concept

A Colorado company displayed at the Air & Space Force Association’s annual conference this week a model of a new very heavy lift cargo jet it is designing. Though still in its aspirational phase, Radia’s WindRunner concept comes at a time when the future of heavy lift cargo capabilities is in question, including within the U.S. military as it looks to eventually replace its fleet of aging C-5M Galaxy and C-17A Globemaster III transports. Globally, the ability to move very large, outsized loads over long distances by air also has something of an expiration date, without any clear replacement for existing aircraft waiting in the wings. So, while by all accounts Radia’s dream may be a big long shot, it’s certainly worth examining.

The four-engined WindRunner, far bigger in size than either of the two U.S. Air Force airlifters, was originally designed to carry 300-foot-long wind turbine blades. In other words, it originated with the goal of offering a transport solution to commercial customers. However, Radia claims that when it’s built, it could be an attractive airframe for moving tanks, helicopters, collaborative combat aircraft (CCAs) and other large war materiel to austere locations, as well as rocket boosters and other outsized loads.

“As interest grew and development progressed, WindRunner’s unprecedented volume similarly appealed to the defense, aerospace and commercial cargo sectors,” company spokesperson Grace O’Connor told The War Zone.

The C-17A, which first entered service in 1995, has a maximum payload capacity of some 82 tons, according to the official Air Force fact sheet.

The much larger C-5, which has been around since the 1970s, and is now in its enhanced C-5M configuration, can carry up to 140 tons. What’s arguably more important than just the raw weight it can lift, the C-5 can carry far larger items than the C-17.

Capable of being refueled in flight to extend their range, neither this aircraft nor the C-17 is currently in production.

By comparison, Radia states that the 356-foot-long WindRunner, first conceived of in 2016, will be able to deliver 72.6 tons of cargo. However, payload weight only tells a small part of the story, the company suggests.

“Current defense cargo aircraft run out of room before they run out of lift capability,” O’Connor posited. “In other words, military operations cube out on missions before they gross out, making volume the limiting factor. The massive dimensions of today’s military aircraft, modern satellites, missile systems, and mobile hospitals make it challenging to transport mission-ready.“

Instead, many weapons systems have to be disassembled to fit aboard a Galaxy or Globemaster.

Radia claims that WindRunner, with some 270,000 cubic feet of cargo space, delivers seven times the volume of a C-5 and 12 times the volume of a C-17. Among other cargo, Radia says WindRunner can carry six ready-to-fly Chinook C-47 helicopters. The placement of the cockpit in a bulge above the cargo hold offers more vertical space to roll items into its very long hold.

The WindRunner is also claimed to be able to take off and land on 6,000 feet of runway, which is pretty short for such a large plane. One limiting factor, however, may be range. While the C-17 can fly about 2,400 miles with a heavy load without refueling and the C-5 can fly over double that distance with cargo packed in its belly. The WindRunner has a loaded range of just 1,200 miles, according to Radia. So, aerial refueling capability would be a prerequisite for U.S. military service. Still, this may be a worthwhile trade for the ability to easily move very large cargoes while keeping the cheapest aircraft acquisition price possible and tankers already service the C-5M and C-17A fleets heavily for long-distance missions. It may also be possible to extend the giant aircraft’s 261-foot wingspan to increase its range, among other concepts commonly employed to increase an aircraft’s range, such as auxiliary fuel tanks. Radia told us aerial refueling capability would be added for military contracts, but not for the initial tranche of commercial jets

As a scale-model mockup of the WaveRunner was on display on the conference showroom located at the sprawling Gaylord Conference Center at National Harbor, a top Air Force general was in a small meeting room two stories above, talking about the future of the service’s heavy lift.

The U.S. Air Force is still in the early stages of figuring out what it needs for a Next Generation Airlift (NGAL) platform that will replace the C-5s and C-17s. However, the flying branch said it will emphasize greater speed and operational flexibility, as well as the ability to better defend against growing threats when on the ground and in the air.

The commander of AMC, Air Force Gen. John Lamontagne, told reporters, including from The War Zone, that the service currently seeks one aircraft to replace both the Galaxy and Globemaster. Given various budgetary and functional considerations, it is unlikely that a future NGAL would have the same cargo capacity as the Galaxy. You can read more about the tough choices the Air Force faces over its NGAL program in our story here.

Among the NGAL options is an aircraft with a blended wing body, or BWB, configuration. The design could provide increased lifting abilities with large amounts of internal volume, among other advantages. In 2023, the Air Force selected aviation startup JetZero to design and build a full-size demonstrator.

