[Stock] 30 sec Altitude Challenge!

[info600]

I will post once I'm able to improve it a little. I've been trying to make a version that will lag or crash less, but have just met some hilarious spectacular failures. I'll post some pics of those too

are some of the problems involved the spent seperatrons coming back up and hitting the ones in use? Cause that's the ones I had trying to get the results from the previous page.

[zarakon]

are some of the problems involved the spent seperatrons coming back up and hitting the ones in use? Cause that's the ones I had trying to get the results from the previous page.

I'm basically doing what Ojimak did here: http://forum.kerbalspaceprogram.com/showthread.php/27751-Stock-30-sec-Altitude-Challenge%21?p=341710&viewfull=1#post341710

Except with the low-drag cockpit instead of the probe core, and a lot more stack separators to make up for the weight difference. It's actually the cubic strut scaffolding that causes all the lag, so I'm trying to find ways to pack in more separators with less struts. So far those attempts have just resulted in them firing in series instead of simultaneously, leaving me with a giant snake-like stack of separators underneath the pod and not much velocity

Edited June 19, 2013 by zarakon

[Fel]

What about covering everything with RCS ports so that it has near zero drag?

[Pbhead]

THinking about this a bit I thought that weight really isnt the issue here, drag is. Perhaps aerospike engines, with their lower drag coefficient, despite their lower TWR might work better, especially better than solid fuel rockets with their 0.3 drag coefficient.

I mean, clearly you want high twr initially to get to high speeds, and you want it once you clear the atmosphere, but i think there is a small section in there where drag is more important than TWR.

So I went to test this theory.

It has, alas, so far has mostly ended in glorious explosions... and tons of lag... because you have to put the aerospikes above the fuel tanks on scaffolds of cubic struts because of the lower drag making the thing want to flip.

Kinda pretty, in a computer killing sort of way.

just before it explodes...

Edited June 20, 2013 by Pbhead

[bgraves]

THinking about this a bit I thought that weight really isnt the issue here, drag is. Perhaps aerospike engines, with their lower drag coefficient, despite their lower TWR might work better, especially better than solid fuel rockets with their 0.3 drag coefficient.

I mean, clearly you want high twr initially to get to high speeds, and you want it once you clear the atmosphere, but i think there is a small section in there where drag is more important than TWR.

So I went to test this theory.

It has, alas, so far has mostly ended in glorious explosions... and tons of lag... because you have to put the aerospikes above the fuel tanks on scaffolds of cubic struts because of the lower drag making the thing want to flip.

That is the most terrifying rocket I've ever seen.

[Pbhead]

I think it kinda looks like Atlantis.

[metaphor]

I didn't see a rule saying the part that goes highest has to be a probe core or cockpit. So I tried to use an RCS thruster (drag coefficient 0.001) as my spacecraft and give it a large initial impulse on the launchpad. It works in that the RCS thruster almost doesn't feel the atmosphere's drag at all. The problem is the initial speed.

I tried something like this first:

but it was too slow, only about 1 km/s initial speed.

Then I tried using decouplers:

This is a lot more promising. You can get about 1 km/s initial speed with only 6 decouplers, 2 km/s with 12 decouplers, etc. The problem is getting rid of the probe core. If the probe is decoupled at the same time as the main decouplers, the whole thing fizzes out. If it's decoupled right after, the decoupler somehow gets stuck to the RCS craft and raises its drag so that it doesn't work well. I've tried a bunch of different configurations, but that decoupler just doesn't want to come off. If anyone wants to use this design and solve this problem, go ahead.

[zarakon]

The other problem with trying to use something that isn't connected to the capsule or probe core is that when you detach it, the MET for that object restarts at 0. So you can't detach the probe core any time after the initial launch without invalidating your time.

I think the reason you can't launch just the RCS blocks at high speed using the stack separators is that they are actually massless just like the cubic struts. I think massless structures are handled as a special case when detached from decouplers or separators, to prevent them from going infinitely fast.

[dimovski]

The other problem with trying to use something that isn't connected to the capsule or probe core is that when you detach it, the MET for that object restarts at 0. So you can't detach the probe core any time after the initial launch without invalidating your time.

You take something else as your 1st part...one of those structural elements, later you place the decoupler and the core below it, this way your time stays all right.

[Ninety-Three]

Inspired by metaphor's craft, I built a ship that uses decouplers for propulsion. I designed a build method that allows for a 1.5 ratio of decouplers to octo-struts. Unfortunately, it -still- doesn't work well. I can use 200 decouplers (about as much as my computer can handle, the load times get very bad) to launch a probe core straight up, but in ten seconds it's slowed to just a few hundred m/s, and it's only 10 km up. Unfortunately, drag reduction doesn't seem to work under current KSP physics. Using a low-drag manned cockpit leaves you with way too much mass, and you can't attach anything to the probe core to reduce drag because the astounding impulse of launch tears off anything with mass (fun fact, struts and the tiny 0.001 mass blocks don't actually have mass, despite what the game says) (and no, it doesn't tear it off at mach ten, the part reaches some reasonably high speed, tears off, and leaves the rest of the ship to continue accelerating).

