Silent and Simple Ion Engine Powers a Plane with No Moving Parts

Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by TheSpiceIsLife on Wednesday November 21, 2018 @05:03PM (#18506472)

At high altitudes there’s also a lot less ground.

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by ccozan on Wednesday November 21, 2018 @04:27PM (#18506247)

so why not use jets to reach cruise altitude, then switch to ion thrusters ( for which you don't need fuel )?

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by ghayes on Wednesday November 21, 2018 @06:24PM (#18506870)

In the video included in this article [https://arstechnica.com/science/2018/11/small-drone-soars-on...], the subject discusses that ion thrusters are less effective at higher altitudes as the air is rarified.

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by fwip on Wednesday November 21, 2018 @06:15PM (#18506835)

Ion thrusters still need "fuel" in the form of electricity from batteries.

These ion thrusters have worse thrust/watt than an electric propellor drive, and far worse than the jet engines they use.

So there's not really any reason to use ion thrusters at cruising altitude, unless the relative silence is worth paying a lot more per-ticket.

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by girvo on Thursday November 22, 2018 @01:59AM (#18508370)

> These ion thrusters have worse thrust/watt than an electric propellor drive, and far worse than the jet engines they use.

From the Ars article (for others who were curious about this):

> Measurements showed the thrusters collectively generated five newtons for each kilowatt of power, which is actually similar to the output of jet engines. But because of many inefficiencies in the system, the overall efficiency was only about 2.5 percent—well below that of conventional aircraft.

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by taneq on Wednesday November 21, 2018 @06:51PM (#18506977)

> So there's not really any reason to use ion thrusters at cruising altitude, unless the relative silence is worth paying a lot more per-ticket.

Even then, I'd imagine that a significant portion of the noise in an airliner is wind noise rather than engine noise. Your plane is only going to get "less noisy", not "silent". Good noise canceling earphones are a far better solution (I have some specifically for plane flights, they're awesome!)

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by mrfusion on Wednesday November 21, 2018 @09:15PM (#18507491)

Potentially lower maintenance costs with no moving parts. Plus potentially cheaper to manufacture.

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by ccozan on Thursday November 22, 2018 @06:27AM (#18509340)

And also need to transport only a fraction of the jet fuel

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by fwip on Saturday November 24, 2018 @01:37AM (#18520818)

But many more pounds of batteries.

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by gaius on Thursday November 22, 2018 @09:32AM (#18510180)

so why not use jets to reach cruise altitude, then switch to ion thrusters ( for which you don't need fuel

Because you would need to restart the engines to land, and that is when they are at a higher risk of failure. You could maybe throttle them right back but keep them ticking over.

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Re:Silent and Simple Ion Engine Powers a Plane with No Movin... by soperj on Thursday November 22, 2018 @12:18PM (#18511196)

only reason you want no noise is for take off and landing. No one really cares once it's at cruising altitude.

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