# Ion Lifter Thrust Calculation Problem

I've recently started building an ion lifter. I tried calculating the thrust the lifter produces but I came to a value that is way to high for such a small lifter. I'm using a 40kV at 1800mA AC transformer. With those values I came to a total thrust of 0.7N. Meaning the craft should be able to lift anything up to 70g. Which seems a lot especially since it struggles to lift off while it only weighs 2g. Any help on how to calculate the actual thrust? Especially since I thought that the surface area where the ionization takes place plays a factor in the calculation, but it doesn't. Help would be much appreciated!

• It's difficult to answer this question because there is not enough information here. You don't explain how you did the calculation, so it's impossible to say if it's right or not or how it can be improved. To calculate thrust you need a velocity and a mass per unit time. How many ions did you produce per second and what speed can they attain? Is this happening in a sea-level atmosphere, or at high altitude, or in space? The mean free path of an ion at sea level is a handful of microns only, so the best you can produce is a gentle wind with most of your energy just going into heating the air.
– uhoh
Jun 10 '20 at 6:42
• For example see this answer to Troubleshooting a DIY Ion Thruster and also see How to measure thrust of experimental ion engine
– uhoh
Jun 10 '20 at 6:43
• That's an insanely powerful PSU if it provides full current and full voltage simultaneously - the fusor.net guys would love to have something like that Jun 11 '20 at 10:33