US-Belgian start-up Cosmic Aerospace is celebrating securing $4.5 million in seed capital, allowing it to accelerate early stage development of its Skylark all-electric regional airliner.

Cosmic aims to develop a 24-seat aircraft capable of flying missions of up to 540nm (1,000km) for service entry around the end of the decade.

Cosmic Skylark-c-Cosmic Aerospace

Source: Cosmic Aerospace

Cosmic says embedded-wing configuration is key to promised efficiency gains

Rather than banking on improvements to battery technology, it has based the Skylark around the performance levels of current cells and instead relies on a low-drag design – including the distinctive embedded wing - to realise efficiency gains.

Cosmic has previously raised $1.5 million in pre-seed funding, which was partly used to design and build a full-scale version of its electric engine for static ground testing.

Although the engine is not yet flight-ready, it has been “very successfully tested” and the design de-risked, says Cosmic co-founder and chief executive Christopher Chahine.

Chahine is keeping the exact size and performance levels of the engine close to his chest but does disclose that each 40-50cm (16-20in)-diameter high-speed ducted fan will deliver thrust in the low single-digit kilonewton range.

“To our best knowledge the most power-dense electric engine of its size,” he says, boasting performance equivalent to a similarly sized gas turbine.

Overall, the Skylark’s thrust-to-weight ratio is “quite similar” to today’s narrowbody jets, Chahine asserts.

Digital renders of the proposed design show 16 of the electric motors embedded in each wing, although Chahine declines to reveal a specific number. 

Although the aircraft’s appearance invites inevitable comparisons with the de Havilland Comet, Chahine says the embedded-wing configuration is a key driver of the Skylark’s aerodynamic efficiency, allowing the use of a high-aspect-ratio composite wing without adding weight and drag.

“It is the integration of the propulsion system in the structure that enables the long-span wing,” he says.

Although there are additional aerodynamic benefits to the design, achieving the desired wing length while avoiding weight and drag penalties was “the main goal”, he says.

Indeed, with a planned 36m (119ft) length, the wingspan is double the proposed fuselage length of 18m.

Maximum take-off weight will be around 24t, says Chahine, in no small part driven by the batteries. Cosmic has based the design around batteries of 320Wh/kg at pack level or 400Wh/kg at cell level; “these are cells that exist today”, he adds.

Cosmic Engine-c-Cosmic Aerospace

Source: Cosmic Aerospace

Company has already built and ground tested electric engine

As the batteries are housed inside the aircraft a wider-diameter fuselage is required. However, this has the knock-on benefit of allowing a 2-2 seat layout, rather than the 2-1 configuration typically seen on regional jets.

Cosmic aims to build and fly a full-scale demonstrator of the Skylark in 2026; assembly and testing of the aircraft will take place at its US site at Centennial airport near Denver, Colorado.

But the next step will be to progress the design and development of the wing, including the assembly of a section of the structure for ground and windtunnel testing.

This will likely be a scaled demonstrator, but Chahine says the company is also evaluating the benefits of building a full-scale wing with integrated propulsion system.

However, others in the space, notably rival developers Heart Aerospace and Maeve Aerospace, have significantly changed their designs since launching, upping seat counts and switching from full- to hybrid-electric powertrains.

Although Chanine says Cosmic is “not opposed” to implementing a range-extending hybrid-electric system “if it makes sense”, he adds: “Our design philosophy is very much focussed on [achieving] the best range possible with an all-electric architecture.”

Cosmic is discussions with various airlines regarding the Skylark and is receiving “really good feedback”, he says, with no pressure to increase passenger accommodation.

“What ultimately drives that decision is the operating cost per seat. What I think is really relevant here is that the aircraft makes business sense for the airline and that is why we are seeing a lot of those conversations happening.”

Chahine, a former aerospace engineering academic at the von Karman Institute for Fluid Dynamics and the University of Oxford, founded Cosmic with chief technology officer Marshall Gusman, who had previous stints at NASA, Kittyhawk and Boom Supersonic.

The team also includes Joe Wilding, a veteran in aircraft development and former co-founder and chief technology officer of Boom.

Cosmic’s seed-funding round was led by climate technology-focused venture capital firm Pale Blue Dot with participation from investors including Aera VC, Visionaries Club Tomorrow, Fifty Years, Possible Ventures, Syndicate One, Course Corrected, Understorey Capital and Samurai Incubate.

Cosmic Skylark ground-c-Cosmic Aerospace

Source: Cosmic Aerospace

Cosmic believes service entry will be possible by end-decade