Overair is using an advanced prepreg carbon fibre from Toray Composite Materials to build the full scale prototype of its Butterfly tilt-rotor eVTOL air taxi.

The Butterfly is a low noise, zero emission eVTOL aircraft that will provide sustainable aerial ride sharing in densely populated cities where traffic is a problem.

The Butterfly prototype aircraft utilises Toray’s T1100/3960 prepreg system, a material that is formulated for high performance aerospace applications where the optimal ratio of strength to modulus properties is critical. It is optimised for increased performance and allows for autoclave and out-of-autoclave curing. The resin is synergistic with the TORAYCA T1100 next-gen intermediate modulus plus (IM+) carbon fibre, which is the highest tensile strength fibre available today. The T1100/3960 unidirectional and plain weave prepreg is utilised in the Butterfly’s airframe structure and propulsion units.

"We're excited to be working closely with Toray's advanced materials as we continue the development of our all-electric Butterfly experimental prototype aircraft," says Overair founder and CEO Ben Tigner. "Our unique propulsion system requires materials that provide a unique combination of high stiffness and high strength, while also maintaining the optimal weight targets for the vehicle.”

Overair recently completed full scale testing of Butterfly's propulsion system. The successful testing programme validated the company's design choices and Butterfly's expected performance capabilities. Butterfly's propeller will be showcased at the Farnborough International Air Show this month.

"It is an honour for Toray to partner with Overair on this endeavour and provide the Butterfly a unique performance advantage with our 3960 prepreg system," says director of business development for aerospace Jeff Cross. "We're excited for the future as it proceeds with full scale development and testing. The proven performance of our materials gives me confidence that we can help achieve the objective of producing the safest, most efficient, and reliable eVTOL aircraft."