5,000 Fund Speed Run

[Ultimate Steve]

Continuing in the vein of the twenty ton and two ton speed run challenges, I present the 5,000 Fund Speed Run! The goal? Go as fast as possible with only 5,000 funds!

Rules:

• No cheating with the debug menu, cheat mods, etc.
• No mod parts may be used
• No mods that alter physics may be used
• Visual/informational, etc. mods may be used
• Speed must be measured before Kerbin's SOI is exited, and must be measured in the "orbit" velocity mode.
• The craft must cost less than 5,000 funds
• Kerbals do not count towards cost. If you need to spawn one in, the command pod, as long as it is jettisoned before takeoff, does not contribute to cost.
• The craft does not need to be manned, it can be either manned or unmanned.

That's all I can think of right now. It's a relatively simple challenge.

Leaderboard:

 

Enjoy!

Edited April 26, 2019 by Ultimate Steve

[Geonovast]

16 minutes ago, Ultimate Steve said:

Kerbals do not count towards cost. If you need to spawn one in, the command pod, as long as it is jettisoned before takeoff, does not contribute to cost.

Does this imply that this must be manned?

[Ultimate Steve]

Just now, Geonovast said:

Does this imply that this must be manned?

Nope, it can be either manned or unmanned. I should have clarified that, I'll go add that in.

[dnbattley]

Great challenge. Can I assume Mun slingshots are disallowed?

[Jestersage]

Quote

Kerbals do not count towards cost. If you need to spawn one in, the command pod, as long as it is jettisoned before takeoff, does not contribute to cost.

So i assume that is for pre-1.6, as after 1.6 you can spawn a kerbal into the External seat directly.

[Ultimate Steve]

13 minutes ago, Jestersage said:

So i assume that is for pre-1.6, as after 1.6 you can spawn a kerbal into the External seat directly.

Ah, right, I forgot about that, I haven't done much in the newer versions. Yep, that rule is for pre 1.6.

18 minutes ago, dnbattley said:

Great challenge. Can I assume Mun slingshots are disallowed?

Yes. Try to avoid them, but an accidental encounter that doesn't change velocity too much won't disqualify you.

[l0kki]

Did the challenge. Reached 4000m/s. Got stuck in solar orbit.

Spoiler

https://kerbalx.com/l0kki/5000funds2speed

 

[dnbattley]

My starter for 10: a shade over 7.8km/s. Unmanned. Exactly 5k credits (re-reading the rules I now realise I should have clarified that 5k was allowed since it actually says "less than")

Mk 2: 7.87km/s. Unmanned. 4,977 credits

Mk 3: 7.9km/s. Pictures to follow (time for bed now).

Spoiler

 

Edited April 26, 2019 by dnbattley
Updated for Mk3

[bayesian_acolyte]

8,541 m/s 

To save some cash I used a stayputnik with no reaction wheel and relied on the spark's gimble and MJ to point in the right direction. I also used a small hardpoint attached to the kickback radially and then moved to the top to save 240 funds over a decoupler. I was able to fit in 20 baguette tanks. I suspect an ant design might be best but I couldn't figure out how to engineer it right in the time I had.

Spoiler

Edited April 27, 2019 by bayesian_acolyte

[dnbattley]

4 hours ago, bayesian_acolyte said:

8,541 m/s 

To save some cash I used a stayputnik with no reaction wheel and relied on the spark's gimble and MJ to point in the right direction. I also used a small hardpoint attached to the kickback radially and then moved to the top to save 240 funds over a decoupler. I was able to fit in 20 baguette tanks. I suspect an ant design might be best but I couldn't figure out how to engineer it right in the time I had.

Very nice. Glad I got my entry in first before it was blown out of the water...

I also considered the stayputnik, but without using MJ it proved too hard to maintain a non-reaction wheeled course without using a more advanced (and hence expensive) probe. How did you maintain an initial flight trajectory without fins/control for the SRB?

Regarding Ants: I am not surprised it was tricky to engineer something here: despite their weight and hence dV advantage, they have a surprisingly low "cost/thrust" ratio that is also an important factor in these sorts of challenge (c.25% of spark)

[dnbattley]

8.9km/s

Spoiler

Edit: now with a little more time to outline the additional innovations used to get this improvement.

• Use of engine plate as a very cheap decoupler
• Creating a series of weight-balanced "rings" of baguettes which can be released to slip off the craft backwards using a single off-centre hardpoint decoupler
• 3 x thumpers, instead of 1 x kickback, with a slight offset of stage 1 thrust providing the gravity turn

Edited April 27, 2019 by dnbattley
detail

[bayesian_acolyte]

Nice flying! From that KER readout it looks like your ship had slightly lower vacuum dV than mine, but you were still able to smash my record. Part of that is related to this question:

Quote

How did you maintain an initial flight trajectory without fins/control for the SRB?

I didn't. I just pointed straight up and then circularized with the spark. I wonder how much of your better speed has to do with this and how much was made up in other flying improvements. I think at the very least I could improve by inducing a gravity turn either by having the payload be slightly off-center or starting the whole ship at a tilt, but I'm not sure if this alone would be enough to catch up. I should have some time later today to mess around with this or maybe see if I can make ant viable.

Edited April 27, 2019 by bayesian_acolyte

[dnbattley]

5 minutes ago, bayesian_acolyte said:

Nice flying! From that KER readout it looks like your ship had slightly lower vacuum dV than mine, but you were still able to smash my record

Thanks! I'm pretty sure you'll be able to beat it eventually, but in the meantime my latest (and, I suspect, last for now at least) result is 8,977m/s: tantalisingly close to, but not quite attaining, 9km/s.

Spoiler

 

[bayesian_acolyte]

This will be tough to beat. I'm curious what that circular part is between the bottom baguette and the fairing base? Seems like it should be obvious but I can't figure it out.

[dnbattley]

1 minute ago, bayesian_acolyte said:

This will be tough to beat. I'm curious what that circular part is between the bottom baguette and the fairing base? Seems like it should be obvious but I can't figure it out.

It's an inverted engine plate.

[bayesian_acolyte]

Up to 9293 m/s in large part thanks to stealing @dnbattley ring drop tank design. This score could be improved by at least a bit as I ran out of fuel ~35s before my Pe at 90.5km, but I didn't have time tonight to get a 70km Pe and better burn timing. I also improved the launch by tilting to around 9 degrees before ignition.

Spoiler

 

I got a working ant design but my best run topped out at 8.9km/s. It had almost 500 m/s more dV than the above ship in a maximally elliptic orbit for the final approach, but very long burn times (~1hr30m total, thank you better time warp) made the final burn far less efficient with less Oberth effect, and accelerating earlier meant less time for gravity to accelerate the ship on approach.

Edited April 28, 2019 by bayesian_acolyte

[Pds314]

Ladders intensifies