Ion Engines.

[Jas1126]

I'm attempting to alter the Ion Engine to use a different amount of Xenon but altering the part file does nothing. I am able to alter the engine's electrical use however (within the same file).

What would I need to do in order to manipulate the Xenon usage?

Thanks very much.

Edit: Ah, figured it out. I just had to alter the weight of Xenon Gas (resource) itself.

Edited May 14, 2014 by Jas1126

[Streetwind]

That doesn't really do anything for you, though, because that also alters the amount of xenon in the tanks. In terms of mass, mind you, not in terms of volume units. But while the volume units are completely arbitrary in KSP (they're not even liters or anything comparable, they're just made up randomly), mass does matter, because that part goes into the rocket equation. Ultimately, you changed your ion engine to draw a different amount of mass from tanks that contain a different amount of mass. If you tested it, you'd find that the thruster will run the exact same time on one tank's worth of fuel in both cases.

To change your xenon usage, you need to change the engine's Isp or thrust, or both. Xenon mass flow rate is a direct result of the amount of thrust that is produced, and the the efficiency at which said thrust is produced (Isp) - it's a fixed physical relationship, which is why you cannot edit it. If you want to keep the thrust fixed but want more (or less) xenon to be used, then Isp must go down (or up). Similarly, if you want to keep Isp static but change the mass flow rate, then thrust must go up or down.

If I were you, I'd restore your stock numbers and then go into the ModuleManager thread, where you can ask how to achieve your goal using this neat little tool that lets you modify all paramters without touching any stock files at all.

Edited May 15, 2014 by Streetwind

[Jas1126]

I changed the Xenon weight, the amount in the tank as well as the electrical usage and the Ion engine's thrust about an hour after this post. It worked out great! Thanks for the info though. I'll check out the tool. Sounds quite handy.

I have the original files backed up just in case I, in all my noobiness, did something wrong. XD

Edited May 15, 2014 by Jas1126