KSP ARM Parts list (SPOILER)

[vidboi]

Are the new engines better than 48-7S?

I think that the ion engines may be too powerfull now, I would be OK with 4 times the thrust

OR 1/4 the electricity but both make the engine seem OP (Landers that use ion engines???)

Not quite. The new ion engines have 4 times the thrust for the same electricity usage (i.e. they still use 12/sec at full power). The OP just doesn't make it clear that the reduction is 1/4 of the amount of electricity per unit thrust.

[Random Tank]

Not quite. The new ion engines have 4 times the thrust for the same electricity usage (i.e. they still use 12/sec at full power). The OP just doesn't make it clear that the reduction is 1/4 of the amount of electricity per unit thrust.

Check the spoilers in UmbralRaptors's post on the first page of this thread; Ion's use 8.7/sec now for 2kN of thrust. IMHO, they didn't need a thrust boost, just an energy usage drop

[Holo]

Introducing the newest product line from Rockomax, the SYK or "Screw You Kerbodyne!" series of rocket components, so large even Jebidiah hesitated to use them for about half a second

You want to deorbit Minmus?

Buy SYK.

[LtHeckard]

Thanks for sharing this.

[magnemoe]

Check the spoilers in UmbralRaptors's post on the first page of this thread; Ion's use 8.7/sec now for 2kN of thrust. IMHO, they didn't need a thrust boost, just an energy usage drop

Power has not really been an issue, using the 1x6 panels on strut masts works well, the problem has always been the low trust making for painfully long burn even with minimal cargo like the light science stuff or kethane mapping, last also need plenty of power but also bateries and or RTG both are heavy in ion perceptive.

With the update ions have become far more interesting.

[CaptainArchmage]

Wait the ion engine uses 4x less electricity and produces 4x as much thrust? Does that mean at maximum throttle it uses the same amount of electricity as it does now, while producing 4x as much thrust, or does it mean that at maximum throttle it uses 4x less electricity and produces 4x as much thrust? It looks like ion-powered landings will be possible on more celestial bodies!

Edit: I did some calculations.

The TWR of ion engines technically allows a full Tylo ascent, but in practice solar panels will still be needed. However, Moho landings on ion engines should be possible now.

Edited March 30, 2014 by CaptainArchmage

[vidboi]

Check the spoilers in UmbralRaptors's post on the first page of this thread; Ion's use 8.7/sec now for 2kN of thrust. IMHO, they didn't need a thrust boost, just an energy usage drop

That's interesting, in Scott Manley's demo video he showed the Ion Engines power requirements being the same. I guess there's some changes between the dev builds so I'm not sure exactly what to expect with the final release.

[IrRedemption]

Wish it didn't have spoilers now got too clicks so much

[Woopert]

Please address this Squad! My OCD is disturbed by this! (although Squad still is amazing, don't worry )

How the KS-25 cluster currently looks:

[GusTurbo]

I agree with Woopert. The evenly spaced version looks much better.

[carazvan]

I'm waiting for release because on one of the twitch livestreams I also saw their ISP go down from 4200 to 2100 besides the other changes which makes requirements be (16.7 electricity/sec; 0.89 xenon /sec)

I've played around with both setting and the deltaV for ion probes and ARM pushers can be pretty ridiculous now with the 4200ISP (had a 20k deltaV rocket with 0.15TWR at ~5t and a 7k deltaV 0.13TWR Ion/Jet SSTO at ~6t)

I say lets wait for a few more days and then we can see just how great Ions are now. (Either way the extra Thrust makes them very useful for ships under 10t)

Wait the ion engine uses 4x less electricity and produces 4x as much thrust? Does that mean at maximum throttle it uses the same amount of electricity as it does now, while producing 4x as much thrust, or does it mean that at maximum throttle it uses 4x less electricity and produces 4x as much thrust? It looks like ion-powered landings will be possible on more celestial bodies!

Edit: I did some calculations.

The TWR of ion engines technically allows a full Tylo ascent, but in practice solar panels will still be needed. However, Moho landings on ion engines should be possible now.

