|Title of Invention||
A BREACH MECHANISM FOR CONDUCTING SIMULATING TESTS FOR BIRD HIT ON AIRCRAFT
|Abstract||The present invention relates to a breach mechanism for conducting simulating tests for bird hit on aircraft comprising a mild detonating cord (MDC), a diaphragm and a triggering device held between, a holder (2) with a groove on its inner face and a lid (3), a high explosive material in a linear explosive cord with an initiator (4) for triggering and detonating with its propagation velocity, thereby causing the diaphragm to cut off by guillotine action.|
The present invention relates to a breach mechanism for conducting simulation tests of bird hit on aircraft. The breach mechanism according to the present invention consists of a bursting diaphragm, detonating cord and a triggering unit for cutting a diaphragm held between the flanges of an air reservoir and a gun barrel.
Breach mechanisms are used for conducting simulation tests of bird hit on aircraft. A diaphragm in the breach mechanism is ruptured such that air at high pressure gets released into a gun barrel from an air reservoir. The simulated bird mass is kept in a canister in the gun barrel. In conventional mechanism, breach is achieved by using a bursting diaphragm is required, which ruptures at a predetermined pressure. This has the limitation that for each pressure at which the experiment is conducted, a separate burst diaphragm is required which ruptures at the predetermined pressure. When a metallic burst diaphragm is used, a higher dispersion is observed at the burst pressure and repeating the experiments at the same pressure has been difficult.
In the breach mechanism known in the prior art a metal bursting diaphragm with its mounting is assembled between the flanges of an air reservoir and a gun band. Pressure inside the reservoir is increased upto the rupture pressure of the bursting diaphragm. On rupturing of the bursting diaphragm, the high pressure air gets released into the gun barrel which in turn ejects the projectile on to the target. Deformable bursting diaphragms may be made of plastics, metals, metal alloys or other suitable materials. Most bursting diaphragm are round and flat or of domed shape.
One of the main disadvantage of the known breach mechanism is that tor conducting experiments under different burst pressures, burst diaphragms of dififerent thickness are required to match with burst pressure equal to each of the desired experimental pressure values. This limits the number of data points in the experiments. Because of the large dispersion in the burst pressure of diaphragms the test at a particular pressure cannot be repeated accurately for confirmation. Also this method may not provide accurate results because precise bursting at desired pressure is not possible.
From the above limitations of the conventional breach mechanism it has become abundantly clear about the requirement of a breach mechanism which permits to conduct experiments at as many pressure levels as possible and also to repeat experiments accurately at the same pressure for reconfirmation. Whenever there is a doubt in the experimental results, it is necessary to repeat the experiments. These requirements demand feasibility to conduct tests with identical test set-up at ditierent pressures and also to repeat tests accurately at a prescribed pressure. "
When a high explosive material in a linear explosive cord is suitably initiated by proper means at one end, it propagates with its detonation velocity. In an explosive-actuated breach mechanism, cut off operation is achieved within milliseconds by guillotine action due to the explosion pressure resulting in severance of sheet material at the edge of the burst diaphragm held between supports along a specific curved line. The burst mechanism according to the invention uses a linear explosive cord.
The main object of the present invention is to provide a breach mechanism in which the bursting diaphragm can be made to burst at any desired pressure below the actual burst pressure of the bursting diaphragm without causing any damage to the air gun. This will eliminate the requirement of separate calibrated bursting diaphragms for each predetermined pressures at which the experiment is conducted.
A further object of the present invention is to cause instantaneous severing of the diaphragm at the required pressure within milliseconds on command.
A further object of the present invention, is to conduct simulation tests for bird hit on aircraft, more precisely and accurately by incorporating an integrated computer based firing unit, which can issue a firing command when the pressure in the reservoir attains the desired experimental pressure.
Another object of the present invention is to provide reuse of all the main components except for the detonating cartridge and bursting diaphragm.
Accordingly the present invention provides a breach mechanism for conducting simulating tests for bird hit on aircrafts said breach mechanism being held air tight between the mouth of a pressure reservoir and a gun barrel with simulated bird mass in the gun barrel characterised in that the said breach mechanism comprises a detonating cord and a bursting diaphragm held between a holder and a lid, the said holder being provided
with a groove to seat the said detonating cord in the said holder in contact with the said bursting diaphragm and a detonating cartridge triggering means being connected to the said detonating cord for exploding the detonating cord .
