Stock Payload Fraction Challenge: 1.0.5 Edition

[tseitsei]

Ok SSTO series: 49.79% payload fraction

18.377t ship and 9.150t payload

http://imgur.com/a/T3Zz4

EDIT: here is another picture from assembly hangar http://imgur.com/uRHi7wW

Edited September 16, 2015 by tseitsei

[Red Iron Crown]

Nice entry, tseitsei, does the ship have a name so I can add it to the board?

Also: I would prefer that the mass readouts be visible for future entries, makes it much easier to verify.

[Val]

Ok SSTO series: 49.79% payload fraction

18.377t ship and 9.150t payload

http://imgur.com/a/T3Zz4

EDIT: here is another picture from assembly hangar http://imgur.com/uRHi7wW

#DammitTseitsei

That is an impressively light craft. I did not know you could make RAPIER builds that efficient.

It must be the good TWR. I've noticed in my own designs that high TWR is just as important as overall mass per engine. Which, among other things, is why my designs with >32 t per RAPIER, like the Chibi Skylon, have smaller payload fractions.

Must beat this new record. I will not sleep until I do...

[tseitsei]

Nice entry, tseitsei, does the ship have a name so I can add it to the board?

Also: I would prefer that the mass readouts be visible for future entries, makes it much easier to verify.

Ok I'll put the readouts visible for future entries. Alltough I calculated the mass of my ship and the mass of my payload part by part to get more accurate reading because the SPH readouts only give masses with one digit

And let's name it Simple Is Beautiful because IMO the design is surprisingly simple to be that efficient (Getting just the right amount of fuel on board and the correct ascent profile wasn't that simple tough )

#DammitTseitsei

That is an impressively light craft. I did not know you could make RAPIER builds that efficient.

It must be the good TWR. I've noticed in my own designs that high TWR is just as important as overall mass per engine. Which, among other things, is why my designs with >32 t per RAPIER, like the Chibi Skylon, have smaller payload fractions.

Must beat this new record. I will not sleep until I do...

Yeah TWR is very important because you need to spend less time fighting the drag if you have high TWR...

And I hope you have a loooooong night ahead

[Val]

Take-off mass: 52.4 t

Cargo mass: 26.5 t

Payload fraction: 50.57 %

Woohoo! I broke it! I broke the 50 % barrier.

I knew/hoped this design was not fully tapped in my previous attempt. And it's recoverable, in theory, with a few improvements. I overheated on the way back. Didn't have enough battery. Became uncontrollable. And with the ultra-low drag, that it is. It didn't slow down...

Craft file

This is the hardest craft, to pilot, I've ever built. It breaks so easily, because of those wobbly docking ports.

Different ascent profile than my usual. Make sure to do very gentle attitude changes, when speed is above 300 m/s.

1. 5° pitch off runway to 300 m/s.
2. 10° pitch to 8 km.
3. 5° pitch to 15 km.
4. 8° pitch until AP >60 km, then prograde.

• Nuke at 18 km.
• RAPIER Mode at 22 km.

Edited January 12, 2016 by Val
Forum upgrade formatting fubar

[tseitsei]

Well. That didn't take long GJ though

[Red Iron Crown]

Looks legit Val, added to the board. (Go to sleep. )

[Val]

Well. That didn't take long GJ though

Thank you. I'm expecting you'll beat it soon, though

Looks legit Val, added to the board. (Go to sleep. )

Thank you, but I'm not going to sleep, yet. Saw that Cradle game mentioned in the Unigine thread. Gonna check it out.

And keep an eye on here to see if anyone beats me or challenges the legitimacy of my entry. It is almost unbelievable. And I only did it once. What if it was a fluke?

[tseitsei]

Okay Val. Tomorrow I'll give this a serious try again. I hope I can beat it but it won't be easy...

[Val]

Okay Val. Tomorrow I'll give this a serious try again. I hope I can beat it but it won't be easy...

Looking forward to seeing your entry

[tseitsei]

Looking forward to seeing your entry

...IF I can beat you Not much reason to post if I don't

[RCgothic]

Very curious how multistage air-breather is only 2% better than ssto. Is this because anything staged is a fraction loss? The rocket multistage performance is ~2.5x the ssto entry!

[Val]

I don't think staged parts are fraction losses. They wouldn't count as payload anyway, according to the rules.

I have a some of guesses, though

• Because the top multi-stage haven't been beat yet, no one has bothered to put in the effort.
  
• Structural/tankage mass is so highly optimized, on these spaceplanes, that staging doesn't give as much benefit as on non-airbreathing.
  

Edited September 23, 2015 by Val
Duplicate words

[Val]

• It's harder to make a multistage plane, that is stable after staging?
  
• More efficient ascent profiles have been found since. The multistage entries are older than the singlestage.
  

Edited September 23, 2015 by Val
Grammars

[RCgothic]

Sounds like it's ripe to be beaten then!

[Right]

Greetings! So I'm late to the KSP 1.0+ party, but better late than never. This challenge represents the bread and butter of KSP rocket science, and thus is my first stop haha.

My primary attention at the moment is focused on duplicating or surpassing the most efficient rocket designs. I've reconstructed Nefrums "Bigger is Better" I believe exactly (part count, mass, dV, TWR, etc...) but I can't quite get it into orbit. Best I can do is 49k/18k Ap/Per. @Nefrums I've tried matching your flight path from the screen shots, but I lose 50-100 m/s between stage 1 and 2 that I haven't figured out how to eek out. Any tips?

