Mirko Hornung

• Prof. Dr.-Ing.
• Managing Director at Bauhaus Luftfahrt e.V.

This paper introduces a methodology to assess hydrogen aircraft fuselages in preliminary design. Considering the overall tank arrangement, number of passengers, seat abreast and more, the tool derives a variety of fuselage geometries. These concepts are then evaluated on both fuselage and overall aircraft level using key parameters to identify the...

Current research in commercial aviation is exploring numerous propulsion and aircraft technologies to mitigate its environmental impact. While purely hydrogen-powered aircraft face manifold challenges, combining hydrogen and conventional fuel may facilitate the introduction of hydrogen-based flight. This study outlines the conceptual design of a pa...

Active flutter suppression (AFS) was demonstrated in real-life conditions during the project FLIPASED (Flight Phase Adaptive Aero-Servo-Elastic Aircraft Design Methods). It was done by passing the flutter speed with a subscale demonstrator called P-FLEX. Two different flutter suppression controllers were used in this case, both of which proved to d...

This paper analyses the possibility of using photovoltaics as additional energy provider for small to medium-sized eVTOL UAVs. A simplified model for eVTOL UAVs, which covers all relevant areas of aircraft design, including aerodynamics, structural mechanics, propulsion and systems modelling, is presented. Sensitivity studies covering various desig...

This paper deals with the influence of engine failure during hover on the wiring harness mass of electrical Vertical Take-Off and Landing (eVTOL) aircraft. It starts by presenting possible strategies which can be used to distribute the additional thrust needed during an engine failure among the remaining engines. The most efficient strategy is sele...

Advanced Air Mobility (AAM) vehicles like air taxis and cargo unmanned aerial vehicles (UAVs) operate close to urban areas. Therefore, it is necessary to keep the noise footprint of such aerial vehicles at a minimum to gain societal acceptance for AAM vehicle operations. Cargo UAVs are typically highly integrated in terms of functions leading to a...

A wide range of aircraft propulsion technologies is being investigated in current research to reduce the environmental impact of commercial aviation. As the implementation of purely hydrogen-powered aircraft may encounter various challenges on the airport and vehicle side, combined hydrogen and kerosene energy sources may act as an enabler for the...

One of the goals of the projects FLEXOP (Flutter Free Flight Envelope Expansion for Economical Performance Improvement) and FLIPASED (Flight Phase Adaptive Aero-Servo-Elastic Aircraft Design Methods) was to test an active flutter suppression system in-flight with the help of subscale flight demonstrators T-FLEX and P-FLEX. The 65kg takeoff weight,...

Presentation at the 13th EASN International Conference on “Innovation in Aviation and Space towards sustainability today & tomorrow", 5-8 September 2023, Salerno, Italy, https://easnconference.eu/

For an efficient eVTOL UAV design process, a multi fidelity design tool is needed. The presented design tool covers all aspects of the aircraft design process, relevant for this class of UAVs. It incorporates the necessary design steps in different levels of fidelity and allows quick design iterations. One key aspect is the integration of XFOIL and...

The geometric assessment of physical demonstrators are an integral part of several research projects conducted at the Chair of Aircraft Design at the Technical University of Munich. The projects range from several research UAVs, a sailplane morphing wing to propellers. There are different project objectives like the assessment of manufacturing devi...

Urban air mobility (UAM) applications such as cargo electric vertical takeoff and landing (eVTOL) unmanned aerial vehicles (UAVs) promise additional transportation capacities for congested urban areas. A major drawback facing UAM operations in future is that the new aerial vehicle movements are bound to lead to additional traffic noise emissions af...

The aviation industry is currently experiencing a social shift in the attitude towards flying due to the increasing awareness of the impact on climate change. This has led governments and industries to set emissions targets, although their achievement for long-range flights is subject to an ongoing debate. Among promising candidates are hydrogen an...

To reduce the environmental footprint of the aviation industry, aircraft with new propulsion systems are increasingly under consideration. In this paper, the potential of a fuel cell hybrid-electric aircraft (FCHEA) powered by hydrogen and kerosene is assessed. First, the methodology for the conceptual design of a single-aisle short-range FCHEA is...

