6.

  This has the effect that zone 9 emerges from shoulder 6, which in turn results in sliding.

  from the hoof to the rear of the projectile 1 The blades 5 ensure that the hoof does not compromise the flight of the projectile by ensuring that the hoof remains parallel to the projectile during the rejection process.

  your 15 of the projectile are kept lowered by the

  vanes 5 both before and during rejection and then jail-

  smooth in known manner, the instant at which the projecti-

his normal ballistic flight follows him.

  Another variant of the invention

  tion is shown in Figures 4 and 5, wherein a shoulder 33 comprises an annular bracelet 34 of polytetrafluoroethylene with a metal reinforcement in one piece 35 The bracelet 34 is relatively flexible along the axis EE 1 but is rigid along the axis FF 1 and is fitted into a notch 36 formed on the body

  of the projectile When the shoe 3 stops abutting

  tre shoulder 33, air can enter between it and notch 36 The air pressure is sufficient to smash the polytetrafluoroethylene and the fine 9. sections 37 of the metal reinforcement; bracelet 34

is thus rejected.

  Note that the separation of the shoe 3 and the projectile 1 can be obtained by other methods than that described above; for example:

  a) a combustible or explosive means for separation

  rer a hoof, b) a separation of the hoof which uses the

  air to "unlock" the shoe after combustion of the propellant according to

  a process similar to the rejection of the shoulder-

ment 33.

  It will also be noted that the plug 16 at

  complete combustion is not the only way

  ble to ignite the propellant Any process can be used, for example a timed detonator, an igniter

  with inertial switch or any other appropriate means.

  The present invention is not limited to the embodiments which have just been described, it is on the contrary subject to modifications and

  variants which will appear to those skilled in the art.

10.

Claims (17)

  1 shoe (3) for use on a projectile   launched by a cannon, characterized in that it is configured   re so as to define a propellant chamber (14) which is intended to contain a propellant (20) to reinforce the propulsion of the projectile while the latter comes out of the barrel tube.   2 shoe according to claim 1, character-   dried in that the propellant chamber is configured so that the propellant surface is exposed   gases from the main charge of the gun during the launch.   3 Shoe according to claim 1 or the claim   cation 2, characterized in that the thruster chamber is annular.   4 Shoe according to any one of the claims   1, 2 or 3, characterized in that it is configured to   so that the gas pressure produced during the launcher   hold the shoe (3) on the projectile.   5 shoe according to claim 4, characterized in that there is a gap (24) for equalization   gas pressure in the thruster chamber.   6 Shoe according to any one of the claims   above, characterized in that the shoe and the projectile together define a convergent / divergent nozzle (15)   7 Shoe according to any one of the claims   tions above, characterized in that it comprises a multitude of blades (5) extending longitudinally for   stabilize the hoof while it is rejected.   8 shoe according to claim 7, characterized in that it is configured so that the fins (17) of the projectile, which can be deployed, are maintained   lowered by the blades both before and during re- hoof throw. li.   9 Shoe according to any one of the claims   tions, characterized in that it comprises a   means for inhibiting agglomeration of the propellant during the launch.   10 Sabot according to any one of the preceding claims, characterized in that the propellant (20) is solid.   11 Shoe according to any one of the claims   cations 10, characterized in that the solid propellant   is wedged against the hoof walls.   12 shoe according to claim 10 or claim 11, characterized in that the propellant   solid is bonded by an adhesive to the walls of the hoof.   13 Shoe according to any one of the claims   previous cations, characterized in that it is agen-   so that the propellant (20) ignites during   launch just before the hoof and projectile dye the end of the barrel tube.   14 Shoe according to any one of the claims   previous cations, characterized in that it comprises a plug (16) with complete combustion to initiate the combustion of the propellant.   Projectile, characterized in that it is   fitted with a shoe (3) according to any one of the res- previous indications.   16 Projectile according to claim 15, characterized in that it comprises a shoulder (6, 33)   against which hoof stumbles during launch.   17 Projectile according to claim 15 or claim 16, characterized in that it comprises   a removable strap (34) providing said shoulder- ment (33).   18 Projectile according to claim 17,   characterized in that the bracelet is solid under the effect   longitudinal compression, but can be extended relatively easily 12. in the direction   radial for rejection after launch -