EM drive - Page 1
Forum section: electronics / projects

author: K9BF
author_rank: Newbie
timestamp: November 28, 2016, 02:12:13 am
content: Someone, please talk Dave into building an EM propulsion drive.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 28, 2016, 03:36:45 am
content: These things remind of a previous "electro-gravitic" craze: lifters.http://www.instructables.com/community/ionocraft/

author: jwm_
author_rank: Frequent Contributor
timestamp: November 28, 2016, 04:17:05 am
content: The EM drive doesn't need any more EEs to develop it, the electronics are easy. It needs physicists with proper vacuum chambers and measurement experience with effects so small to design proper experiments with real control cases. The NASA paper was woefully inadequate in that regard which is why it wasn't picked up by a physics journal. I wish they were less sloppy with their experimental procedures so we could have gotten actual data out.

author: JoeN
author_rank: Frequent Contributor
timestamp: November 28, 2016, 06:28:21 am
content: Quote from: jwm_ on November 28, 2016, 04:17:05 amOr they could just miniaturize it down to a few hundred pounds, haul it up to ISS on the next supply mission, toss it out the hatch and see if it goes. Maybe they can convince The Discovery Channel to sponsor it.ISS was built largely to do experiments to do in zero gravity. This one actually needs it.

author: jwm_
author_rank: Frequent Contributor
timestamp: November 28, 2016, 11:41:31 am
content: Quote from: JoeN on November 28, 2016, 06:28:21 amThere are much more interesting experiments they can be doing up there and spending money on bringing up. There is nothing about the EM drive that is easier to test in space than on earth and a lot that is harder. If we can't see any effect in controlled conditions on earth then we would have no idea how even to actually 'miniaturize' it. We can measure femptonewton level forces in the labs here. Any actual EM drive effect should be extremely obvious in a properly designed experiment.John

author: EEVblog
author_rank: Unknown
timestamp: November 28, 2016, 12:19:34 pm
content: I might have a video on something similar soon, but this something actually works...

author: Bud
author_rank: Super Contributor
timestamp: November 28, 2016, 01:23:55 pm
content: There is at least 3 threads about this same thing. Could be a good idea to join them in one or lock the last ones with a link to the original thread.

author: wolf32d
author_rank: Contributor
timestamp: November 28, 2016, 04:49:52 pm
content: Quote from: JoeN on November 28, 2016, 06:28:21 amIf it goes it could be due to the momentum given by the few microwaves that leak out. The same effect can be obtained with visible light... Here on earth the sunlight provides about 5 micropascals/m² (along with 1.3 kW of power on the same 1m² surface).Photons carry both energy and momentum

author: calexanian
author_rank: Super Contributor
timestamp: November 28, 2016, 06:56:14 pm
content: +1 for experimental physicists to create experiments and generate genuine results. Until then don't get too excited.

author: Berni
author_rank: Super Contributor
timestamp: November 29, 2016, 07:15:09 am
content: The main issue with this EM drive is that there are plenty other effects that can cause the thrust.Microwaves leaking out could be one thing, but the most likely thing is the fact of how hot the thing gets during operation since all that power being put in has to go somewhere.When something gets hot in air there are a array of various thermal effects that push against the air and could produce a force. Then once you put it in to vacuum there is the fact that it gets even hotter due to having no air to cool it. As such it has to dissipate the heat trough infrared radiation and doing that you basically create a infrared lamp that is firing out IR photons. And since photons carry momentum that can also cause a force(tho a incredibly tiny one)Then there are also the effects we engineers are more familiar of. The massive amounts of RF energy could easily escape in tiny amounts and get in to some of the incredibly sensitive force measurement equipment that is sitting right next to the EM drive.Science has got things wrong many times in the past and it is certainly possible there is thrust being produced, but it is clear that if there is thrust, it must be so incredibly tiny that it is hard to measure even.But don't worry if you really wanted electricity powered thrust in your next cube sat project you might want to look at this:http://www.accion-systems.com/technology/#accion-techThey make a tiny "solid state" ion engine that gives you quite a large amount of thrust for its size. The supply of "ion fuel" does eventually run out, but does last quite a while, its not like you are going to have the power available to run it full blast all the time.