FLY LIGHT

We are students of the Military School of Aeronautics, belonging to the Uruguayan Air Force. As for the challenges presented by the Space Apps Challenge 2019, we choose the Fly-By-Wireless challenge since it seemed the most oriented to our profession, since day by day we are being constantly challenged in the air defence of our homeland. We are very proud to belong to this force and we would like to make our contribution to the aeronautics field worldwide. Concerning the engineering of an aircraft, it has been difficult for us to understand it`s structure in detail since we have not yet completed our career or have enough experience to know in detail the operation of various aircraft worldwide. In spite of this we were able to understand the use of technologies and apply them to contemporary aviation. We use large aircraft`s wiring data and the implementation wireless systems in them.

Objective

The objective of this project is to reduce the weight of an aircraft or spacecraft, replacing copper wiring by other alternatives.

Introduction

Taking in to account that a large aircraft`s wiring system is 470 kilometres length and weights 5700 kilograms, attempts have been made in order to reduce the wiring of the aircraft with the main purpose of reducing its weight. According to several studies, you can reduce up to 30% of weight due to wiring using other systems. Several ways have been projected such as using wireless systems; optical fibre and thermoelectric energy generated by Peltier cells to reduce the wiring of the power supply.

By reducing weight we would achieve greater payload capacity, lower fuel consumption, lower maintenance and assembly costs.

Project development

It has been shown that the use of copper wiring presents several disadvantages which are: difficulties in maintenance, placement of the system in aircrafts and aircraft`s assembly; difficulty updating systems; electromagnetic interference; greater probability of failures and greater difficulty detecting them; high cost of acquisition and pollution to the environment.

Now there are several technologies that allow their replacement.

Wireless systems

Wireless communications are those made without the use of wiring, by means of radio waves, improving efficiency and providing a higher level of security by means of information encryption and an interrogation system that sets the order in which they data is received so all systems are not transmitting at the same time. Cryptography can be performed by means of a cryptographic Co-Processor.

Within the aircraft there is an established frequency, already approved for use in aviation. Within all the bands studied, only the frequency band between 4200 and 4400 MHz shows that sharing is possible.

Wireless systems isn`t recommended to be used in critical areas of the aircraft. On the contrary, it would only be used for the transmission of audio, video, cabin light control and sensors not included in the flight control areas.

Through the use of wireless sensors, it is possible to place more types of sensors that record and save the data for later use in flight analysis. This use allows that in case of failures, once reached the ground, the use of such data would be analyzed.

Easier maintenance is also achieved with optimization of human resources.

Within the aircraft structure, the penetrations necessary for formerly wired connections are eliminated.

Continuing with the transmission of critical data, the Fly Light project considers that the wireless system should not be used in critical areas of the aircraft. This is due to the fact that flight control systems are fundamental and possible attacks or attacks on the communications system must be taken into account in relation to the handling of the aircraft itself. The pilot must have sufficient assurance that the information provided by the control panel is completely correct and that it has not been interfered with by external agents.

It is therefore that other alternatives are used such as the use of Optical Fibre.

Optical fibre

It is a data transmission system based on the complete internal reflection of light within a silica fibre or other transparent material. It has numerous advantages over copper wiring such as: Immunity to electromagnetic interference; high bandwidth since several data can be sent by the same fiber; among other advantages.

In this project the optical fibre was used in the controls of the flight surfaces as well as in the engines since given the importance that these systems have for the control of the aircraft the wireless means did not offer the necessary security. Thus, it is intended to replace the Fly-by-Wire system with the Flyby Light system.

Based on the fact that the copper wiring weighs approximately 4.5 kg / km and that the optical fibre weighs 0.44 kg / km, it is concluded that it would reduce the approximate weight of the wiring for the control of the aircraft by 90%, to in turn it has a smaller size contributing to reduce wiring complexity. In addition, the optical fibre has a greater bandwidth, a greater range and does not present problems of electromagnetic interference being very difficult to intercept the signal and modify it. These characteristics make the fly-by-light system more reliable and secure.

Thermoelectric Energy

Thermoelectric energy is that which is obtained by transforming caloric energy into electrical energy. This is obtained by applying the Seebeck effect which states that if we have two plates connected between them and there is a temperature difference between them and a potential difference is generated. Thanks to this effect we can generate electricity with a Peltier cell.

There is a large temperature difference between the interior and exterior of an aircraft at great heights, as well as there is a large temperature difference between takeoff and landing and cruise flight. In spacecraft there is also a large temperature difference between the sunlit part and the shadow part.

These temperature differences can be exploited for the generation of electrical energy.

In order to reduce the power supply wiring, thermoelectric energy is used at the place of use to supply the lighting of the passenger cabin and the sensors of the aircraft. According to studies carried out by the Vienna University of Technology, it is possible to supply the structural sensors taking advantage of the temperature differences between takeoff and cruise flight. You can also use Peltier cells placed in the fuselage which take advantage of the temperature difference between the interior and exterior of the aircraft to supply electric power to the lighting of the passenger cabin. With a module of 5 Peltier cells connected in series, it is possible to supply 5 seats with electrical power, leaving a surplus. In this way, if modules are placed along the fuselage of the aircraft, the entire passenger cabin can be supplied with electrical energy. This helps reduce the power supply wiring by not having to connect the lighting and sensors to the battery. In the case of motor sensors they would be connected to the motor generator by means of a circuit breaker.

In the case of Airbus A380, a surface area of 1.3 square meters Peltier cells would be required to provide electric power to the passenger cabin lighting, said surface is minimal compared to the total surface of the aircraft.

Currently, there are enough technologies to have a communications system capable of providing detailed instant information of the aircraft automatically. Based on this, Fly Light consists in creating a constant security system where it is possible to automatically emit the information of the aircraft on other frequencies not used until now. The black boxes of the plane, having wireless systems, make it possible to transmit data to be captured by servers on the ground trained to obtain this information and store it in order to use it in case the black box is lost or unable to locate The aircraft. These servers would belong to the Aviation Directorate of each country.

It should not be overlooked that the time used for the realization of this project was not enough to enter to specify about the beneficial uses of the wireless system such as the black box system.

In conclusion we think about continuing to deepen the project later and share it as we move forward in our career within the Air Force and civil aviation in general.

References

https://newatlas.com/energy-harvesting-module-airc...

https://phys.org/news/2015-02-wireless-sensors-air...

https://www.phaseivengr.com/solutions-demos/aerosp...

https://www.technologyreview.com/s/406560/fiber-op...

https://www.intechopen.com/books/green-energy-adva...

https://www.digikey.com/en/articles/techzone/2011/...

http://www.aulastecnopole.com/trabajos/Memoria_SAU...

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa....

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa....

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa....

Energy Harvesting for Autonomous Wireless Sensor Nodes in Aircraft

https://core.ac.uk/download/pdf/81927407.pdf