OEM Original Equipment Propellers.. Hartzell propellers are original equipment on more than 50 aircraft models currently in production. With broad market penetration Hartzell has developed a large array of basic blade designs for OEM companies to choose from. Hartzell employs a large team of engineers who work directly with the OEM to design the right propeller for their aircraft. World-class manufacturing and the latest in advanced design tools means OEMs get the best blade for their aircraft. Coupled with unmatched customer support, Hartzell has become the leading provider of OEM propellers.