Stock Payload Fraction Challenge: 1.0.5 Edition

[Red Iron Crown]

Bomaye, sorry but payload cannot be clipped to fit in a smaller bay. It gives less drag than there should be for that payload if unclipped, I have disqualified entries before for this. If there is clipped payload in an entry I have accepted then I likely just missed it.

[Bomaye]

Ohhh, but I think the Scarab MK2 is either tweak scaled or clipped it looks like both, but dont know.

- - - Updated - - -

Aaaaaand now the images are gone.....

[Val]

Ohhh, but I think the Scarab MK2 is either tweak scaled or clipped it looks like both, but dont know.

- - - Updated - - -

Aaaaaand now the images are gone.....

The pictures are not gone, http://imgur.com/a/nyZPL, but something's up with the embedding.

I have to agree. Something looks off with the payload.

[Bomaye]

Yeah, because I tried and it wont fit.......

[Bomaye]

White Knight 4

Did some more tweaks while, and flew by "hand"

Craft: https://drive.google.com/file/d/0B4NjxbmXIiYwcmYxY3BBNF83cm8/view?usp=sharing

Take-off: 409,3t

Payload to orbit: 193,25t

Payload fraction: 47,21%

Pics here: http://imgur.com/a/4JuT3

[Red Iron Crown]

I have reviewed the Scarab Mk2 and have found that the payload is clipped too much to be acceptable as an entry for this challenge, so I have removed it from the board. It also has a lot of offset tool trickery to minimize drag by putting multiple engines in a single stack, which I find a bit exploitative but not specifically against the rules (I had less of an understanding of the new aero when I wrote them). Apologies for missing this in my initial review of the entry.

Bomaye, I've added your latest entry to the leaderboard, well done.

[Bomaye]

White Knight 4 on test 3

Take-off: 412,3t

Payload to orbit: 196,25t

Payload fraction: 47,59%

And that was done with pilot assistance, but I can't seem to find a good way of switching from surface to orbital control. As you can see I added just 3x2t to the ore containers.

PS. Tseitsei's Simple Is Beautiful doesnt seem single stage to me.

Pics: http://imgur.com/a/g6ukX

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Ohhh and Val, your design is damn efficient

[Red Iron Crown]

I've moved your White Knight 4 up the board, Bomaye. I love seeing people take a good design and tweaking it even further.

PS. Tseitsei's Simple Is Beautiful doesnt seem single stage to me.

It does not appear to discard anything before reaching orbit, and only has two decouplers whose function is clearly visible. What makes you think it is multistage?

[Bomaye]

I've moved your White Knight 4 up the board, Bomaye. I love seeing people take a good design and tweaking it even further.

It does not appear to discard anything before reaching orbit, and only has two decouplers whose function is clearly visible. What makes you think it is multistage?

Ahhh, maybe I missunderstood that the payload should separate without rendering the craft useless? I was just thinking that was an SSTO since it actually can return.

[Red Iron Crown]

It's single stage to orbit, return is not a factor in this particular challenge (though I know many people think of "SSTO" as fully recoverable as well).

[Bomaye]

No problemo, I like this challenge I didnt construct it for it, but just looked at some crafts that was fit for it.

Hmmm will try design something new

[Val]

White Knight 4 on test 3

Payload fraction: 47,59%

And that was done with pilot assistance, but I can't seem to find a good way of switching from surface to orbital control. As you can see I added just 3x2t to the ore containers.

Gratz on the improved results.

I'm impressed that you can get such a high fraction with a design that has relatively high drag (struts, many stacks) and heavy cockpits.

Ohhh and Val, your design is damn efficient

Thank you!

Not having to encase the payload does save a lot of weight, but it's not very practical, even if I my design is theoretically recoverable. I suspect typical career payloads would have too much drag to achieve that kind of fraction.

I have some ideas to improve the usability of the design, but it would probably cost in fraction and still suffer with draggy payloads.

I've also been working on a new design with enclosed payload, but it's on hold at the moment due to a thermal bug (entry #23), so I have not tested whether it's feasible, yet. Waiting for 1.0.5 to continue work on it.

[djmad]

Hi, here my participation

after trying around with smaller ships always at ~19% payload i went to bigger rockets :-)

Now i reach 486,197t / 1797,91t --> 27,04%

still 40m/s spare or some payload more possible....

many possibilitys on ascend to optimize

a video of my launch is added

https://youtu.be/DuzES-jO6mc

craftfile:

only mechjeb is needed to open the craft

https://drive.google.com/file/d/0BwlEwNF5gHnyOV9SVVo1VzROYWc/view

greets djmad

[Red Iron Crown]

djmad, I tried your craft file and it does not work in a stock game. Each stack is connected by only a single decoupler without any struts, it just falls to pieces when physics kicks in.

I am sorry to say that this entry is not acceptable, it seems like the only way this craft could work is by using a physics-altering mod such as Kerbal Joint Reinforcement.

