#20 - Sustainable Regional AircraftSustainability is the driving force behind the design of RELIGHT, an innovative regional air-craft. However, requirements such as compliance with safety regulations, economic competitive-ness and ability to fly from relatively rudimentary airports with a take-off distance of less than1500 meters are also taken into account. Three potential concepts were explored: strutted wingconcept, hydrogen based concept, and blended wing body concept. Among the three aforemen-tioned concepts, the hybrid concept is selected for further development because of its superiorperformance from a sustainability point of view. During research and development the choiceis made to commit to a full hydrogen airliner. A market analysis of current and future trendsshow that hydrogen will become a more attractive fuel than kerosene. Hydrogen fuel also fitsthe current global trend of moving towards more green fuel sources, since no carbon dioxideand very little nitrogen oxides are emitted with respect to kerosene. All the aforementionedpoints highlight the great value proposition that RELIGHT provides to the customer.

Mission ObjectiveThe mission DSE group 20 and it’s RELIGHT aircraft is: "to design a novel regional aircraftwith at least 25% lower environmental footprint than Bombardier CRJ700 series, to transport75 passengers over 2000km".

System Design

The main challenge lies in carrying the hydro-gen in the aircraft, due to its low volumet-ric energy density. The aircraft needs a largeamount of hydrogen to fulfill its mission, re-quiring large tanks. The design solution to thestorage of hydrogen is carrying a total of threecryogenic tanks, one tank placed in the aft sec-tion of the fuselage, and two external tanks onthe wings. Current propulsion systems can bepowered by hydrogen very efficiently, with mi-nor adaptations; therefore, a conventional veryhigh-bypass turbofan engine will power RE-LIGHT. Furthermore, the aircraft will have tocarry less fuel mass when compared to tradi-tional kerosene counterparts.The approximate production cost of the air-craft will be 37 million US Dollars, while thedevelopment costs will be approximately 879million US Dollars for the aircraft. The air-craft is able to operate from rudimentary air-ports with a hydrogen supply, while being ableto take-off from a 1530 meter runway at an al-titude of 1500 meters. RELIGHT reduces the

amount of emissions at all stages of aircraftlife. At start of life, the reduction in emis-sions is achieved by using metals that requireless energy for production. During operationRELIGHT, manages a 77.68% environmentalfootprint reduction w.r.t the CRJ700. At endof life, the majority metal aircraft ensures re-cyclability of major parts, further reducing thetotal footprint.

To conclude, the RELIGHT aircraft is a greatleap forward in terms of sustainability, whilemeeting or exceeding the competition in allother fields.

Delft University of Technology Design Synthesis Exercise 2020