Stock Payload Fraction Challenge: 1.0.5 Edition

[Slugy]

The root part oddness is interesting - at least it sounds like an easy to fix bug.

Drag does seem lower all round than 1.02, but that might just be getting used to it.

For placing things in cargo bay Editor Extensions is really handy - you can easily toggle surface attachment with 'T' - not having it installed was why there was a stack separator rather than a docking port in the cargo bay.

[Red Iron Crown]

For placing things in cargo bay Editor Extensions is really handy - you can easily toggle surface attachment with 'T' - not having it installed was why there was a stack separator rather than a docking port in the cargo bay.

That's been a stock feature since 0.25, hold down Alt (or Rshift on Linux) to disable surface attachment.

Definitely agree that drag seems lower in 1.0.4 compared to 1.0.2, especially in the transsonic range. Seems like the "hump" in drag at Mach1 is a good bit smaller.

[LittleBlueGaming]

Oh yeah, a name... Orebringer Mk1

Nothing special, just how I usually go about building these things. Asparagus staged. Flew the ascent profile a bit steeper than I normally do because the last engine by itself is just too underpowered in thicker atmosphere, but it naturally transitions to a shallow 50km-70km climb.

513.92t on the pad, 113.6t in orbit = 22.10%

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[Red Iron Crown]

Added you to the board, LittleBlueGaming, that's a clean design that looks much like a real world rocket. Well done!

Anyone else find it funny that we're using advanced rocketry to lift rocks into orbit?

[Jouni]

A more serious attempt this time. The A4 uses a Rhino as a sustainer engine and two pairs of Twin-Boar-based boosters in asparagus configuration.

Well, not precisely coasting. I had to burn 18 m/s to counter the drag losses.

The interstage is the same as in the Needle.

The topmost fuel tank in the payload was launched empty.

The craft file without MechJeb

151.05 tonnes of payload for 577.32 tonnes of launch mass means that the payload fraction was 26.16%.

[Red Iron Crown]

That's a fantastic fraction, Jouni! Added to the top of the board.

Would you say the A4 was a clean sheet of paper design?

Sorry, couldn't resist that awful pun.

[Nich]

I am very proud of this one it is based off a 2 man exchange orbital refuel SSTO.

Not sure how to add an imgur album or a craft file

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40.34% but I am sure someone could fly it better and get more. I skimmed the water till about 400. Pulled up to 15 degrees until 10 km slowly level out to 8 degrees until AP reaches 71km, circularize.

Edited June 27, 2015 by Red Iron Crown
Fixed album embed.

[Red Iron Crown]

Forgive me, Nich, but I have to ask: Are you using Kerbal Joint Reinforcement or similar? Seems like that should be really bendy, especially under pitch commands.

[Nich]

It is extremely bendy. It is not too bad to fly just tap the s key about 50 times and it will pitch up a degree. I also ran a strut from the first ore tank to the first mk2 adaptor tank that helped stiffen it up. If I had a joystick it would be even easier, bendy and full deflection controls surfaces do not play nicely together

[Red Iron Crown]

I'm impressed you even got it off the runway, tbh. Added you to the board. I also took the liberty of fixing your imgur album embed, you can take a look at how it is done by editing your post.

[LittleBlueGaming]

Added you to the board, LittleBlueGaming, that's a clean design that looks much like a real world rocket. Well done!

Anyone else find it funny that we're using advanced rocketry to lift rocks into orbit?

Don't laugh at science. Microgravity-lithopetrologic-durabamalleabilogy is very important for the advancement of Kerbal... advancement.

[LittleBlueGaming]

Edit: oh, ffs. I forgot to disable the two tanks in the payload. I'll change those out and update this.

Woot. This is my first successful spaceplane that can actually carry a payload.

Archer Mk1

33.7t on launchpad, 10.17t payload = 30.17%

Have to fly pretty much level off the runway until it crosses the trans-sonic region, then it climbs like a champ.

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[Starhawk]

I've finally made a spaceplane for this challenge. May I present "LKO Ore Bust" (in homage to Kuzzter's brilliant graphic novel Duna, Ore Bust).

Masses 32.997 tonnes on the runway, and dropped off 10.6 tonnes in LKO, for a payload fraction of 32.12%

Not on the level of many of the entries here, but respectable nonetheless.

Thanks for the challenge!

Happy landings!

btw - Why the rule about leaving the decoupler/docking port with the lifter?

[LittleBlueGaming]

Alright, I dunno what happened, but the Archer Mk1 stopped working. I added a pair of struts to the back, and took out the two small fuel tanks in the cargo bay, and I could no longer get to mach 1. Taking the struts back off, I still couldn't. I've heard of some drag bugs with cargo bays, so I wonder if I tripped that somehow.

Anyway, after some redesign, I got the Archer Mk2 working. A little more LF/O, a little less payload mass, and it's simple enough to get to orbit. Crosses mach1 more easily than the first, at the expense of payload %.

Archer Mk2

35.5t on runway, 9.9t payload in orbit = 27.88%

Still very glad I can finally(without just copying someone else) get payload into orbit with a spaceplane.

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[Nao]

Started designing this before Jouni's rocket, ended up using the same engines - so there is a chance that it's the theoretical best configuration, although i used more power (1.4 mN compared to Jouni's 1 mN) to lift a touch lighter craft.