[Bomaye]

So i re-designed some heavy parts (cockpits removed, was thinking same Val) and removed some fuel and monoprop.

White Knight 5

Craft: https://drive.google.com/file/d/0B4NjxbmXIiYwTVlBT1dUNUc5dG8/view?usp=sharing

Take-off: 405,6t

Payload to orbit: 199,25t

Payload fraction: 49,12%

Pics: http://imgur.com/a/uvaRw

Still think the ascent can be optimized and there is still some fuel left......hmmmm can it beat 50% barrier?

Edited October 22, 2015 by Bomaye

[Red Iron Crown]

Updated your entry Bomaye, you're edging closer to the magic 50%.

[tewpie]

Apologies, I didn't know payload clipping was against the rules. I also didn't think stacking engines was that big of a deal.

Both the clipping and stacking were not done for performance reasons - I clipped the payload so I could keep part count down and fine tune CoM balance. Likewise I stacked the engines so I could keep them in a tight cluster without using too many struts. Ironically, not using those techniques actually gave a sizable performance boost due to fewer external struts and better rigidity (at the cost of worse aerodynamic handling and weird looking engine layout). Result:

Scarab Mk3 SSTO (.craft)

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Payload Fraction: 53.07%

Ascent Profile:

1) Takeoff at 5 degrees pitch and gradually pitch down to maintain level flight

2) At 450m/s pitch up gradually to 12 degrees

3) At 12km fire LV-N

4) At 22km switch to closed cycle

5) Engines off when AP reaches 71km

Edited October 23, 2015 by tewpie
Added link to craft file

[Bomaye]

Nice one tewpie! I was wondering why you would stack engines like that as it has no benefits

Ohhh and a question or 2:

How you switch from surface to orbital using that flight mod......for it always flipps or do wierd stuff so I fly by "hand" in the end.

And i always seem to get heat issues at ca 12km to 36km alt and speed of 1200m/s to 1500m/s, any advice?

Edited October 23, 2015 by Bomaye

[djmad]

Hi Red Iron Crown

Sorry in this case it was cheating.

I copied my KSP and deleted all mods, strut it down and gesend it :-)

my corrected craft with struts

https://drive.google.com/file/d/0BwlEwNF5gHnyQjZ5Sk9kUHBzUnM/view?usp=sharing

New specs: 486,197t / 1800.11 --> 27.01%

starts the same way, but 10m/s less fuel left

same settings for mechjeb, no changes

if needed for valid entry i remake video too

after editing around i also found a better solution

Lifter V2 186.199 / 1793.66 -> 27.1%

https://drive.google.com/file/d/0BwlEwNF5gHnydFdaeVhYdjR2X3c/view?usp=sharing

https://drive.google.com/file/d/0BwlEwNF5gHnySFpNUHZBb05YWUE/view?usp=sharing

choose one :-) both now conform and working

Edited October 23, 2015 by djmad

[tewpie]

How you switch from surface to orbital using that flight mod......for it always flipps or do wierd stuff so I fly by "hand" in the end.

You can setup separate profiles for orbit and surface using the "P" button on the top right, but this is not needed if you balance the ship well. One trick to keeping CoM in front of CoL is to disable fuel flow in your fore fuel tanks until the other tanks run out.

And i always seem to get heat issues at ca 12km to 36km alt and speed of 1200m/s to 1500m/s, any advice?

Use steeper climb angle, either by adding more air-breathing engines and pitching higher, adding more wings, or angling existing wings higher. Try to stay as close to terminal velocity as possible during your ascent (atmospheric efficiency = 100% in KER).

Edited October 23, 2015 by tewpie

[Red Iron Crown]

Sorry for the slow update, my subscription wasn't reporting new replies.

tewpie, thanks for revising your entry to be compliant, and improving on it to boot! I've added it to the board as the top single stage entry.

djmad, glad to hear you got a compliant version working. If you could add some pics or video to confirm your entry I'll add it to the board.

[djmad]

As requested a launch video of my craft

https://youtu.be/GDbI3SsyO5E

the Craft FIle

https://drive.google.com/file/d/0Bwl...ew?usp=sharing

Edited October 29, 2015 by djmad

[Val]

I'm getting very close to beating tewpie's latest with a new pure RAPIER C-1 Payday Mk.6

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Needs a little more work.

[Bomaye]

I broke the 50% barrier (barely) with the White Knight!!! (Very fun doing this trials)

Craft: https://drive.google.com/file/d/0B4NjxbmXIiYwV0xsZ3AxRnQ3Zjg/view?usp=sharing

Take-off: 410,8t

Payload to orbit: 205,53t

Payload fraction: 50,03%

Pics here: http://imgur.com/a/MosSB

[Red Iron Crown]

Nicely done, Bomaye, congrats on making it to the 50% club! Added to the board.