Description This HX 15 Stirling helicopter engine model adopts a 16 cylinder swash plate Stirling cold and hot cylinder opposing structure This cold cylinder and hot cylinder opposing structure is conducive to preventing heat conduction between cold and hot cylinders improving the heat exchange capacity of the engine keeping the temperature difference of the engine lasting and making the output power more stable The use of glass with a hardness exceeding that of metal as the cylinder piston reduces the weight of the piston improves the sealing and wear resistance of the cylinder piston and is not easy to damage the surface due to high speed operation and will not rust and is super hard and maintenance free The power output transmission of this mechanical structure is also very intuitive The movement direction of the piston of the opposing cylinder the two circular gears change the speed ratio and the four bevel gears change the power output direction by 90° and transmit the power to the main propeller of the helicopter and the small propeller at the tail respectively so that the mechanical structure is intuitively reflected Specification Product Model HX 15Product Name Stirling Engine Helicopter Model Assembly Kit Base Material Black Walnut Solid WoodGear Material BrassFlywheel Material BrassHeated Red Copper Material 304 Stainless SteelPiston Connecting Rod Material 304 Stainless SteelBody Material 6061 Aluminum AlloySleeve Outer Bright Material 6061 A