Why are the cannon barrels tapered?

DE3940807A1 - Protection device against muzzle flash effects in guns - Google Patents

Protective device against muzzle flash effects in guns

info

Publication number
DE3940807A1
DE3940807A1DE3940807ADE3940807ADE3940807A1DE 3940807 A1DE3940807 A1DE 3940807A1DE 3940807 ADE3940807 ADE 3940807ADE 3940807 ADE3940807 ADE 3940807ADE 3940807 A1DE3940807 A1DE 3940807A1
Authority
DE
Germany
Prior art keywords
tube
cladding tube
cladding
shot
opening
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
DE3940807A
Other languages
English (en)
Other versions
DE3940807C2 (de
Inventor
Manfred Dipl Ing Buchstaller
Friedrich Moessmer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dornier Luftfahrt GmbH
Original assignee
Dornier Luftfahrt GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dornier Luftfahrt GmbHfiledCriticalDornier Luftfahrt GmbH
Priority to DE3940807ApriorityCriticalpatent / DE3940807C2 / de
Publication of DE3940807A1publicationCriticalpatent / DE3940807A1 / de
Application granted granted Critical
Publication of DE3940807C2publicationCriticalpatent / DE3940807C2 / de
Anticipated expirationlegal-statusCritical
Expired - Lifetimelegal-statusCriticalCurrent

Left

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  • 238000005253claddingMethods0.000claimsdescription60
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  • 239000011358 absorbing materialSubstances0.000claimsdescription2
  • 239000000463materialSubstances0.000description15
  • 238000009423ventilationMethods0.000description9
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  • 239000000843powderSubstances0.000description5
  • 230000005540biological transmissionEffects0.000description4
  • 238000009413insulationMethods0.000description4
  • 230000035939shockEffects0.000description4
  • 230000000875correspondingEffects0.000description3
  • 230000001681protectiveEffects0.000description3
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  • 238000010304firingMethods0.000description2
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  • 238000001816coolingMethods0.000description1
  • 231100000078corrosiveToxicity0.000description1
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Classifications

    • F — MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41 — WEAPONS
    • F41A — FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
    • F41A21 / 00 barrels; Gun tubes; Muzzle attachments; Barrel mounting means
    • F41A21 / 32 — Muzzle attachments or glands
    • F41A21 / 36 — Muzzle attachments or glands for recoil reduction; Stabilizer; Compensators, e.g. for muzzle climb prevention
    • F — MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41 — WEAPONS
    • F41A — FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
    • F41A21 / 00 barrels; Gun tubes; Muzzle attachments; Barrel mounting means
    • F41A21 / 32 — Muzzle attachments or glands
    • F41A21 / 34 — Flash dampers

