the point of ion?

[lukeoftheaura]

What's the point of those weedy little ion things?

And why do they use so much electric?

Edited December 8, 2014 by kerbingamer376

[sal_vager]

The Ion Thruster

Wikipedia, circa 2014.

[Oafman]

To move little things a really long way.

Even though my ions have been significantly nerfed by near Future, I still use them for probes which I think might not get a great response from my beamed power network. If I was stock only, I would use them even more often.

[UmbralRaptor]

High ÃŽâ€V low TWR missions. (Though the PB-ION has so much TWR you can land on smaller bodies with it...)

As for the electrical requirements, see sal_vager's post.

[RainDreamer]

Move things with very, very little fuel in exchange for a lot of energy and very low thrust. Good for probes on long, long term missions. Require a lot of calculation and preparation to make maneuver with as little ÃŽâ€V as possible or it will take you minutes to hours of burn to get anywhere meaningful (though sometimes you will still have to do that kind of burn anyway).

Overall, great for station keeping or interplanetary probe mission.

[Stratzenblitz75]

Ions have insanely high ISP at the cost of TWR. Even then, its TWR is good enough to land vessels on celestial bodies up to the size of Duna. Also, Ions don't consume that much power. I was able to use a single ion engine at full throttle on Eeloo with only 8 4L-OX solar panels. You could probably get away with much less in the inner Kerbol System.

Theoretically, if you didn't factor in costs, Ions would be the best option for planetary transfers and landers for anything except Duna, Eve, Tylo or Laythe. Although, In practice, part counts combined with long burn-times make Ions unbearable for anything but small vessels.

[Slam_Jones]

Extremely light, extremely efficient. I shudder to put them on anything bigger than a probe due to ridiculous burn times, but it certainly has its uses.

[TheAnimePug]

and you can make electric planes with it (its rly hard though)

[Slam_Jones]

Example electric plane:

Powered by two Ion engines, can take off at about 23 m/s.

Other folks have made much better ones, even ones that can make LKO off just Ion power. Mine can't

[xub313]

Ions certainly aren't limited by small payloads:

While the burns were longer than your standard chemical rocket, they were quite reasonable in my opinion. The biggest downside is the lack of larger xenon tanks, and thus a high part count.

[TheAnimePug]

Example electric plane:

http://i.imgur.com/itqTzcu.jpg

Powered by two Ion engines, can take off at about 23 m/s.

Other folks have made much better ones, even ones that can make LKO off just Ion power. Mine can't

Is it okay if i use a simmilar design for my youtube series? im making a beach resort/vab but i want it to be self independed too with s.t.t.o and electric planes and reusable rockets

[Mitchz95]

I often use them as emergency thrusters and/or escape pods for my larger interplanetary ships. On one mission I ran out of liquid fuel and had to tap into my xenon store to get the crew home. It was a pretty big ship and the burn time was absurd, but it did the job.

[Starman4308]

While the burns were longer than your standard chemical rocket, they were quite reasonable in my opinion. The biggest downside is the lack of larger xenon tanks, and thus a high part count.

NecroBones's Modular Rocket Systems has larger xenon tanks: one is a 0.625m sphere (1400 xenon), and the other is a 1.25m sphere (12500 xenon). They're also RealFuels compliant now, if you use that mod.

Edited December 3, 2014 by Starman4308

[LordFerret]

Ions certainly aren't limited by small payloads:

http://i.imgur.com/YVuyp8g.png

While the burns were longer than your standard chemical rocket, they were quite reasonable in my opinion. The biggest downside is the lack of larger xenon tanks, and thus a high part count.

Yes, I problem I just spent several days pulling my hair out over... and as of last night, abandoned the project. :/

[Laie]

Other problems include that the tanks themselves are rather heavy (~40% of a xenon tank is the tank itself) and generally, the whole propulsion system (engine, tanks, panels) has a Kerbin-TWR of ~0.25 even without any payload.

Ions are great for really small probes (like, everything but propulsion and probe core is weightless parts), but trying to push anything bigger quickly becomes more trouble than it's worth.

