Are CRTs Suitable for Use in Ion Thrusters?

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Discussion Overview

The discussion revolves around the feasibility of using cathode ray tube (CRT) electron guns in the construction of a simple ion thruster for a science fair project. Participants explore various components and alternatives for creating thrust, focusing on the principles of ion propulsion and related technologies.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant expresses interest in using CRT electron guns for an ion thruster but questions their suitability for generating thrust.
  • Another participant clarifies that electron guns and ion guns serve different purposes, emphasizing the mass difference between ions and electrons.
  • Suggestions are made to explore DIY ion thruster projects that create ionized air currents rather than direct thrust.
  • A participant proposes the idea of simulating ion thrusters using radiometers and infrared light sources, questioning the appropriateness of CRTs for this purpose.
  • There is a suggestion to consider air-breathing electric engines using magnetohydrodynamics (MHD), noting that traditional ion engines typically operate in vacuum conditions.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the suitability of CRTs for ion thrusters, with multiple competing views on the best approach to achieve thrust for the project. The discussion remains unresolved regarding the most effective method or components to use.

Contextual Notes

Participants mention the need for high voltages in some proposed methods, indicating safety concerns and the necessity for supervision when experimenting with electrical components.

Who May Find This Useful

Individuals interested in DIY science projects, particularly those exploring ion propulsion, electric engines, or related experimental setups for educational purposes.

RamSkull
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Hello!

I'm trying to make a simple ion thruster that will be used in a science fair so I'm not concerned about its efficiency but just creating at least some thrust. However I wanted to make it as close as reality as possible, using every component and respecting its details if possib
electron-gun-2.jpg
le.


Ion thrusters use 2 electron guns, and this is when I came across those electron guns used in CRTs inside old monitors and televisions. However, I don't know if they are suitable for this task. If not, are there another alternatives for the electron guns?

Thanks!
 
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That sounds very ambitious and exciting. I hope you succeed.

Ions are much more massive than electrons. An electron gun is not an ion gun, so don't confuse the two.

A Google search for DIY ion thruster finds many hits. However, most of those are not useful. One that does sound real is this

https://www.popularmechanics.com/mi...-fair-experiment-to-aircraft-engine-15326499/
and

http://lae.mit.edu/2013/04/03/ehd/
In those cases, the device did not try to levitate itself, but rather to create a wind of ionized air. The wind current could make some bits of paper move to demonstrate nonzero thrust.

So, first see if you can understand those articles. Then, I would recommend that you try to contact the MIT professor Steven Barrett mentioned in the article and talk to him about doing it as a science fair project.

However, be aware that even that project requires some high voltages. You can do that safely only with the supervision of a mentor or adviser with you face-to-face, not by asking strangers on the Internet. We do not discuss dangerous topics on PF, so if this thread goes in a dangerous direction, we may have to close it.
 
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Try google up 'arc thruster'. I think that's DIY-able, without much vacuum involved.
 
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One could simulate thrusters, even build a scale model depending on the rules and education level of the science fair.

Radiometers are evacuated glass bulbs with a rotor with four vanes mounted on a spindle. Each vane has a dark absorbing side and a white or silver reflecting side.

Simulate the ion engines with a device that emits infrared (IR) and/or visible light. Not sure if CRTs are the proper device. Perhaps you could rig an IR source. A carbon rod arc-light with an IR filter certainly works but may be over-kill and requires adult supervision. Would laser pointers work?

Aim your simulated engine at the radiometer to simulate thrust by spinning the rotor.

1564509833283.png


For extra credit the OP could explain how Crookes radiometers work.
 
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Does it make sense just to make an air-breathing electric engine using MHD? Your ion engines are not working in a vacuum chamber by the way
 

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