Suggestion for the 0.24 update

[greg12]

Hi everyone!

I tried to make an ultimate deltaV craft by putting together an asparagus stage with ion engines.

Problems:

-I can`t transfer fuel with fuel lines from xeon tanks.

-why ion engines work like RCS thrusters? they don`t need physical connection with the fuel tanks.

I would like to suggest for the devs to fix the problems above and move the xeon tanks and the ion engines to the propulsion tab. Please!!

I would like to hear what you think about it.

[r4pt0r]

Hi everyone!

I tried to make an ultimate deltaV craft by putting together an asparagus stage with ion engines.

Problems:

-I can`t transfer fuel with fuel lines from xeon tanks.

-why ion engines work like RCS thrusters? they don`t need physical connection with the fuel tanks.

I would like to suggest for the devs to fix the problems above and move the xeon tanks and the ion engines to the propulsion tab. Please!!

I would like to hear what you think about it.

i belive ion used to be in propulsion and there was discusion on moving it to utlility. also, ion is like rcs, you dont need to connect fuel lines to make it work. as for dropping asperagus stages, what you would do is alt+click your bottom stage ion tank, and alt+click the empty tank to transfer all the fuel out of the stage youre dropping.

[KvickFlygarn87]

It now drains from earlier stages before later ones, so theres not even a need for fuel lines!

[Red Iron Crown]

As of 0.23.5, xenon and monopropellant now drain by stage priority rather than equally from all tanks, which is a welcome change.

Edit: ninja'd

[Rusty6899]

There is nothing special about asparagus staging to earn extra delta-V. All it does is provide more thrust for the same amount of delta-V, when compared to a rocket with the same configuration, but only fired two radial engines at a time.

Obviously it offers much more Delta-V than a ship that has 6 radially mounted tanks and engines firing consecutively, but that isn't an efficient way of designing a ship in most cases.

Realistically, you should probably only be looking to use asparagus staging for launch stages (for the extra thrust) and the new parts in 0.23.5 are doing there best to make this type of staging obsolete.

I don't really think that Ion engines will provide a much larger delta-V total than could be achieved with Nukes. Remember the fuel tanks for Xenon gas have a fuel/tank mass ratio of between 1.33 and 1.4, compared to liquid fuel which generally has a ratio of 8. It's possible to get a lot of delta-V on your ship, but not significantly more than can be achieved through other methods.

[Red Iron Crown]

I don't really think that Ion engines will provide a much larger delta-V total than could be achieved with Nukes. Remember the fuel tanks for Xenon gas have a fuel/tank mass ratio of between 1.33 and 1.4, compared to liquid fuel which generally has a ratio of 8. It's possible to get a lot of delta-V on your ship, but not significantly more than can be achieved through other methods.

That's demonstrably not so. The 5x greater Isp and far lighter engines more than compensates for the differing dry mass of the tanks. Higher amounts of delta-V are possible with ions than nukes, just try it and see.

[r4pt0r]

SNIP*

...and the new parts in 0.23.5 are doing there best to make this type of staging obsolete.

yeah but people will still do it, using the better parts. alot of people think the new parts need to be balanced much better.

[Rusty6899]

That's demonstrably not so. The 5x greater Isp and far lighter engines more than compensates for the differing dry mass of the tanks. Higher amounts of delta-V are possible with ions than nukes, just try it and see.

Having run my calculations, I humbly admit that you are right (with the caveat that in cases with extremely high payloads, nukes can outperform Ion engines and that the delta-V will depend on the amount of fuel, which is obviously going to make it difficult to provide a fair comparison).

[Red Iron Crown]

In gameplay terms, I consider nukes and chemical engines superior to ions as ions are just too painfully slow to use. I haven't messed around enough with the new, higher thrust ions to see if that's changed. Sometimes having fun trumps eking out that last bit of efficiency.

There's also part count to consider, my modest PC would choke on an ion array large enough to propel some of the spacecraft I use in a reasonable timeframe.

[Rusty6899]

In gameplay terms, I consider nukes and chemical engines superior to ions as ions are just too painfully slow to use. I haven't messed around enough with the new, higher thrust ions to see if that's changed. Sometimes having fun trumps eking out that last bit of efficiency.

There's also part count to consider, my modest PC would choke on an ion array large enough to propel some of the spacecraft I use in a reasonable timeframe.

Obviously the thrust is still pretty bad. An asparagus staged design with 6x symmetry and one "large" xenon gas container above each engine takes about 10 hours to burn through. Interestingly, asparagus staging only seems to provide about 10% extra delta-V compared with a single engine with 7 xenon gas tanks for a 3 tonne payload.

I haven't ever really considered using the Ion engines, but I can see why they may be useful for adjusting orbits and the like. I haven't ever really needed that level of precision, though, and I'm pretty sure the game isn't really set up that well for establishing perfect geostationary orbits and the like.

One problem with getting maximum efficiency, is that running your Ion engines at 1% power will actually increase your delta-V, considering that you would require fewer solar panels/RTG's to run it and would therefore reduce the weight. I'm looking forward to when the monetary system is in place and there will be an economic consideration to put a realistic cap on the pursuit of efficiency.

[Red Iron Crown]

I believe the appropriate Internet meme is, "Ain't nobody got time fo dat." I can barely stand ions at full power, I would never run them at reduced power to eke out another few percent of dV.

Ions appeal to the side of me that seeks maximum efficiency, but I have to be realistic. I have a finite amount of time to play KSP and watching an ion-powered craft burn prograde for an hour is not a fun use of my play time.

[raygundan]

In gameplay terms, I consider nukes and chemical engines superior to ions as ions are just too painfully slow to use. I haven't messed around enough with the new, higher thrust ions to see if that's changed. Sometimes having fun trumps eking out that last bit of efficiency.

There's also part count to consider, my modest PC would choke on an ion array large enough to propel some of the spacecraft I use in a reasonable timeframe.

I've been using them quite a bit lately, and they're definitely more fun to fly than they used to be. At four times the thrust, that's a substantial improvement already-- but the more recent versions of the game also seem to work reliably at 4x physics warp for me-- meaning your "real world" burn times with ion engines are 1/16th as long as they used to be. The thrust is probably unrealistically high for the ions, but it's a good compromise to make the engines "playable" for exactly the reasons you outline. Using them before 23.5 was a ticket to dullsville.

The part count thing remains an issue, though. The engines aren't so bad-- but enough of those tiny fuel tanks to move a big ship gets ridiculous. A slightly larger Xenon tank would be fantastic.