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


Mister Dilsby

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On 2016-02-02 at 9:06 AM, Kuzzter said:

And don't worry about Mister Blocko's timer, Bill already reset it off-panel. I'll let @Parkaboy keep his monopoly on countdowns to file corruption doomsday :) 

This seems to indicate the timer was dealt with.

And I'm pretty sure Bill wouldn't leave a ninety-days-to-the-end-of-the-world timer running and then head off to Jool. :)

Happy Concerned landings!

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Regarding the Blocko timer: I was writing a response to explain that yes, Bill reset it (he didn't remember what he was resetting exactly, he was following a note he left for himself in his kpad)-- as I was typing the note I got a popup notification that @Starhawk had replied to the thread, and guessed correctly that he had not only answered the question but cited the correct reference to prove it. Which was great, because I was in the middle of a spaceplane launch...

Ld7z24P.png

2NZx8O5.png

V1XAMXz.png

9D8FU6Z.png

I wanted to play&post all the way through to docking, but ran out of time sorry! This Skimmeroo is a little different from the test version. First off, @Deddly was right about the canards, I rotated them flush with the cockpit body. Next I removed all the OX-STAT solar panels, which (1) tend to explode on ascent and (2) will be useless, and instead stashed a pair of RTGs in the cargo bay. Realized I had to do this, because life support will consume 0.5 kwatts/kerbal. (that's 0.5 EC/ second per kerbal, not 500 EC/second. Kwats are not to be confused with kilokwatts. :) )

More random discussion. Kuzz Jr. showed me a World War K video in which @EnterElysium tested a B-2 Spirit replica. EE ended up making a "derpy" version with four engines distributed above and below the centerline, rather than the RL config of two shrouded engines above. EE stated in the video that it would have been impossible to control the unbalanced config, however you can see that the Skimmeroo manages this quite well :) The key was rotating the engines upwards so that their thrust vector passes closer to centerline. You can see that angle pretty well in the third page, bottom panel, and also that I'm using RCS to hold the nose up as canards are no longer effective to maintain attitude in the stratosphere--this is with a max thrust offset of about 3 degrees, which reduces to a more manageable one degree once I get to orbit and can re-distribute some fuel :) 

Edited by Kuzzter
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Excellent updat.  Jeb and Melbe really are fun together.

"I!! LOVE!! MY!! JOOOOOOOOOOOB!!" was a wonderful moment.  :)

57 minutes ago, Kuzzter said:

-- as I was typing the note I got a popup notification that @Starhawk had replied to the thread, and guessed correctly that he had not only answered the question but cited the correct reference to prove it. Which was great, because I was in the middle of a spaceplane launch...

Always glad to be of service.  I was quite surprised how far back I had to look to find the reference.  This thread is growing very quickly!

Happy Concerned landings!

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31 minutes ago, Starhawk said:

Always glad to be of service.  I was quite surprised how far back I had to look to find the reference.  This thread is growing very quickly!

Yeah, I know! Really love all the comments and engagement. You all drive me to better comics, or at least to better NOMS-based food puns :) 

BTW as an aid to first-time readers confronted with 53 pages of replies, I've posted links to Chapter 4 and to Bill's Engineering Updates in the OP.

3 minutes ago, Angel-125 said:

@Kuzzter: You are much better at SSTO designs than I, my stuff usually ends up falling short. The best I've done is taken the Aeris 4 and putting a nuke on the back. Any tips on how to get those things to fly to orbit? :)

Thanks! Well, you can get much better technical advice from guys like @GoSlash27, @Rune and @Snark than you can from me. But since you're asking me, what I can tell you is that the first priority is making sure you can get up over 340 m/s at 8-10km. Depending on your jetplane TWR this might be really easy (as it is for Skimmeroo) or you might have to climb slowly, go level flight at 8km to accelerate or even dive slightly. This speed is key to reaching the "tipping point' where your jet thrust will continue to increase, accelerating the craft to maximum velocity. Other important factors for getting there are making sure you have enough intakes (you really don't need many) and minimizing drag. Again, this is easy with Skimmeroo--it has hardly any wing area and its payload is all in the cargo bays. Note that I could not SSTO this design when I had an external docking port, but I can do it with the Mk2 inline version. Most failed SSTO designs I've seen have too many doodads sticking off the exterior, or have too much wing area.