Presentation at the 12th EASN International Conference on “Innovation in aviation & space for opening new horizons", 18-21 Oct 2022, Barcelona, Spain, https://easnconference.eu/

This paper develops three scenarios for the aviation industry's recovery from COVID-19 until 2030 by utilizing the scenario methodology. Besides the short- and mid-term pandemic development, the study takes into account the industry's adaptation to changes in the market environment, e.g., toward sustainability and hygiene requirements. The resultin...

To increase aerodynamic performance of a sailplane, a morphing forward wing section and a flap can be applied. A composite skin is designed to achieve desired airfoil shapes for cruise and slow flight. A modelling approach which considers spanwise wing bending is shown, as this influences the elastic behavior of the morphing skin. With that, a para...

This paper deals with the influence of the shape of the discharge curve of Lithium Ion battery cells on the wiring harness of electrical vertical takeoff and landing aircraft. A simulation framework is presented which enables a detailed simulation of the wiring harness performance over the complete mission of an aircraft. Three common reference air...

The FliPASED project aims to design an actively-controlled wing with an aero-servo-structural optimization toolchain to achieve drag reduction, and test the new design on the T-FLEX demonstrator, which is a 7m wingspan unmanned aircraft with a V-Tail. Accurate and fast predictions of aerodynamic characteristics is vital in this preliminary design o...

An omnipresent conflict in aircraft design optimization is the need for fast yet accurate analysis tools. For a broad search in a design space, a trade off is required. One approach is to perform the broad search using low fidelity methods and to perform higher-fidelity calculations only at a few design points. The knowledge gained at these higher-...

Urban Air Mobility is a novel concept of transportation with unknown market potential. Even in conservative estimates, thousands of operations could be expected on a single vertiport. This exceeds known heliport operations, which is the most comparable existing mode of transport—by far. Vertiport operations, in particular the dynamics on the airfie...

View Video Presentation: https://doi.org/10.2514/6.2022-3740.vid The mission success of civil UAVs depends significantly on the sensor data quality obtained during the mission. Therefore, the interaction between the sensor and the environment should be taken into account as early as possible in conceptual UAV design optimization. For this purpose,...

View Video Presentation: https://doi.org/10.2514/6.2022-3659.vid The environmental impact of aviation has gained increasing interest in the last two decades, resulting in investigations of novel aircraft concepts involving advanced propulsion technologies. For a holistic evaluation of the environmental footprint of these new aircraft concepts in co...

View Video Presentation: https://doi.org/10.2514/6.2022-3739.vid This paper presents and evaluates a multi-fidelity approach for the calculation of lifting surface aerodynamics in a conceptual mission-based design process for civil unmanned aerial vehicles (UAVs). In general, aerodynamic computations significantly influence the final aircraft desig...

View Video Presentation: https://doi.org/10.2514/6.2022-3558.vid This paper discusses a test approach for evaluating the steady-state performance of small to medium sized actuators for UAV applications. The used test system is the Iron Bird Test Facility available at the Chair of Aircraft Design at the Technical University of Munich. This test faci...

The overarching goal in the GNOSIS project is to holistically evaluate the potential through aircraft propulsion system electrification at the two temporal assessment horizons in 2025 and 2050. In this context, one of the evaluation parameters is the CO2 equivalent emissions associated with aircraft operations. In this study, the aforementioned emi...

View Video Presentation: https://doi.org/10.2514/6.2022-3315.vid Limited airport capacities pose a constraint on future air traffic growth. Although the current pandemic eased this problem for some years, with growing post-crisis air traffic it will probably return and with it the demand for solutions. This paper aims to integrate airport capacity...

Electric powertrains have different characteristics than conventional powertrains with combustion engines and require unconventional aircraft designs to evolve their full potential. Therefore, this paper describes a method to identify potential aircraft designs with electrified powertrains. Promising technology options in the fields of powertrain a...

