Development of a pyrotechnic door actuator

Citation

(2009), "Development of a pyrotechnic door actuator", Aircraft Engineering and Aerospace Technology, Vol. 81 No. 1. https://doi.org/10.1108/aeat.2009.12781aaf.012

Development of a pyrotechnic door actuator

Article Type: Features From: Aircraft Engineering and Aerospace Technology: An International Journal, Volume 81, Issue 1

Modern aircraft manufacture is fiercely competitive. There is immense pressure on to keep costs low. Requirements for efficiency and environmental considerations for wide-bodied aircraft demand research and innovation from every conceivable field. A Bavarian scientific and industrial consortium is breaking the mould in the construction of aircraft doors and emergency opening systems.

Weight minimisation is a particular challenge in the construction of jets. Aircraft doors are a critical factor in this weight balance. The safety-sensitive classified emergency opening systems are an area where highly specific weights and costs are demanded.

This is where the ambitious research project Pyrotak comes in. It is a collaboration of research projects from Bavarian businesses and universities which are already a success. The participating businesses and universities under the direction of consortium leader Eurocopter Deutschland GmbH, Donauwörth want to develop a new door actuator which in an emergency opens the doors of wide-bodied aircraft such as the Airbus A350 Extra Wide Body. Additionally, this innovative concept provides the potential to upgrade the existent fleets of aircraft such as the A300, A320, A330/A340 or A380 families. It is also possible to apply this to broader uses within the field of actuators which have a similar application profile in the air industry, such as emergency opening systems for aircraft passenger doors. Positive consequences for the Bavarian economic region are expected not only in terms of development and manufacture of emergency openings but also for the whole field of the aerospace industry.

The research project Pyrotak, which comprises a volume of €2 million, should be completed by the end of 2010. The Bavarian Research Foundation funds 50 per cent of the project. It is expected that from the development, up to start of production of this innovative passenger door system Bavaria will be strengthened as an aviation region. This will also further the creation and security of new jobs at the participating companies.

The starting point is to look at the previously known procedures for emergency openings of aircraft passenger doors, electronic or pneumatic such as those used in the Airbus A380. However, these are not the best options in terms of weight, maintenance expenses, complexity of the electronic system and the energy density.

Pyrotechnic propellants have not yet been developed sufficiently in aeronautics; the full economic potential of this drive option has been so far unused. The aim of Pyrotak is the development of a pyrotechnic rotary drive system for the opening of passenger doors when in an emergency the doors must be relied on to open automatically.

The introduction of totally innovative technology such as pyrotechnics for rotary actuators requires an extraordinary amount of cooperation among science, research and industry. The company Eurocopter Deutschland GmbH, Donauwörth is a leading manufacturer of doors and cargo doors for commercial aircraft, especially for Airbus. On board for the development of the pyrotechnic door actuator are various prestigious universities and companies.

The development of pyrotechnic propellant is the responsibility of the company HS Product Engineering in Alling. A particular challenge is to gain insights into the use of pyrotechnics for slow operating systems.

Further scientific assistance for the project comes in the form of Prof. Johann Höcherl (Validation) and Prof. Dr rer. nat. Michael Pfitzner (Thermodynamics), both from the University of German Federal Armed Forces in Neubiberg.

Prof. Dr-Eng. Bernhard Frenzel and Prof. Dr Peter Kurzweil, both from the University for Applied Sciences Amberg-Weiden are responsible for the conception and design of the ignition device. The pyrotechnic propulsion unit which is activated by the ignition device supplies the motor with the necessary working gas. The rotating actuator drives the aircraft doors.

There are two different drive concepts in the collaboration research project: a direct gas motor and an indirect gas motor which is equipped with an additional reduction gear.

The flow mechanical design of the gas motor is undertaken by Prof. Dr Eng. Andreas P. Weiß of the University for Applied Sciences Amberg-Weiden.

The concept of the direct gas motor is to be devised by the engineers of the Bavarian company HS Product Engineering.

The pyrotechnic ignition indirect motor with reduction gears is however created in the development laboratory of DEPRAG Schulz GmbH & Co. For over 75 years, the Amberg Company has been producing a wide variety of air motors. The central element to this tool is the air motor as drive unit. Depending on application an air vane motor, tooth wheel motor or turbine drive can be used. For the research project, the turbine drive is most suitable as this has the highest power density and allows oil free operation.

High-drive performance can be achieved in the smallest spaces and with very low weight by use of a suitable turbine motor. Up to 4 kW capacity can be realised by a machine which weighs less than 2 kg. DEPRAG turbines are used for example in hand-held air grinders.

These characteristics – low weight and high performance – make the DEPRAG turbines of highly compatible for use in the Pyrotak emergency door system. The engineers at DEPRAG are now pulling out all the stops to develop this ambitious project, a pyrotechnic ignited gas motor with reduction gears which should deploy its torque directly on the door opening drive.

Last but not least, the Bavarian company Elektro-Metall from Ingolstadt has taken over the constructive integration of the actuator unit.

With the low-maintenance needs, reliability and reduced weight of this emergency opening system Pyrotak, the research consortium sees the chance to take the leading role in this expanding market. In the future, aircraft manufacturers will improve their cost position further and further by trusting complicated systems to their familiar suppliers. So it is to be expected that tender for the aircraft doors of the emergency system, the doors monitoring and emergency slide will become part of a “complete package”. With these visionary technologies such as Pyrotak not only Eurocopter Deutschland GmbH but also the other participating companies can look forward to security and growth.