ÿ�մ���

DUBAI—Honda has revealed new details about its previously secretive electric vertical-takeoff-and-landing (eVTOL) aircraft development plan and the turbogenerator at the heart of its hybrid-electric vehicle design.

Making its debut at the Dubai Airshow, Honda displayed a mockup of the eVTOL cabin, a model of the aircraft’s 250-300 kW turbogenerator and the third-scale demonstrator it has used to validate flight control software.

Building on its sub-scale work, Honda aims to begin flight tests of a full-scale proof-of-concept aircraft in spring 2026 and is targeting certification of an initial hybrid-electric production eVTOL in the early 2030s. The company has also conducted ground tests of the compact turbogenerator, successfully achieving continuous and transient power runs.

Weighing less than 100 kg (220 lb.), the turbogenerator is 2.6 ft. long by 1.3 ft. in diameter and has a specific fuel consumption of less than 0.3 kg/kWh, Honda says. Other details of the unit, which is compatible with 100% synthetic aviation fuel, are not being disclosed. Honda says it is leveraging experience gained during development of the company’s HF120 business jet engine and F1 automotive race car to help with the design, system redundancy and certification for the eVTOL project.

Scaled demonstrator tests using two vehicles have been underway at San Luis Obispo, California, for two years, says Taylor Oxford, manager of Test and Evaluation at Honda Research and Technology. “We're taking that little bit longer to make sure we get the technology right, and part of that is making sure that the vehicle not only works aerodynamically, but the systems can all work together and handle failure cases, because we at Honda want to make sure that we raise the level of safety.”

The sub-scale demonstrator, like the full-scale proof-of-concept vehicle, is configured with eight boom-mounted lifting propellers and two aft-located pusher-propulsors. The booms are supported at the front of the aircraft by forward-swept wings, and at the rear by aft-swept wings. The aft wing is larger in span with tip-mounted vertical stabilizers for improved directional stability and yaw control.

“Going into the transition area, we're still able to use a lot of our vertical propulsors, but the stabilizers save us a lot of energy because we can relax how much we're relying on the propulsors for yaw control. It's much easier just to use the control surface,” Oxford says.

Flight control law development was undertaken using the sub-scale demonstrator. “It allowed us to do a lot of things from our initial envelope expansion until we got into the initial transition area, which is very complicated,” Oxford says. “This is because you have to use both your lifting propulsors and your control surfaces and make sure they all function correctly together. Then we started getting into failure mode testing to see what happens if you lose one of your vertical propulsors. We want to make sure our control law compensates accordingly,” he adds.

Delays to some of the off-the-shelf components meant that the full transition to wing-borne flight was not tested at sub-scale. “But we feel that's just less technically risky, because aircraft have been flying like that for a long time, and being able to get into that transition where you're having everything's going at once is probably the higher priority, technically, for us to investigate,” Oxford says.

Flight tests in sustained wing-borne flight mode will be performed using the full-scale demonstrator. The lifting props will stop in flight and align with the air flow. “It's different than some of the other eVTOLs where the blades individually align. Ours just fix with one prop facing forward and then the others just end up in the flow,” Oxford says. Honda is also investigating the potential use of stationary prop blade pitch angle trimming in the cruise mode for greater efficiency.

Measuring almost 50 ft. in span and length, the full-scale concept demonstrator is all-electric powered. “We want to make sure we can figure out the configuration items before having to deal with some of the complexities of doing the hybrid,” Oxford explains. “The hybrid system is being tested in its own test cell right now, and then eventually we're going to merge those two.”

“We don't have an exact timeline for when we're going to merge the electric and turbogenerator systems, and we don't even necessarily know if it's going to be this particular vehicle or if we'll produce another one that's more specifically driven for having a hybrid system,” he adds.