Ion engine doesn't have a "Newtons third law" force programmed in?

[Themohawkninja]

When it comes to the jet and rocket engines, Squad implemented them in such a way that there is a force that travels in the opposite direction of the rocket (just like a real rocket/jet works), however I decided to do a little experiment with the Ion engine, and when I had the engine that is blocked with a structural panel on at full throttle, the accelerometer (finally, a really good use for science parts!) read .03. When all engines are off, it reads .00 since I am in orbit, and when the unblocked engine is at full throttle, the accelerometer reads .03 as well. With both on, the accelerometer reads .07.

Feel free to try the experiment yourself, and if one of the devs could confirm/deny this post, that would be great!

[Fried]

no all engines will move you even with stuff blocking the thrust. as for the .7 I think this is because they produce .035 and the accelerometer dose not show it.

[skykooler]

no all engines will move you even with stuff blocking the thrust.

That is not true. Try putting a fuel tank below a mainsail; you will see you will go nowhere.

[Themohawkninja]

no all engines will move you even with stuff blocking the thrust. as for the .7 I think this is because they produce .035 and the accelerometer dose not show it.

No, If you block the exhaust, it won't move.

I do agree with the reason for the .7 thrust though.

[Eric S]

To the best of my knowledge, RCS thrusters work fine when blocked, liquid chemical engines don't. If ion engines fall into the "works fine" category, it may be that it's the liquid engines that have a check that other engines don't rather than RCS skipping that check.

[NovaSilisko]

I think it's just an oversight in the thrust blocking thing. Right now, things like the mainsail have thrust damage enabled - the same block of code which also handles disabling any thrust it produces if it happens to be blocked. Some of the smaller engines have it disabled since they're generally too small to cause any damage to parts (like the ion engine), so the actual thrust-being-blocked parts and causing-damage parts need to be separated.

[Colonel_Panic]

My guess is it wasn't implemented the same as liquid engines because the nature of the engine is different. Clearly if you have an ion engine completely blocked, it shouldn't give you any thrust, however, since it operates via a combination of expulsion and magnetic repulsion, and at such a low rate of expulsion, the exhaust can probably still produce usable energy while dissipating, even when something is in the way directly behind. It was probably overlooked as a matter of lesser importance because of this.

[dahud]

I'm pretty sure that's not the case, Colonel Panic. Real ion engines have to take into account not only the path ionized gas coming out of the engine, but also the negatively charged ions pulling the spacecraft backwards. Also, the exhaust velocity out of an ion engine is absurdly high. Ionized atoms are just very very light.

[Colonel_Panic]

I'm pretty sure that's not the case, Colonel Panic. Real ion engines have to take into account not only the path ionized gas coming out of the engine, but also the negatively charged ions pulling the spacecraft backwards. Also, the exhaust velocity out of an ion engine is absurdly high. Ionized atoms are just very very light.

charged particles are highly entropic, and always traveling at an absurdly high velocity. AFAIK an ion engine is more about reducing entropy than accelerating particles. In the vacuum of space, the particles should scatter very quickly.

[Themohawkninja]

charged particles are highly entropic, and always traveling at an absurdly high velocity. AFAIK an ion engine is more about reducing entropy than accelerating particles. In the vacuum of space, the particles should scatter very quickly.

An ion engine accelerates particles to very high velocities, and propels them out of a grid (the one in KSP appears to be the type with an acceleration grid) which causes an equal and opposite force. I've never heard of entropy playing a role in the engine principle before.

[Dem Wot Goz Ub]

An ion engine accelerates particles to very high velocities, and propels them out of a grid (the one in KSP appears to be the type with an acceleration grid) which causes an equal and opposite force. I've never heard of entropy playing a role in the engine principle before.

Which is probably a good thing, as far as "going to space today" is concerned. If DWOG found out that Head Engineer Clippy Kerman was trying to reduce entropy to power our ships, we'd jail him for Contempt of Thermodynamics.

Yew don' want ta know wot we duz ta Kerbz wot iz in Contempt a Termodinamikz.

[Colonel_Panic]

An ion engine accelerates particles to very high velocities, and propels them out of a grid (the one in KSP appears to be the type with an acceleration grid) which causes an equal and opposite force. I've never heard of entropy playing a role in the engine principle before.

That's because we don't care what happens to our particles after they do their job and leave the grid.