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Kerbfleet: A Jool Odyssey-END OF CHAPTER 21! (and hopefully not so many talking heads in 22!)

Mister Dilsby

By Mister Dilsby
in KSP1 Mission Reports

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Just Jim

Just Jim

Posted
Posted
4 hours ago, FyunchClick said:

That makes me wonder, if Kerbfleet was ever in a position to put (evil) Kenlie Kermulan (or any other Kerbulan) on trial, would they be ready to deal with someone so violent, being the peaceful bunch that they are? They don't even have a word for murder, let alone a law dealing with it. Or from a different perspective, there's no law to break, so technically murder (or intent) may not be against Kerbfleet law?

Kerbfleet is throwing the book at him!  He's going to get such a time-out!  15-16 minutes at least!!!    :D

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FyunchClick

FyunchClick

Posted
Posted
8 minutes ago, PotentiallyHabitable578 said:

Senatus Populusque Kerbulus! 

I remember first coming across SPQR in an Asterix & Obelix comic as a kid, wondering what it meant, and having to trudge to the library to find an encyclopedia to look it up. Good ole days be darned, I love my internets.

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FlyingPete

FlyingPete

Posted
Posted

Looks like Bill and Wernher have been hard at work on the Weltraumfahrzeugträger! :D

One question though- it looks as though the first tanks to drain will be A-D. Will that not shut down the LV-N engines under them first? And the last engines running will be the Rhinos under pods L-R?

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Mister Dilsby

Mister Dilsby

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Posted
1 hour ago, Starhawk said:

As one Kerbfleet fan (and a fan of amazing engineering feats) I appreciate all the beautiful hard work that is going in to this.

Thank you! Am cautiously optomistic that it will survive orbiting, its first refuel, and V1.1 in that order :) 

6 minutes ago, FlyingPete said:

One question though- it looks as though the first tanks to drain will be A-D. Will that not shut down the LV-N engines under them first? And the last engines running will be the Rhinos under pods L-R?

Good question. I think it'll be OK. This ship carries a lot more LF than OX, which means that the Rhinos in pods L and R will burn for (IIRC) less than a minute before they cut out. I'm intending to fire those only when I want the extra thrust, for example getting to LKO or shortening an ejection burn. Most of the work is done by the LV-Ns, which will run quite a bit longer. You're correct that pods A-D will run out first, leaving just the 12 engines fueled by pod H. However, each of A-D carries 30,000 units of LF while pod H is just two Mk2 tanks for a total of 1600 units. H is really just meant as a mounting point for the engines and a distribution hub. If I ever get to the point that A-D are drained and those engines cut out, I'm running on vapors anyway. And if I think I'm going to need ALL the LF, I can always pump pod H empty once the first 1600 units are consumed.

BTW, fully loaded Kerbin TWR on LV-Ns alone should be right around 0.12-0.15, which I consider acceptable :) Rhinos would push it over 0.50, not bad for a ship that big. 

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FlyingPete

FlyingPete

Posted
Posted
3 hours ago, Kuzzter said:

Good question. I think it'll be OK. This ship carries a lot more LF than OX, which means that the Rhinos in pods L and R will burn for (IIRC) less than a minute before they cut out. I'm intending to fire those only when I want the extra thrust, for example getting to LKO or shortening an ejection burn. Most of the work is done by the LV-Ns, which will run quite a bit longer. You're correct that pods A-D will run out first, leaving just the 12 engines fueled by pod H. However, each of A-D carries 30,000 units of LF while pod H is just two Mk2 tanks for a total of 1600 units. H is really just meant as a mounting point for the engines and a distribution hub. If I ever get to the point that A-D are drained and those engines cut out, I'm running on vapors anyway. And if I think I'm going to need ALL the LF, I can always pump pod H empty once the first 1600 units are consumed.

That makes sense now. So the Rhinos are limited by the Ox available in pods B and Q more than anything else. As long as that's less than what's available in A-D, it should work fine. It might be an idea to have bidirectional fuel lines between A-D and H so they drain evenly. Once you run out of Ox, any remaining LF in the L-R tanks can be pumped across to the others.

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Mister Dilsby

Mister Dilsby

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12 minutes ago, FlyingPete said:

That makes sense now. So the Rhinos are limited by the Ox available in pods B and Q more than anything else. As long as that's less than what's available in A-D, it should work fine. It might be an idea to have bidirectional fuel lines between A-D and H so they drain evenly. Once you run out of Ox, any remaining LF in the L-R tanks can be pumped across to the others.

Right, though I am doing my best to make the fuel flow monodirectional, to avoid the usual headaches of one symmetrical line taking precedence over another. As it stands I did just boost to orbit, with 4600 dV left in the tanks! (admittedly, there are no landers aboard nor lots of other equipment)

However A pod seems to be contributing more than its fair share and draining faster than C, D and E. Debugging... maybe there's a stray line in there somewhere, hopefully I don't have to rip apart too much of the ship to figure out the problem.

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Starhawk

Starhawk

Posted
Posted
37 minutes ago, Kuzzter said:

Debugging... maybe there's a stray line in there somewhere, hopefully I don't have to rip apart too much of the ship to figure out the problem.

I feel you there.  Building stuff is fun.  Tearing it apart to find the problem and then rebuild it, less so.  Hope it goes smoothly.

Happy Concerned landings!

