The Cheap and Cheerful Rocket Payload Challenge 1.0.5

[Norcalplanner]

4 hours ago, GoSlash27 said:

I've done it! It wasn't such a bad rocket. All it needed was a little love...

http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/CnCRocketFactory/Cheep135II

$124,697 on the pad minus $34,825 payload = $89,878 disposable launcher.

divided by 135.7 tonnes in orbit equals $662.68 per tonne *cool shades*

Best,
-Slashy

 

Well done, Slashy.  Adding you to the top of the leaderboard.

[GoSlash27]

Norcalplanner,

 Grazi. I'm sure I won't be on top for long

Best,
-Slashy

[Nich]

Slash, 

Does it rely on KJR?  Mind sharing the craft file?  Mind if I use the craft in a challenge citing reference of course?  I have an idea for a new challenge

[maccollo]

Reaching 650 funds per ton.

It's the same launch vehicle as my previous entry. Nothing has changed. I'm just pushing it to the limit by adding an additional 4 tons to the payload. It's probably the most perfect launch I'm capable of doing. Took me 5 tries to get those last few m/s

https://www.youtube.com/watch?v=S7LDbW-dCwI

Launcher cost: 106626
payload: 164.045 metric tons
649.98 funds per ton

Edited February 2, 2016 by maccollo

[Nich]

Couple more failed attempts.  First a pull dragger was able to get 830 funds/ton.  It might be viable but I cant seem to get it.  The more I loaded it up the worse it did.  Second was a shuttle type asymmetric to cut down on the cost of decouplers however the vector is so expensive it can never make up for it coming in around 1150 funds/ton

 

[GoSlash27]

2 hours ago, maccollo said:

Reaching 650 funds per ton.

maccollo,

 Wow, one whole day, huh?

 Okay. I've still got some stuff I can do...

Best,

-Slashy

[GoSlash27]

6 hours ago, Nich said:

Slash, 

Does it rely on KJR?  Mind sharing the craft file?  Mind if I use the craft in a challenge citing reference of course?  I have an idea for a new challenge

Nich,

 Sure. Here ya go:

http://wikisend.com/download/706948/Cheep135II.craft

No, it doesn't use KJR or any mods. 100% stock.

Best,
-Slashy

[Nich]

Thanks Slashy

HAHA i had some fuel locked that was not payload on the puller :/  Once unlocked I was able to get to 740 funds/ton which is about the best I can do.  You guys might be able to get more out of it with a better launch and optimization.

[GoSlash27]

8 minutes ago, Nich said:

Thanks Slashy

HAHA i had some fuel locked that was not payload on the puller :/  Once unlocked I was able to get to 740 funds/ton which is about the best I can do.  You guys might be able to get more out of it with a better launch and optimization.

Remember, anything under $900 per tonne is pretty epic. Most players in that region are using partially recoverable lifters.

 If we were partially recovering our boosters, we'd be competitive with SSTO spaceplanes.

Best,
-Slashy

Edited February 3, 2016 by GoSlash27

[Norcalplanner]

7 hours ago, maccollo said:

Reaching 650 funds per ton.

It's the same launch vehicle as my previous entry. Nothing has changed. I'm just pushing it to the limit by adding an additional 4 tons to the payload. It's probably the most perfect launch I'm capable of doing. Took me 5 tries to get those last few m/s

https://www.youtube.com/watch?v=S7LDbW-dCwI

Launcher cost: 106626
payload: 164.045 metric tons
649.98 funds per ton

Wow, I never thought things would get this low.  Putting you back on top of the leaderboard.

I've set a personal goal for myself of getting below 700 funds/ton with my own design.  Entering the VAB...

[GoSlash27]

Well... my "streamlining" didn't pan out.

 I'll have to gin up a new spreadsheet to theoretically try different combos so I can find the optimal price points. Hopefully I'm not already there...

Best,
-Slashy

[maccollo]

@GoSlash27
Perhaps this has made you reevaluate your opinion of the Rhino.
With your proposed cost reduction I would be at 589 funds per ton

Edited February 3, 2016 by maccollo

[GoSlash27]

I was able to optimize my design some more.

http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/CnCRocketFactory/135C

Changes included:

- Moving a SRB pair from the sustainer to the booster

-Readjusting thrust balance to force SRB/ tanks to fly away from the stack at burnout

- Deleting sepratrons

-Adding payload to take advantage of increased capacity.

New numbers:

$124,857-$35,585= $89,272

$89,272/ 137.3 tonnes = $650.20 per tonne.

I think there's still a little more I can do with this design.

Best,
-Slashy

[GoSlash27]

4 hours ago, maccollo said:

@GoSlash27
Perhaps this has made you reevaluate your opinion of the Rhino.
With your proposed cost reduction I would be at 589 funds per ton

Perhaps. Then again, perhaps not.

You'd best get crackin' if you think you can do that, 'cuz that's where I'm headin'.

Best,

-Slashy

[numerobis]

$650/t is half the cost of the cheapest jet-based SSTO I've made using Tier 4 science. The Panther changes things of course.

