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KSP Cheat Sheets?


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Hello all,

I am finding a lot of data online, though most of it appear potentially outdated as it is most from far before 1.0.

The RT2 Planner (http://ryohpops.github.io/kspRemoteTechPlanner/) is fantastic for any sort of battery/solar calculation, but does not work for landed structures.

This (http://i.imgur.com/UUU8yCk.png) Seems to be an up to date Dv chart.

But what I am really struggling on now is more required acceleration. It is completely doable to create a Mun lander with the required Dv, I am just not sure how much thrust I need to not to crash into the surface/take off.

Edited by wisnoskij
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But what I am really struggling on now is more required acceleration. It is completely doable to create a Mun lander with the required Dv, I am just not sure how much thrust I need to not to crash into the surface/take off.

That's a function of TWR, which did not change in version 1.0.x. Thrust-to-weight ratio (TWR) equals thrust divided by a quantity equal to the mass of the craft times the surface gravity of the world in question. Or, in short:

TWR = T / mg.

The wiki has the Mun's surface gravity data; it's 1.63 meters per second per second. Any engine you would use on Mun would produce its vacuum thrust, of course. A craft with a TWR value of greater than 1.0 can take off from the Mun; one with less than that won't be able to take off/will crash.

So - example time. Let's say you've got a craft utilizing a single Terrier engine; in vacuum, its maximum thrust is 60 kN. Let's say you want a craft that has a 1.2 TWR on Mun. You just solve for mass and plug in the numbers you have:

TWR = R (making a notation change here - nothing else)

R = T / mg

Rmg = T

m = T / Rg = 60 / (1.2*1.63) = 30.6748 tonnes.

So, your single Terrier would support a thirty tonne craft easily enough. You wouldn't want to go much heavier than that with a single Terrier, incidentally.

Edited by capi3101
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That delta v map is not up to date. The numbers for atmospheric ascend are too high. The rest of the values are still the same.

It takes about 3800m/s to orbit Kerbin. If you go really agressive on TWR, you can get it done with 3300m/s, but that is rediculous. ;)

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That's a function of TWR, which did not change in version 1.0.x. Thrust-to-weight ratio (TWR) equals thrust divided by a quantity equal to the mass of the craft times the surface gravity of the world in question. Or, in short:

TWR = T / mg.

The wiki has the Mun's surface gravity data; it's 1.63 meters per second per second. Any engine you would use on Mun would produce its vacuum thrust, of course. A craft with a TWR value of greater than 1.0 can take off from the Mun; one with less than that won't be able to take off/will crash.

So - example time. Let's say you've got a craft utilizing a single Terrier engine; in vacuum, its maximum thrust is 60 kN. Let's say you want a craft that has a 1.2 TWR on Mun. You just solve for mass and plug in the numbers you have:

TWR = R (making a notation change here - nothing else)

R = T / mg

Rmg = T

m = T / Rg = 60 / (1.2*1.63) = 30.6748 tonnes.

So, your single Terrier would support a thirty tonne craft easily enough. You wouldn't want to go much heavier than that with a single Terrier, incidentally.

So do you just always want 1 TWR for landings/launches without atmosphere?

OK, so I am under-powered. I am trying to do it with poodles, because they have great stats, but I need to do some experiments to see exactly how much using a less mass/ISP efficient engines will effect it. The KW Vesta is the next best thing, and I think that Dv is potentially manageable (it seems a little low).

11246186_10153317281734242_3529236030752930459_o.jpg

10275458_10153317287804242_2062252350420839810_o.jpg

- - - Updated - - -

That delta v map is not up to date. The numbers for atmospheric ascend are too high. The rest of the values are still the same.

It takes about 3800m/s to orbit Kerbin. If you go really agressive on TWR, you can get it done with 3300m/s, but that is ridiculous. ;)

Aren't those FAR numbers? Or did the atmospheric update make stock numbers closer to FAR numbers?

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Aren't those FAR numbers? Or did the atmospheric update make stock numbers closer to FAR numbers?

These are stock. FAR takes less than this, actually. To orbit Kerbin in FAR you'll need about 3000-3300m/s

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Also, I will be shedding the scanning sat on top before landing (and I plan on removing the nose cones with KAS/KIS in orbit). But that is only like 1t total.

Edited by wisnoskij
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So do you just always want 1 TWR for landings/launches without atmosphere?

No, you need more than 1 to overcome the gravity. And you should switch the reference body in KER to the body you want your lander to land on to get the local TWR.

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OH, so 1.0 TWR is a thrust equal to gravity. That makes sense. But the problem I was having, I can slow down, you just don't have very long to slow down in a 10K circular orbit.

OK, so changing the body I have a ~4TWR, and enough fuel. And sure, I see how it might be possible to land theoretically. I don't know if I will be able to do it, I ended up crashing into the ground at about 70 m/s. It seems I will basically be starting a suicide burn directly from a 10K orbit, and if I let off that throttle for a second I will be going to fast to survive. I cannot see how a 1.2 TWR would ever work; 4 really seems like the bare minimum.

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I was just throwing 1.2 out there as an example; most folks usually wind up in the 3-4 range for Munar landings. Nothing wrong with having it that high on Mun, since there's no atmospheric drag to bleed off your delta-V.

Since you've got KER, toss up the Surface and Vehicle tabs when you go to make your Mun landing (be sure to add one of the KER flight computer parts to your craft before you launch). On the Vehicle tab, there'll be a stat telling you the distance to suicide burn - you want to begin a full power retrograde burn (Z-key) when that figure gets as close to zero as you can manage (try not to start your burn after it gets below zero; at that point a crash is pretty much inevitable). And, as with any time you go for a suicide burn, quicksave before you start...

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You don't need KER parts with an engineer or upgraded tracking station, and I will have both.

But great suggestion. That would make it easier.

But I am almost wondering if attaching some "Thuds" might overall make the craft more efficient to land. If I am thinking straight, a TWR of 4 is only 3/4 efficient, While one of 8 would be 7/8s efficient. Which should be far more important than a few pounds and ~20 ISP.

They even could be attached to the miner.

- - - Updated - - -

OK, turns out I was actually in much better shape than I thought I was. Those miner tanks were not connected to my main rocket. So I can give my miner a TWR, capable of doing small suborbital hops, with some terriers, increase my Dv dramatically, and make my overall TWR go through the roof. All while giving my miner the ability to do small suborbital hops theoretically.

Edited by wisnoskij
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