Derivatives
The Rocket Racing League aircraft currently in development, the Mark-III X-racer, is a design descendant of the EZ-Rocket aircraft. Although XCOR is not the developer of the rocket engine for the Mark-III, XCOR did develop the rocket engine for the Mark-I X-Racer, the first of the X-Racers to use use a single rocket engine on a Velocity SE basic airframe, and the first X-Racer to utilize kerosene instead of isopropyl alcohol fuel. XCOR used both design and operational experience from the EZ-Rocket in the Mark-I rocket aircraft design.
Read more about this topic: XCOR EZ-Rocket