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Windspren

Windspren

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Posted
17 hours ago, FyunchClick said:

That makes me wonder, if Kerbfleet was ever in a position to put (evil) Kenlie Kermulan (or any other Kerbulan) on trial, would they be ready to deal with someone so violent, being the peaceful bunch that they are? They don't even have a word for murder, let alone a law dealing with it. Or from a different perspective, there's no law to break, so technically murder (or intent) may not be against Kerbfleet law?

Hey, Evil Kenlie, you've been promoted to the commander of Eve Prison 1! The position will even come with life support if you tell us the Kerbulan plans!

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Geschosskopf

Geschosskopf

Posted
Posted
23 hours ago, Kuzzter said:

I assure you he was applying forward thrust with his EVA pack the whole time. :) But hey, let's figure this out... if a Kerbulan cartridge is comparable to 9mm parabellum, we're talking a 7.5 gram bullet leaving the barrel at 380 m/s. As everyone knows, a Kerbal (or Kerbulan) suited for EVA masses 94kg. 

Conserving momentum: (.0075 kg * 380 m/s ) / 94 kg = .030 m/s. Not a lot. Total momentum of the four shots he fired would have sent Kenlie backwards with a total velocity of 12 cm per second--just enough to mess up his grouping a little :) 

 

Actually, a single 9mm x 19 round produces a recoil energy of about 500-600 J depending on make and model of the round.  Call it an average of 550 J per shot.

Work (Joules) = Force (Newtons ) * s (meters of distance)

W = m (mass) * a (acceleration) * s

Assuming constant acceleration (for the duration of the bullet moving in the barrel anwyay), vf2 - vi2 = 2as

so a = (vf2 - vi2) / 2s, and if vi = 0, then a = vf2)/ 2s

Thus, W = m * (vf2) * s / 2s = (m * vf2) / 2 (same as kinetic energy, actually)

So, 550 J = .(94kg * vf2) / 2 so vf = 3.42m/s.

IOW, after 1 shot (assuming he held the pistol in line with his CoM), the Kerbulian would be moving backwards at 3.42m/s.

After 2 shots.....

550 = 94 * (v22 - (3.42)2) / 2 so v2 = 4.84 m/s in reverse, and it goes on from there.  Actually, a bit faster because now he's lighter due to having fired 2 rounds, but we'll ignore that.

Of course, if the Kerbulian wasn't holding the pistol in line with his CoM, he'd instead be rotating at ever-increasing rate,quite enough to throw his aim well off.  But being a trained space warrior, he probably knows how to hold the gun in line with his CoM :D  So at the very least, he's rapidly increasing his range from the target.

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Mister Dilsby

Mister Dilsby

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42 minutes ago, Geschosskopf said:

IOW, after 1 shot (assuming he held the pistol in line with his CoM), the Kerbulian would be moving backwards at 3.42m/s.

I think you may have misplaced a decimal, my friend. Are you telling me that if a 200lb man (94kg, close enough) stood on a hockey rink in nice sharp skates and fired a single 9mm round, he would be propelled backwards at over 7 1/2 miles per hour? That's Hollywood gun physics, that is :) 

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GDJ

GDJ

Posted
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6 minutes ago, Kuzzter said:

I think you may have misplaced a decimal, my friend. Are you telling me that if a 200lb man (94kg, close enough) stood on a hockey rink in nice sharp skates and fired a single 9mm round, he would be propelled backwards at over 7 1/2 miles per hour? That's Hollywood gun physics, that is :) 

Probably stumble and fall on his butt because of the shock loading and he won't be able to compensate, unless he was leaned a bit forward and the same foot on the side of the shooting arm was dug into the ice a bit.

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Deutherius

Deutherius

Posted
Posted
7 hours ago, Geschosskopf said:

Actually, a single 9mm x 19 round produces a recoil energy of about 500-600 J depending on make and model of the round.  Call it an average of 550 J per shot.

Work (Joules) = Force (Newtons ) * s (meters of distance)

W = m (mass) * a (acceleration) * s

Assuming constant acceleration (for the duration of the bullet moving in the barrel anwyay), vf2 - vi2 = 2as

so a = (vf2 - vi2) / 2s, and if vi = 0, then a = vf2)/ 2s

Thus, W = m * (vf2) * s / 2s = (m * vf2) / 2 (same as kinetic energy, actually)

So, 550 J = .(94kg * vf2) / 2 so vf = 3.42m/s.

IOW, after 1 shot (assuming he held the pistol in line with his CoM), the Kerbulian would be moving backwards at 3.42m/s.

After 2 shots.....

550 = 94 * (v22 - (3.42)2) / 2 so v2 = 4.84 m/s in reverse, and it goes on from there.  Actually, a bit faster because now he's lighter due to having fired 2 rounds, but we'll ignore that.

Of course, if the Kerbulian wasn't holding the pistol in line with his CoM, he'd instead be rotating at ever-increasing rate,quite enough to throw his aim well off.  But being a trained space warrior, he probably knows how to hold the gun in line with his CoM :D  So at the very least, he's rapidly increasing his range from the target.

Math checks out, but where did you get the recoil energy from? A quick look at some random table tells me that a 9mm round should have a recoil of about 5 ft. lbs. (which google tells me is about 6.78 J - two orders of magnitude away from your value). That gives me a velocity change of ~0.14 m/s. Still a lot, but much more in line with common sense.

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The Error

The Error

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Posted

Could be Kerbulan ballistics are gyrojet. Reduced recoil, still good velocity. Don't need much oomph to punch through a hull (or a spacesuit).

And if he's using a sidearm, he can reach a leg holster.  Maybe they just aim by best guess? Laser sight? HUD? I'unno.

 

 

 

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