Short Burn Challenge

[ihtoit]

This just in: I have brain flashes, and this might be the best yet.

WITHOUT using physics cheats like infinite fuel or vastly OP'd engines, what's the highest altitude you can attain with just ONE SECOND of burn?

THE RULES:

- Your vessel must carry one Kerbal in a capsule.

- Kerbal must survive launch, burn, ballistic arc (if any) and landing (if any).

- Your vessel must use LFO rockets as the primary and only method of propulsion.

- Any structural parts valid except bits that jetisson.

- Any LFO rocket is good. Please indicate clearly what you're using.

- Nothing may break or fall off, burn or explode.

- No launch clamping.

- No exploitable airfoils, this includes procedural fairings and infiniglide flaps.

- No SRBs, seperatrons, RCS, ullage or any other thrust, jet or other dV source including force decouplers.

- Your rocket must burn for no more than ONE second. In terms of SD video capture, that's 25 frames. 30 if you're capturing in NTSC.

- Kerbin escape velocity counts as "infinite". Can you do "infinite" on just one second of burn?

SCORING:

Maximum altitude attained AKA Kerbin apoapse.

(Cue the decoupler exploits. No. LFO engines only).

(Note: all the information is there, for those of you who can do math, to calculate just how much fuel is needed for each engine to burn for exactly one second and to top the tanks accordingly. This would be advisable to do).

Leaderboards:

1. Challenger: 2193m (KWRocketry Griffon Century and 360u LF/440u O)

Challenger's Entry: Mammoth and an FL-T200 tank for 4/5sec fuel load, to 1190m and a safe two-chute landing (the capsule is the Firespitter fighter jet cockpit):

There is a more powerful engine (the KWRocketry Griffon Century) but it's a beast to land without it exploding - I think the nozzles are made from explodium.

EDIT: got the Griffon to not explode:

For 2193m, on five chutes:

Edited August 1, 2015 by ihtoit

[HoloYolo]

Going to try this now....

EDIT: Do we need a video for a valid entry?

Edited July 30, 2015 by HoloYolo

[ihtoit]

video would be nice, not essential though.

[Nich]

Sorry but maybe I don't see the point wont everyone enter a Mainsail with a full t200, a little less then half full oscar-b lander can and parachute?

Edited July 31, 2015 by Nich

[Nefrums]

Mammoth have higher twr than mainsail.

The is actually a lite more to it than that. Even a one second burn will get you to ~200m/s at those speeds aerodynamic forces are more important than gravity.

But you are right in that it is basically to take the engine with highest surface twr and add just enough fuel for a one second burn. And then try to make it more aerodynamic.

I could get a mammoth, lander can and fuel to about 1700m,

This one made 1958m:

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[More Boosters]

I believe Spark has the best TWR?

Edit: Confused the two, Twitch is useless lol.

Edit 2 : Would it be okay to leave the pod behind, enter a command seat and launch with a Spark?

Edited July 31, 2015 by More Boosters

[ihtoit]

nice try nefrums, but you missed the rule about nothing breaking off or exploding. But you do have the right idea.

@everyone: think the Thrust KSC Land Speed Record challenge but vertical.

@More_Boosters: #2: nope. that would violate the same rule (the bits breaking off bit) and the one about the Kerbal being in a capsule requirement.

[Leibniz]

1939m stock. I removed a tiny bit of fuel in the craft file to get exactly 1s burn, although I could get the same effect by burning it off.

The design is pretty similar to Nefrums with an extra parachute for landing. It is helpful that the Mammoth also has 20m/s impact tolerance.

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Craft File

PS The fuel formula is LF = (90 * Thrust) / (g * ISP). I think g=9.82 in KSP. You can use vacuum thrust and ISP, or sea level thrust and ISP, but not a mixture. Replace 90 with 110 for oxidiser.

[GoSlash27]

http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/onesec

I got 1,757m.

Best,

-Slashy

[smjjames]

Is it okay if the engine has it's own internal fuel tank? I mean, the 'twin boar' does. Also, theres an even more powerful engine than the one the OP used.

Have to figure out how many chutes I need to keep it from exploding on landing though as the whole thing is HEAVY, 57.5t

Edit: Oh, a tip, KER measures the burn in tenths of a second while MJ doesn't, so that would help to make it more accurate.

WITHOUT using physics cheats like infinite fuel or vastly OP'd engines, what's the highest altitude you can attain with just ONE SECOND of burn?

Hm, how powerful would you consider vastly OP? The Super-Ratite I just used is a POWERFUL engine, but that's because it's designed to be a heavy lift engine.

The engine is from SpaceY heavy lifters, the pod is from USI Exploration pack.

