Vertiflite May/June 2021

The Jaunt Journey gyrodyne will have an airframe made largely of thermoplastic composites to cut production cost and time, and fit mass production schemes. (Jaunt Air Mobility)

Stamping Out Air Taxis

M aking lightweight, crashworthy aerostructures affordable is essential for advanced air mobility (AAM), given the huge number of aircraft needed to unclog roads. AAM fleet projections vary greatly, but a presentation in January for the Vertical Flight Society’s Eighth Annual Electric VTOL Symposium by Toray Advanced Composites senior application engineer DeWayne Howell baselined 5,000 deliveries a year around 2040. Howell noted his conservative estimate is about five times more than the current helicopter industry output and comparable to specialty automobile production. In high-volume manufacturing, thermoplastic composites can help churn out aerostructures faster and cheaper than commonly used thermosets. Howell acknowledged, “There’s a lot of work to be done to… have materials and production processes that will allow us to do that.” He concluded AAM mass production will require partnerships between original equipment manufacturers (OEMs) and material suppliers to build prototypes, refine processes, qualify materials and certify aircraft. In December, Toray in Morganville, California, announced a long-term supply agreement with Joby Aviation for carbon fiber- reinforced composites to build eVTOL air taxis. The material maker offers composites impregnated with either thermosetting or thermoplastic resins. Thermosets cured in pressurized autoclaves undergo a chemical reaction to achieve full strength. Thermoplastics melted in molds re-solidify without chemical By Frank Colucci Moldable, weldable thermoplastic composites may make electric vertical takeoff and landing (eVTOL) aircraft affordable in mass production.

change. Joby refused to discuss material tradeoffs, but Howell at Toray summarized, “If you’re going to make a typical thermoset part, you have to give time for the resin to cross-link and make that chemical change to solidify.With thermoplastics, if they’re stamp- formable, you can produce parts in minutes rather than hours.” In February, Jaunt Air Mobility — headquartered in Dallas, Texas — announced a Small Business Technology Transfer (STTR) contract from the US Air Force Research Laboratory to work on thermoplastic technologies and low-cost production techniques for eVTOL aircraft. The company is developing its four-passenger Journey Reduced-rotor Operating Speed Aircraft (ROSA) with mostly thermoplastic structure. Jaunt CEO Martin Peryea explained, “The entire airframe is going to be made out of thermoplastic materials. All the major primary structural components will be based on thermoplastics. The outside body, tailboom, rudder, stabilizer, all of that will be made of thermoplastic materials.” He added, “The rotor blades, because of the maturity of the manufacturing technology, those will use conventional thermosets.” Jaunt plans first flight of its electric gyrodyne next year and aims at certification and full-rate production in 2026. The company ultimately plans to turn out 2,500 aircraft a year at each of two manufacturing centers. Thermoplastics are key to mass production. Peryea offered, “It’s the automation of hot press forming very large structural components and welding those together with very minimal touch labor — there’s a significant cost savings associated with that. You can produce at much higher rates and volumes.” Toray, Hexcel, and other material makers supply snap-cure thermosets that save manufacturing time, but thermosets deny manufacturing engineers the chance to melt and re-form complex parts several times in successive production steps.

May / June 2021

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