Parked on the ground, these 5-meter wings slanted up oddly, making the Axe look rather odd if you’re used to conventional planes. But it’s not a traditional aircraft, and dynamically, it’s closer to a large multi-rotor. It rises vertically on four large 1.5-meter-diameter propellers, and like a consumer drone it leans forward to develop horizontal speed. So once it moves at the speed associated with generating lift on the wings, the whole plane will lean forward, and the wings are level when flying.
The Axe uses only four propellers. Generally speaking, six is the minimum for these machines. The Air One has eight, mounted coaxially. The extra propellers are used for redundancy; if they fail they take the load so the plane doesn’t fall out of the sky. Most eVTOLs have redundant backups for all critical systems.
Does this mean that SkyFly has abandoned the concept of redundancy? –it’s not true. In this case, each of the four propellers has two 35kW motors acting on it, so a failure of up to two motors is covered. The flight control system also has quadruple redundancy and two independent battery packs in case one fails, SkyFly says. Not to mention there are control surfaces on the wings that you can use to land yourself and do a regular landing if you have enough airspeed. So the only thing not covered here that other eVTOLs are capable of handling is propeller destruction in hover.
As for specs, the Axe weighs 428kg and has a 48kWh battery pack on board. It can lift two people, has a maximum weight of 172kg, and can fly up to 160km on battery power. There’s also a hybrid option if you want to go further, using a smaller battery pack and an extended-range generator. This version allows the mileage to reach a range of 320 kilometers. The maximum take-off weight is 600 kg and the maximum thrust is 700 kg.
The Axe runs a set of three-wheeled landing gear, and interestingly, SkyFly says it can do short conventional takeoffs on a 50-meter runway, if you don’t want to burn the battery with full VTOL. Presumably the rear propeller gave it a little extra power, which caused the entire plane to pitch forward and glide along the ground on the nose wheel, which allowed the propeller to pitch further forward for STOL maneuvers. Conversely, in VTOL operation, the cabin is tilted backwards, so presumably there are cameras and other things to help the pilot land in circles.
Because the plane can operate like a fixed-wing, the Axe can be flown with a standard fixed-wing pilot’s license — at least until eVTOL-specific licenses start to appear. In fact, SkyFly is positioning this thing as a training platform for pilots planning to get into air taxi jobs. Customers can register it as a package or certify it as an ultralight or a UK experimental aircraft.
And price is an issue. SkyFly is taking pre-orders for a base price of £150,000. Some options seem a bit pricey, such as the extended-range version that will set consumers back £50,000, or £20,000 if they want the final ballistic parachute on board.
Prototype flight video released by SkyFly
