Competition: The Great Velocity Race!

[/scI/owan]

For the last week, the members of my Physics III class have been competing in KSP to reach higher and higher goals of distance, velocity, and force. It's been a lot of fun and we wanted to open up our little competition to the rest of the community. So strap on your SRBs and hold on tight - The Great Velocity Race has begun!

Objective:

The objective of The Great Velocity Race is simple - build the fastest rocket you can! The current record holder is displayed below and will be updated every day/couple of days and as higher velocities are reached the first person to break a velocity milestone will be listed as well. These milestones will be determined as the competition progresses.

Rules:

1 - Basic components only! No mods, addons, or altering of the part files. The point of the competition is to test your rocket-making skills, not your ability to download mods.

2 - You must provide a screencap of either your ship at apogee or the end mission screen. (posting both is preferred)

3 - Be Honest! This is just a friendly competition, there's nothing to prove and no reason to cheat! If shenanigans are suspected you may be asked to post your rocket file for confirmation.

CURRENT RECORD

Highest Velocity - 10418.9 m/s - Minthos

MILESTONES

(to be added)

[DeCi]

Sounds fun. TO THE BATCAVE! There's science to be done!

[Finrandojin]

What are the rules concerning the trajectory? is it straight up or are parabolic trajectories allowed?

[illectro]

indeed if speed is all that matters then you want to boost upwards into an eliptical orbit and then wait until you're falling back towards the kearth to use up the rest of your fuel - ideally you burn up all your fuel and grab a photo as you sling by perikee. Going straight up will mean you're recording your final speed at altitude, so you'll be missing out on some potential energy.

[feanor]

it could also be very nice to post the .craft files or atleast link to them to further avoid cheating - to make sure that, even if you dont throttle perfectly, you can at least see that the design comes close to advertised; an attempt to further validate the records.

[Xinvoker]

Here is my best: (OUTDATED, look below)

how it looks on the launchpad:

EDIT: Same rocket, by going horizontally, I managed to do 8164m/s

[laurog]

there is a natural cheat which i'm not sure if it's possible to prove.

the rocket gets very fast - when it's falling back to earth...

like i said, i'm very familiar with this game to say if there's a way to prove if that speed was achieve by the engines or by gravity.

[cjameshuff]

indeed if speed is all that matters then you want to boost upwards into an eliptical orbit and then wait until you're falling back towards the kearth to use up the rest of your fuel - ideally you burn up all your fuel and grab a photo as you sling by perikee. Going straight up will mean you're recording your final speed at altitude, so you'll be missing out on some potential energy.

That, and doing the final burn close in gives you an additional boost due to the Oberth effect. Your engines and tanks will give you the same delta-v no matter where you are, but if you make that delta-v during a high-speed flyby of a planet, the change in your orbital energy can be much higher. Burns to increase or decrease velocity are most effective when potential energy is lowest and kinetic energy is highest.

(The difference between 0.5*v^2 and 0.5*(v + dv)^2 is bigger if v is bigger. Someone I know once remarked that this felt like cheating...it doesn't violate conservation of energy as it might first appear, because rockets move by throwing reaction mass in the opposite direction, and the energy you gain by taking advantage of the Oberth effect is lost from the exhaust.)

This is tricky and hard to repeat, though. I'd suggest two competitions: a straightforward max-velocity one like this, and one to reach the highest hyperbolic excess velocity at burnout on a straight-up trajectory...I've been using the latter as something of a benchmark for my rockets, while the former depends heavily on piloting skills.

[cjameshuff]

there is a natural cheat which i'm not sure if it's possible to prove.

the rocket gets very fast - when it's falling back to earth...

like i said, i'm very familiar with this game to say if there's a way to prove if that speed was achieve by the engines or by gravity.

That's not really a cheat, gravity can only give back what it took away on the way up.

[dreadmullet]

I came close...

Burning perpendicular along the ground instead of straight up gave me an extra 700 m/s. I don't know what I would have gained if I had burned at the next periapsis.

Heres what it looks like at launch: link

I think I need about eleventy more engines.

[Iskierka]

The maximum speed you could reach falling back would only be around 3.3 km/s. As this would be escape velocity.

For any craft to fall faster than this, it would have to go up to a high orbit, then thrust back down intentionally - which I can only think would be highly inefficient. I can't imagine that getting faster than a trajectory leading away.

I have a design which should be a competitor, but I want to make some changes before I go get proof. Current version reached 7920 m/s.

Edit: will get a speed tomorrow, did some other testing and now it's getting late where I am.

