Midterm Report - Aetheria, hydrogen-based long-range eVTOL designed for crashworthiness

Midterm Report of the Design, Synthesis and Exercise (DSE) carried on during the Spring DSE 2023, group 11, assignment "hydrogen-based long-range eVTOL designed for crashworthiness".

Tutors: Saullo G. P. Castro & Fulvio Scarano

Coaches: Marina B. Lopez & Justus Benad
Institution: Delft University of Technology
Place: Faculty of Aerospace Engineering, Delft
Submission Date: Monday 29th of May, 2023

Summary

There has been a significant increase in research and development for alternative modes of transportation in the quest for faster, more effective, and more sustainable travel options in recent years. Additionally, the need for solutions has become more urgent due to air pollution and traffic congestion. Electric Vertical Take-Off and Landing (eVTOL) aircraft may hold the key to this issue’s resolution. The addition of hydrogen-based propulsion to the eVTOL design is a development that will increase the aircraft’s potential range. Therefore, the goal of this DSE project is to use hydrogen to improve the performance of battery-powered long-range eVTOLs. The Mission Need Statement (MNS) of the project is as follows:

Design a safe and sustainable long-range hydrogen eVTOL that can transport four passengers

This report will serve as the basis for creating the final, detailed design of an eVTOL called Aetheria. Tradeoffs will be performed based on three predetermined configurations. Preliminary estimates are made for parameters in each technical department for each configuration, and given a score relative to one another. Finally, the scores will be used to pick one design to pursue in the final report.

Design Options and Trade-Off Criteria

Three designs are evaluated, involving design J1 that is inspired by Joby Aviation and has two tilting rotors on each wing, and another tilting rotor on the horizontal stabiliser. The second design is the L1, inspired by Lilium, which features a tandem wing and has tilting ducted fans on each wing. The last one is the W1, inspired by the Wigeon group, and has tilting tandem wings with
fixed rotors.

To assess each design, trade-off criteria have been made, each with its own score. These are the mission energy, stability & controllability, crashworthiness, noise, production costs, and operational costs excluding fuel criteria. Each has been given relative weights of 30%, 20%, 20%, 10%, 10% and 10%, respectively.

Based on the centre-of-gravity envelopes, a trade-off value has been given to each conceptual design based on how restrictive stability and control is for them. A high value corresponds to a low compromise, flexible design concept. If a design cannot meet the cg excursion requirements it is automatically discarded. Due to this, a new design J2 had to be introduced, which is an improvement on the J1, due to J1’s unacceptable vertical flight controllability characteristics.

Trade-Off

Based on the trade-off criteria, the design J2 was chosen as it received a score of 2.4/3, a big lead compared to the other W1 which received a score of 1.8/3 and L1 which received a score of 1.5/3. Design J1 was discarded, as it did not meet control & stability requirements.