1. Title of the invention

Dual Redundant In-flight Egress system (IES) of Canopy severance for Fighter Aircraft.

2. Field of invention

This invention relates generally to a system for fracturing the canopy of an aircraft to allow the egress of the pilot or other occupant. The aircraft canopy fracturing system of the present invention may be applied to any aircraft having a canopy and wherein safe severance with greater degree of reliability and safety are required.

3. Background of Invention

When an ejection seat is jettisoned from the cockpit of an aircraft, it must pass through the region occupied by the transparent canopy of the aircraft. In instances where the canopy is not jettisoned prior to the ejection seat, the ejection seat must be capable of blasting entirely through the canopy. To reduce the risks to the pilot or other aircraft occupant attendant to forcing the ejection seat through the canopy, canopy fracture systems have been provided to fracture the canopy and provide path for the ejecting occupant so as to minimize bodily impact with the canopy.

Canopy fracturing systems may utilize fragilizing or non-fragilizing canopies. For purposes of the present invention, "fragilizing" aircraft canopies are those that may be caused to shatter into a significant number of pieces on application of sufficient pressure or explosive force. Such canopies typically are constructed of cast materials including, for example cast acrylic. "Non-fragilizing" aircraft canopies are constructed of materials that do not shatter on application of explosive force but, rather, may be caused to fracture along a predetermined pattern, referred to herein as a "fracture pattern", such that at least a portion of the canopy may be severed and freed from the aircraft and at least a portion of the ejecting occupant may pass relatively unimpeded through the opening fractured in the canopy. Examples of non-fragilizing canopy materials are stretched acrylic and polycarbonate. The fracturing of a non-fragilizing canopy, such as, for example, a stretched acrylic canopy, using the canopy fracturing system of the present invention will not result in the shattering of the canopy or a portion thereof into a significant number of fragments. However, small shards of the non-fragilizing canopy material localized to the source of fracturing energy may be liberated during fracturing.

Several canopy fracturing systems utilizing various fracture patterns are known for facilitating the emergency egress of aircraft pilots and other cockpit occupants.

4. Use of invention

This invented Dual Redundant In-flight Egress system finds its applicability in Fighter / Trainer aircrafts to safely eject the pilot in case of any emergency.

5. Prior art

Current practice involves usage of Single IES for ejection, which assists in severing the canopy but the current invention improves the reliability of the system by providing redundancy.

6. Draw backs of prior art

a) No redundancy available.
b) Special Reliability of the system is less.
c) In case of failure of the single IES, secondary ejection is available but more prone to injury.

7. Comparison between prior art and present invention
This invented Dual redundant Inflight egress system provides the increased reliability of canopy severance system for assistance in seat ejection, thereby eliminating any possibility of injury to the pilot.

8. Aim of the invention

Aim of the invention is to eliminate the draw backs of the present system.

9. Summary of the present invention

The present invention provides an improved aircraft canopy severance system for creating an opening in the canopy of an aircraft to allow the pilot or other occupant egress from the aircraft in an emergency or otherwise. The present invention canopy severance system utilizes a novel canopy fracture pattern that results in a safe canopy ejection with improved reliability. Below are the salient features of the invention

a) Shaped MDC (Miniature detonating cord) is used to severe the canopy and seat ejects through the opening formed in the canopy bubble.

b) Two line Shaped MDC are pasted on the bubble with ends joined together to provide dual redundancy in primary mode.

c) The present invention can be used in case of fighter as well as trainer aircrafts.

d) The present invention greatly improves the reliability of the canopy severance system.

e) The overall length of the MDC pasting has been increased to so that there is no risk of injury to pilots thighs during ejection.

f) The present system is self sufficient and can work in any emergency situation even when the aircraft is in inverted position.

g) The present system can be employed even when is the aircraft is on ground.

h) The present system qualifies even with respect to noise levels. The sound levels due to explosion are within acceptable limits, i) The explosion due to IES is directed outwards from the pilot by the usage of attenuator which minimizes any risk of injury to the pilot, j) The present invention severs the bubble along the pasted line of MDC thus eliminating risk of injury to the pilot due to shattering of the glass, k) The present system involves zero maintenance costs till life expires which is 4 years. I) The present invention facilitates the ejection of seat in fraction of a second time.

10. Brief description of drawings

Fig-l - Dual Redundant IES Fig-2 - MDC Pasting on Canopy Fig.-3 - Attenuator

11. Statement of invention

This invented Dual Redundant In-flight Egress system(IES) of Canopy severance for Fighter Aircraft does all the function of severing the canopy to allow for safe ejection of pilot with greater reliability and safety.

12. Detailed description of invention
The Dual redundant in-flight egress system consists of the following parts/Assemblies

1) Pressure actuated initiators
2) Explosive transfer lines
3) Shaped Miniature detonating cord (MDC)
4) Mounting brackets and junction boxes

In Case of emergency, when the pilot pulls the seat handle, due to this pressure is generated, there are two PAI, first one PAI (Pressure activated initiator) gets activated which in turn activates ETL (Explosive transfer line). ETL is connected to MDC through the junction boxes. Explosion gets transferred to MDC by means of two junction boxes mounted on canopy (Refer Fig -1). MDC fractures the canopy forming a clean cut thus providing unobstructed path for seat ejection of safe egress of pilot. In case the first PAI fails the second one gets activated after a time interval of few milli seconds thereby activating the MDC.

Claims

1. Dual Redundant In-flight Egress system (IES) of Canopy severance for Fighter Aircraft is unique in design that can cater safe ejection of pilot by providing unobstructed path for seat ejection by severing the canopy.

2. The present developed system can be employed in fighter as well as trainer aircrafts.

3. The system is self sufficient and is not dependent on other systems so that it can work in case of failure of any other sub system.

4. The usage of two rows of shaped MDC increases the reliability of the system.

5. The increase in MDC length aids in safe ejection of pilot as this provides clear path for seat ejection

6. Dual Redundant In-flight Egress system (IES) of Canopy severance for Fighter Aircraft is designed for zero maintenance throughout its life.