Engineers Fly First-Ever Plane with No Moving Parts: Silent, Fuel-Free 'Ion Drive'
MIT engineers have designed and flown the first-ever plane with no moving parts. The lightweight aircraft is powered by an "ionic wind" — a strong flow of ions produced aboard the plane generates enough thrust to propel the plane over a sustained flight. Unlike turbine-powered planes, the aircraft does not depend on fossil fuels to fly; and unlike propeller-driven drones, the design is silent. In a paper published in Nature , the MIT team describes how they created the "electroaerodynamic-powered plane" — one that uses solid-state propulsion (no propellers, or engines with expendable fuel). The team says the new "ion drive" technology could power silent drones.
Transcript
00:00:00 The future of flight shouldn't be things with propellers and turbines and should be more like what you see in Star Trek; with a kind of blue glow and something that silently glides through the air. When I got an appointment at University I thought well, now I've got the opportunity to explore this and started looking for physics that enabled that to happen. The sort of mechanism that I found that works was ionising air and then using electric fields to accelerate the air. What we achieved, was the first ever sustained flight of an aeroplane that is propelled by electroaerodynamic propulsion.
00:00:38 And that's also by many definitions the first ever solid-state flight, meaning no moving parts. Well the idea is - is kind of - it dates back until at least the 1920s. Where an eccentric inventor at the time started experimenting with high high voltage electrodes. And thought he had discovered anti-gravity, which of course was not the case. But that set some of the initial groundwork on mechanisms for creating what's called an ionic wind in the atmosphere, by having high-voltage electrodes ionising air and then accelerating the ionised air. So what we did for this design is to try and stick to something that looks somewhat like a conventional aircraft.
00:01:31 But under the wing rather than conventional engines it has a series of electrodes. And those consist of an array of very thin wires at the front, and then an array of aerofoils at the back. Now those thin wires at the front are set at a very high voltage - plus 20,000 volts and that constitutes the source of ions - this is ionised nitrogen from the atmosphere. Now the the aerofoils at the back there set at minus 20,000 volts and so that creates an electric field. So the ions go from the positive to the negative colliding all the way with neutral air molecules and creating this wind that goes behind the plane.
00:02:07 And that's essentially how it flies. The flight was about sixty meters long, something like ten seconds - so quite short. It was constrained by the size of the gym that we found to fly it in. Lacking infinite money in time and just wanting to do things as quickly as possible that was what was on hand and so we just asked the facilities manager if they would let us use the gym, they forced us to create a very long and detailed safety management plan but then we were able to go ahead. Many attempts failed because of various things going wrong like structural failures, the power electronics frying itself
00:02:39 so there are many many first days, but the first day that it actually worked wasn't a sustained flight it was about 50% power, so it was a power glide. Until that occurred we still didn't know 100% whether this was really achievable. But after that point we knew that we were then within touching distance of successful flights. And the first sustained flights followed quite soon after, which were... which were pretty exciting. It's probably the first solid-state flight of a heavier-than-air vehicle and I think that is, has the potential to be a step that is very interesting. Of course we don't yet know whether it will be
00:03:16 practically useful and widely used and obviously I hope it will be and have an expectation - there are a number of applications. There are definitely some limits, so one of the limits is the breakdown voltage of air and that varies as a function of altitude. And we've worked out theoretically what the limits are to the thrust density which is the amount of thrust force per unit area that's producible. Now what that suggests is that in the nearer term, it will be easier to create smaller vehicles like drones for example.
00:03:44 I think the near-term advantage is probably in noise especially if you think that perhaps in ten years we might have urban areas that are filled with drones doing things like monitoring traffic, monitoring air pollution or many other services we're yet to imagine. And drones today are quite noisy and irritating. Now we wouldn't want our urban environments to be polluted by all this noise, so developing a way of propelling drones that's silent or near silent would be advantageous in that context. In many ways it's much easier to make progress now than it was in the past.
00:04:18 I mean if you look at this wonderful aircraft behind us which was the first ever transatlantic flight - about 1919 I mean people were risking their lives to make that kind of progress. Today we're not risking our lives we're able to test things using a remote control, without having to have pilots on board test vehicles. That means the vehicles can be much smaller which enables us to build them and test them with less resources. In terms of how this fits in I don't know whether you'll see large aircraft carrying people anytime soon.
00:04:49 But obviously I'd be very excited if that was the case.