A battery thermal management system (BTMS) for a hybrid electric aircraft is designed. Hot-day takeoff conditions are assumed, resulting in an ambient temperature higher than the allowed battery temperature. Thus, a heat pump has to be employed in the BTMS. All available heat pump technologies are assessed and compared. In a qualitative downselecti...

Urban air mobility (UAM) is the idea of creating a future mobility market through the introduction of a new mode of aerial transport with substantial travel time advantages. A key factor diminishing travel time savings is vertiport processes. So far, vertiport throughput capacity has only been studied in a static manner using analytical methods, wh...

An integrated techno-economic cost-benefit analysis is presented to analyze the impact of damage detection-based SHM on an Airbus A320-based reference aircraft, instrumented with ultrasonic and fiber-optic sensors. The operational performance of aircraft with and without SHM is compared in terms of inspection effort, dispatch reliability, payload c...

This paper presents an approach for consciously tailoring the lift distribution of a given wing geometry in early stages of aircraft design. Based on Top Level Aircraft Requirements and minimal user input, conceptual aircraft design suites such as the MICADO environment, an RWTH Aachen University (ILR) in-house development, generally enable the des...

This paper presents a novel tool for the modeling of partial turboelectric propulsion systems together with a corresponding case study for a commercial single-aisle aircraft. In order to reduce the environmental impact of air traffic, radically new aircraft and propulsion concepts with a high market penetration are needed. Partial turboelectric pro...

Urban Air Mobility (UAM) is an emerging transportation concept promising to introduce a fast and flexible mode of transport, which may become affordable for the larger public. The anticipated demand coupled with the highly constrained urban environment creates a complex problem for infrastructure. Vertiports, as an interface between air-side and gr...

View Video Presentation: https://doi.org/10.2514/6.2022-1297.vid Aircraft noise models are required to account for the aircraft specific noise emissions in design and operation of Unmanned Aerial Vehicle (UAV) systems. While in the past most aircraft noise models were based on a semi-empiric modeling approach, a solely numeric approach is demonstra...

View Video Presentation: https://doi.org/10.2514/6.2022-2333.vid To reduce the environmental footprint of the aviation industry, aircraft with new propulsion systems are increasingly under consideration. In this paper, the potential of a fuel cell hybrid-electric aircraft (FCHEA) powered by hydrogen and kerosene is assessed. First, the methodology...

View Video Presentation: https://doi.org/10.2514/6.2022-1827.vid Optimization of aircraft's performance often requires careful consideration of aerodynamic drag. However, direct measurement of drag of a flying vehicle is not feasible. Therefore, in order to measure the change in drag for different configurations of a flying aircraft, in-flight thru...

This publication shows the semi-empiric noise modeling of an electric-powered vertical takeoff and landing (eVTOL) unmanned aerial vehicle (UAV) by means of system identification from flight noise measurement data. This work aims to provide noise models with a compact analytical ansatz for horizontal and vertical flight which are suited for integra...

Noise and greenhouse gas emission targets set by e.g., the EU commission, NASA, and ICAO oblige the aviation industry to reduce its environmental footprint. Battery-powered hybrid-electric aircraft are currently being investigated in this regard as they can potentially reduce in-flight greenhouse gas emissions and noise. However, most studies to da...

Urban Air Mobility (UAM) is an emerging transportation concept promising to introduce a fast and flexible mode of transportation, which may become affordable for the larger public. The anticipated demand coupled with the highly constrained urban environments creates a complex problem for the infrastructure. Vertiports, as an interface between air-s...

Urban and regional air mobility is a new mode of transportation currently attracting a lot of attention. Much effort is being put into preliminary design studies for various electric vertical takeoff and landing (eVTOL) concepts. Especially the aerodynamic modeling poses major challenges to both applications, the preliminary design and the control...

FLEXOP is a project within the European Union's Horizon 2020 framework which develops methods for aeroe-lastic wing tailoring and active flutter suppression. The developed methods are integrated within a subscale flight demonstrator named T-FLEX. The demonstrator is a 65kg takeoff weight, 7m wingspan unmanned aircraft with a V-Tail and is powered b...

