The eVTOL, codenamed “Butterfly” by Overair will undergo its first flight test in the second half of 2023. Butterfly strategically uses new generation carbon fiber/epoxy resin prepreg from Toray to further reduce structural weight, alleviate battery power supply pressure, and provide a quieter flight experience.
On July 7, 2022, Overair announced the establishment of a partnership with Toray Composite Materials USA, a carbon fiber material supplier. The company’s new generation T1100/3960 carbon fiber/epoxy resin prepreg will be used to construct the main body components of test flight aircraft, such as the fuselage, some wing components, and rotor blades.
Previously, Karem had selected T1100/3960 material as the material for the DARPA/Army equipment project, so it was natural for the Butterfly aircraft to choose T1100/3960. The 3960 provided by Toray is a high toughness 177 ℃ cured epoxy resin with a glass transition temperature (Tg) of 204 ℃, and TorayT1100 carbon fiber is currently the carbon fiber with the highest tensile strength that can be applied.
The carbon fiber composite material manufactured by T1100 has previously been studied for application in large structural components such as fuselage panels and wings. Toray USA and Textron also reached a cooperation agreement in May 2022 to jointly support the National Center for Advanced Material Performance (NCAMP) in developing design allowable values for Toray’s latest 3960 prepreg system. The T1100/3960 material system has great potential to become an ideal choice in the future aviation industry.
The Overair team has chosen T1100 carbon fiber, which is mainly used in components that require high stiffness without sacrificing strength and damage tolerance.
Researchers have shown that using high modulus carbon fibers can achieve higher stiffness, but the strength performance of the fibers has to be abandoned, and the resin performance has decreased. T1100 can provide the required performance balance and can be applied in components that require a certain degree of stiffness to avoid dynamic resonance problems.
For components in different application environments, this carbon fiber can be applied to unidirectional belts or fabrics. In addition, other advantages of T1100 carbon fiber include excellent fiber properties and its good processability.