First Rotary Ionic Engine with Contra-Rotating Propellers

Ionic propeller systems have recently demonstrated potential for the development of an ionic rotorcraft/drone to fly in planetary atmosphere. Such rotorcraft would use the ionic wind to spin the propellers that will further generate conventional thrust. The propeller, the associated electrodes, and electrical power source are the only source of propulsion. We demonstrate and study coaxial ionic contra-rotating propeller (CRP) systems for the first time. Experiments indicate that ionic-activated axial propellers can spin in opposite directions (no axial/shaft adaptors) creating zero-angular-momentum systems. If further developed, such systems can be useful to the design of zero-angular momentum ionic drones with no shaft adaptors. Emitter electrodes on a 25-cm-diam (propeller 1) and 12.6-cm-diam (propeller 2) propellers were optimized for speed in grounded cylinder electrodes. For propeller 1 systems, up to 936 rpm was recorded for single-propeller systems, whereas for CRPs 710 rpm was the maximum obtained. For propeller 2 single-propeller systems a maximum of 2812 rot/min was recorded versus 1720 rot/min previously reported. CRPs spinning up to 2035 rpm, -29.5 kV, and 340 mu A (source limit) were also designed. The power-to-speed ratio was proportional to the current for all the systems. The propeller kinetic energy-to-power ratio presents a maximum with respect to voltage, current, speed, and power, and it can be used to differentiate between systems.