The invention will now be described with reference to the accompanying drawings.
Figure 1 shows a longitudinal section of the flanges of gun barrel and the air reservoir with the breach mechanism according to the present invention between them.
Figure 2 shows a plan view of the breach mechanism according to the invention against a gun barrel.
Figure 2A shows a cross sectional view along sectional line A-A shown in figure 2.
Figure 3 shows a detailed view of the portion "X" indicated in figure
Figure 3 A shows a detailed view of the portion "Y" indicated in figure 3.
In figure 1, the breach mechanism according to the present invention is held between a high pressure reservoir (HPR) and a gun barrel (GB). The
breach mechanism is provided with a detonating cord (I) and kept in contact with a bursting diaphragm (8) in a holder (2). A lid (3) is provided to hold the detonating cord (1) in the holder (2) and the bursting diaphragm (8) in an air tight means. A groove (9) is provided on the inner face of the holder (2) for holding the detonating cord (1) in position and another groove (11) in the lid matching with the groove (9) in the holder (2).
An "O" ring (10) may be desirable to provide a leak proof joint between the holder (2) and the lid (3). A triggering device is connected to the detonating chord. The bursting diaphragm (8) is placed between the holder (2) and the lid (3). A detonating cartridge with tri^ering means (4) and a lead wire (5) for activating the detonating cartridge is connected to the detonating cord (1). Assembled breach device is placed between the mouth of the gun barrel (GB) and the high pressure reservoir (HPR) and tightened by means of nuts and bolts (6). Gaskets (7) may be provided at the joints to ensure air tight seal between the respective sides of the breach mechanism, gun barrel (GB) and high pressure reservoir (HPR).
While conducting the simulation test for bird hit on aircraft with the breach mechanism according to the present invention, the high explosive material is detonated on activating the detonating cartridge. When the diaphragm is cut off by guillotine action resulting in severance of the sheet material air with high pressure rushes to the gun barrel from the high pressure air reservoir. The simulated bird mass is kept in a canister and located in the gun barrel. In this way the rupturing or bursting of the
bursting diaphragm will not damage the remaining parts of the breach mechanism and it can be xeused without any adverse effects. Any bursting diaphragm with bursting pressure more than the test pressure may be used for conducting the simulation tests. Thus pre-calibrated bursting diaphragms for rupturing at various pressures are not required to conduct the tests.
The breach mechanism according to the invention can be used to conduct precise and yet simple way of conducting a simulated test of bird hit on air crafts.
1. A breach mechanism for conducting simulating tests for bird hit on aircrafts said breach mechanism being held air tight between the mouth of a pressure reservoir (HPR) and a gun barrel (GB) with simulated bird mass in the gun barrel characterised in that the said breach mechanism comprises a detonating cord (1) and a bursting diaphragm (8) held between a holder (2) and a lid (3) the said holder (2) being provided with a groove (9) to seat the said detonating cord (1) in the said holder (2) in contact with the said bursting diaphragm (8) and a detonating cartridge triggering means (4) being connected to the said detonating cord (1) for exploding the detonating cord (1).
2. The mechanism as claimed in claim 1 wherein the said mild detonating cord is provided with an explosive such as RDX.
3. The mechanism as claimed in claim 1 wherein the said detonating cartridge with triggering means (4) is provided with remote activation means.
4. The mechanism as claimed in claim 1 wherein the said bursting diaphragm (8) is made of a sheet material selected from aluminum, steel and polymeric sheet.
5. A breach mechanism for conducting simulating tests for bird hit on aircraft substantially as herein above described with reference to the accompanying drawings.
|Indian Patent Application Number||197/CHE/2003|
|PG Journal Number||45/2010|
|Date of Filing||10-Mar-2003|
|Name of Patentee||INDIAN SPACE RESEARCH ORGANISATION|
|Applicant Address||ISRO HEADQUARTERS, DEPARTMENT OF SPACE, ANTARIKSH BHAVAN, NEW BEL ROAD, BANGALORE 560 094,|
|PCT International Classification Number||B64D45/00|
|PCT International Application Number||N/A|
|PCT International Filing date|