Featured Research

from universities, journals, and other organizations

Ionic thrusters generate efficient propulsion in air

Date:
April 3, 2013
Source:
Massachusetts Institute of Technology
Summary:
Thrusters powered by ionic wind may be an efficient alternative to conventional atmospheric propulsion technologies. When a current passes between two electrodes -- one thinner than the other -- it creates a wind in the air between. If enough voltage is applied, the resulting wind can produce a thrust without the help of motors or fuel. Researchers have now found that ionic thrusters may be a far more efficient source of propulsion than conventional jet engines.

Private jet. Researchers have now found that ionic thrusters may be a far more efficient source of propulsion than conventional jet engines.
Credit: bertys30 / Fotolia

Thrusters powered by ionic wind may be an efficient alternative to conventional atmospheric propulsion technologies. When a current passes between two electrodes -- one thinner than the other -- it creates a wind in the air between. If enough voltage is applied, the resulting wind can produce a thrust without the help of motors or fuel.

This phenomenon, called electrohydrodynamic thrust -- or, more colloquially, "ionic wind" -- was first identified in the 1960s. Since then, ionic wind has largely been limited to science-fair projects and basement experiments; hobbyists have posted hundreds of how-to videos on building "ionocrafts" -- lightweight vehicles made of balsa wood, aluminum foil and wire -- that lift off and hover with increased voltage.

Despite this wealth of hobbyist information, there have been few rigorous studies of ionic wind as a viable propulsion system. Some researchers have theorized that ionic thrusters, if used as jet propulsion, would be extremely inefficient, requiring massive amounts of electricity to produce enough thrust to propel a vehicle.

Now researchers at MIT have run their own experiments and found that ionic thrusters may be a far more efficient source of propulsion than conventional jet engines. In their experiments, they found that ionic wind produces 110 newtons of thrust per kilowatt, compared with a jet engine's 2 newtons per kilowatt. The team has published its results in the Proceedings of the Royal Society.

Steven Barrett, an assistant professor of aeronautics and astronautics at MIT, envisions that ionic wind may be used as a propulsion system for small, lightweight aircraft. In addition to their relatively high efficiency, ionic thrusters are silent, and invisible in infrared, as they give off no heat -- ideal traits, he says, for a surveillance vehicle.

"You could imagine all sorts of military or security benefits to having a silent propulsion system with no infrared signature," says Barrett, who co-authored the paper with graduate student Kento Masuyama.

Shooting the gap

A basic ionic thruster consists of three parts: a very thin copper electrode, called an emitter; a thicker tube of aluminum, known as a collector; and the air gap in between. A lightweight frame typically supports the wires, which connect to an electrical power source. As voltage is applied, the field gradient strips away electrons from nearby air molecules. These newly ionized molecules are strongly repelled by the corona wire, and strongly attracted to the collector. As this cloud of ions moves toward the collector, it collides with surrounding neutral air molecules, pushing them along and creating a wind, or thrust.

To measure an ion thruster's efficiency, Barrett and Masuyama built a similarly simple setup, and hung the contraption under a suspended digital scale. They applied tens of thousands of volts, creating enough current draw to power an incandescent light bulb. They altered the distance between the electrodes, and recorded the thrust as the device lifted off the ground. Barrett says that the device was most efficient at producing lower thrust -- a desirable, albeit counterintuitive, result.

"It's kind of surprising, but if you have a high-velocity jet, you leave in your wake a load of wasted kinetic energy," Barrett explains. "So you want as low-velocity a jet as you can, while still producing enough thrust." He adds that an ionic wind is a good way to produce a low-velocity jet over a large area.

Getting to liftoff

Barrett acknowledges that there is one big obstacle to ionic wind propulsion: thrust density, or the amount of thrust produced per given area. Ionic thrusters depend on the wind produced between electrodes; the larger the space between electrodes, the stronger the thrust produced. That means lifting a small aircraft and its electrical power supply would require a very large air gap. Barrett envisions that electrodynamic thrusters for aircraft -- if they worked -- would encompass the entire vehicle.

Another drawback is the voltage needed to get a vehicle off the ground: Small, lightweight balsa models require several kilovolts. Barrett estimates a small craft, with onboard instrumentation and a power supply, would need hundreds or thousands of kilovolts.

"The voltages could get enormous," Barrett says. "But I think that's a challenge that's probably solvable." For example, he says power might be supplied by lightweight solar panels or fuel cells. Barrett says ionic thrusters might also prove useful in quieter cooling systems for laptops.

"Efficiency is probably the number one thing overall that drives aircraft design," Barrett says. "[Ionic thrusters] are viable insofar as they are efficient. There are still unanswered questions, but because they seem so efficient, it's definitely worth investigating further."


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. The original article was written by Jennifer Chu. Note: Materials may be edited for content and length.


Journal Reference:

  1. K. Masuyama, S. R. H. Barrett. On the performance of electrohydrodynamic propulsion. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2013; 469 (2154): 20120623 DOI: 10.1098/rspa.2012.0623

Cite This Page:

Massachusetts Institute of Technology. "Ionic thrusters generate efficient propulsion in air." ScienceDaily. ScienceDaily, 3 April 2013. <www.sciencedaily.com/releases/2013/04/130403122013.htm>.
Massachusetts Institute of Technology. (2013, April 3). Ionic thrusters generate efficient propulsion in air. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2013/04/130403122013.htm
Massachusetts Institute of Technology. "Ionic thrusters generate efficient propulsion in air." ScienceDaily. www.sciencedaily.com/releases/2013/04/130403122013.htm (accessed September 30, 2014).

Share This



More Matter & Energy News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Argentina's Tax Evaders Detected, Hunted Down by Drones

Argentina's Tax Evaders Detected, Hunted Down by Drones

AFP (Sep. 30, 2014) Argentina doesn't only have Lionel Messi the footballer, it has now also acquired "Mesi" the drone system which monitors undeclared mansions, swimming pools and soy fields to curb tax evasion in the country. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Do Video Games Trump Brain Training For Cognitive Boosts?

Do Video Games Trump Brain Training For Cognitive Boosts?

Newsy (Sep. 29, 2014) More and more studies are showing positive benefits to playing video games, but the jury is still out on brain training programs. Video provided by Newsy
Powered by NewsLook.com
CERN Celebrates 60 Years of Science

CERN Celebrates 60 Years of Science

Reuters - Business Video Online (Sep. 29, 2014) CERN, the European Organisation for Nuclear Research, celebrates 60 years of bringing nations together through science. As Joanna Partridge reports from inside the famous science centre it's also planning to turn the Large Hadron Collider particle accelerator back on after an upgrade. Video provided by Reuters
Powered by NewsLook.com
This 'Invisibility Cloak' Is Simpler Than Most

This 'Invisibility Cloak' Is Simpler Than Most

Newsy (Sep. 28, 2014) Researchers from the University of Rochester have created a type of invisibility cloak with simple focal lenses. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins