IL30095A - Projectile having a useful charge which must be released at a point on the projectile trajectory - Google Patents

Description

Projectile having a useful charge which must be released at a point on the projectile trajectory COMPAONIE PRANCAISE THOMSON HOUSTON HOTCHKISS BRANDT 0:-28420 < The present invention relates to projectiles of the type having a useful charge, such as an illuminating or flare charge which must be released at a point on the trajectory and then braked relative to the rest of the projectile.

In known projectiles of this type, the useful charge is usually separated from the rest of the projectile at a given point on the trajectory by means of a time fuze containing a small explosive charge of the black powder type and a clock mechanism which is set before firing the projectile. The useful charge is provided with a parachute which opens at the moment of separation and, owing to the braking action thereof, allows the useful charge to continue its descent at low speed.

Now, at the moment of separation, the projectile splits up into a plurality of parts. Some of these parts are heavy and large and, in continuing on their trajectory at a speed in the neighbourhood of that of the projectile at the moment of separation, can encounter the canopy of the open parachute or the partly-open parachute so that there is a risk of tearing this canopy or preventing its opening. The base of the projectile constitutes in fact the most dangerous part for to this canopy owing/ its weight and position. This part of the projectile is heavy since, when firing, it must be capable of withstanding the thrust of the gases and consequently its wall is thick and strong. Further, this base carries in many cases a rear fin structure or, when it concerns a self-propelling projectile, propelling means. It must be realised that, upon separation of the useful charge and the opening of the braking parachute, the risk of the base of the projectile damaging the parachute increases very rapidly with the dimensions of the parachute and this necessitates limiting the weight of the useful load and consequently the characteristics of the projectile.

The object of the invention is to provide a projectile of the aforementioned type which remedies these drawbacks.

The projectile according to the invention is of the type comprising a time fuze for igniting the useful charge and an explosive ejecting charge adapted to eject, from the body of the projectile, the useful charge which is connected to a braking parachute, wherein the base of the projectile contains, in addition to said charge for ejecting said useful charge, a propelling charge and carries a lateral nozzle which is located at the rear of the centre of gravity of the projectile so as to create, under the effect of the ejection of gases produced by the combustion of said propelling charge, a couplewhich tilts the projectile, delay means being disposed between said fuze and said ejecting and propelling charges whereby the combustion of said propelling charge precedes the ignition of said ejecting charge.

The ignition of the time fuze therefore first produces the ignition of the useful charge and propelling charge, the projectile tilts owing to the ejection of the gases through the lateral nozzle, then the useful charge is expelled with its parachute in a direction parallel to the axis of the tilted projectile, that is, at an angle relative to the tangent to the trajectory of the projectile, and consequently the canopy of the parachute opens off the trajectory of the body of the projectile so that the latter cannot damage it.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawings.

Iryfche drawings ?, Fig. 1 is a longitudinal sectional view of a projectile according to the invention; Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. 1 j Fig. 3 is a partial detail longitudinal sectional view of the projectile on a scale larger than that of Fig. 1, and Figs. 4-8 are diagrams showing the elements of the projectile in the various stages on the projectile trajectory.

In the illustrated embodiment, the invention is applied to a projectile comprising a head A, a body B, a base C and a fin structure D carried by the latter. This projectile contains a useful charge or load E which, in the presently-described embodiment, is an illuminating device or flare.

The head A of the projectile comprises a time fuze 1 containing an adjustable delay means and an explosive charge 2 of the black powder type fixed on a support 3.

The body B of the projectile comprises a cylindrical case 4 the front end of which is connected to the support 3 by shearable pins 5. This body contains the useful charge or load E consisting of a container 6 containing an illuminating charge 7 which can be ignited by the charge 2 of the fuze through pyrotechnic delay means 8.

Fixed to this container 6 by a cable 9 and suspending lines 9a (see Fig. 7) is the canopy 10 of a parachute. This canopy is disposed in an envelope consisting of two half-shells 11 and lla and a pot 12. The half-shells 11 and lla and the pot 12 are retained in the body 4 by a ring 13 which bears against a flange 14 on the pot and is merely a tight fit in the body 4. Screwed in this ring 13 is the front end of the base C.

The body of the projectile has an axial tube 15 which extends therethrough and transmits rearwardly the flames from the combustion of the igniting charge 2 to two rear charges 16 and 17 by way of delay apertures 18, 19.

The charge 16 can ignite , through pyrotechnic delay means 20 (Figs. 1 and 2), a pot ejecting charge 21, whereas the charge 17 can ignite, through apertures 22, an auxiliary propelling charge 23 the ignition of which produces propelling gases v/hich are ejected through the bore 24 of a lateral nozzle 25, after expulsion of a closing plug 26 by the pressure of said gases.