In conclusion: There's no way to reduce your drag, so the magic atmosphere will prevent this method from being effective here. If there's ever a 10 second altitude challenge though, we know how to do it.

[zarakon]

I designed a build method that allows for a 1.5 ratio of decouplers to octo-struts.

How did you manage that?

I'm actually able to get the low-drag cockpit up to 30km in 30 seconds. It's not quite good enough for 1st place though, and it's right on the edge of working/crashing. It takes like 10 minutes to load, then might crash at loading, might crash at launch, and might actually work. If I add anything, it just crashes 100% of the time. If I could improve my separator to struts ratio, I might be able to get more oomph with less crashing.

[Mrbowdn]

Here is my entry

Edited June 20, 2013 by Mrbowdn

[Ninety-Three]

I'm actually able to get the low-drag cockpit up to 30km in 30 seconds..

To borrow a phrase, how did you manage that? 200 decouplers isn't getting me to 10 km in 10 s, and that's putting up minute load times. Awesome computer, or are you just cranking the decouplers up to 11 (hundred) and KSP sometimes allows it?

[zarakon]

Around 1500 total parts, 1/3 of which are the big stack separators, 2/3 are cubic struts

[Ninety-Three]

What are your hardware specs? If mine are similar, knowing that ten minute load times can actually lead to a launch rather than a hang, I'd like to crank mine up to say, 550 decouplers and give it a try. If not (or once I do), I'll happily share the technique (which I think might be further improvable from 3 struts - 2 decouplers to 5 struts - 4 decouplers).

[zarakon]

core i5 2500k (4ghz)

8gb ram

nvidia gtx570

win7 64-bit

SSD drive

[Ninety-Three]

Well hot damn. I loaded up 512 decouplers and it did indeed make 30 in 30 (I also got the design down to 5 struts per 4 decouplers). I'm going to see how much farther I can push it in the hopes of taking a high score.

[zarakon]

I'm not able to test right now..

What happens if you put the lightest probe core on those 512 separators instead?

I'm guessing it won't break 20km altitude, but I'm curious what the initial velocity is. 50 km/s?

[Ninety-Three]

I was getting 43-44 km/s off 200-ish decouplers, so I bet it's even more impressive. I just did a successful manned launch of 576 decouplers to 33966 m, and I'm not crashing yet, so I will continue to turn up the part count. I also need to run a 512 decoupler drone just to see if the magic atmosphere stops applying at sufficiently high velocities, though I'm doubtful.

Edited June 20, 2013 by Ninety-Three

[Mars90000000]

Here is my entry

May I see the ship at lauch (or takeoff)?

It's peculiar that not many have crossed the 30km mark and you come out of the blue with a 48km height!

Besides that, I think you made a new record!

[Ninety-Three]

It's peculiar that not many have crossed the 30km mark and you come out of the blue with a 48km height!

Based on the screenshot, it looks like an infiniglider, which I believe you're disqualifying (based on the earlier infiniglider that hit something like 80k).

Status update on the Decoupler rocket: Just launched 704 decouplers, 40km in 30s. It took half an hour to load. I'm uploading a photo now just to earn those "first to X height" achievements, and continuing to perform larger launches. I've been seeing a pleasingly linear trend of 512 = 30km, +64 parts = +3.3 km, It's looking like I might hit 50!

[Mars90000000]

It appears that we have new leader! Congratulation Ninety-Three!

[Ninety-Three]

And here's my high score for now. I may make an even bigger launch tomorrow, but the loading times on this thing get absolutely insane and I'd like to have my computer for the rest of the night.

768 decouplers, nearly an hour of load time.

Thanks go to metaphor, for the idea to make a single-stage decoupler craft, and to zarakon, for teaching me that several-minute loading times mean you can still double your part count.

Note to Mars: Feel free to not list both this and my 40 km entry in the high scores, as they're the exact same principle, just with more parts alt-clicked onto the side of one.

Edited June 21, 2013 by Ninety-Three

[Mars90000000]

And here's my high score for now. I may make an even bigger launch tomorrow, but the loading times on this thing get absolutely insane and I'd like to have my computer for the rest of the night.

768 decouplers, nearly an hour of load time.

Thanks go to metaphor, for the idea to make a single-stage decoupler craft, and to zarakon, for teaching me that several-minute loading times mean you can still double your part count.

Note to Mars: Feel free to not list both this and my 40 km entry in the high scores, as they're the exact same principle, just with more parts alt-clicked onto the side of one.

Exact same principles is fine, exact same ship launch twice, maybe not.

Besides, Asparagus staging, for example, was used by many. I'm not going to start eliminating everyone because someone else used it first

As long as theres no mod or cheat or bug exploitation (like infinite glide), it's all good.

[Alienor]

I don't get how that things work,are you using the fact that the decoupler have a little force/power when seperating two parts?So that 700 and more decouplers have a huge force?

If it's the case,that's insane,and brilliant at the same time