The Thermal Hopper is basically a Space Bug without the fuel tank. It has a needle valve and venturi mounted on an aluminum plate instead. These were designed for free flight and could also be used for control line flying. It allowed the user to put a fuel tank of their choosing on. The engine output was recorded at 0.066 bhp @ 17,000 rpm with a torque of 4.5 Oz.in at 10,000 rpm.