The delay means 8, 20, 22 are such that the operation of the fuze 1 and the ignition of the charge 2 at time T results, firstly, in the ignition, by way of the apertures 22, of the propelling charge 23 whose combustion lasts about 0.04 second and,then, the ignition by way of the delay means 20, of the pot-ejecting charge 21, at about time T + 0.06 second, and, finally, the ignition, by way of the delay means 8, of the useful charge 7 at about time T + l second.

The projectile therefore operates in the following manner s At the end of time T, adjusted by the fuze, the latter ignites the charge 2. The projectile is at P1 on its trajectory. It is for example propelled at a speed V of the order of 200 metres per sec.

The propelling charge 23 is ignited and burns from about T to T + 0.04 second. The gases it produces eject the lateral plug 26 and then the jet J of these gases (Fig. 4) gives rise to a lateral reaction force R located at the rear of the centre of gravity G of the complete projectile. The latt r t i T + and its longitudinal axis then makes an angle of, for example, 30° with the tangent T of the trajectory. At this moment, the combustion of the auxiliary charge 23 has stopped but the projectile continues to tilt under the effect of the inertia of the impulse and reaches, at time T + 0.06 second, the position P for example inclined at 40°. At this moment, the pot-ejecting charge 21 is ignited, while the speed of the projectile is still V.

This charge 21 explodes and the pins 5 shear under the effect of the pressure created and the contents of the projectile, namely the fuze 1, the charge E and the parachute with its envelope (11,12) is expelled forwardly in a direction parallel to the longitudinal axis of the projectile (Fig. 6) with a speed v relative to the assembly (body E, base C, fin structure D) for example of the order of 10-20 metres per sec .

Within a few hundredths of a second, for example at T + 0.10 second, the useful charge E has travelled through a few decimetres relative to the assembly (E,C,D) and the angle of tilt is then about 45° (Fig. 6) .

At about T + 0.12 second, the canopy 10 of the parachute starts to open at the end of the suspending lines 9a, which connect it to the charge E through the cable 9, whereas the half-shells 11, lla and the pot 12 are separated therefrom (Fig. 7) .

The relative disposition of the canopy 10 of the parachute and of the rear assembly (B,C,D) is then such (Fig. 6) that, when the parachute is completely open, its canopy is at the rear of this assembly and offset therefrom a distance a of the order of at least 30 cm and, thereafter, said assembly of dangerous parts continues its travel at the speed V ( of the order of 200 metres per sec) , whereas the charge E slows down from 200 metres per sec. to v = about 5 metres per sec. owing to the braking action of the parachut there being no risk of a dangerous part encountering the parachute .

The arrangement according to the invention has therefore the following advantages : There is no longer any risk of the canopy of the parachute being damaged by the parts B, C, D and the charge E, ignited at time T + 1 second, descends slowly in producing the desired effect (illumination in the present case) .

The device is of utility for projectiles of small calibre (60-81 mm) since it requires very little space.

The assembly is very strong owing to the fact that the shearable pins 5 are located in the front part of the projectile, since the assembly Af B, C constitutes a rigid, unit .

Although a specific embodiment of the invention has been described, many modifications and changes may be made therein without departing from the scope of the invention as defined in the appended claims. 30095/2

Claims (4)

1. A projectile having a useful charge which must be released at a point on the projectile trajectory, said projectile being of the type comprising a time fuze and ail igniting charge for igniting on the one hand the useful charge and on the other hand an explosive charge adapted to eject ' from the body of the projectile said useful charge which is connected to a braking parachute, wherein the base of the projectile contains, in addition to said charge for ejecting said useful charge, a propelling charge and carries a later^al nozzle which is located at the rear of the centre of gravity of the projectile so as to create, under the effect of the ejection of gases produced by the combustion of said propelling charge ignited by said igniting charge, a couple which tilts the projectile, delay means being disposed between said fuze and said ejecting and propelling charges whereby the combustion of said propelling charge precedes the ignition of said ejeoting charge.

2. A projectile as claimed in Claim 1, wherein said body constitutes with said base a rigid assmebly and it is connected in the front part of the projectile to the support of the fuze by shearable pins.

3. A projectile as claimed in Claim 1, wherein the parachute is contained in an envelope which comprises the combination of two merely juxtaposed half-shells and a rear rus oconical pot.

4. A projectile as claimed in Claim 1, wherein said ejecting and propelling charges are connected through delay means to an axial powder charge located at the rear of an axial tube which transmits the flames produced by said fuze charge. released at a point on the projectile trajectory,, said projectile being of the type comprising a time fuze for igniting the useful charge and an explosive charge adapted to eject from the body of the projectile said useful charge which is connected to a braking parachute, said projectile being substantially as described with reference to and as shown in the accompanying drawings.