Project Radia WindRunner: A Heavy-Duty Transport Aircraft
The design concept for the WindRunner aircraft
Modern military transport aircraft are capable of carrying tens of tons of cargo, but they have size limitations. American company Radia Inc. has promised to solve this problem. It announced the development of a new aircraft, the WindRunner, capable of carrying heavy and oversized cargo. It will eventually be offered to the US Air Force and other potential customers.
Objective limitations
The Lockheed C-5 Galaxy is the largest and most capable aircraft in the US Air Force. Its latest modifications are capable of carrying over 120 tons of various cargo. The direct equivalent of this military aircraft is the Soviet/Russian An-124 Ruslan, which has the same cargo capacity.
The American C-5 has a cargo compartment measuring 37 meters long, 5,8 meters wide, and 4,1 meters high, for a total volume of 880 cubic meters. The Ruslan's fuselage, on the other hand, offers over 1000 cubic meters of cargo space. The cabin is 36,5 meters long, 6,4 meters wide, and 4,4 meters high. Both aircraft feature a lifting nose with a folding ramp, as well as an aft hatch for loading and unloading.
The WindRunner compared to other modern aircraft: the C-5 Galaxy, A400, and C-130
The An-124 and C-5 are capable of transporting not only heavy but also large military and civilian cargo. However, some objects are excessively large. To accommodate them inside the military transport, they must be partially disassembled and several flights must be arranged. All this complicates the transportation process.
The issue of cargo dimensions can be addressed in various ways. For example, the reusable Space Shuttle and Buran spacecraft were transported on modified heavy-lift aircraft, mounted on external supports. Special aircraft with enlarged cargo compartments, such as the Airbus A300-600ST Beluga, were also developed.
New solution
The Air, Space & Cyber 2025 conference, dedicated to the development of aviation and space systems. As part of this event, an exhibition of promising projects and concepts for this field was held.
Wind turbine blade loading – currently only available in graphic form
At this exhibition, the American company Radia Inc. first unveiled a concept for an advanced military-transport aircraft, dubbed the WindRunner. This project was based on the idea of maximizing the cargo compartment to accommodate a wide range of cargo. This goal determined the aircraft's entire design and its estimated performance characteristics.
The WindRunner project is currently in the development stage. Design work and wind tunnel model testing are underway. Radia has already released various promotional materials in the form of computer graphics, diagrams, and so on. Furthermore, the calculated characteristics of the future military-technical aircraft have been disclosed. In the published materials, the new aircraft is openly compared to the Galaxy and Ruslan—naturally, to its advantage.
The WindRunner project is expected to take several more years to develop. Construction of a prototype aircraft is expected to begin in the coming years. Its maiden flight is expected by the end of the decade, but a more precise date has not been announced. Subject to orders, serial production of the aircraft will begin in the next decade. The site where assembly will take place has not yet been determined.
Accommodation of maximum length cargo
The developer believes its new military aircraft will appeal to a variety of customers. The aircraft will be offered to air forces and civil carriers from various countries. As always, the US Air Force is considered the most attractive customer. The WindRunner is expected to complement existing heavy military aircraft, but will not replace them due to differences in key characteristics.
Increased volume
The WindRunner project envisions the construction of an aircraft with a conventional aerodynamic configuration and utilizes a number of traditional solutions. At the same time, new ideas are being developed that should significantly impact the overall appearance and performance of this military aircraft.
The WindRunner aircraft will feature a fuselage of distinctive shape and design. Its nose and center section will be shaped like a large-diameter cylinder. The tail section will be tapered, but will retain a significant cross-section and internal volume. The cockpit will be housed in a fairing atop the nose section. Two pairs of similar fairings are proposed for the landing gear, located on the lower sides. This arrangement of the cockpit and landing gear will eliminate the need for additional space within the fuselage.
A straight wing with prominent, downward-curved wingtips is proposed. The wing will house four engine pylons. Extensive high-lift systems are planned across virtually the entire wingspan. The tail unit is H-shaped with a slightly swept stabilizer.