Interactions between UAV propellers and other objects are investigated with respect to their mutual influences using a Vortex Lattice Model for all considered bodies, which are coupled with a Free Wake Model. To increase overall calculation performance the mirror method commonly used for the prediction of helicopter ground effects is modified and a...

Unmanned, subscale technology demonstrators have gained interest as research platforms in the recent years due to their cost saving potential in comparison to manned aircraft and versatility. The customization of technology demonstrators to research purposes often leads to specialized configurations that elude conventional design rules, which has l...

A sailplane with a morphing forward wing section allows a promising increase in performance. As a consequence, the morphing forward section leads to a smaller primary structure and reduced torsional stiffness. As the shear center is moved aft the aerodynamic center, an aeroelastic twisting moment is induced on the high-aspect-ratio wing. The layup...

Nowadays, a multitude of flight control computers and sensor systems are available to support research activities related to testing various unmanned aircraft systems. Either for initial flight testing of a newly designed aircraft or for retrofit purposes, most flight control computers offer a wide variety of functionalities, with a clear exception...

In the German LuFo research project AVACON, the project partners jointly developed a mid-range aircraft concept for the year 2028 with an over-wing engine configuration. With every new iteration of the initial concept, an adapted cabin concept was derived. This paper introduces the different cabin concept derivatives and assesses them regarding the...

A specialized field of aircraft development is the design of high-performance military fighter jets. This paper outlines the steps undertaken to enhance an existing aircraft design environment using a central data model as a single data source for the conceptual design of fighter aircraft. New design challenges were, among others, the approximation...

View Video Presentation: https://doi.org/10.2514/6.2021-2801.vid With increasing numbers of established companies and start-ups pushing into the market for Unmanned Aerial Vehicles (UAVs), e.g. for cargo delivery, the demand for graduates capable of and experienced in flight testing UAVs is increasing. Current flight testing classes typically focus...

A Battery Thermal Management System (BTMS) for a hybrid electric aircraft is designed. Hot day take-off conditions are assumed, resulting in an ambient temperature higher than the allowed battery temperature. Thus, a heat pump has to be employed in the BTMS. All available heat pump technologies are assessed and compared. In a qualitative down-selec...

View Video Presentation: https://doi.org/10.2514/6.2021-3020.vid Typically, civil unmanned aerial vehicles (UAVs) are used to inspect a designated area by means of onboard sensors as for instance in crop monitoring or search and track missions. The quality of the sensor data obtained during the mission has a considerable impact on the mission perfo...

A sailplane with a morphing forward wing section offers a promising performance increase compared to current designs. The morphing shell has to fulfill requirements that differ from those of a conventional shell. It shall adopt the desired aerodynamic shape even in between the ribs which impose the deformation onto the shell. Low actuation work for...

The introduction of low-cost air transport services to short-haul routes has significantly shaped the structure of this market segment. Recent research investigates and discusses the transferability of the low-cost carrier business model to long-haul routes and identifies respective challenges such as lower cost advantages over the competing full-s...

Urban Air Mobility promises to introduce a fast mode of on-demand transportation that is envisioned to be affordable for a broad public in the future. Personal aerial vehicles have been studied since the dawn of commercial flight, but in recent years, these concepts experienced a revival due to novel technologies such as distributed electric propul...

Recognizing the attention currently devoted to the environmental impact of aviation, this three-part publication series introduces two new aircraft propulsion concepts for the timeframe beyond 2030. The first part focuses on the novel steam injecting and recovering aero engine concept. In the second part, the free-piston composite cycle engine conc...

The Institute of Aircraft Design of Technical University of Munich designs, builds and tests Unmanned Aerial Vehicles (UAV) with take-off weights of up to 65~kg for the purpose of technology demonstration in flight. This purpose often leads to the incorporation of uncommon features. With growing size and unconventional features, the domain of valid...