Hopefully I can improve upon 28.48%

[Nefrums]

the trick is to keep the ship pointing as close to the center of the prograde marker as possible, to avoid losing dv. Do not use prograde lock as it causes the thrust to flip back and forth all the time, i.e not pointing directly forward all the time.

[Right]

Thanks for the tip! I know this was 3 months ago and I apologize for all the minutia. If you're uninterested I won't be offended. XD

I assume you're referring to surface prograde to reduce atmospheric drag losses. I hope you don't mind a few questions as I'm still failing. Is this KSP 1.0.4? Are you running stock aerodynamics? Is the ascent in the pictures and the ascent that succeeded the same? Are you full throttle until you reach orbital speed?

I'm noticing at T+20s I am moving faster at a higher altitude and with less mass/dV. I believe this indicates you're throttling down at some point. I've double checked my fuel flows.

I'm having trouble adhering to your tip between the first and second stages (technically stage 3 and 2), I think this is the key to success. You're facing surface prograde at T+20 and T+47, but if I match you at T+20, I have to deviate from prograde by 10° for more than 15 seconds to match you're heading at T+47. At this point I'm 50m/s behind you.

[tewpie]

Here's my multi-staged airbreathing/nuclear design (.craft):

Scarab

Javascript is disabled. View full album

Payload Fraction: 53.37%

Ascent Profile (flown using Pilot Assistant):

1) Take off at 4 degrees pitch

2) At mach 1.1 (~500m altitude), pitch up to 8 degrees

3) At 10km, pitch down to 4 degrees

4) At 18km, start nuclear engines

5) Jettison turbojets after flameout

6) At 23km, switch RAPIERs to closed cycle and pitch up to 12 degrees

7) Jettison RAPIERs after flameout, pitch down to 8 degrees

8) When apoapsis reaches 75km, cut engines and hold prograde

9) At 45km, jettison canards

10) ???

11) Orbit!

Edited October 6, 2015 by tewpie

[Red Iron Crown]

Welcome aboard, tewpie, that's an impressive entry and new highest fraction! I've added you to the top of the board.

[MatBailie]

@Nefrums - What about setting the engines gimbal to locked? Then using prograde lock, relying on SAS to keep your nose pointed forward? I'm looking to learn as much as I can from these posts, so people explaining my mistakes would be quite useful

[Val]

Scarab

http://imgur.com/a/ASIvW

Payload Fraction: 53.37%

Excellent entry, tewpie.

I wonder if I should give multistage air-breathing a go, though, it didn't go as planned, when I tried rocket-only.

[EvermoreAlpaca]

Not really a submission... but relevant?

Merely putting this here because this is the place where people are discussing interesting ideas for efficient SSTOs! This design is intended to be practical, and not an all out fractional payload champ, and as a result sports 2 Mk3 CRG-100 cargo bays, batteries/TRG/easy flight and landing characteristics. I'm very pleased with the early results.

35.35t dry, 95.28t wet, 167.28t with 72t payload. Considering just the cargo bays alone add 12 tons of essentially dead weight, i'm going to see what improvements better design and flight profile planning can make! Thank you to Val on inspiration for a RAPIER/LVN combo.

Edited October 7, 2015 by EvermoreAlpaca

[Val]

...

Thank you to Val on inspiration for a RAPIER/LVN combo.

Thank you for the flatter, but I can hardly take credit for RAPIER-Nuke combos. I may have a part in showing its potential, but I stole the idea from was inspired by Red Iron Crown, after seeing this.

Not really a submission... but relevant?

Merely putting this here because this is the place where people are discussing interesting ideas for efficient SSTOs! This design is intended to be practical, and not an all out fractional payload champ, and as a result sports 2 Mk3 CRG-100 cargo bays, batteries/TRG/easy flight and landing characteristics. I'm very pleased with the early results.

35.35t dry, 95.28t wet, 167.28t with 72t payload.

...

https://i.gyazo.com/8daf1090fd14d05c724f654445388597.png

https://i.gyazo.com/ffbcb1d98979156076e56b8d54848ba9.png

A very nice design. Is it pure RAPIER? Looking at the pictures I can't really figure out the engine layout. I see 9 engines in staging, but I can only see 8-ish engines in the pictures.

Considering just the cargo bays alone add 12 tons of essentially dead weight, i'm going to see what improvements better design and flight profile planning can make! ...

Yeah, cargo bays are heavy. My best fractions with them are 44 and 45%, respectively, for Mk3 and Mk2.

...

I wonder if I should give multistage air-breathing a go, though, it didn't go as planned, when I tried rocket-only.

I tried a Multi Stage design last night. It's loosely based on my C-5 Modular design, but I couldn't even beat my own Single Stage fraction. I suck at Multi Stage

Devnote Tuesday: Kerbal Space Program 1.0.5

I'm so excited.

• New opportunities for firsts​.
  
• Clean slate on the leaderboard.
  Is this a good time to discuss new sub categories on the leaderboard?
  Recoverable vs. nonrecoverable designs? (Show that the craft is deorbit- & landable)
  
• New physics to figure out.
  

Any predictions as to whether fractions will go up or down?

[Red Iron Crown]

We'll see if things change significantly before starting a new board. Aero doesn't seem to be changing, and I'm not sure any of the new parts will be relevant (maybe the new rocket engine, depending on its stats).