Universal Staging Calculator XLS

[Corona688]

http://burningsmell.org/ksp/KSP4.xls

This does not handle xenon, RCS, or nuclear engines, just LFO with a bit of boosters nailed on.  What it can do is straight staging, asparagus staging, twisted candle staging, droptanks, or most combinations thereof.

How to use it:

1. Set the payload weight.  All the way in the upper right.
2. Tell it what engines you'll be using.  See the big green "engine inputs" area?  Set engine to "thud" to pull up a thud's stats above it.  Then set 1 for "atmo" if you'll use primarily in-atomsphere or 0 if primarily in vaccuum.  Then tell it how many of that engine it will have under "# Engines".
3. Describe the stage.  "Staging inputs" is where the magic happens.  You put 1 where you want engines to fire, 0 where you want engines doing nothing, and -1 where you want engines ejected. You can see that at "liftoff", every single engine will fire, because this is an asparagus lifter.  But no particular order is enforced, so you can calculate straight staging just as easily.
4. Set the stage name.  They don't do anything, they're just for your own sanity.
5. Input LFO for the stage.  Right beside "staging inputs" you see "LFO" and "Solid".  The liftoff stage has 2880 LFO, meaning its intended to burn 2880 fuel then throw away the empty tank.  It also has 5200 solid from two kickback boosters.
6. Set the "fudge" value.  This is a lift-off thing.  How much delta-v is wasted in low-TWR and atmospheric drag?  I roughed it with 0.5 for 50% at liftoff.  I might figure out a better way, at least there's a place for it to go.

Example:  "The Refresher".  Because why not pick a rocket which exposes gaping problems in my spreadsheet.

This is more or less the rocket shown in the spreadsheet.

• Payload weight is 10 tons.
• It has four sets of engines:  A single skipper, a pair of thuds, another pair of thuds, and a pair of skippers.  The thuds are two independent sets so they can be ejected independently.
• Liftoff:  All engines fire.  The skipper, the thuds, the kickbacks, everything.  In my staging, that's a 1,1,1,1.  All couplers have fuel crossflow enabled, with the bottom tanks burning first.  Bottom-most stage has 1440+720 fuel.
  • You might notice a problem already:  A kickback burns an entire minute, my bottom LFO stage does not.  In truth, with crossflow enabled, that wasn't a problem though, just wait longer.
• Sustain:  All the thuds remain burning, but the kickbacks and skipper are thrown away.  There is 1440 fuel in this stage.  That's a 1,1,-1,-1.
• Circularize:  A set of two thuds are thrown away, the remaining two keep burning.  1,-1,0,0.

This is more like a 20-ton-to-orbit booster, much to my surprise, which technically halves the cost per ton.  And technical which saves you money is the best kind of technical.

Edited December 6, 2017 by Corona688

[hab136]

18 hours ago, Corona688 said:

twisted candle staging

I've never heard of this.  Found this page that explains it:

which links to a very helpful picture from https://imgur.com/a/DBqIh:

 

That's.... inventive.  It supposedly is more efficient than asparagus staging, though it's limited in the number of stages you can have.

[Corona688]

Twisted candle is asparagus staging which throws away the bottom of the rocket like normal stage-atop-stage stacking.  This avoids the "fat rocket" drag problem and lets you throw away your heavier engines, but needs some sort of radial engine for the upper stages.  "The Refresher" is twisted candle with all those thuds.

1 hour ago, hab136 said:

That's.... inventive.  It supposedly is more efficient than asparagus staging, though it's limited in the number of stages you can have.

Oh, yikes.  The Spark engine used to be hyper-efficient due to its very high thrust for its weight.  "What engine do I use?"  "Sparks!"  "But its tiny" "Use more".  Things like this happened until they nerfed it (to oblivion).  Party over.

Edited December 6, 2017 by Corona688