Loading CH-47 Chinook helicopters
The WindRunner military transport aircraft will have a total length of 109 meters, a wingspan of 80 meters, and a parking altitude of 24 meters. The aircraft's weight parameters have not yet been specified. Given the stated dimensions and payload, the maximum takeoff weight could exceed 180-200 tons.
The aircraft will be powered by four turbojet engines of an unspecified model. Its cruising speed will reach 0,6 Mach. Its ceiling will be 12,5 m. With a maximum payload, the estimated range will be 2000 km. The WindRunner will require a 1800 m runway for takeoff and landing.
Radia offers an intriguing cargo compartment layout. Almost the entire interior fuselage, with the exception of the nose and tail fairings, is dedicated to cargo stowage. Cargo is proposed to be stored both in the cylindrical section of the cabin, on the horizontal deck, and on the inclined plane in the tail. Loading will occur with the nose fairing raised.
This cabin can accommodate objects up to 105 m long, 10 m wide, and 9 m high. Its volume is 6,8 cubic meters. The maximum cargo weight is 72,6 tons. Loading and unloading can be performed under the cabin's own power, using pallets, or other equipment.
Accommodation of helicopters in the cargo compartment
The developer cites several examples of how the future military-technical vehicle might be loaded. For example, the WindRunner will be able to transport wind turbine blades. In recent years, turbines with blades longer than 100-105 meters have been developed. Transporting such items by land is particularly challenging, and transporting them by air is virtually impossible. A prospective military-technical vehicle with a special fuselage design will be able to accommodate such cargo.
Promotional materials demonstrate the transport of CH-47 Chinook transport helicopters. The cargo compartment can accommodate six of these helicopters with their rotors folded. The capability to transport tactical aircraft is also mentioned. For example, the WindRunner can accommodate four F-35 fighter jets after some preparation.
The cabin's dimensions allow for the transportation of automotive equipment and various systems based on them, arranged in several longitudinal rows. This does not require dismantling the components, and the systems can begin operating almost immediately after unloading. The design of the military-technical vehicle is not intended to be adapted for passenger transport.
Preparing for aircraft transportation
The problem and its solution
Various aircraft manufacturers regularly propose new heavy-lift military transport aircraft designs. The primary goal of these developments is to increase the payload capacity of existing aircraft. Meanwhile, the American company Radia has chosen a different goal.
She noted the market and military demand for long-haul cargo. Existing military transport vehicles cannot carry objects longer than 30-35 meters and wider than 5-7 meters. The new WindRunner project aims to solve this problem.
The issue of increasing capacity is addressed in the simplest way—by increasing the fuselage's linear dimensions. It's worth noting that some interesting layout solutions have also been proposed. For example, the cargo compartment now occupies almost the entire fuselage, with the exception of the nose and tail fairings. Furthermore, the cockpit, landing gear, and other components are located outside the fuselage.
The WindRunner aircraft will have a cabin that surpasses all existing military aircraft. It will be able to transport objects up to 105 meters long—many times larger than the C-5 or An-124. However, this comes at the expense of cargo capacity, which will be 1.5 times lower than that of the Ruslan or Galaxy.
Radia has set itself some very challenging goals, and it's still unclear whether it will be able to fully achieve them. It will have to develop a full-fledged design and then build the proposed aircraft using available technologies and materials. They aim to accomplish all of this in less than five years, by the end of the current decade.
Questions also arise regarding the very necessity of such an aircraft. An aircraft with this combination of characteristics could find a place in transport aviation and complement existing aircraft, but it would not represent a fundamental breakthrough. The WindRunner would become a highly specialized tool, used significantly less frequently than traditional military transport aircraft. The economic feasibility of such an aircraft may be questionable.
Concept or curiosity
Thus, Radia identified a problem that seemed urgent and proposed a solution. It developed an original concept and began implementing it as a full-fledged project. The company is currently conducting the necessary research and preliminary design work.
By the end of the current decade, Radio plans to build and test a prototype WindRunner. The appearance of a real aircraft will likely attract the attention of potential customers. They will be able to evaluate not only the general concept but also draw conclusions. It will then become clear whether the new project has real potential or is just another technical curiosity.
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