Anyways here are the photos:

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craft name: SYNC.ART'S

The new aero definitely has it's good points but i kind of miss the soupospehere, there was room for finesse control and adjustment especially later in the flight, while now everything is settled within first 10s of the launch and you just wait for results

At first i was using ore instead of fuel for cargo as it's denser and suffers less drag, but i kind of wanted to have comparison to Jouni's design and ditched it. The launch left me with 3.6t of fuel so adding that to payload i guess +28.2% would be possible but thats for another time

Also the drag glitches of many parts like big probe cores and fairings made me use separate stage at the top to hold control elements (smallest core, ASAS and small batery), the big docking port also helps as it has less mas and drag than standard decoupler.

Edited June 28, 2015 by Nao

[Red Iron Crown]

Added you to the board, Starhawk. Great entry, you were carrying a lot of speed at 26km while still airbreathing (my planes typically don't get much more than 1300m/s), and you cut the margin rather thin on circularization. Well done!

The reason for the decoupler remaining with the lifter is that, in theory, any of these craft could have another payload put in place of the test payload and still work, and not count decouplers as part of the useful payload.

I've also added your entry, LittleBlueGaming. I feel your pain with something that previously worked no longer working, especially with spaceplanes. I've had ones where I replaced the test payload with a real one and suddenly I can't get to orbit anymore (or not as efficiently), and I'm never sure if it's a glitch, some effect i don't know about, or just inconsistency in my ascent. Still a good entry, and it is a good feeling when you finally start getting payload spaceplanes to work.

[LittleBlueGaming]

I still had roundabouts 100oxidizer left after circularizing, and more than enough LF to match, so there's a bit more that could be added back to the payload. I was just getting really sick of that stupid design

It was only my 15th attempt or so

[Starhawk]

you were carrying a lot of speed at 26km while still airbreathing (my planes typically don't get much more than 1300m/s), and you cut the margin rather thin on circularization.

I flattened right out shortly after reaching 12 km and let the pitch rise naturally. The velocity dropped a bit between 20 km (1477 m/s) and the 26 km shown.

Thin margin indeed. My first test runs had liquid fuel tanks in place of ore and the craft made orbit easily. Switching to ore changed everything. The first run I managed a higher speed on air-breathers (1582 m/s!), but pulled up way too hard, messed up the ascent enough that I was short of circularization. The run shown was the second attempt with ore as cargo and she performed significantly better than I had hoped. I expected to have to do more fine tuning.

I have yet to attempt deorbiting the craft, but hopefully I can manage it with the 51 m/s left in the tanks.

Thanks again.

Happy landings!

update: The deorbit burn was done with less than 30 m/s and landed her without even lighting the engines.

Edited June 28, 2015 by Starhawk

[Red Iron Crown]

Nao, that's a new high for rocket entries, looks like you're the top of both boards for the moment. Well done!

[Jouni]

Started designing this before Jouni's rocket, ended up using the same engines - so there is a chance that it's the theoretical best configuration, although i used more power (1.4 mN compared to Jouni's 1 mN) to lift a touch lighter craft.

And I was still struggling to get the payload fraction above 27% with a six-booster design. I was also using different amounts of fuel in the boosters, but I didn't think that trading away fuel for dry mass (and TWR) would be a good idea.

[Nich]

YA improved with an MK3 design "SSTO V8 57.63"

Decoupler was attached to the payload. I have no idea how to get it to flip when working inside a cargo bay so need to subtract .025 from the payload

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Flight path is as follows. Brake and full throttle engines until a whiplash gets 95 kn+. At the end of the runway don't pull up too hard or the back end will hit the grass. Not splashing in the water takes a large AOA 15 degrees at least DONT HIT THE WATER lol. Accelerate level till 400 and move LF forward to center the COM (you can tell by how much up force is on the tail fins). Tip up to 15 degrees until 10 km and then follow propagrade. Things will get hot and can explode don't be afraid to back off the throttle if it is over 1100m/s below 10 km. Air breathers die at about 22-23 km and 1350ish m/s Switch to LF OX the moment your not accelerating. This thing is a tank do lose to much upward momentum by waiting until it is too late. 57.605/129.86 44.36% and all i have to do is add airbrakes and possibly a parachute (i didn't for the purpose of the challenge)

My first successful try made it with 100 LF and 67 OX left but I screwed up the screen shots :/

How do you upload a craft file?

Edited June 28, 2015 by Nich

[Red Iron Crown]

Awesome entry, Nich, a new top air-breathing SSTO on the board. This pic really shows how marginal the takeoff is, it should be leaving a wake! Well done!

[Nich]

SSTO V8 57.63 if the link doesn't work let me know

https://drive.google.com/file/d/0B0iPRE-stt2CbGFlOUtoQ1ExanM/view?usp=sharing

[Nich]

So after about 30 attempts i have come to the conclusion you can not land a shuttle on the runway with wsad :/

Has anyone else managed to do this?

[rofltehcat]

Have you tried activating capslock for finer controls? What is your problem with it?

The WASD controls can be fiddly but if the space craft is designed correctly I can usually land it (after a few tries).