There likely won’t be a replacement aircraft that can match the size of the Galaxy, meaning the Air Force will have to look externally to move its largest cargo. However, there are limited options right now. There are a small number of commercially chartable An-124 Condors, which have roughly similar roll-on, roll-off heavy lift capabilities as the C-5, available today. The existing Soviet-designed Condors won’t last forever. It’s possible that Ukraine could put the Condor back into production in modernized form, but this would be a very large undertaking and it won’t solve the U.S. military’s issue of losing its organic ability to move outsized loads if the single aircraft that will replace the C-17 and C-5 won’t be capable of meeting the latter’s ability to swallow massive cargoes, which seem very unlikely.

It’s worth noting that the world’s largest operational cargo hauling aircraft at the time, the An-225 Mriya, which is an outgrowth of the An-124, was destroyed by Russia at the beginning of its all-out invasion of Ukraine. It served for decades as the heaviest-lifting charter aircraft available, supporting everything from wars to disaster relief operations to moving rail cars and aircraft.

With all this in mind, Radia’s giant cargo hauler could offer the U.S. military a new option to move big loads, if it actually becomes a real aircraft. While this may be more of a niche capability, even if it was offered just on a contracting basis, it would likely be an attractive option for some missions. A militarized version of this aircraft is a far bigger reach, but a small fleet could help fill the gap left by a ‘compromise’ C-5 and C-17 replacement design. The Pentagon has certainly been intrigued with far more exotic heavy lift concepts than this.

Radia claims it is shooting for the first flight of its WindRunner by 2030.

“Radia has raised over $150 million to date and is in discussions to raise additional billions through government support, commercial partnerships, and private capital to complete WindRunner development and production,” O’Connor said when asked how much it will cost to turn the clean sheet design into reality. “Radia has completed concept development and wind tunnel testing and is now preparing for system integration and manufacturing. WindRunner uses largely proven, off-the-shelf systems that are currently certified and flying today. We’ve focused on digital design and analysis, and we are now progressing toward building the full-scale aircraft for certification.”

Radia “has received Letters of Intent (LOIs) from major global customers across wind energy, defense, aerospace, and cargo sectors,” O’Connor added. However, an LOI is not a contract for delivery.

At this point, it is not publicly known where Radia intends to build these jets, if it actually gets the opportunity to do so.

“We are getting closer to publicly announcing our final assembly line location and production capacity,” O’Connor explained.

Radia may not ultimately produce any jets that wear USAF insignias — or any jet at all. However, there appears to be a heavy airlift gap that may form in the coming decades and it may take a mixture of assets, commercial and military, to fill it.

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Boeing has provided a new rendering for its F/A-XX proposal, and it’s remarkably similar to concept artwork that has already been released for its F-47, selected for the U.S. Air Force’s Next Generation Air Dominance (NGAD) ‘fighter’ initiative. While it’s important not to read too much into declassified conceptual renderings of either of those aircraft, based on the artwork, the new art does, at least, correspond with Boeing’s previous hints that the F/A-XX and F-47 would incorporate significant commonality.

The new rendering of the F/A-XX proposal from Boeing was first shown at the Tailhook Symposium last week. The rendering was subsequently published by Aviation Week and is also seen at the top of this story. An F-47 rendering, for comparison, is seen below.

As we reported only earlier this week, Navy Vice Adm. Daniel Cheever, commonly referred to as the service’s “Air Boss,” is still “eagerly awaiting” a decision on the F/A-XX down-select, despite the uncertainty now swirling around that program.

Like previous F-47 depictions, the new Boeing F/A-XX rendering obscures the aircraft in clouds but adds a Navy flattop below, befitting its role as a carrier-based tactical jet. The tail surfaces of the aircraft are fully concealed in clouds. Meanwhile, the aircraft’s ‘bubble’ canopy appears to be very similar to that presented in F-47 renderings. While the radome appears to be smaller and shorter than the notably wide one shown on the Air Force jet, this might be due to the viewing angle. Based on the angle of the wing leading-edge extension, it seems that the F/A-XX concept may well also include canard foreplanes.

As we discussed in an in-depth feature on the topic, canards were a surprising feature of the F-47 renderings that appeared once Boeing had been announced as the winner of the Air Force’s NGAD fighter program. In the F-47 renderings, the details of the canards are also deliberately obscured, but are clearly present.

Above all, canards are a feature that’s not immediately associated with an aircraft optimized for low observability (stealth), range, payload, and speed. Instead, this is a feature that’s normally included on tactical fighters on the basis of maneuverability.

First off, we should note that the new F/A-XX rendering might not include canards, and the degree to which the rendering may reflect the final Boeing design proposal remains open to question. There may also be some counter-intelligence work at play in the F/A-XX rendering, as well as those of the F-47, by pushing concept art that alludes to a prominent feature that the aircraft actually doesn’t have.

However, canards would be of particular benefit for a carrier-based aircraft like the F/A-XX. In this case, the foreplanes enhance low-speed maneuverability, which is especially important during carrier approaches and landings.