[Jouni]

Are the new engines better than 48-7S?

All new liquid fuel engines have better TWR than the 48-7S. The KR-2L has slightly worse ISP at sea level, but otherwise the new engines beat the 48-7S in that too. After the update, the 48-7S is only competitive in small to medium ships, where the huge new engines would be overkill, and in career mode, where you can unlock it early.

[Woopert]

Another thing to point out, I wish the tanks were either 4.2 meters or 4.125 meters. 4.125 would be more logical as it "fits in" more with the other sizes, as it's a multiple of 1/8. The reason being for that is a S-IVB stage is 4.125 meters proportional to the Mk1-2 pod; 4.2 is proportional to the SLS core stage (and STS external tank). But since they're so close, it would make sense to use the 4.125.

I know all the part mods use 3.75 m (KW Rocketry, NovaPunch, Lack SXT), but it really doesn't make much sense other than being in line with the 1.25 m increment used for the other parts.

Edited March 31, 2014 by Woopert

[GusTurbo]

I really don't think the new parts are 3.75m. I took some measurements in Photoshop on these two screenshots from moments apart in the same video, and the ratio of the larger parts to the 2.5m parts as best I could tell was about 1.6, making the new parts 4.0m at the very least.

I may be doing something wrong here, so maybe someone else can do better.

Edited March 31, 2014 by GusTurbo

[NERVAfan]

Edit: I did some calculations.

The TWR of ion engines technically allows a full Tylo ascent, but in practice solar panels will still be needed. However, Moho landings on ion engines should be possible now.

Ick. That is too good IMO.

I personally think ion engines should have thrust-during-non-physical-time-warp (it's been done in a mod so definitely possible) and much less thrust so they actually act like... ion engines.

I honestly don't know why Squad doesn't do that... maybe because it would require a totally different kind of trajectory and that's considered too hard or too complex for players? I don't know why that should really be a problem though... you don't really need ion engines because KSP's solar system and its delta-v requirements are scaled down, and KSP has the NTR engine.

But even leaving out thrust-during-timewarp, I can see them having double the thrust, but 4x seems too much (to me).

Actually, I think they're fine as they are now... niche, yes, but again - that's because you don't really NEED them in KSP.

[GusTurbo]

Here's a link to the video I used to make my measurements:

http://youtu.be/04o3Ll0H7ws?t=4m48s

[Sandworm]

But even leaving out thrust-during-timewarp, I can see them having double the thrust, but 4x seems too much (to me).

Actually, I think they're fine as they are now... niche, yes, but again - that's because you don't really NEED them in KSP.

It's all about the asteroids. I'm sure that they have designed the asteroid capture mission around the new parts. A pusher craft with enough delta-V to intercept with enough remaining energy to then capture asteroid, all in a single launch, probably requires ion engines. So imho the change is rooted in keeping the asteroid capture mission playable.

Edited March 31, 2014 by Sandworm

[Deathsoul097]

Dude, even HarvestR said the parts are 3.75m. Nuff said:

[GusTurbo]

Dude, even HarvestR said the parts are 3.75m. Nuff said:

Yeah, and people call them 2x4s when they're really 1 1â„2 in × 3 1â„2 in.

[Deathsoul097]

Yeah, and people call them 2x4s when they're really 1 1â„2 in × 3 1â„2 in.

I don't see the relevance. This would have more credence if he had said they were 4m, or 3m, but he said 3.75m. An exact number. So, I refuse to believe any random forum user and their easily botched calculations based on two dimensional renders of a virtual three dimensional space over a dev of the game saying something contrary to afore mentioned user.

[magnemoe]

I don't see the relevance. This would have more credence if he had said they were 4m, or 3m, but he said 3.75m. An exact number. So, I refuse to believe any random forum user and their easily botched calculations based on two dimensional renders of a virtual three dimensional space over a dev of the game saying something contrary to afore mentioned user.

This is easy to test, just put an 1.25 meter part on top of the 3.75, then put two on the sides on it and the width should be the same.

