The Colorado company that plans to build the largest-ever fixed-wing aircraft originally envisioned WindRunner as purpose-built for moving wind turbine blades on its own behalf, with no plans to sell the jet to cargo operators.

Radia has since reconsidered that stance. It is now signalling interest in global aircraft sales and has been engaged in “a bit of customer interactions” at the Paris air show, founder and chief executive Mark Lundstrom tells FlightGlobal on 17 June.

The company is considering commercial cargo and military logistics applications for WindRunner, a conceptual four-engined aircraft with a nose-to-tail length of 108m (356ft) and a maximum payload of 72,575kg (160,000lb).

WindRunner is designed for dirt runways, with relatively short take-off and landing capabilities thanks to a massive straight wing. 

“We are essentially looking at building a platform for moving the biggest things in the world in the hardest-to-reach places,” Lundstrom says. “Wind turbines are some of the biggest ones, but there are other large military payloads as well.”

The freighter could accommodate, for example, “six Chinook helicopters with the blades on”, Lundstrom says, adding that “almost every one of largest rockets in the world will fit inside WindRunner”.

He also identifies Lockheed Martin F-16s, Bell V-22 Ospreys and large satellites as potential payloads, along with “anything that is moved by Antonovs today”.

No new heavy airlift platforms have been introduced since the late 1980s. Lundstrom believes Radia’s potential market could be huge, as it is the only company aiming to enter service with such an aircraft before the end of the decade.

“By 2030, there is probably no other option in the world to get new strategic airlift,” he says.

The Boulder, Colorado-based company came out of a years-long period of stealthy development in early 2024 and WindRunner concept made its worldwide debut at the Farnborough air show later that year.

Lundstrom launched the project nearly 10 years ago based on feedback from wind turbine manufacturers that were frustrated because they “knew how to make turbines that are gigantic – the size of the Eifel Tower, with blades that are longer than a football field – but they could only deploy them in the North Sea offshore”.

Tunnels, bridges, roundabouts and windy roadways prevent major wind turbine structures from moving on the ground. Lundstrom believed the market called for a massive aircraft that could fly directly to wind farms in remote locations. 

But he did not set out to build a ”massive aerospace manufacturing company”, choosing rather to lean on the existing supply chain. Off-the-shelf materials and components will be used to the greatest extent possible, he says. 

Radia identified several key suppliers ahead of the Paris air show, including Spain’s Aciturri Aeronautica to develop the aircraft’s empennage and Brazil’s Akaer Engenharia to lead development of the pressurised cabin. Wisconsin-based Astronautics Corporation of America will develop and integrate WindRunner’s avionics.

The company previously disclosed partnerships with Italian aerospace manufacturer Leonardo to develop WindRunner’s fuselage, Spain’s Aernnova to supply wings and engine pylons and AFuzion of Southern California to advise on safety and certification.

Radia has selected the engines that will power WindRunner but Lundstrom declines to identify the engine maker, suggesting an announcement is forthcoming.

Notably, the aircraft will feature an aluminium fuselage – in the name of more-straightforward manufacturing and repair – with carbon composite material used for the wings and empennage.

WindRunner’s design is inspired by “several precedents”, according to Etan Karni, Radia’s head of advanced systems. 

”The upswing cargo nose is a very common feature,” he tells FlightGlobal. ”The C-5 Galaxy, 747 Freighter and Anotonov 124 all use this feature. This lets us load very large cargo into the maximum cross-section of the fuselage, and use the full length of the aircraft for our primary cargo, the wind turbine blades.” 

Karni says WindRunner’s dual-nose landing gear is inspired by the Boeing B-52, while the high-mounted wings keeps engines well off the ground, protecting turbofans from ingesting foreign objects off “semi-prepared runways”. 

Finally, the twin-tail structure is inspired by the Antonov 225, the world’s longest and heaviest aircraft prior to the only example’s destruction in 2022. 

Where to build WindRunner is another matter. Radia is currently exploring sites for a massive manufacturing facility in both Europe and the USA, and courting governments to help finance the project.

Radia does not intend to build a prototype but rather to assemble a test fleet that will eventually enter revenue service. Lundstrom says the first example of WindRunner will be fully assembled “three years from now”, with flight-testing to follow.