Novel aircraft and operational concepts imply changes of important operational parameters and thus of the whole air traffic network structure. Following the introduction of a holistic concept for long-range air travel proposed by Bauhaus Luftfahrt e.V., the paper at hand assesses its impact on airline fleet scheduling. The concept includes a hydrog...

While literature about the design and assessment of hybrid-electric aircraft (HEA) often refers to the potential CO2eq emission reductions compared to reference aircraft on a single design mission, this paper focuses on a more holistic approach including the emissions of other pollutants in-flight and on the ground using a 1D climate model and the...

In recent years, aircraft concepts employing wake-filling devices to reduce mission fuel burn have gained increasing attention. The study presented here aims at a detailed physical understanding of the effects of integrating a propulsive fuselage device on a commercial aircraft. Compared to an isolated, axisymmetric fuselage-propulsor configuration...

Ram air–based thermal management systems (TMS) are investigated herein for the cooling of future hybrid-electric aircraft. The developed TMS model consists of all components required to estimate the impacts of mass, drag, and fuel burn on the aircraft, including heat exchangers, coldplates, ducts, pumps, and fans. To gain a better understanding of...

The aircraft cabin and boarding procedures are steadily increasing focus points for both aircraft manufacturers and airlines, as they play a key part in the customer experience. In the German research project AVACON (AdVAnced Aircraft CONcepts), the boarding procedure is assessed using the PAXelerate boarding simulation. As the project demands an i...

The aerodynamic design methodology of a wing with a morphing forward section for an 18 meter class sailplane is shown in this paper. The airfoils have been designed by numerical optimization and reworked using inverse design methods. For the wing planform design a multiple vortex lifting line method has been coupled with an optimization algorithm....

This paper deals with the influence of the wiring harness on the system performance of electric vertical takeoff and landing (eVTOL) aircraft. The architecture and connections of the wiring harness are formalized using graph theory. The adjacency and incidence matrices provided by algebraic graph theory are used to define the harness connections an...

This paper analyses the possibility of using hydrogen fuel cells as main energy provider for small to medium-sized eVTOL UAVs. A simplified model for eVTOL UAVs, which covers all relevant areas of aircraft design, including aerodynamics, structural mechanics, propulsion and systems modelling, is presented. Sensitivity studies with various design pa...

This paper presents the modeling, system identification, simulation and flight testing of the airbrake of an unmanned experimental aircraft in frame of the FLEXOP H2020 EU project. As the aircraft is equipped with a jet engine with slow response an airbrake is required to increase deceleration after speeding up the aircraft for flutter testing in o...

Recognizing the attention currently devoted to the environmental impact of aviation, this three-part publication series introduces two new aircraft propulsion concepts for the timeframe beyond 2030. The first part focuses on the novel steam injecting and recovering aero engine concept. In the second part, the free-piston composite cycle engine conc...

The cabin is a crucial aspect of today's and future aircraft as it is the single most important element passengers are in contact with during a flight. This paper introduces a novel fast way to automatically assess and visualize a cabin by displaying it in three dimensions with highly increased detail. This enables a deeper understanding of a cabin...

This presentation introduces an advanced passenger movement model developed for the AVACON project using the open-source boarding tool PAXelerate. The new dynamic approach allows for a more detailed and accurate walking behavior of passengers inside a cabin and thus enables a better understanding of cabin layout changes and their impact on the pass...

Aircraft structures experience various kinds of loads over their entire lifetime, leading to fatigue and ultimately structural failure. In order to avoid structural failures during operation, the maximum number of flight cycles and flight hours is regulated by laws ensuring continued airworthiness. However, since every flight impacts the aircraft d...

A configuration for an unmanned electric fixed-wing VTOL aircraft is proposed. To proof its feasibility despite difficult circumstances with regard to controllability, a prototype was built and successfully test flown. The aircraft combines a tricopter with main wings and an elevon/rotor tilt tailplane. Thus, it gets along with a minimum of control...