[GusTurbo]

I guess we'll see, won't we. I was surprised when the 3.75m number was being thrown around, because it simply looks bigger than that to me, regardless of my botched calculations.

[Xavven]

Wait the ion engine uses 4x less electricity and produces 4x as much thrust? Does that mean at maximum throttle it uses the same amount of electricity as it does now, while producing 4x as much thrust, or does it mean that at maximum throttle it uses 4x less electricity and produces 4x as much thrust? It looks like ion-powered landings will be possible on more celestial bodies!

Edit: I did some calculations.

The TWR of ion engines technically allows a full Tylo ascent, but in practice solar panels will still be needed. However, Moho landings on ion engines should be possible now.

EDIT: Ah, stupid me, I didn't read your post well enough. You had said "but in practice solar panels..." so you had actually come to the same conclusion. But anyway, the stats below should give everyone some idea of how practical (or not) ion engines are for landers. The full package of the ion lander with science instruments is 3 tonnes, compared to my regular rocket fuel lander being 4 tonnes but with waaay more thrust.

Can you show me your calculations? I'm not coming to the same conclusion, even with a bare command seat as the payload. Add some science parts and you're not going anywhere. Remember you have to account for the weight of the xenon tank, solar panels, and a basic battery.

Payload

1 command seat: 0.05

1 Z-200 battery: 0.01

6 OX-4L Solar Panels: 6x 0.0175 = 0.105

Total: 0.165

Xenon Fuel Tank

Wet Mass: 0.12

Dry Mass: 0.05

Ion Engine

Mass: 0.25

Thrust: 2

Stats

Initial Mass (m0) 0.535

Final Mass (m1) 0.465

Mass Ratio (m0/m1) 1.151

Total Thrust 2

Acceleration Full 3.7

Acceleration Dry 4.3

Delta-V in Vacuum (ÃŽâ€v) 2892

3.7 m/s² is not enough to get off Tylo, which has a surface gravity of 7.85 m/s². I started increasing the engine count, but it barely moved my acceleration, and without adding solar panels, I had to go up to literally 50 (fifty) ion engines to reach hover values in Tylo's gravity. You can imagine the hover wouldn't last long as the battery gets drained to 0 in less than a second. Adding solar panels back in makes it impossible to get off the ground.

In career mode, I always land with a lander can, a science jr., a mystery goo, and the other measurement instruments which have negligible mass. Adding this in gives me a lander with a payload of around 1.065 tonnes. With that payload, one ion engine doesn't cut it. I increased it to 4 engines and got only 600 ÃŽâ€v, so then I increased the number of xenon tanks to 4 as well (might as well since I need something to mount the engines to anyway). Then I had to increase the solar panel mass, making the payload more like 1.56 tonnes.

Stats

Payload 1.56

Engine New Ion Engine 4

Tank Tiny Xenon Tank 4

Initial Mass (m0) 3.04

Final Mass (m1) 2.76

Mass Ratio (m0/m1) 1.101

Total Thrust 8

Acceleration Full 2.6

Acceleration Dry 2.9

Delta-V in Vacuum (ÃŽâ€v) 1993

Still not great! You might be able to manage a Mun landing with that, but my usual lander has more than 4x the TWR.

Edited March 31, 2014 by Xavven

[Deathsoul097]

I guess we'll see, won't we. I was surprised when the 3.75m number was being thrown around, because it simply looks bigger than that to me, regardless of my botched calculations.

I hope you don't take any offense to what I have said, I was simply stating a view point. Studying and working in graphics and design, I know how out of scale 2d representations of 3d objects can be, even though they may seem perfectly coherent. Trying to take measurements and use ratios on an image of objects (Especially ones that are angled, like the one we have been given.) can be, and almost always are inaccurate.

[GusTurbo]

Yeah, I'll concede on this. I did some more measurements from a different point in the video and got different ratios because it was different angle, proving your point. I wasn't offended, so no worries. Just having some fun while waiting for this patch to drop.