Explained
How a flying roadster works.
Two ways to stay up
This roadster is a concept, not a real product, but it's built on the same principles as the electric vertical take-off and landing aircraft, or eVTOLs, being developed today. It has two ways of staying in the air. At low speed four ducted fans blow air downwards, so it can lift off straight up and hover like a drone. Once it's moving, its short wings and front canards make lift the way an aeroplane's wings do, and the lift fans can ease off.
That switch matters because hovering is expensive. To hover, the fans have to push down enough air every second to balance the aircraft's whole weight, which takes a lot of power. A wing, on the other hand, makes lift from the air flowing over it, and that lift grows with the square of airspeed: double the speed and you get roughly four times the lift. So the most efficient flight is fast, wing-borne cruise, with hovering kept to the take-off and landing.
Electric propulsion
Instead of one big engine, the roadster uses several electric motors, an approach called distributed electric propulsion. Electric motors are small, light for their power and easy to control precisely, so a flight computer can vary each fan's speed many times a second to keep the aircraft level. With several motors, the loss of one can be handled by the others. Putting the fans inside ducts shields the spinning blades and can raise the thrust each fan makes at low speed.
All of those motors draw on a lithium-ion battery mounted low in the body. Batteries store much less energy per kilogram than aviation fuel, which is the main reason electric aircraft today have limited range. Every design decision, from the streamlined body to the efficient wings, is about stretching that stored energy as far as possible.
Flying it
Open play mode and choose Fly. Hold Up to lift off and climb, use the stick or the arrow keys to turn and accelerate, and steer through as many rings as you can before the clock runs out. The rear thrusters push you forwards and the lift fans hold your altitude when you let go.
Parts glossary
- Body
- A streamlined composite body holds the occupants and the systems. Its smooth shape reduces drag in forward flight.
- Canopy
- A clear canopy gives the pilot a wide view, which is especially important when hovering close to the ground.
- Ducted lift fans
- Four electric fans spin inside ring-shaped ducts and push air downwards for vertical take-off and hover. The duct shields the blades and can improve thrust at low speed.
- Rear thrusters
- Two rear-facing electric thrusters push the roadster forwards once it's airborne. The glow here is artistic: electric thrusters move air rather than burning fuel.
- Wings and canards
- Short wings and front canards make lift in forward flight, so the lift fans can be throttled back to save energy at cruise. Fun fact: A wing's lift rises with the square of its airspeed, so doubling speed gives about four times the lift.
- Battery
- A lithium-ion pack low in the body powers every fan. How much energy a battery can store for its weight is the biggest limit on electric aircraft today.
- Landing gear
- Three short legs with small wheels support the roadster on the ground and let it be pushed around a landing pad.