Next you have to actually survive that velocity, which can be 1350-1500m/s. I usually use radiators: Skimmeroo has its inside the cargo bay. Gliido, a heavier ship, has its distributed abaft the cockpit. Your testing should reveal which parts are liable to exploding, and you can choose to move, eliminate or protect them. You can also change your flight profile--Skimmeroo is powerful enough that I climb at about 20 degrees until rocket mode transition, both (1) because I can, and (2) because in level flight at 20km it would overheat and explode. Gliido, on the other hand, accelerates at a more sedate 5 degrees until I light the LV-Ns at 18km (note it's a LF-only design, I carry no oxidant for the RAPIERS), then drives on jets+ rockets until i run out of air and nose up to 30 degrees to complete the orbit.

And that's about all I have to say about that. :) 

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Much appreciated, @Kuzzter, thanks! I was concerned that my plane slowed down until it hit 8k, then it sped up again. This is what I came up with, the nuclear aerospikes are mine; they are from DSEV (I pulled them awhile ago and rebuilt them over the weekend.)

HK1pA80.png

Now I just need to finish outfitting it...

Edited by Angel-125
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It's that time again....  TRANSCRIPTION TIME!

CHAPTER FIVE: FLIGHT OPERATIONS

Gene: Skimmeroo, you're up-intercept of their next orbit!
Melbe: I reckon we should launch when they're 'bout four hundred klicks west, Kernel.
Jeb: Sounds good, Melbe!  And that's coming up right... about...
...now! *Z*
Melbe: Yeee-haaa!

New page:

Jeb: Whooo!  I could do that all day!
Melbe: You do do that all day!
Jeb: Hey, you're right!
Jeb: I!! LOVE!! MY!! JOOOOOOOOOOB!!

New page:

*Skimmeroo is...*
Melbe: Passing fifteen thousand-Mach three point four.  Heating nominal!
Jeb: Angels twenty-five, going to rocket mode!
Melbe: Shucks, Kernel, that was smooth!  Think it'll work that good on Laythe?
Jeb: Only one way to find out...
Jeb: Hey, is that what I think it is?

New page:

Melbe: If y'all think it's the Intrepid, then heck yeah!
Jeb: Wow, just look at her!  Hellll-o, gorgeous!
Bob: Hello yourself, munatic.
Bill: Be nice, Bob!  Hey Jeb, great to see you!
Clauselle: You'll be just in time for lunch, Kernel- I hope you like soupe a l' oig-NOM!

 

Have I mentioned how nice is to read these comics without spelling errors.  It really makes a difference in reading it. :)


 

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6 hours ago, Kuzzter said:

Thanks! Well, you can get much better technical advice from guys like @GoSlash27, @Rune and @Snark than you can from me. But since you're asking me, what I can tell you is that the first priority is making sure you can get up over 340 m/s at 8-10km. Depending on your jetplane TWR this might be really easy (as it is for Skimmeroo) or you might have to climb slowly, go level flight at 8km to accelerate or even dive slightly. This speed is key to reaching the "tipping point' where your jet thrust will continue to increase, accelerating the craft to maximum velocity. Other important factors for getting there are making sure you have enough intakes (you really don't need many) and minimizing drag. Again, this is easy with Skimmeroo--it has hardly any wing area and its payload is all in the cargo bays. Note that I could not SSTO this design when I had an external docking port, but I can do it with the Mk2 inline version. Most failed SSTO designs I've seen have too many doodads sticking off the exterior, or have too much wing area.

Next you have to actually survive that velocity, which can be 1350-1500m/s. I usually use radiators: Skimmeroo has its inside the cargo bay. Gliido, a heavier ship, has its distributed abaft the cockpit. Your testing should reveal which parts are liable to exploding, and you can choose to move, eliminate or protect them. You can also change your flight profile--Skimmeroo is powerful enough that I climb at about 20 degrees until rocket mode transition, both (1) because I can, and (2) because in level flight at 20km it would overheat and explode. Gliido, on the other hand, accelerates at a more sedate 5 degrees until I light the LV-Ns at 18km (note it's a LF-only design, I carry no oxidant for the RAPIERS), then drives on jets+ rockets until i run out of air and nose up to 30 degrees to complete the orbit.

