DESCRIPTION TECHNICAL FIELD

This invention describes the new manufacturing technique of shear pin for production aircraft that is used in the release mechanism of Brake parachute system of Fighter and trainer aircraft.

BACKGROUND OF INVENTION

Shear pin of brake parachute system is a critical component for flight critical safety, it is a failsafe device. In the event, an excessive load is imposed upon the release mechanism after the parachute has been intentionally deployed, the shear pin located in the release mechanism should fail and instantaneously jettison the parachute from the aircraft. Earlier manufacturing and testing procedure yielded only one component in a batch which will cater to only one aircraft. The Team developed a best manufacturing process which is airworthy certified and yields to 4 components in a batch which will cater to 4 aircraft sets.

The Brake Parachute System (BPS) consists of a parachute assembly, end cap assembly, release mechanism, cockpit controls and shear pin. The Release mechanism consists of a bracket assembly, parachute link assembly, a set of linkages and an Electro-mechanical linear actuator. ' The parachute is attached to the parachute link assembly through shear pin. To stream the ■ parachute, pilot has to select the cockpit switch to stream position. The actuator retracts and the release mechanism locks the parachute link and open the end cap hook which make the end caps to open sideways during opening of the pilot chute initiates the auxiliary chute to the airstream and it get extracts and deploys the main parachute from the container for streaming. In order to jettison the parachute, the pilot has to select the cockpit switch to jettison position.

This reverses the current actuator and the actuator gets extended and the release mechanism unlock the parachute link which facilitate the jettisoning of parachute. The parachute link along with the streamed parachute gets jettisoned.

DRAWINGS

Fig.l: Layout for test piece and shear pin conventional method
Fig.2 : Flow chart for manufacturing process

Fig.3: Shear pin

Fig.4 : Layout for test piece and shear pin new method.

Fig.5 : Flow chart for new method ■

Fig.6 : Shear pins developed in new method.

SUMMARY OF INVENTION

CONVENTIONAL METHOD OF MANUFACTURING PROCESS

Conventional method calls for test specimen and useable components in 2:1 ratio. (Fig.l). Flow chart for manufacturing process is described in fig.2. In the conventional process a round bar stock of weight 3.7 kg is required for making a single piece weighing 0.06 kg. (Fig.3). the ratio of useful material to test piece material is more in this process.

NEW METHOD FOR MANUFACTURING SHEAR PIN

New method calls for 1:1 test piece and shear pin. (Fig.4). The new manufacturing technique is described in process flow chart (Fig.5). New set of components are shown in (Fig.6)

CLAIMS

We claim that.

1. The new process is economical than the conventional method used for Fighter/Trainer aircraft

2. Manufacturing and testing lead time reduced.

3. Wastage of material is reduced.

4. Output rate per process is increased 4 times as compared to conventional method.