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Demonstration of a Reverse Engineering Process for a Historic Aircraft Model Based on 2D-Drawings

Michael Lampesberger, a team member, was analysing the design process of an aircraft in his bachelor’s thesis. He performed his task by creating a historical flight model through reverse engineering. The foundation is the 1932 published blueprint of the so called ‘Hochdecker-Rumpfmodell’. To optimize the flight performance of the ‘Hochdecker’ (high winged aircraft), the model will be designed according to essential adaptive aircraft features.
Nowadays the CAD-Software CATIA V5®, developed by Dassault Systems, is usually used in aviation. To design and digitize, the 87 years old blueprint must be prepared due to its poor condition. To be able to do so, several steps and software tools are necessary. Due to the inaccuracies of the blueprint, appropriate actions must be taken.
The entire ‘Hochdecker-Rumpfmodell’ had been drawn with CATIA V5®. This was realized using the Generative Shape Design and the Part Design development environments. Additionally, the material to all parts created were properly allocated in order to analyse the aircraft mass.
With the described procedures, a complex CAD model was created, which can be adapted quickly to the required geometrical conditions by using Adaptive Design.
Furthermore, the Airplane performance was analysed with xflr5.

Concept and Design of a Modular CNS / ATM Receiver System

A high-frequency receiver must be designed very careful and well-considered to get useful signals. Jakob Bauer designed a receiver chain that is additionally modular constructed to be used as an illustrative material in lectures as well as a generally usable flexible receiver. The design process starts with the selection of the most useful receiver structure. For this the elements for a certain application, in this case the reception of GPS-frequency at 1.5 GHz and the reception of the hydrogen line at about 1.4 GHz must be chosen. This concerns a radio frequency bandpass filter, a low-noise amplifier, mixer with a local oscillator and an intermediate frequency receiver in the use receiver chain.

 

The chosen circuit must be controlled for his efficiency and the signal quality. At first the needed microstrip width of the circuit board must be calculated. Following this a link-budget calculation takes place which adds up all gains and losses of the single elements. Additionally, the noise of the elements is considered. With those two values the signal to noise ratio can be calculated, which gives a good overview of the whole circuit and the output signal.

The second test is about the so-called S-parameters, which are very important at high frequencies. For that a simulations program is used, in which a schematic circuit with all important values around the operating point gets calculated. The output of this analysis takes place via a smith-chart.

After a successful analysis the circuit is constructed in EAGLE and gets manufactured. At the end it gets assembled and tested for its functionality.

Concept Development for a Heavy-Duty Drone

The need for drones is growing steadily. Therefore, new and more efficient concepts are needed especially for increasing payloads and as a replacement for helicopters. Benjamin Haller, a team member, wrote his bachelor’s thesis about such heavy-duty drones.

A scientifically proven drone design requires a close look at the individual components and the interaction in the overall system. It starts with an analysis of weight and geometry and goes into bigger detail in calculations of propulsion and structural analysis. In the overall design, the determination of an optimal propulsion system with modern power supply, efficient propellers and sufficient flight performance is a big point. In this bachelor’s thesis, the actuator disc model is used primarily. Furthermore, a special system is designed for the automatic pickup and dropdown of payloads. The construction together with structure calculations are done with a modern CAD program.

The design and structure calculations with FEM methods visualize the appearance and strength of the drone. The final result is a parts list with the most important components, the costs and the suitable suppliers to produce the heavy-lift drone.

The conventional hover-drones are relatively inefficient but accomplish their purpose without big problems. The result is a good solution for a heavy-lift drone for lifting or carrying payloads over short distances.

Mechanical Conception and Construction of a Dualcopter

Klaus Graf, a team member who is currently doing his master’s degree in aviation, worked on a very interesting project in his first bachelor thesis. A dualcopter in general is an exotic type of multicopter. The realization can pursue in different ways. This project focuses on the concept of the tilt-rotor approach and contains the design, preliminary calculation methods and the manufacturing of two prototypes.

The first and smaller prototype was made to get an inside view of the in-flight-behaviour and to test early control unit designs. To fulfil the requirement of easy replacement, RotorBits® and some 3D printed parts were used. A detailed CAD model in CATIA® also provides the moment of inertia for further control unit designs and simulation purposes.

Expertise and weak points of the first prototype were analysed and taken into consideration for the development of the final prototype. The tilt mechanism was designed to be as rigid as possible, fast and precise to handle the 15” propeller and its deviation moments. Frame plates were milled out of CFRP and aluminium components were manufactured on a lathe to withstand the enormous forces.

Simulation of Flight Data in MATLAB®

The aim of this project, which Arian Ghoddousi a member of Team Drone Tech is currently working on, was to compute and simulate aircraft flight data. The data output was designed to look like a common general aviation plane cockpit, like the Cessna C172.

During the coding process it became clear that the potential of this program is greater than just a stand-alone project. When the whole code was recoded in order to convert it from procedural programming to object orientated code, it was coded in module blocks, which can work separately and can be put together as desired, especially, the gauges and the trajectory plot. This method enables a larger spectrum of usage. The main program is designed to compute all the necessary data by itself. A different method and the next step would be the usage of sensors which gather data. Therefore, a hardware interface, like an Arduino, is needed.

The possible usage of this project for Team Drone Tech could look like this:

A drone could be equipped with different sensors, for example, for pressure and acceleration and then establish a connection to, e.g., a radio transmitter. On the ground station, a receiver is required, which needs to be connected to a microcontroller, such as the Arduino, which then will transform the data, gathered by the sensors, into concrete values. The last step is the communication between microcontroller and the MATLAB® host computer. The program receives the calculated data and can save it in variables, which then will be plotted on the display. The information provided on the output screen enables the drone pilot to fly under similar circumstances as IFR-pilots. If the drone gets out of sight, the drone pilot still has some information such as:

  • Altitude or Height (Depending on altimeter is set to QNH or QFE)
  • Attitude
  • Speed
  • Vertical Speed
  • Heading and Track
  • Position (either absolute via GPS or in relation to the pilot or departure point)
  • Any other information being sent to the host computer

Furthermore, this project could also be the basis for a drone autopilot. Therefore, an interface which can control the drone’s engines and other control devices would be needed.

Matlab Programming Project

During the third semester students have to fulfil a MATLAB® programming project. One of these projects was realised by Victoria and Annika together with two fellow students. It was a quadcopter failure simulation which will be used in a later task to analyse failures of individual motor shutdown or a total shutdown and visualizes graphs and animations.

The main goal of this project was to create quadcopter failure simulations on MATLAB® and Simulink®. The variables of the simulations would be saved in a multidimensional matrix, which can contain millions of simulations worth of data. This data can be read into Artificial Intelligence, which would then be able to recognise the type of failure as it is happening in real-life and combat it.

This was achieved by expanding on an already existing MATLAB® code, which simulated a quadcopter in stationary flight. The program expansion included the implementation of shutdown variables, interpolation of data, implementation of a regulator and the creation of a graphical user interface.

The GUI enabled the user to choose the desired parameters of flight. The user can choose from a list of simulation options, including the type of flight, type of failure, time of the failure, time and number of simulations, wind velocity and wind angle. The settings can also be set to random. The program then shows a simulation of the desired flight and failure of a quadcopter, and plots how the various variables are affected over time.

The system also allows the plotting of variables from multiple simulations to observe how the different failure modes lead to different plots on the same graph.