California-based eVTOL start-up Overair has selected Toray Composite Materials America to supply advanced materials for its Butterfly eVTOL prototype. 

Overair’s Butterfly is a six-seat eVTOL aircraft designed to provide a sustainable aerial ride-sharing option for urban areas with dense populations and heavy traffic. Toray will provide a carbon fiber composite infused with an epoxy resin—also known as a “pre-impregnated” material, or prepreg—for the Butterfly prototype’s structural components and propulsion units. Specifically, the Butterfly will use Toray’s T1100/3960 prepreg material, which is specially formulated for high-performance aerospace systems. 

"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," said Ben Tigner, co-founder and CEO at Overair. "Our unique propulsion system requires materials that provide a...combination of high stiffness and high strength, while also maintaining the optimal weight targets for the vehicle."

The Butterfly’s design, which is based on the patented optimum speed propulsion system developed by company founder Abe Karem, features four large tilting propellers that spin slowly in hover mode and even slower during cruise flight. Overair says this all-electric propulsion system will reduce power consumption, boost the payload-carrying capacity, and allow the Butterfly to produce significantly less noise than helicopters and other eVTOLS. 

“By using the ‘optimum speed’ for each phase of flight, Butterfly uses less battery power, leaving extra margins for safety and performance in tough weather, as well as range and payload,” Overair says on its website.

Overair began ground testing the Butterfly’s propulsion system in January 2022, and the company expects its new aircraft to take flight in 2023. It said that it is on track to complete FAA Part 23 type certification by the end of 2025, and it aims to start commercial operations in 2026.