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The Rocket Javelin Challenge!


SamNxGn
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I've just launched another flight, this was stabilised at 4872m, over triple the height of the previous one. It'd be nice if it meant triple the distance and a broken 300km barrier but It's descending and moving forwards more quickly in the thinner atmosphere so I don't know what'll happen - although at least I should be able to report the results in less than seven and a half hours. This was with a flat launch but I managed to detatch quickly after firing the booster this time.

@NetBlitzer: If you accidentally delete a part then undo is ctrl+z. It only has a history of one action though so it doesn't always work, but if you haven't made other changes then reloading the rocket you have open will revert it to it's last saved state.

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1:26 MET and it's at 2100m. Looking like 4-5 hours total flight time.

Edit: It's hit 1600m at 1:53 doing 15.4m/s

Looks like around 4 and a quarter hours flight time.

EDIT2:

peC1e.jpg

EDIT3: Flight ends after four hours and ten minutes having covered a nice round distance of 250 Kilometres (and 696 metres) and having reached a maximum altitude of 7,974m.

[ATTACH=CONFIG]31838[/ATTACH]

More pics: http://imgur.com/a/7SCXL

And the craft file as promised:

[ATTACH]31839[/ATTACH]

Now I'm off to launch this thing at different angles and see if I can get any better glides out of it.

Edited by EndlessWaves
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Darn, looks like I got pushed out of the lead again! And Endless, I knew about the undo option, but I didn't realize I had messed up until several modifications later, so that craft is completely lost. :(

Edit: By the way OT, is it possible that we can use a sled to propel our gliders? Like, have the SRB propel a sled along the runway, and then launch the gliders from there? Many of my designs seem to not work thanks to the fact that the SRB propels them too fast and they suddenly lose control seconds before the SRB dies.

Edited by NetBlitzer
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It looks fine Munrockets. And anyways, I don't think it would matter since it's not contesting with the 100+km marks :P

Just keep messing with the wing layouts! Adding more wing in the front lets it pull up (or use tilted wings) and more in the back pulls it down. Mess with the balance and you'll get far!

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It's a great day! Get off work early, and I have some new ideas to try.

In the same spirit of creative thinking that brought you bounce-launching, I had a thought. The booster is a liability once it's burned out, heavy and draggy. And, there's nothing in the rules which says we <i>can't</i> stage the rockets! Now, you're thinking, but Treb, we can't stage an uncontrolled rocket! Gentlemen, that's where the creativity comes in. Design the rocket so you stage it <i>before</i> you release the booster, but it's held together by parts. That way it will boost up, and the draggy booster, once it isn't thrusting you, will fall away.

Which is all simpler in theory than in practice, but I've managed to semi-reliably do it, now.

EndlessWaves's rocket has an amazing lift/drag ratio, but my "Angel" superglider shames it. It has a vertical component of approximately .03 m/s, meaning it takes somewhat more than 30s of gliding to lose a single meter of height. This means the current flight is going to break 200 km despite being prematurely released really, really low.

EDIT: The relationship between lift, drag, and speed for this thing means that it definitely could reach 1000 km if I could only get the bastard up to the proper height. Also, no italics? Nuts.

EDIT: The sheer time-wasting aspect of an unmanned glider makes it difficult for someone to participate in your other challenge and this one at the same time.

EDIT: I almost wonder if you could, if the stars were right, invoke an Inverse Space Kraken and design something so low drag that the physics engine would round it to zero.

EDIT: 3 hours. 17 minutes. I have dropped 380m or so since I started.

Edited by Trebuchet-Launch
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Haha, that sounds amusing. In attempting this particular challenge, I managed to get an overly complex "javelin" to fly steady and stable. It'd launch, spin out of control, and then right itself and glide seemingly indefinitely. Perfectly stable. For some reason, it just stopped and literally fell out of the sky after about an hour of flight, losing 1m of height every minute or so. It was up around 10km high too :(

Tweaking it just caused me to lose the design that really worked xD

I almost beat everyone here by a large margin. Given about ten hours of flight. If it hadn't unexpectedly just dropped out of the sky all of a sudden.

Ah well. Back to HQ for another shot :D

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I launched during the day. I flew all through the Kerbal night. And now, at dawn, the lil' bastard is still flying.

EDIT: It has lost a grand total of 0.4 m/s of forward speed. The Angel has ludicrously low drag.

EDIT: 6.5 hours. STILL FLYING.

EDIT: 7 hours. It's still up.

EDIT: Kerbol is setting on this thing for the second time.

EDIT: The Angel has bizzare properties in the water. I don't think the game knows what to make of it. It randomly speeds up in the water.

EDIT: I'm ending flight, as this bizzare Motorboat Angel bug isn't really 'gliding'.