 

Wait, no, I got confused. It's equal to the cost of that SSTO.

Edited February 4, 2016 by numerobis

[Norcalplanner]

Just a few things to say before I sign off:

Mainsail sustainer with quasi-asparagus staging.

118.63 ton payload.

699.23 funds/ton.

Pictures tomorrow.

[GoSlash27]

A new record, but just barely.

http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/CnCRocketFactoryII/IIc2

$124,605-$35,585=$89,020

$89,020/137.3 tonnes = $648.36 per tonne.

Best,
-Slashy

[maccollo]

This time I had to make modifications. Changed how the solids were attached. Before I had them attached to the radial tank via cubic struts. Now they are attached radially to the center booster. This allowed me to remove the ring of struts holding them in place. So that reduced the cost by almost 1000 funds.

Total cost: 142496
Payload cost: 36564
Launcher cost: 105932
Payload: 164 tons
Cost per ton: 645.93

launch video:
https://www.youtube.com/watch?v=2_e7KHbSd9c

screen dumps:
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/launcher6.png
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/payload6.png

This isn't actually the most optimal balance between booster and sustainer. I can push the cost per ton down further, I have to make the rocket ugly or resort to fairly extreme clipping. As far as performance goes it makes no difference, but still...

Edited February 5, 2016 by maccollo

[GoSlash27]

I'm thinking at this point I have no choice but to switch over to the Rhino.

It's like $10,000 more for the core stage, but the improved Isp looks to save more than that in the overall launch stack. 

 No regrets for the time I spent tinkering with the Twin Boar; I got it under $650 per tonne and learned a lot in the process.

Best,
-Slashy

[Norcalplanner]

Slashy and maccallo,

Both of your recent entries have been added to the leaderboard.  Sadly, my screenshot folder got screwed up so I lost my evidence of my flight, so I won't add myself to the leaderboard.  Given that it took many, many tries to finally eke out an 80 km by 1.1 km orbit, I'm not anxious to repeat the exercise anytime soon.

I'm going to be busy the next few days, so I may not be able to update the leaderboard (which is very difficult to do on my smart phone).  Keep it up, but it will be awhile before the OP gets updated.

I also think that while we've learned a lot, we're also reaching a period of diminishing returns.  I'm going to set an official end time for this challenge of Saturday, February 20th, or whenever 1.1 drops if it comes out before then.  Thanks to you two and everyone else who participated for pushing the boundaries of rocket economics further than they've ever gone.

Norcalplanner

[Nefrums]

I'll have to give this a try!

[Nich]

After doing this challenge for a while I decided to go back and play my career game.  I just about cried when I saw how inefficient my Duna Explorer launcher was.  I ended up getting it into space without using any fuel in the center stage.

[GoSlash27]

13 hours ago, GoSlash27 said:

I'm thinking at this point I have no choice but to switch over to the Rhino.

It's like $10,000 more for the core stage, but the improved Isp looks to save more than that in the overall launch stack. 

 No regrets for the time I spent tinkering with the Twin Boar; I got it under $650 per tonne and learned a lot in the process.

Best,
-Slashy

After reviewing the numbers, I just can't imagine that I can build anything with the Rhino that I couldn't do cheaper with the Twin Boar. Clearly Maccollo is getting more out of his design than I am getting out of mine. So for better or worse, I have to stick with what I'm doing.

Best,
-Slashy

[maccollo]

Increased the number of kickbacks from 18 to 26 and increased the amount of fuel on the core by 10%. This lowered the cost per ton to 630 funds/ton. I ended up just clipping the extra kickbacks around the center kickback. If I was using far this would give me and advantage, but with stock aerodynamics this is no different than just hanging them on the sides. It's just looks nicer this way

Total cost: 174914
Payload cost: 44132
Launcher cost: 130782
Payload: 207.65 tons
Cost per ton: 629.82

launch video:
https://www.youtube.com/watch?v=ycGODL0XwSo

screen dumps:
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/launcher7.png
https://dl.dropboxusercontent.com/u/22015656/cheapLaunch/payload7.png

Edited February 5, 2016 by maccollo

[Meithan]

Fantastic work, maccollo, that design is not only super efficient but also shines for its simplicity. I wonder, though: is it possible to scale it down?

Which brings me to the following. Now that Norcalplanner is thinking about closing the challenge in its current form (since, I agree, it seems you guys have reached the highest efficiency level possible), I think it would be interesting to see what kind of cost efficiency can be obtained for smaller payloads. As Slashy originally pointed out, there's an economy of scale for rocket design in the game, which is reflected by the fact that all current entries in the leaderboard (except one) have payload masses above 100 tonnes.

While heavy launchers like these are certainly useful, there's also a "market" for smaller payloads in the game. For instance, most satellite launch contracts for Kerbin's SOI (I must have completed a few dozens) can be fulfilled with a satellite weighing less than 2 tonnes, and many functional (in a Career mode sense) crew shuttles, basic space stations and mining ships (to name a few examples) can be designed and built for in-orbit masses usually not above, say, 30 tonnes.

So what do you guys (Norcalplanner, specially) think about this?