Edit -- oops, missed that one:

Ions certainly aren't limited by small payloads:

http://i.imgur.com/YVuyp8g.png

After a quick piecing-together of parts, I wonder if a single orange tank plus Nerva would not have done the job just as well, at a fraction of the cost and part count. Wouldn't look as cool, though. I especially like the missing solar panels.

Edited December 3, 2014 by Laie

[tsotha]

The funny thing is Kerbal ion engines have waaaay more thrust than real life ion engines. Usually ion engine thrust is compared to the weight of a piece of copier paper.

IRL ion engines are valuable because they have an enormous ISP. Newton's second law and all - the faster your fuel gets shot out the back the more efficient it is. The problem is ion engines are used for days or weeks at a time. Or they're used for a few minutes on every orbit for months. As a game mechanic this just doesn't work - nobody is going to sit and do a burn for a week.

So the developers tried to give you the ion flavor (low thrust, high efficiency) without trying to be too realistic.

[Slam_Jones]

Is it okay if i use a simmilar design for my youtube series? im making a beach resort/vab but i want it to be self independed too with s.t.t.o and electric planes and reusable rockets

Absolutely! I can upload the .craft file later tonight if you wanna work off of it

[FlyingPete]

I found six of them are enough to comfortably fly a low-speed aircraft on Kerbin. Cover the wings with the small solar panels and it can fly around quite happily during the day, and of course works on Eve or Duna too.

[pincushionman]

The funny thing is Kerbal ion engines have waaaay more thrust than real life ion engines...So the developers tried to give you the ion flavor (low thrust, high efficiency) without trying to be too realistic.

They originally were a lot worse about it. HarvesteR discussed it with Scott Manley a little when he interviewed him a little before the 0.23.5 release; the more-realistic capabilities meant that you might have had to "burn" for days to make a maneuver...but you can't time-warp through a maneuver, so they just weren't very fun to use. So they upped the thrust and the power requirements, and I believe slashed the Isp as well. Which is still a lot of Isp. In his words, they were already different enough from chemical rockets in that instead of a fuel-management puzzle, they're an energy- or power-management puzzle. So they changed it to not be so absurd from a gameplay perspective.

the discussion on ion engines starts at around 13:50 or so.

[AlexinTokyo]

The I_sp wasn't changed.

They kept it constant but quadrupled (IIRC) the thrust, which has the effect, simultaneously, of quadrupling the fuel consumption.

Unfortunately, that was the same update where "simulate in background" stopped working. You used to be able to Alt-Tab out during a burn and the game would happily continue in the background, so a 30-minute ion burn basically meant a Scott Manley video. Now, I rarely do ion probes.

[King Arthur]

As far as I'm aware, simulation in the background works as of 0.25. I alt-tab out a lot and never noticed the simulation stopping anywhere except if I were in the KSC scene.

[MarvinKitFox]

The I_sp Unfortunately, that was the same update where "simulate in background" stopped working. You used to be able to Alt-Tab out during a burn and the game would happily continue in the background, so a 30-minute ion burn basically meant a Scott Manley video. Now, I rarely do ion probes.

Just press alt-enter, to un-fullscreen your KSP.

It will now quite happily churn away in the background, while you can read a good webpage, watch a movie(maybe), or play simpler games while waiting for ksp to do its thing.

It is only the fullscreen view that freezes when it loses focus.

[technion]

This sucker made it from Tylo orbit, to Bop (landed), to Pol (landed), and to rendezvous with the mothership in a Vall orbit. Packing this makes a Jool 5 tour significantly lighter than it otherwise would be.

[cantab]

They excel on light craft with high delta-V requirements, where a chemical engine would need a lot of fuel and a nuclear engine is just too heavy.

They can also be useful on heavier craft with extreme delta-V requirements, where even a nuclear engine would require a lot of fuel. Unfortunately the part counts bite there, but mod tanks holding more xenon can help.

[tsotha]

This sucker made it from Tylo orbit, to Bop (landed), to Pol (landed), and to rendezvous with the mothership in a Vall orbit. Packing this makes a Jool 5 tour significantly lighter than it otherwise would be.

No landing on Tylo?