Description

The invention relates to a device according to the preamble of claim 1.
Powder gases cause a number of problems with aircraft or anti-aircraft mounts that carry automatic, small or medium-caliber cannons or similar armament. The gases flowing out at the muzzle with high pressure of up to 100 bar and high temperature of up to 1500 ° C can exert a high load on the surrounding receiving structure and equipment, especially if the armament is integrated into an aircraft part. The gases are very corrosive and the corresponding deposits can adversely affect the effect of other devices, for example optical devices. However, jet engines are particularly at risk from sucking in powder gases or from influencing the pressure on the intake air. The further development of modern small and medium-caliber, fast-firing cannon systems led, among other things, to an increase in the muzzle flash rate (vO) of the projectiles to more than 1000 m / sec. The advantages of improved external ballistics and the effect in the target (kinetic energy) essentially result from considerably increased gas pressures in the cannon system. The sound level of up to approx. 240 dB100 bar that occurs at the end of the tube in these cannon systems, as well as the aerodynamic requirements for low-resistance and largely submerged, i.e. fully integrated or partially integrated installation of the entire cannon system in aircraft structures, led in the past to considerable incompatibilities between cannon systems and aircraft. The hot gases of the emerging shock wave (approx. 1500 ° C at the end of the pipe) can heat up the nearest aircraft structures and the enormous sound pressure affects all pressure and sound-sensitive structures and devices (e.g. electronic devices, sensors, optronics and engines) in this area. The attachment of deflection vanes (muzzle brake) and deflectors alone do not significantly reduce the bubble effects.
From EP 01 16 023 a device for diverting powder gases is known, in which gases are diverted from the muzzle through a beveled attachment to the front and bottom and meet guide plates which guide them perpendicularly away from the firing direction. With this device, however, only a diversion of the powder gases from endangered points, for example from engine intakes, is achieved.
The object of the invention is to provide a protective device for a cannon system, preferably installed in aircraft, with which the damaging effect of the muzzle flash and the shot gases on the aircraft structure and important equipment parts of the aircraft is reduced and at the same time a considerable reduction in the cannon recoil forces is achieved.
This object is achieved by the invention according to claim 1. Further refinements are the subject of subclaims.
The device according to the invention essentially consists of the following components:
Depending on the muzzle blast and the geometric installation conditions, high-strength, dimensionally stable and heat-resistant deflection blades are detachably connected to the cannon barrel. These are adapted to the internal ballistics of the cannon system and correspond to the contour of a cladding tube that surrounds the deflecting vanes and the cannon barrel. The deflection radii of the blades as well as their inner and outer diameters are optimized for the given geometrical conditions and gas pressure conditions. The deflection blades cause the majority of the shot gases to be deflected against the direction of the projectile's shot. This supports the deflection effect in the ogival part of the cladding tube. If the deflection vanes are dispensed with, the effect of the cladding tube is considerably reduced. The deflecting vanes also serve to transmit the force of the muzzle brake induced at the front end of the cannon barrel to the cannon barrel. This force counteracts the recoil load of the cannon, which considerably reduces the reaction force of the cannon system introduced into the aircraft structure.
The cannon barrel including the muzzle brake is completely enclosed in the front area up to the first cladding tube bearing by a thin-walled cladding tube made of tough, heat-resistant material. V2A steel, for example, or any other material that is also resistant to aggressive substances can be used as the material. With a suitable choice of material and shape, wall thicknesses of less than 2 mm are also possible for mouth pressures of up to 100 bar. Compared to the reinforcement plates customary today, which are necessary for protection and whose wall thickness is approx. 15 mm, a significant saving in weight is achieved, which is of particular importance in aircraft. In the front area (corresponding to the muzzle brake) the cylindrical tube tapers to an optimized, ogival structure according to the geometric conditions, the blow pressure, the effect of the muzzle brake, the tube vibration behavior and the bullet dispersion. This contour ends in the form of a deflecting vane of the muzzle brake with an attached cylindrical, conical or ogivally diverging piece of pipe that serves as an outlet opening for the projectile. The diameter of this outlet opening is adapted to the tube vibration behavior during the shot (scattering) and the caliber. For an optimal reduction of the noise / pressure load, cannon systems with a well-damped pipe bearing, i.e. H. low scatter, and depending on the positioning of the pipe bearing, the diameter of the outlet opening can be set to one and a half times the caliber.
The rear part of the cladding tube, which serves as an outflow channel for the shot gases and the ram air, ends in front of the tube bearing in at least one outlet opening, the cross-sectional area of ​​which is adapted to the amount of shot gas and the installation requirements. The opening is reinforced by doublers and cross bars. Preferably and given the geometrical installation conditions, two or more outlet openings for symmetrical loading of the cannon barrel and a conical shape of the cladding tube are advantageous. The rear end of the cladding tube is detachably connected to the tube bearing attached to the cannon barrel. At this connection point, the cladding tube force induced by the cladding tube is transmitted to the cannon barrel against the recoil force of the cannon and reduces to the same extent the reaction force of the cannon system introduced into the aircraft structure. The otherwise normally necessary introduction of the forces resulting from the gas deflection in the cladding tube into the receiving structure is eliminated.
Should the connection of the cladding tube with the cannon barrel have negative effects on the self-dynamics of the cannon, an improvement can be achieved in return-damped weapons by connecting the cladding tube with the damper.
In order to optimize the shot dispersion and utilize the geometrical boundary conditions of the cannon barrel, it is also conceivable to mount the barrel and transfer the corresponding cladding tube forces at the front end of the cannon barrel via a muzzle brake designed as a star wheel with the cladding tube connected to it.
In the front area of ​​the cladding tube, to protect the surrounding structures from heat, a ventilation tube with a similar contour to the cladding tube at a sufficient distance including inlet funnel can be permanently connected to the cladding tube via several webs distributed around the circumference. The webs are preferably arranged perpendicularly on the cladding tube. As a result of this arrangement, the cladding tube heated by the shot gases is cooled on the inside and outside by ram air flowing past. The air flowing past is discharged at the rear end through the outlet opening for the shot gases.