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Edit: I broke 3km with another engine (also from SpaceY heavy lifters), so you're going to have to define what is OP here because an engine that is both powerful and efficient is going to be at the top.

Edited August 1, 2015 by smjjames

[ihtoit]

the Luvodicus Super Atomic used to be considered OP, until the plasma jets came in - the only difference between the two being that once you had the prerequisites for the plasma to actually run (a nuclear reactor) it had about the same unloaded TWR and better efficiency. And that's a stock motor.

OP here would be the obviously-OP like taking a 1.25m engine (like one of the KWRocketry topstages) and ramping the thrust to 12MN (Griffon in a box?).

Oh, almost needed an edit for this: it's great if the engine has its own LFO tank. Not that I've seen one, are they any better in terms of payload fraction than a separate tank? Or is it just a part count thing?

This bit I did need an edit box for: fuel load for this challenge is simply the amount needed for one second of burn at sea level. The RMB info box tells you this. I generally go shy of this number as by the time it burns out I'm already at 600-700m and at that altitude you're already burning less fuel.

Edited August 1, 2015 by ihtoit

[smjjames]

the Luvodicus Super Atomic used to be considered OP, until the plasma jets came in - the only difference between the two being that once you had the prerequisites for the plasma to actually run (a nuclear reactor) it had about the same unloaded TWR and better efficiency. And that's a stock motor.

OP here would be the obviously-OP like taking a 1.25m engine (like one of the KWRocketry topstages) and ramping the thrust to 12MN (Griffon in a box?).

Okay, so, the Super Ratite, a 5m engine which masses in at 45tons with a max ASL thrust of 13,778.95, max Vac thrust of 15400, ISPs of 255 (ASL) and 285 (vac) isn't overpowered?

Also the related 'Multi Ratite', a 5m engine which masses at 25t with a max ASL thrust of 10051.72, max Vac thrust of 265 (ASL) and 290 (Vac)?

They are both designed and intended to be heavy lifter engines though. The 'Super Ratite is the one with it's own fuel tank, the other one doesn't.

Oh, almost needed an edit for this: it's great if the engine has its own LFO tank. Not that I've seen one, are they any better in terms of payload fraction than a separate tank? Or is it just a part count thing?

It depends on the engine really.

This bit I did need an edit box for: fuel load for this challenge is simply the amount needed for one second of burn at sea level. The RMB info box tells you this. I generally go shy of this number as by the time it burns out I'm already at 600-700m and at that altitude you're already burning less fuel.

Do you mean the RMB info box from KER? Stock doesn't have that display.

[ihtoit]

yeah, OP in the case would be 12MN in an engine that weighs like 1 or 2 tons. 25-45 tons for a heavy lifter would be kind of expected - those bells aren't weightless. Here you're playing with deadweight TWR, 1 second's worth of fuel (I've seen engines that need over 300u LF/sec), and by the time you've got your supersouped engine up and ready to burn you're looking at no better pad TWR than a KWRocketry Wildcat... so yeah, this isn't just a case of slapping a FL-T800 on the top of a Griffon and hoping the thing doesn't explode on firing (though it has been known to happen; my Griffon firing would have killed a video producer for the number of takes before I actually made a repeatable landing), the rules are such that you have to actually think about survivability of every component.

I'm actually pretty sure I could get a better apoapse with a Wildcat than with the Griffon, I'll post later (it's Dark O'Clock right now and I'm tired) and let y'all know how I get on.

(oh, I didn't know about stock not having the right button info box on each component, I thought it did, going by this:

).

Edited August 2, 2015 by ihtoit

[smjjames]

Oh, I thought you were referring to right clicking in the editor window itself.

Anyways, most of the reason why the multi ratite got higher altitude was because its 20 tons lighter, the slightly better ISP certainly helped. Not to mention that the super ratite was hauling lots of dead weight as the tank was 90% empty.

Edited August 2, 2015 by smjjames

[ihtoit]

yeah just ran the numbers (it's really easy, that'll be (ASL thrust/(mass*9.81)) and the Super Ratite is actually worse in terms of deadweight TWR than the KR-2L (which was pure random pick on my part - because it was the first infobox that came up on a google search), by all of 10%. So before you even start with fuel load and capsule, the KR-2L is the better engine for the task.

(there's a table on the wiki showing dry TWR of stock engines. YMMV by the time you've got your fuel tank etc sorted. According to that the Mammoth is the engine to have if you're running stock, with a TWR of over 25).

[Kermen]

By launching from Gilly, I was able to achieve escape velocity with 1s burn. Does this count?

[ihtoit]

no because the scoring is Kerbin apoapse, you're not even in the right postal district.