What I've been noodling on is how to convert that energy into thrust to create an all electric model rocket. I got as far as realizing that dumping electricity from a battery into a capacitor might result in fast enough power discharge, but I am stuck on converting that electricity into thrust for a model rocket. Any ideas?

This is related to the following Stack Exchange question: Are LiPo really 100 times more energy dense than model rockets?

  • $\begingroup$ That's an interesting question. Even if its not strictly about robots, I'd be interested in reading any answers. $\endgroup$ Commented Oct 19, 2017 at 18:38
  • $\begingroup$ Welcome to Robotics Jonathan Koomey, but I'm afraid that Unbounded Design Questions are off-topic because there are many ways to solve any given design problem. We prefer practical, answerable questions based on actual problems that you face, so questions which ask for a list of approaches or a subjective recommendation on a method (for how to build something, how to accomplish something, what something is capable of, etc.) are off-topic. Please take a look at How to Ask & tour for more information on how stack exchange works. $\endgroup$
    – Chuck
    Commented Oct 19, 2017 at 21:16
  • $\begingroup$ If you're looking to go from electricity directly to thrust, with no moving parts, the engine you're probably interested in is an ion thruster. If you're okay with moving parts, it's called a fan. $\endgroup$
    – Chuck
    Commented Oct 19, 2017 at 21:17
  • $\begingroup$ It's not really possible to turn electricity directly into rocket thrust; you must accelerate SOMETHING in order to get thrust, and accelerating only electrons would be very inefficient (ion drives accelerate ions which are far larger). But, if you really wanted to get lift using ONLY electricity as the power source, there are two ways. First, you could rest the base of the rocket on a big magnet, and use the electricity to generate a magnetic field that opposes the big magnet. The repulsion will lift the rocket a bit. Alternatively, look into railguns - you could use a similar principle $\endgroup$ Commented Oct 20, 2017 at 18:25
  • $\begingroup$ I disagree with Chuck's assessment of my question as being out of bounds. The two substantive answers brought up examples (ion thruster, fan, magnetic repulsion, and rail guns) that are right on point. I had previously thought of 1,2, and 4, with 3 being a variant of 4, but each of these has issues that I was hoping this discussion could illuminate. If I add those examples to the question would that make it specific enough? I would also note that one commenter didn't have an answer but was interested in the answers that come up. $\endgroup$ Commented Oct 20, 2017 at 19:23


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