And that's about all I have to say about that. :) 

Summon me, and I shall appear! First off, congrats on the comic. I've been following it, and it keeps on being awesun. The intrepid is quite the thing! I only hope you have the stamina to endure the time dilation during burns.

And now, to the SSTO tip section!

The main thing that you left unsaid is that, like anything else in rocketry, SSTOing is all about the ratios, not the naked numbers. The important figures that will determine whether you get to space today are TWR, and mass ratio. TWR will give you the profile on airbreathers, and mass ratio has to be enough so you can make orbit afterwards (remember, dV is only a function of Isp and mass ratio, not thrust). In practical terms, going by personal experience, that means the best results are achieved with RAPIERs at about ~0.5 TWR on the runway (if you weight X mT, you need 5·X kN), and about 33% of your takeoff weight being payload, 33% fuel, 33% everything else, A.K.A. mass ratio 1.5 (or in other words, >1km/s left in the tanks when you run out of liquid fuel with ~300s engines). Oh, and don't fret too much about airbreathing cutoff speed. It'll be between 1,250 and 1350m/s, give or take a few dozen m/s, no matter what you do (heat barrier), and going fast on airbreathers will cost you a lot of tons in engines. The trick for absurdly efficient SSTOing is to use just enough engines to go supersonic, and minimize drag to the absolute minimum (no open nodes, smallest possible cross-section).

 

Rune. Gotta keep up with my reputation, I guess. :D

Edited by Rune
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Just now, SpaceplaneAddict said:

Ecole PolyKerbnique is the school Clauselle graduated from, which is in Montreal, Quebec, Canada.. making my opnion she's a canadian french :)

How about French Canadian?

*Runs away*

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L'ecole Polytechnique is a famous engineering school in France.

Montreal also has an Ecole Polytechnique.  Unfortunately, that is famous for a much sadder reason.

Unhappy landings.

btw: In English speaking Canada, French Canadian is the common term.

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3 minutes ago, Starhawk said:

L'ecole Polytechnique is a famous engineering school in France.

Montreal also has an Ecole Polytechnique.  Unfortunately, that is famous for a much sadder reason.

Unhappy landings.

btw: In English speaking Canada, French Canadian is the common term.

Yeah, I'm in Alberta, wouldn't know too much french stuff anyway ;)

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2 hours ago, Rune said:

The trick for absurdly efficient SSTOing is to use just enough engines to go supersonic, and minimize drag to the absolute minimum (no open nodes, smallest possible cross-section).

Your treatise is definitely the true and lively word on efficiency in terms of money,  And saving money is one of the main reasons  why spaceplanes are attractive in real life, so maxing that out in KSP is just carrying the concept to its logical conclusion.  But I think it important to add the caveat that such a low-TWR spaceplane will take about 20-30 minutes off of your remaining lifespan just to get to orbit (or fail to, so back to the drawing board).  IOW, each launch attempt has about the same health effect on you as smoking a cigarette.

But the thing is, this sacrifice is only necessary in KSP if you're very broke, which is only likely to happen with very hard career settings.  At less masochistic settings,  you'll never really be strapped for cash, so the incentive to save money isn't really there.  And if that's the case, you're more interested in saving real-life time, which brings spaceplanes directly into competition with conventional, disposable rockets.  If that's your situation, you should probably make spaceplanes with much higher TWR so they're don't take significantly longer to get to orbit than rockets.  Of course, this means more engines, more fuel for them, and thus CONSIDERABLY less payload for the size of the thing.  But hey, it's still got that spaceplane coolness factor :D

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7 hours ago, Angel-125 said:

Much appreciated, @Kuzzter, thanks! I was concerned that my plane slowed down until it hit 8k, then it sped up again. This is what I came up with, the nuclear aerospikes are mine; they are from DSEV (I pulled them awhile ago and rebuilt them over the weekend.)

HK1pA80.png

Now I just need to finish outfitting it...

GIMME THE ENGINES!!

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