[/scI/owan]

For the time being, the goal is 'highest velocity on a straight(ish) trajectory'. No hyperbolic trajectories/slinghosts/etc for now (maybe we'll have a 'best/craziest maneuver' competition later )

[Xyrion]

I've managed to achieve a top speed of 8211.7 m/s at 1550 km.

Here is the proof.

The 'Orbit VI ee n mk8000x' at it's startposition

But i still need more speed, to reach my goal of 9000 m/s only with original parts.

And for that i think, in need to improve the design.

Or even come up with a new one.

[cjameshuff]

For the time being, the goal is 'highest velocity on a straight(ish) trajectory'. No hyperbolic trajectories/slinghosts/etc for now (maybe we'll have a 'best/craziest maneuver' competition later )

Practically speaking, given that the velocities already reached are several times escape, that is a hyperbolic trajectory.

I suggested hyperbolic excess velocity because of this, and because straight velocity isn't particularly meaningful alone. Hyperbolic excess velocity remains the same from burnout on, it's the velocity you'd reach infinite distance with, and so it makes a straightforward comparison between rockets that's not affected by how deep in the gravity well burnout occurs, and won't be biased against low-thrust, high-propellant-efficiency upper stages.

[dreadmullet]

I managed to beat the original velocity: http://i.imgur.com/e8hVN.jpg The best way to go seems to be to follow a standard orbit insertion, but just keep the engines going. I just need one more tank of fuel. But that means I'll go slower... :S rocket science is hard.

I don't think there should be any trajectory limits. Trying to go straight up doesn't make sense, because if you're 5 degrees off thats an advantage. I think this should be based on piloting skills, as well as ship design.

[Iskierka]

8487.8 m/s.

As near dead-vertical as I could've gone without the booster stage wanting to go a long way left. Straightened up and went a little way right for fairness.

On the pad, and wanting to fall over the whole time:

Assuming they're light enough, I can't wait for trusses.

Actually, since it's my first stage, I might use them regardless. Stability might make up for the increased mass.

[illectro]

So, for the speed nuts out there, I made a video explaining that travelling straight up won't always produce the highest speeds or altitudes.

[cjameshuff]

So, for the speed nuts out there, I made a video explaining that travelling straight up won't always produce the highest speeds or altitudes.

It's not optimal, it's just easily repeatable, and thus of some use for benchmarking the rocket.

[dreadmullet]

8487.5 m/s. http://i.imgur.com/Qgey6.jpg

The ship: http://i.imgur.com/Vcji3.jpg

Can we call this a tie?

[Iskierka]

Damn, wow. I have to say I am amazed at how close that is.

A nicely insane rocket too. I'd say it's a tie, for now; they both round to 8488. Will be interesting to see if anyone can beat our records.

[cjameshuff]

Damn, wow. I have to say I am amazed at how close that is.

A nicely insane rocket too. I'd say it's a tie, for now; they both round to 8488. Will be interesting to see if anyone can beat our records.

8485.7 m/s at 1248 km gives an excess velocity of 8146 m/s.

8485.1 m/s at 1666 km gives an excess velocity of 8234 m/s.

Their velocities at the times those shots were taken were similar, but the former would lose a bit before it reached the altitude of the latter.

And both of you beat escape velocity so soundly it let you keep over 8 km/s of velocity at infinite distance.

[/scI/owan]

Wow! Really impressed everyone! Keep up the amazing work!

[Jarvitä]

I don't think there should be any trajectory limits. Trying to go straight up doesn't make sense, because if you're 5 degrees off thats an advantage. I think this should be based on piloting skills, as well as ship design.

Agreed. 'Straight up' is hard to define and impossible to achieve due to the ship's handling, anyway, and it's an inefficient choice of trajectory if your goal is max. velocity relative to the surface.

[/scI/owan]

As stated a few times in the thread already - a straighter trajectory is a good control for the competition - it's easy to repeat and puts the focus on rocket building rather than piloting. And in the even that someone's results are suspect - it's easier to prove or disprove the accusations with a straight shot than it is trying to hit a 'sweet spot' trajectory.

[cjameshuff]

As stated a few times in the thread already - a straighter trajectory is a good control for the competition - it's easy to repeat and puts the focus on rocket building rather than piloting. And in the even that someone's results are suspect - it's easier to prove or disprove the accusations with a straight shot than it is trying to hit a 'sweet spot' trajectory.

And as a baseline that repeatably demonstrates the rocket's basic capabilities, it also shows what the piloting on fancier flights actually accomplishes.