Edited by Trebuchet-Launch
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Flight ended. Statistics:

Highest Altitude Achieved: 812m

Ground Distance Covered: 207,628

There were many, many things that could have gone better here: a higher release, and one that didn't tumble the glider (killing almost all its speed, and meaning it crawled forward at slow speed) would have crushed all previous records. Still, this puts me in the 200km+ club. And the 7 hour and 14 minute flight itself is remarkable.

I think I need one of those Imgur accounts for screenshots. Blurry shots won't cut it.

EDIT: After seven hours, I forget how I got the stupid thing to reliably detach at any reasonable height at all.

EDIT: It is, indeed, possible to build a glider which, by all appearances, has zero drag and never descends. At the moment this modified version of the Angel is drifting at an insanely slow speed (because of extremely poor separation at low altitude causing it to flutter and kill almost all its speed) but has not come down a single meter in over an hour.

EDIT: I discovered a reliable way to get the Angel just above 1km in height, but that's not enough for 1000km.

Edited by Trebuchet-Launch
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EDIT: It is, indeed, possible to build a glider which, by all appearances, has zero drag and never descends. At the moment this modified version of the Angel is drifting at an insanely slow speed (because of extremely poor separation at low altitude causing it to flutter and kill almost all its speed) but has not come down a single meter in over an hour.

Yes...that would indeed be why the questionable physics on control surfaces/canards are known as the "Infinite Glide Glitch". It might be prudent for there be a categorical separation between designs with any control surfaces, and designs without.

Edited by Clouds
typo
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That glitch requires a capsule and/or SAS and comes from the interplay of forces. Here, the control surfaces are inert. I am pretty sure the bug doesn't work under those circumstances; certainly all the gliders I've been firing seem to work normally, except one very specific version of the Angel. I'm fairly certain that the apparently infinitely gliding version of the Angel is glitched because the physics engine is rounding something to zero - it only works at extremely low speeds (like... 3 m/s and below).

EDIT: I've taken to turning the booster backwards and using it as a cannon to fire the Angel (the normal version) into the air. Much simpler, and kinda fun.

EDIT: Testing the Infinite Glide Glitch at the launch pad. It does work without a capsule or SAS, but results in a comically hovering object. I now have space junk hovering over my launch pad.

EDIT: You also need a *lot* of canards without SAS. It didn't work until I put way more control surfaces on the thing than any sane person would.

EDIT: Unmanned Infinite Glide glitching seems to have some pretty stable properties: they never really lose altitude, period, and they fly at their extremely slow speed. I'm guessing it really is some sort of zero in the system. My normal Angel doesn't act like that; it slows down and loses altitude.

EDIT: Oh, man, you CAN create some sort of Inverse Space Kraken! I put 48 canards on a single decoupler and blasted it with the big booster, and the whole screen is shaking. The behavior is BIZZARE.

EDIT: 96 canards creates an unholy monster that shakes crazily and accelerates skywards. Hmm.

EDIT: It's definitely some sort of Kraken-like floating point glitch. The 96 canard version just shook itself into structural damage and is shedding canards like a dandelion.

EDIT: It looks like a giant version of those stupid spinner hubcaps. The inner ring of canards looks like it's somehow spinning faster.

EDIT: Has anyone else fired off unmanned magic turbines of this size before? This is some crazy stuff.

EDIT: I suspect the unmanned versions of these are ultimately unstable. The twitching mass of canards I have is slowly tilting over, anyways.

EDIT: Yup, it's losing altitude. So, unmanned, those who live by magic turbines die by magic turbines.

EDIT: Many people are going to beat the magic turbine. It's drifted into a dive.

Edited by Trebuchet-Launch
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Hmm. I wonder how far one can get using a Magic Turbine with this. of course, it'd have to be balanced, so that it actually flies relatively straight, or else it'll get nowhere. I'll give it a look a bit later...

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EDIT: You also need a *lot* of canards without SAS. It didn't work until I put way more control surfaces on the thing than any sane person would.

Well, I don't have the patience you do so I don't have proof of the long-term behavior, but I got a decoupler (never would've thought to try launching JUST a decoupler - it's fun!) to glide on a slow and level flight with 4 canards and no control input (see the next part).

RCn0L.jpg

The heart of the Magic Turbine is that there's an accelerating force, not just levitation, from control surfaces that are not centered, but applying rotation. Also, handily, control surfaces stay at their last commanded position when decoupled...

8O5A5.jpg
Hmm. I wonder how far one can get using a Magic Turbine with this. of course, it'd have to be balanced, so that it actually flies relatively straight, or else it'll get nowhere. I'll give it a look a bit later...

I gave it a shot and had 800+km ground distance and no sign that it would ever cease bouncing into and out of the atmosphere. Then, I ran out of battery power unexpectedly and lost the flight. ;.;

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