Various companies, mainly startups, are currently developing eVTOL. Most of them are all-electric eVTOL, which fly only on battery power and are limited to short-distance flights with a range of about 100 kilometers (approx. 62 miles). However, market research has identified that eVTOL transportation in the biggest demand is for inter-city travel with a range of up to 400 kilometers (approx. 249 miles) or so. Today, and probably even 20 years from now, it will be difficult for aircraft to fly long-distance solely on batteries. Therefore, Honda decided to develop the Hybrid eVTOL that features a power unit utilizing a gas turbine generator and battery to realize the long range travel.

In general, aircrafts are more often used for travels of over 400 kilometers (approx. 249 miles). For example, in North America, for travel of up to 400 kilometers (approx. 249 miles), many people choose to drive their car, taking 3 to 4 hours to get to the destination. On the other hand, Hybrid eVTOL, like helicopters, can take-off and land as long as there is a certain amount of space, enabling passengers to get in and out of the eVTOL at a familiar location, such as the rooftop of a popular building, and eVTOL fly at a speed of more than twice as fast as a car. This enables passengers to travel 400 kilometers (approx. 249 miles) in only about 2 hours, providing significant value for people. Need for such convenient inter-city transportation exists not only in North America, but in other regions as well.

Another reason why we chose to develop Hybrid eVTOL is Honda's core technologies. The development of the innovative hybrid-electric propulsion system (“Gas Turbine Hybrid System”) was made possible by Honda’s original technologies amassed through a rivalry among Honda engineers with all kinds of expertise in various mobility-related technologies.

Gas Turbine Engine technology

Honda began its research into aero engines in 1986, and in 2003, the HF118-2 aero engine developed independently by Honda was installed in the HondaJet experimental aircraft and successfully completed its first flight. Based on the HF118-2 technology, Honda began joint development of the HF120 engine with General Electric (GE), which received airworthiness certification from the U.S. Federal Aviation Administration (FAA) in 2013. The HF120 is now installed in HondaJet and flying around the world.
The aerodynamic, combustion and other technologies amassed through the development of aircraft engines are now being applied to engines for gas turbine generators.

Electrification technology

Honda has a proven track record of offering a number of hybrid vehicles to customers all around the world and also developing the ultimate hybrid power unit for F1^™ racing. The motor, battery and energy management technologies Honda has amassed through hybrid system development are being optimized for our eVTOL, and the energy regeneration technology of the F1^™ power unit is being leveraged for the ultra-high RPM gas turbine generator.

Experience in obtaining certification

To obtain the type certification, precise quality control such as procedures related to design and analysis, procurement and manufacturing of materials and parts, assembly and delivery of power units, and traceability of parts and the demonstration of various certification criteria related to the system and the performance is required in every aspect. Honda has experience in obtaining certification for the HF120, an aero engine developed jointly with GE. This experience will be useful to conduct development and evaluation which take into account the precise standards for durability, performance, safety, functionality and reliability set by the authorities.

Honda eVTOL will be equipped with a series hybrid system that generates lift and thrust by driving a motor that turns propellers (rotors) with electricity from a gas turbine generator and battery. During vertical take-off and landing, when high output is required, the electricity from the gas turbine generator and battery are combined to power the eVTOL. During cruising after reaching proper altitude, the eVTOL flies with motors while storing generated electricity in the battery. Honda is pursuing energy management suitable for an eVTOL, so that it can safely fly longer distances using less fuel.

Honda utilizes aerodynamic and combustion technologies amassed through its long history of aero engine development to achieve lighter weight, more compact size and higher efficiency of its gas turbine engines, which are indispensable to achieve long-distance transportation.

Aerodynamic technology:

Honda’s aerodynamic technologies are applied to a compressor that raises the pressure of the incoming air to the point where it is suitable for combustion, as well as to the turbine that extracts the power to rotate the generator from the combustion gas.

Combustion technology:

Honda’s combustion technologies are applied to the combustion chamber that generates combustion energy by mixing compressed air and fuel.

Honda technologies for the MGU-H^*, one of the components of F1^™ power units, is being utilized to reduce the weight and increase the efficiency of the generator. The rpm of a reciprocating engine for hybrid vehicles is in the several thousands, whereas the rpm of a gas turbine generator for Honda eVTOL will be several tens of thousands, and the power density will also be more than 10 times higher than that of a mass-produced hybrid vehicle.
*MGU-H (Motor Generator Unit Heat): A regenerative system that converts engine exhaust gas into electrical energy.