The cladding tube is supported radially at the transition from the front ogival part to the rear part via a bearing. The cushioned bearing can influence the dispersion of the projectiles and reduce the transmission of vibrations and structure-borne noise to a minimum. In addition, this bearing enables a reduced transfer of heat and a tension-free compensation of the enlarged cladding tube diameter in the heated state, for example in the case of longer volleys. Such storage is described in DE-PS 36 28 586, for example.
The part of the ventilation pipe connected to the receiving structure and the damped gas outlet opening can be encased in a heat-resistant, sound-absorbing material. The material should lie loosely and not be glued. It must not sit or dissolve, even under shock and heat. The sound-absorbing material is continued into the area of ​​the ogival ventilation pipe. A thin-walled, heat-resistant support tube with an adapted contour is provided in this area to increase the sound insulation and to prevent the insulation material from dissolving when exposed to shock. Mineral fiber materials are particularly suitable as insulating material.
The invention is explained in more detail with reference to figures. It shows
Fig. 1 shows a cross section through the device according to the invention;
Fig. 2 shows a cross section through an advantageous embodiment;
Fig. 3 shows a cross section through a further embodiment.
The Fig. 1 shows a longitudinal and a cross section through the protective device according to the invention 2who have favourited the end of the pipe 4 a cannon barrel 6, starting in front of the first pipe store 8, along the axis of the cannon barrel to over the end of the barrel 6 beyond surrounds. At the end of the pipe 4 is a muzzle brake 10 in the form of two deflection blades here 14 and 16 preferably detachable. Around the end of the pipe 4 around is a cladding tube 18 arranged, the internal dimensions of which on the deflection vanes 14 and 16 are adapted. The cladding tube 18 runs almost cylindrically in the area B-C and then tapers towards the end of the cannon barrel in an ogival shape. At the front end 20 is an opening 24 provided, through which a shot projectile the cladding tube 18 leaves. At this opening 24 is a cylindrical piece of pipe 26 attached, the diameter of which is adapted to the caliber of the cannon and the dispersion of the projectiles. The smaller the diameter, the greater the effect of the cladding tube 18. The cladding tube 18 is opposite the cannon barrel 6 by a cladding tube bearing 27 supported with several webs distributed around the circumference. The deflected muzzle flashes leave the cladding tube 18 through an outlet opening 32. The inner contour of the cladding tube 18 is designed in this way, for example by means of an inclined sheet 36that the powder gases have little resistance in the direction of the outlet opening 32 be directed.
The Fig. 2 shows a modified version of the protective device 2. The same components are identified by the same reference numbers. On the pipe section 26 and the cladding tube 18 are supported to the extent of stabilization bars 28 starting the one around the cladding tube 18 lying further pipe 30 wear. This pipe 30 is with its inner diameter on the outer diameter of the cladding tube 18 adapted so that a gap is formed between these two tubes through which cooling air is passed. At the rear end have ventilation pipe 30 and cladding tube 18 Access to at least one common outlet opening 32. The cross section of this outlet opening 32 is adapted to the amount of shot gas and the installation conditions and is widened to the outside by internal webs 34 supported.
To the outer tube 30 around or on the pipe 30 can be used for further sound and heat insulation insulation material 38 be applied that the cladding tube 18 includes in part or in full. At the front end of the guard 2 is between pipe 30 and the insulation material 38that is in this area by a support tube 40 may be carried, a circumferential cavity 42 provided that with the returning cannon barrel to accommodate the ventilation tube 30 is used when the barrel runs forward after the shot has been interrupted. The cladding tube 18 and its surrounding parts are in the front part by a bearing 44 supported on the receiving structure.
The Fig. 3 shows the device 2 with a combined pipe and duct storage facility 50with which both the duct 18 opposite the cannon barrel 6 as well as opposite the ventilation pipe 30 finds a storage. There are also options for fastening this storage to the receiving structure, for example in the form of bores 52, intended. On a pipe store 8as in the Fig. 1 and 2, can be omitted in such a constellation. Other components have the same reference numbers as in Fig. 1 and 2.
The proposed cladding tube as well as its shape and choice of material significantly reduce the propagation of the sound pressure, focus the blast effects inside the cladding tube and favorably influence their effect on aircraft or anti-aircraft mounts including their equipment in the following way:
The radially radiated sound pressure is reduced and instead of critical structures or devices, the ogival part of the cladding tube is heated. Due to the ram air flowing through the cladding tube and the ventilation tube that may be slipped over it, the cladding tube is permanently cooled to a subcritical level on at least one side. Most of the resulting shot gases are deflected backwards at the muzzle brake and in the ogival part of the cladding tube and passed on to the intended outlet opening, which significantly reduces the influence on equipment parts that are sensitive to shot gas, for example engine, windshield, IR dome or radar dome and carbon parts can be. There is a reduction of the free propagation of the sound pressure in the firing direction to a level tolerable for the engine, sensors and optronics and a reduction of the firing force induced on the receiving and surrounding structure by the pressure force generated in the ogival part of the cladding tube, that of the cannon force via the possible connection points , in addition to the muzzle brake force, counteracts, achieved. As a result, a weight reduction can be achieved on the receiving structure and, if necessary, on the weapon recoil suspension mechanisms (dampers). The normally necessary storage of electronic components on shock mounts can therefore be dispensed with.
On the one hand, the duct is permanently cooled by the ventilation pipe and, on the other hand, the radial propagation of the sound pressure and thus the introduction of structure-borne noise, especially into the aircraft structure, is additionally reduced. A further reduction in noise and structure-borne noise effects on the aircraft structure can be achieved by embedding the ventilation pipe in sound-absorbing material.
In the case of return-damped cannon systems, an additional air chamber must be provided in the front area of ​​the cladding tube with ventilation tube, which causes an additional reduction in the sound pressure in the area of ​​the highest sound intensity (muzzle brake).
The transmission of the vibration level to the receiving structure can be significantly reduced by a suitable design of the damped mounting of the cladding tube.
With sound-absorbing material, depending on the material thickness and material coating or material type, a reduction in the sound pressure level on the outside can be achieved, which is below the compatibility level of the electronic, sensory and optical equipment usually integrated in the aircraft, as well as the engine.
With the invention, thermal incompatibilities with the receiving structures and devices in the muzzle area and for the entire length of the cannon barrel as well as aerodynamic influences on the flow field in aircraft due to protruding parts of the cannon system, for example the muzzle brake, can be avoided.
The hot, aggressive shot gases can be diverted into a desired, problem-free area and negative influences on the engine functions can be avoided. A considerable increase in the service life of the devices and structures is achieved.

