Three Ton Speed Run

[Ultimate Steve]

Welcome to the Three Ton Speed Run! It's exactly like the Twenty Ton Speed Run, but with a lower mass limit, because the 20t escalated quickly, exceeding 30 kilometers per second, I feel like a limit of 3 tons would make the challenge more accessible. Both challenges will continue to run, however.

Your goal is to take a craft that masses no more than 3 tons (including EVA Kerbals and not including any launch clamps) and reach the highest velocity possible, relative to Kerbin.

 

Fairly simple, so I think I can get away with not submitting something as it's fairly obvious that this challenge is possible.

 

Rules:

• 3 ton limit includes EVA Kerbals and not launch clamps. Don't abuse the launch clamps.
• Velocity is measured using the "orbital" setting on the navball.
• You may not leave Kerbin's SOI for the challenge. You may be on an escape trajectory at the end, but you can't measure your velocity outside Kerbin's SOI or leave before measurement.
• Accidental Mun/Minmus encounters are alright, but try to avoid them.
• Stock and Making History only, although non physics changing mods may be installed, and other parts mods may be installed but not used. Mods which allow faster physics warp are okay.
• In general try to not exploit stuff. No debug menu, .sfs editing, HyperEdit, Kraken drives, etc.
• Proof required is a screenshot at or near your highest velocity. Other screenshots showing your vehicle and how it works are required, unless you have a video.
• There will be separate leaderboards for manned and unmanned entries.

Leaderboards:

Manned:

 

Unmanned:

 

Have fun!

[FleshJeb]

Good challenge. For folks who don't know, EVA Kerbals are 0.9375 tons, and their RCS propellant is massless.

[dnbattley]

Getting my marker in to this challenge quickly, since I am absolutely sure it will be comprehensively beaten: manned @ 3,678 3,860 3,880 m/s, after EVA.

Spoiler

EDIT - updated with latest run, in which I tweaked the fuel loads slightly

2.991T - whiplash lower stage, with spark upper stage and command seat

Better view of interior

 

Edited March 2, 2019 by dnbattley

[Xurkitree]

I did some thinking on this and its better to go into an hyperbolic trajectory against Kwrbin rotation to get more orbital speed.

[dnbattley]

16 hours ago, Xurkitree said:

I did some thinking on this and its better to go into an hyperbolic trajectory against Kwrbin rotation to get more orbital speed.

This would be true for surface speed, but the orbital speed going counter-clockwise and clockwise is identical: it just needs more delta-v to get there against the rotation.

[dnbattley]

Surpassed my previous with a slightly different design, this time managing to get an ion craft into orbit, and ultimately posting a new manned speed of 4,186 4,390 m/s, which, unless I make major changes is probably about as far as I can push this design, although I note that the flight path (particularly in the first few seconds) is such a critical determinant for final speed that 100 additional tries may yield a better result.

Spoiler

Forgive the lack of naming while I played around with this. In fact I now realise I forgot to remove the launch clamp weight so will be able to improve on this further (but not tonight), but 2.998T as shown. Let's assume this will be named the "3T Flyer Mk II"

Now properly named, the "3T Flyer Mk II Rev A"

Energy was at a premium, meaning short burns as far as possible, but here after all Xenon depleted we surpassed 4k 4.1k, then got out...

And thus 4,186 4,390 m/s recorded.

 

Edited March 5, 2019 by dnbattley
Improved times, again.

[joshudson]

I see your 4390 and raise you 619 for a new speed of 5009 m/s. https://imgur.com/a/i2oAw3W

[Magzimum]

Without using Valentina's jetpack, I got her to go 2829.2 m/s, on a chemical rocket.

 

Spoiler

So, it's a 3-stage rocket. Bottom stage is only fuel, no engines, and the bottom is not 100% full to stay within the mass limits.

Launch is uneventful, although it looks a little dinky.

Climbed out of the atmosphere with the fairing still on.

Then went for LKO on 3 tiny engines.

Then increased Apoapsis, lowered periapsis to 60 km, for even more speed.

And took the photo above for the top speed.

I wish I could say that this can be optimized further, but getting a Kerbal into orbit with a limit of 3 tons is actually already quite the challenge for me. I really enjoyed it!

[astrobond]

Hi all  a little more than 3700m/s in escape orbit with this rocket on the first try but could be better with a good last PE burn and better flight plan... xD :

 

 

Fly safe with Valentina

 

Edited March 10, 2019 by astrobond

[astrobond]

Same rocket, my best try 4935m/s (without jetpack)... not enough to have the high score lol grrrr

 

Fly safe with Valentina

[astrobond]

I was so close... so i replaced the 700 xenon tank by 2 x 400, new fairing to keep the weight ok with valentina onboard to be under 3T, and.... 5189m/s xD

 

 

The "new" rocket:

 

Fly safe with Valentina