MIT researchers have used ion drive to fly a model plane a short distance indoors

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Moppy
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MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby Moppy » Fri Feb 22, 2019 12:26 pm

https://spectrum.ieee.org/cars-that-thi ... ving-parts

MIT researchers have flown the first airplane that has no moving parts. The aircraft, packed with lithium-ion batteries, used an ion thruster to fly the 60 meters that were available in the indoor flight area.

“This was the simplest possible plane we could design that could prove the concept that an ion plane could fly,” said Steven Barrett, associate professor of aeronautics and astronautics at MIT. “It's still some way away from an aircraft that could perform a useful mission. It needs to be more efficient, fly for longer, and fly outside.”

The plane weighs a little over 2 kilograms (5 pounds), and its engine has a thrust-to-weight ratio roughly comparable to that of a jet engine. Its lithium-ion batteries put out about 500 watts.

edit: SInce reading this, I've come across this, which is also relevant:

https://spectrum.ieee.org/aerospace/avi ... propellers

Here they use a series of small propellers to blow air faster over the wing, and increase lift, instead of just moving the plane faster. This seems to connect nicely with how the ion drive works, as the ion drive creates an electrode at the front of the wing, causing ions to be accelerated backwards towards another electrode at the rear of the wing, ramming air molecules backwards along the way.
AnotherDilbert
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby AnotherDilbert » Fri Feb 22, 2019 3:12 pm

This is very cool, but also rather unpractical. The drive itself may have comparable thrust to weight ratio as a jet engine, but it uses quite a lot of electrical energy, hence heavy batteries.

If we assume that about half the weight of the aircraft is batteries it can fly at low speed for perhaps 15 minutes (without any payload).

The drive uses 600 W. If we assume a Lion or LiPo battery with an energy density of 200 Wh/kg and 1 kg of battery we have 200 Wh available. 200 Wh / 600 W = 0.33 h. With a bit of inefficiency, e.g. in the transformation to 40 kV needed by the drive, we end up with perhaps 15 min endurance.


It works in space because we only need very low thrust to adjust drifting orbits, and we have "free" power from solar panels.
Sigtrygg
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby Sigtrygg » Fri Feb 22, 2019 3:36 pm

Cover every available surface with solar cells, use the lightest possible materials and battery tech...

I get the feeling we will be seeing this again in the near future for high altitude long duration aircraft/drone tech.
baithammer
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby baithammer » Fri Feb 22, 2019 11:17 pm

Solar power would require far larger body / wing design to provide enough power, however there are advances in lion / Liop density that could make this more feasible in the future.
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby DickTurpin » Sat Feb 23, 2019 3:45 am

The ion drive does not need to be powered by batteries. A bigger plane could carry a fuel powered generator to supply the electricity needed. The only question is does the ion drive provide a more efficient conversion of fuel into motion? I suspect the answer is No for now, but perhaps it can reach that point with more R&D. Or future advancements in electricity storage will create lighter, more energy dense batteries that make the ion drive more practical.
AnotherDilbert
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby AnotherDilbert » Sat Feb 23, 2019 2:05 pm

Quite, ten times more dense batteries might make electrical airplanes practical and fusion power might make electricity too cheap to meter in the next few decades. It would be fantastic!

Unfortunately, I don't believe it's very likely...
Old School
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby Old School » Sat Feb 23, 2019 3:27 pm

Of course its impractical. So was every other energy and trasportstion technology in its first iteration. Its proof of a very limited concept.
AnotherDilbert
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby AnotherDilbert » Sat Feb 23, 2019 4:02 pm

I agree completely.

It is a clear demonstration that an ion drive can drive an aircraft, which is a great leap forward.

But not all possible technologies ever become practical and economical.
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Re: MIT researchers have used ion drive to fly a model plane a short distance indoors

Postby Reynard » Sat Feb 23, 2019 11:47 pm

Reminds me back in the mid 70s I found a book in the college library describing building a working ion propulsion using easy to obtain materials and run on a car battery. It wasn't meant to fly but you should see the unit move in it's harness.

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