Claims (16)

1. Protection device for small and medium-caliber cannons, in particular cannons on or in a flying object, against muzzle flash effects and shot gases, characterizedthat the cannon barrel (6) in its end area by a cladding tube (18) is surrounded so that between the cannon barrel (6) and cladding tube (18) there is a gap and the cladding tube (18) at its front end (20) an opening (24) for passing through projectiles and means for deflecting the shot gases in the direction opposite to the direction of flight of the projectiles and the cladding tube (18) at the rear end at least one outlet opening (32) has to discharge the shot gases.
2. Device according to claim 1, characterized in that at the front end (4) of the cannon barrel (6) a muzzle brake (10) is provided, the at least one deflection vane (14) having.
3. Apparatus according to claim 2, characterized in that at least the deflection vane (14) is adapted to the gas condition conditions at the end of the cannon barrel.
4. Device according to one of the preceding claims, characterized in that the inside of the cladding tube (18) is shaped in such a way that it conforms to the shape of the outside of at least the deflection vane (14) is adapted.
5. Device according to one of the preceding claims, characterized in that the cladding tube (18) the cannon barrel (6) at least up to a first cladding tube bearing (44) encloses.
6. Device according to one of the preceding claims, characterized in that the cladding tube (18) is formed in an ogival shape in its front part and is provided as a cylindrical or conical component in its rear part.
7. Device according to one of the preceding claims, characterized in that at least the opening (32) to divert the gases produced during the shot are matched to the mass flow of the shot gases in order to minimize the pressure effect in this area.
8. Device according to one of the preceding claims, characterized in that at least the opening (32) has a cross-section adapted to the installation conditions.
9. Device according to one of the preceding claims, characterized in that the front end (20) of the duct (18) one to the cladding tube (18) attached, cylindrical or ogivally expanded tube (26) is provided for passing the projectiles, the cross-section of which is adapted to the projectile dispersion.
10. Device according to one of the preceding claims, characterized in that at least one further storage (8) of the cladding tube (18) is provided.
11. Device according to one of the preceding claims, characterized in that the cladding tube (18) is thin-walled from tough, heat-resistant material.
12. Device according to one of the preceding claims, characterized in that the cladding tube (18) outside of another pipe (30) is surrounded by heat-resistant material, with between this tube (30) and the duct (18) there is a gap and at the front end of the tube (30) at least one opening for the inlet and at least one opening for the outlet of air flowing through is provided at the rear end.
13. The device according to claim 12, characterized in that the cladding tube (18) surrounding pipe (30) with a sound-absorbing, heat-resistant material (38) is encased or coated.
14. Apparatus according to claim 12 or 13, characterized in that the cladding tube (18) surrounding pipe (30) is made of sound-absorbing, heat-resistant material.
15. Device according to one of claims 12 to 14, characterized in that an additional support tube (40) is provided with an adapted contour.
16. The device according to claim 15, characterized in that between the support tube (40) and pipe (30) a cavity (42) is provided.
DE3940807A1989-12-09