My idea for an electric jet engine with no moving parts and its potential use:

If you have two metal plates separated by a few inches, and put a very high voltage current across them, air will pick up electrons from the negative side, and then be attracted to the positive plate where it will deposit the electrons, creating airflow. An example of this can be seen in one of the levitation devices in the "antigravity" episode of Mythbusters. The force is not very great, but that can be overcome. Take a very very long thin strip of PET plastic (super high resistance), and coat the top and bottom of the strip with aluminum (high conductivity with low weight). Then coil the strip up into a spiral similar to old car cigarette lighters. Take that entire mess and put in into a pipe, along with several others. As the air moves into the pipe and hits the first at of plates, it will speed up. It will still be moving when it hits the next set of plates. It should keep speeding up until it reaches a terminal point where electrons can't be added and removed quick enough. By the time it comes out the back it should be traveling very very quickly. So, of what use would such a thing be? For a solar powered dirigible, of course! By using these engines, you could potentially increase efficiency, since no power is wasted in converting electricity to motive power via a rotating fan. Flexible, high-efficiency solar panels on the top of the envelope could maintain the power to the jets. Theoretically, if built right, you could have a dirigible that never needs to refuel. If you had a way to collect water on the go, perhaps from rainwater, you could split the molecules to create hydrogen, replacing that lost through natural attrition. You could then have an airship that never even needs to land.