In this work, a study to design a highly flexible flutter demonstrator for the development and testing of active flutter suppression is presented. Based on the UAV mission, a bi-objective design optimization problem can be formulated. The aeroelastic UAV characteristic and imposed constraints, defined by operational aspects and the structural integ...

Fuel is assessed as alternative heat sink for future aircraft applications to avoid excessive drag from conventional cooling systems. Two cooling concepts using fuel as a heat sink are investigated for a hybrid electric aircraft platform with entry into service of year 2035+, 180 PAX and a design range of 1300 nm. The hybrid electric propulsion sys...

This paper presents work from the research project AVACON on subsystem design and analysis: a first potential assessment of a polymer electrolyte membrane fuel cell powering a full electric subsystem architecture and replacing the conventional auxiliary power unit. The electrical subsystems power load calculations and the component sizing of the fu...

***OFFICIAL DOWNLOAD: https://publikationen.dglr.de/?tx_dglrpublications_pi1%5bdocument_id%5d=490207***FIND RELATED PRESENTATION SLIDES ON MY PROFILE*** Fixed-wing VTOL UAV are unmanned aerial vehicles capable of both hover and fast forward flight. A variety of aircraft layouts are imaginable which provide these capabilities. To answer the question...

Slides for the presentation on 'Development of a Reinforcement Learning Inspired Monte Carlo Tree Search Design Optimization Algorithm for Fixed-Wing VTOL UAV Propellers' presented at the AIAA SciTech 2020 Forum in Orlando, FL. Corresponding Paper: https://www.researchgate.net/publication/338399401

***FULL TEXT UPON PRIVATE REQUEST***RELATED PRESENTATION: https://www.researchgate.net/publication/338633536_Presentation_on_'Modelling_and_Performance_Impact_of_High_PowerHigh_Energy_Battery_Hybrids_on_Fixed-Wing_eVTOL_UAV'_held_at_AIAA_SciTech_Forum_2020_in_Orlando_FL*** Fixed-wing eVTOL UAV are unmanned aerial vehicles with electric powertrains...

The paper details the research and corresponding implementation and testing steps of the FLEXOP demonstrator aircraft. Within the EU funded project an unmanned demonstrator aircraft is built to validate the mathematical modelling, flight control design and implementation side of active flutter mitigation. In order to validate the different methods...

********** Full Paper Avalible upon Request *********** A novel Monte Carlo Tree Search Optimization Algorithm that is trained using a Reinforcement Learning approach is developed for the application to geometric design tasks. It is capable of evaluating design parameters and demonstrates the successful application of reinforcement learning strate...

The idea of the EU funded FLEXOP project is to raise efficiency of a currently existing wing by derivative solution with higher aspect ratio at no excess structural weight. In order to enable such a resulting highly flexible wing the project goal is to develop methods for active suppression of flutter and passive load alleviation. The developed met...

Slides for the presentation on 'Modelling and Performance Impact of High Power/High Energy Battery Hybrids on Fixed-Wing eVTOL UAV' held at AIAA SciTech Forum 2020 in Orlando, FL. Corresponding paper: https://www.researchgate.net/publication/338398496_Modelling_and_Performance_Impact_of_High_PowerHigh_Energy_Battery_Hybrids_on_Fixed-Wing_eVTOL_UAV

First patents concerning the integration of Structural Health Monitoring (SHM) capabilities into aircraft have been granted over 70 years ago (Green 1948). Since then, numerous potential applications of SHM along the entire aircraft lifecycle have been identified in scientific literature. However, the application of this technology in commercial av...

Providing sufficient cooling power for an aircraft will become increasingly challenging with the introduction of (hybrid-) electric propulsion. To avoid excessive drag from heat exchangers, the heat sink potential of the aircraft surface is evaluated in this study. Semi-empirical correlations are used to estimate aircraft surface area and heat tran...

The aim of this research is the identification of a unified bookkeeping and evaluation scheme for the integrated performance analysis of a boundary layer ingesting (BLI) concept in the conceptual design phase. A thorough review and classification of existing performance bookkeeping schemes suits as a basis for the derivation of a bookkeeping scheme...