Ion Engines - Can someone explain?

[Sokar408]

I purposefully setup a probe that had a 1.4 thrust to weight ratio purely from ion engines (KSPX Small Ion Engine). While it didn't have anywhere near the power to work for long, it didn't even take off, and even when I got it into space, the thrust was completely unnoticable.

I assume that thrust to weight works different for them, but how exactly?

[Tprocheira]

Ion engines have VEERY low thrust (0.50 kN), so they're actually used for extremely small probes (probably like the one you made). But still, due to this really small thrust, your maneuvers will take long time periods. Ion engines are used in real life to power space probes (like Dawn or Deep Space 1), and to compensate for their extremely low thrust of 240mN (yes, milliNewton), they can run for years. In KSP, I found them pretty useless, as you can't warp to high speeds.

[TheDarkStar]

Ions don't have 50 max power, they have .50 max power. You probably messed up in your math.

[musicpenguin]

Ion engines are purely for super long burns. They are unable to lift themselves on kerbins gravity. Just use them for going to jool or something.

[Spyritdragon]

You'd have to have a very very light ship to accomplish that. Are you sure your calculations are right?

[Moar Boosters]

I think you might want to move your decimal point. An ion engine with the smallest probe core attached has a thrust ratio of 0.18, and that's without fuel or electricity.

[Kosmo-not]

I think he calculated his thrust to mass ratio and not thrust to weight.