Since the tail is entirely hidden in the new F/A-XX rendering, we can’t comment with any degree of authority on this area. However, it’s worth bearing in mind that it’s widely assumed that the F-47 is a tailless design. Previous 6th generation naval fighter renderings from Boeing have also shown a tailless design. Such a configuration would help optimize stealth, although it would sacrifice some maneuverability. To mitigate this, Boeing may have opted to use thrust vectoring and/or canards for its F-47 and F/A-XX proposals.

Otherwise, based on what we already know about the F-47 and F/A-XX, the two aircraft are expected to offer somewhat different capabilities, over and above the carrier compatibility of the Navy jet. According to Aviation Week, the F-47 is presumed to use an all-new adaptive powerplant, the F/A-XX will use a derivative engine, Navy officials have said.

While the Navy previously said that the F/A-XX would be optimized for extended range and survivability, more recent comments suggest its range may only be 25 percent greater than existing tactical jets. This may also be dictated, in part, by the constraints of carrier operations.

There are meanwhile signs that the Air Force might have scaled back its range requirements for the F-47, with the original NGAD fighter having been pitched as a ‘cruiser’ type aircraft with very long endurance suited to Pacific operations. The Air Force now says that the aircraft will possess a combat radius of “1,000+” nautical miles, a significant advance over other fighters currently in the inventory, but not the kind of extended range that many had expected for the Air Force NGAD, especially considering the need to confront advanced enemy air defenses in the decades to come.

The new Boeing F/A-XX rendering appears soon after Northrop Grumman released a rendering for its own submission for the program, something that TWZ was first to report on.

Boeing and Northrop Grumman are understood to be the remaining contenders for F/A-XX.

The Northrop Grumman rendering notably doesn’t include canards, and its overall design appears to be heavily weighted toward stealth, including a flowing, almost organic design, with constantly changing radiused surfaces. Overall, the design has similarities to the passed-over YF-23. You can read more about it here.

Overall, however, Boeing’s new F/A-XX rendering seems to underscore previous affirmations from the company that it would not have a problem building both the Navy and Air Force next-generation fighters.

Earlier this summer, Steve Parker, Boeing Defense and Space CEO, said he didn’t see a problem with his company building both the F-47 and F/A-XX, stating that this had been part of the strategy all along.

Parker’s comments came in response to questions raised by Navy and Pentagon budget officials about the U.S. defense industry’s capacity to produce the two new highly-advanced tactical jets simultaneously.

In particular, Boeing has invested considerable sums in developing a new Advanced Combat Aircraft Assembly Facility in St. Louis, Missouri, which should have the potential to build both aircraft, if the company’s F/A-XX bid is successful. Building the two types in parallel would be made even easier if they were based, at least somewhat, on a core design, with a high degree of commonality.

As we noted earlier this week, the Navy was reportedly close to announcing the winner of the F/A-XX competition in March.

In June, however, the Pentagon announced as part of the rollout of its Fiscal Year 2026 budget proposal that it was moving to complete initial development work related to F/A-XX, but then froze the program indefinitely. It reasoned that it wanted to avoid competition for resources that could affect the Air Force’s F-47.

“They [the Navy] haven’t made a decision yet. So that’s what the down-select is. We’re waiting for the decision, and I’m not the decision maker,” Vice Adm. Cheever told TWZ last week.

Overall, there remains uncertainty around the F/A-XX. In recent months, other senior Navy officials have voiced support publicly for pressing forward with the program. Members of Congress have also been making moves to keep F/A-XX moving ahead as planned in the upcoming Fiscal Year 2026 budget.

“The Navy has a validated requirement for carrier-based sixth-generation aircraft, and it is critical that we field that capability as quickly as possible to give our warfighters the capabilities they need to win against a myriad of emerging threats,” Adm. Daryl Caudle, Chief of Naval Operations, the Navy’s top officer, wrote in response to a question about F/A-XX ahead of his confirmation hearing in July.

Not surprisingly, the Navy considers the F/A-XX as critical to ensuring its carrier air wings can continue to project power in the face of ever-growing threats, especially in any future high-end fight, such as one against China in the Pacific.

Ultimately, if the FA-XX program remains in purgatory, and the F-47 program meets its potential and planned timeline, the Navy could end up buying a navalized F-47 derivative with much lower risk and lower development cost. This might parallel the wait-and-see approach the Navy is taking with its Collaborative Combat Aircraft (CCA), compared to the Air Force (and, to a lesser degree, the Marine Corps). The Navy can capitalize on what is proven to work without investing major funds, but at the cost of waiting.

While we can’t say for sure how close Boeing’s new rendering will be to the company’s final F/A-XX submission, its appearance underlines the fact that the company is very much hoping to follow up its Air Force NGAD success with another sixth-generation fighter contract win, this time for the Navy.

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