Jetoptera, a Washington state-based company developing innovative new VTOL and STOL aircraft concepts using bladeless fan technology, says it is on track to deliver a new prototype to the U.S. Air Force (USAF). In a letter to investors published last week, it reported that it will be ready to begin demonstration flights in 2025.

The start-up is one of 11 companies selected by the U.S. Department of Defense to develop a high-performance VTOL aircraft as part of the High-Speed VTOL Challenge, a collaboration between the Air Force’s Afwerx program and the U.S. Special Operations Command. The HSVTOL Challenge aims to come up with an alternative to the Air Force’s current helicopters, providing new aircraft that can fly faster and longer, carry larger payloads, and provide more flexibility to carry out a variety of defense missions.

Jetoptera’s HSVTOL concept is one of seven designs, including four VTOLs and three STOLs, that utilize the company’s patented fluidic propulsion system (FPS). It is designed to carry payloads of up to 800 pounds (360 kg) across a range of up to 400 miles (630 km), at a speed of 400 mph. The company says the technology is scalable and can be used to power aircraft with a maximum takeoff weight of up to 10,000 pounds (4,500 kg).

The FPS, which Jetoptera has been developing since 2015, is a unique propulsion system that the company has referred to as “bladeless fans on steroids.” Just like Dyson’s bladeless electric fans for domestic equipment like vacuum cleaners, the FPS has no visible moving parts or propellers. Rather, the technology uses a relatively small flow of compressed air from a turbo-compressor to suck in a much greater volume of ambient air, creating a vortex that significantly amplifies the airflow through an aerodynamic loop. The thrust output of the FPS is augmented by additional thrusters.

For now, Jetoptera is relying on gas generators to power its vehicles, but it could also use electrically-powered compressors once the available battery technology improves. The company says the energy required to propel its smallest aircraft at 200 mph (320 km/h) for 30 minutes is 100 kilowatts, which could be provided by either 26 kilograms of jet fuel or 600 kilograms of existing lithium-ion batteries. In order for battery power to be feasible in its designs, Jetoptera says future batteries will need to have an energy density of at least 1,500 watt-hours per kilogram, which is about four times the energy density of batteries available today.

Jetoptera has already tested the FPS in flight with its eye-catching technology demonstrator, a quarter-scale model of the J-2000 eVTOL, which features a peculiar boxed-wing design combined with a canard. The design is significantly quieter than existing rotorcraft, with the company claiming the FPS produces 25 to 30 decibels less noise than even the quietest rotors and propellers on the market today. The company says it has received interest from an undisclosed prospective customers for commercial applications of its planned J-4000 model, which would have a larger payload of up to around 800 pounds and range of 200 miles.

Quarter-scale model of Jetoptera-2000 eVTOL, hover and wingborne

For Phase 1 of the HSTVOL Challenge, Jetoptera partnered with aerospace giants Northrop Grumman and Pratt & Whitney to determine the feasibility of the company’s HSVTOL aircraft and to refine the concept. The team’s analysis, completed in June, found that the aircraft concept “will exceed the maximum speed of the fastest rotary wing aircraft by around 200 knots,” or about 230 mph (370 km/h), Jetoptera officials wrote in the recent letter to investors. Jetoptera says it has submitted proposals for Phases 2 and 3 to deliver a prototype to the USAF by 2025.

Separately, in May, the USAF’s Afwerx program awarded Jetoptera a Phase 2 Small Business Technology Transfer Program (STTR) contract worth $750,000. Under this contract, Jetoptera is partnering with the University of Washington to conduct a wind tunnel testing campaign with a subscale model of one of its concept HSVTOL aircraft, named Hedwig. The Phase 2 STTR contract builds upon the success of two previous Phase 1 STTR contract awards and a Direct to Phase 2 SBIR contract award from the USAF.

In 2021, as part of a Phase 1 STTR contract, Jetoptera and the University of Washington “obtained experimental evidence that FPS can be adapted to provide high-efficiency thrust and lift augmentation to a wing, enabling an aircraft to take off vertically and transition smoothly to wingborne flight,” Jetoptera officials wrote in a May 31 statement.

In the letter to investors, Jetoptera reported it has reached new technical readiness milestones under the USAF’s Direct to Phase 2 SBIR contract. The company said the wind tunnel tests it conducted under this contract have successfully demonstrated lift augmentation using the FPS in combination with an upper surface blown (USB) wing aircraft configuration, and that it achieved “unprecedented” levels of lift coefficients.

This photo shows Jetoptera’s FPS combined with a blown wing flap system, which the company built and tested to support one of its Direct to Phase 2 SBIR programs. (Credit: Jetoptera)

The FPS provided roughly eight times more lift than the wing can produce on its own, and the FPS and USB wing combination produced about 30 percent more lift than competing STOL aircraft concepts that have propellers distributed along the wingspan, according to Jetoptera. The company is now using data from those wind tunnel tests to further develop its VTOL and HSVTOL concepts, and it is exploring the possibility of using the technology for new wing-in-ground-effect maritime vehicles.

In addition to its work with the USAF, Jetoptera is also working with San Diego-based Freedom Flight Works to develop a variant of the FPS under a contract with the U.S. Army. Together with Jetoptera, which was awarded this subcontract in January, Freedom Flight Works aims to demonstrate a powered parafoil fluidic propulsive system (PP-FPS) to enhance the capabilities of the military’s Joint Precision Airdrop Delivery System (JPADS).

Jetoptera procured this recuperated gas turbine turboshaft from Turbotech. (Credit: Jetoptera)

Jetoptera says it has completed the first tests of an FPS thruster prototype for JPADS and procured the first recuperated gas turbine engine to power the air compressor that feeds the FPS. The gas turbine turboshaft was supplied by the French company Turbotech. According to Jetoptera, the first stationary demonstration of Freedom Flight Works’ parafoil system is expected to occur later this year. In its letter to investors, Jetoptera said it plans to reveal details about a second project it is working on with Freedom Flight Works in the near future.

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