Hypercar Electric Motor Tech Teams Up With a Quad-Turbo Diesel V-12 to Boost eVTOL Range

Don’t look now, but the same electric motor technology powering hypercars like the Aston Martin Valkyrie, Czinger 21C, and McMurtry Spéirling has now been paired with a quad-turbo aviation V-12 diesel to create one of the lightest, most power-dense aircraft generator sets yet announced. A few months back, we reported on how the very Helix motor powering those hypercars might soon make supersonic air travel a reality. Now, they’re poised to make electric subsonic travel, including perhaps vertical takeoff and landing (eVTOL) flight, a lot more viable as a range-extending generator set.

Why should car enthusiasts care about electrified aircraft and eVTOLs? Same reason automakers do: Toyota has a joint venture with Joby Aviation, Hyundai subsidiary Supernal is well along on its S-A2 model, Stellantis is a major shareholder in Archer Aviation, Honda’s said to be working on one, and several Chinese automakers are reaching for the sky. Might this help get some of these projects off the ground?

The eVTOL Challenge

Most eVTOLs expend a disproportionate share of their energy climbing vertically, hovering, and transitioning to forward flight. Once established in cruise, power demand drops considerably. That’s one reason today’s battery-electric eVTOLs have relatively modest range, and why a lightweight range-extending generator set like this one could help get eVTOLs off the ground—and safely back down on the ground again, a more useful distance away.

See All 4 Photos4

The Helix SPX177-137D Electric Motor

Relative to the SPX242-94 unit that powers those above-mentioned hypercars and that was used by Astro Mechanica in its proof-of-concept supersonic engine firing tests, this one is smaller in diameter and longer along the axis but is clearly a next-generation member of the same Scalable Core Technology family, sharing the same fundamental architecture, cooling philosophy, and electromagnetic technology. Shrinking the diameter lowers the rotor tip speeds and rotational inertia, enabling higher rpm, while lengthening the stator stack recovers much of the lost torque, optimizing the motor for power density. Output rises slightly to 563 hp peak, 439 continuous, with 97 percent peak efficiency. Best of all: It weighs just 48 pounds—21 pounds less than the hypercar version—and is about the size of a kitchen stockpot.

See All 4 Photos4

The RED A03 V-12 Engine

RED Aviation is a German aircraft-engine manufacturer of modern Jet-A burning diesel engines offered as fuel-efficient alternatives to traditional avgas piston aircraft engines. The company is targeting the range extender business for eVTOLs and electric aircraft in the advanced air mobility and commercial aviation space ranging from regional jets up to single-aisle and wide body aircraft with the current V12 RED A03 engine and future smaller variants from V-8 down to I-6 and I-4 producing 375 hp down to 188 hp of electric output.

For the V-12, each bank of this 80-degree engine is designed to operate independently, providing redundancy should one bank experience certain failures. It features sequential two-stage turbocharging, can be configured for high altitude (49,000-plus feet) and it can produce 510 peak and 439 continuous horsepower while weighing only 772 pounds. Maintenance costs are said to be considerably less than traditional APUs. Another bonus: It’s quiet, registering 75 decibels at a distance of 164 feet—less than half the typical turbine noise.

See All 4 Photos4

A “GM Small Block” of Power Density

The engine and motor-generator are connected through a planetary gearbox that increases generator speed by a factor of 5.4. Helix says the 350-kilogram generator set delivers a level of electrical output that would typically require a roughly two-ton industrial or marine setup, underscoring just how aggressively both the RED diesel engine and Helix motor have been optimized for aerospace weight targets. Helix says this setup has three times the power density of one of the most efficient auxiliary power units on the market today—the Airbus A350’s Honeywell HGT1700.

Clean and Thrifty

Relative to a turbine auxiliary power unit (APU) of equivalent output, Helix says the generator cuts fuel burn—and therefore CO₂ emissions—by roughly 50 percent. Thrift may not describe the purchase price, however. Neither Helix nor RED has disclosed pricing, but given that the certified RED A03 V-12 alone has historically been reported to cost roughly $170,000, the complete hybrid generator will almost certainly command a substantially higher six-figure price. But I know I’ll feel more comfortable taking off in an eVTOL or any other electrified aircraft knowing that landing power is assured by a high-tech diesel V-12 and hypercar motor-generator.