Stock Payload Fraction Challenge: 1.0.5 Edition

[selfish_meme]

Thanks, a good point, and one that should generally be followed. But I did do (almost) that that with the first build, and swapped because of - yaw!

The problem is that it tends to want to yaw/roll when any control input is supplied - it's manageable, but annoying. It's also something that can affect rockets, even if gently flown.

I'm certain that the build is absolutely symmetric, and swapped to the tail piece because I was suspicious that lift was getting applied to one side preferentially when using the small bits used in the canards. Also tried reattaching/rotating things to no avail.

Then I started a new game and copied the plane over - tendency swapped direction! So I will blame Squad/Unity for this one. It will probably go differently next time I load it ...

I have found that random yaw, when not because the vertical control is insufficient is due to flex. The engines at the end of your wings are probably to blame as you suspected. If you strut them it will probably improve your yaw problem but negatively affect your performance.

[Norcalplanner]

Added you to the leaderboard, Norcalplanner. That rocket may not be a top contender from a payload fraction perspective but the cost/ton to orbit is very impressive! Perhaps someone should make a challenge for that metric.

Something similar was done already, but it was specific to fuel rather than just payload - the Economic Fuel to Orbit Challenge.

There was also some good discussion in this thread, that was stickied back in November - Optimizing for Cost.

The only downside is that both of these discussions are for older versions of KSP, so with overhauled aero and other changes some of those old designs won't work as well anymore. Still, good discussion in terms of cheap and disposable vs. expensive and reusable.

[g00bd0g]

Here's one with 50.23% payload fraction (58650/116770), 8 rapiers and 4 turbojets on the first stage, 1 skipper on the second stage:

http://imgur.com/a/umjhl

I am curious if this was ever tested with Shock Cone intakes? Anyone have any further insight into the pros/cons of these two intake for an SSTO like this?

[antbin]

I am curious if this was ever tested with Shock Cone intakes?

Metaphor uploaded it to KerbalX, you can try flying it yourself. My guess is probably not, I found that it is a bit intakeAir-starved and TWR (not drag)-limited.

edit: Nevermind, shock cone OP

Edited June 13, 2015 by antbin

[g00bd0g]

Metaphor uploaded it to KerbalX, you can try flying it yourself. My guess is probably not, I found that it is a bit intakeAir-starved and TWR (not drag)-limited.

edit: Nevermind, shock cone OP

I don't understand your edit. You're saying the Shock Cone is Over Powered? i.e. better?

[g00bd0g]

Delivered 51 tons to LKO and landed at KSC with "MK3 SSTO Cargo 1 Bay".

For my stock aircraft, AUW at takeoff was 174.2t so mass percentage was 29.2% to LKO with enough fuel to de-orbit and land at KSC.

Super practical and easy to fly cargo plane.

Javascript is disabled. View full album

Removing all the extra fuel and practical parts got takeoff weight down to 164t, resulting in a 31% payload to orbit. I bet I could still do better.

Download crafts here:

https://drive.google.com/folderview?id=0B4zLBUio4kInZzA5Z3VnVThjR0k&usp=drive_web&ddrp=1#

Edited June 22, 2015 by g00bd0g

[Maelstrom Vortex]

Yup, I just dropped around here, and my longsword gets into the Leaderboard too, snugly somewhere around the middle:

http://i.imgur.com/VRkrw3A.png

http://i.imgur.com/5pcBwEE.png

With 146.847mT full and 36.4mT of payload (Big Red, ported on both sides with Sr. ports), that works out in my book to 24.78%, putting me on the lucky number seven. And with RCS, docking, and recovery systems and stuff thrown in! And I reckon I can improve on the ascent, I didn't get toasty enough to burn anything and switched modes at around 1,200m/s.

Edit: I just re-read the rules, and I promise all clipping is legal and without the use of F12 (or ALT-Z in my case). Too buggy to be worth it now that we have gizmos, plus we have to worry about unaerodynamic open nodes. For more pictures and details, including download, go to its post. Note, too, that it was built and posted before the (amazing) post into drag reduction measures exploiting the RAPIER's rear node came into being. Not to mention, aesthetics. The tanks on the wings are for show and containing the intakes.

Rune. Low TWR still rules.

That is an amazing design. I hadn't even thought about using the adapters for mk2 to mk 2.5 to connect the quad stack adapters on the rear.

[Red Iron Crown]

Fantastic spaceplane fraction, g00bd0g, I've added you to the leaderboard.

[Rune]

That is an amazing design. I hadn't even thought about using the adapters for mk2 to mk 2.5 to connect the quad stack adapters on the rear.

Thanks! It is quickly becoming one of my best sellers, and so far I hear no complains regarding its use, so it must be easy to fly, even.

However, it is quickly falling in the table, which is only to be expected since it wasn't built to break any records. You guys are really pushing the limits, bravo!

Rune. Form and function, that's my motto.

[RuBisCO]

Someone pushed out my Xylol did they? Fine then: 31.50% 32.14% to orbit with Xylol RB

Javascript is disabled. View full album

I did that last week and did not post it I pushed it to the limit with an orbit just above 70 km and almost no fuel to spare (one way trip) not even sure it could survive re-entry with how few struts it has and its truncated wings.

Since then I've made a Xylol 4 now which has better manual attitude control (due to better weight balance) and fewer yet better placed struts (some hidden inside the wing), pre-coolers cooling the front intakes instead of engines, improve flight regime lifts 36 tons with ease with plenty of fuel to spare, proven to return from orbit, but have not tested max capacity. The Xylol 3/4 though do actual "work" lifting cargo to orbit.

http://www./download/pwwqzdctjb9obeb/Xylol+RB+%26+4.zip

Edited June 14, 2015 by RuBisCO
UPDATE: Even higher % to orbit acheived

[Red Iron Crown]

Hah! A little competition drives innovation and refinement, moved you up a spot, RuBisCO.

[Sauron]

Question: I don't have a computer that can rin ksp right now, but what would happen if instead of a skipper as on Test 1, you udocked and then redocked a few of the rapiers to eliminate the weight of a real s2 engine?

[RuBisCO]

Rapier does not have as high of an ISP or T/W.

Edited June 19, 2015 by RuBisCO

[Sauron]

Right, I just can't check the math without the game. But the thought is that you might be able to get enough weight savings to offset ISP loss

[NikkyD]

@rubisco

just wondering, is there a reason why you built that huge tail wing like a real plane ? KSP doesn't really need that and it creates drag for little control

[RuBisCO]

it was meant to look nice first and foremost, second lift large cargo, great cargo mass to orbit was never its intended design. If you want reduce the tails size, go right ahead, see how well it flies.

[Red Iron Crown]

Looks like aero and part stats have changed enough to make a new leaderboard worthwhile (jets have had their Isp nerfed, drag changes, aerospike buffed). I think this time I will keep separate boards for air-breathers and pure rockets.

Updating the OP, now accepting 1.0.4 entries only.

[Rune]

Looks like aero and part stats have changed enough to make a new leaderboard worthwhile (jets have had their Isp nerfed, drag changes, aerospike buffed). I think this time I will keep separate boards for air-breathers and pure rockets.

Updating the OP, now accepting 1.0.4 entries only.

Well, the Longsword outperforms itself, even though the fuel levels are all wrong. 100 more m/s left in a higher 100km orbit, with ~4mT more in the bay and a wonky fuel mixture since now airbreathers suck more fuel. Can I count the unspent fuel? Otherwise, I'm gonna have to enlarge the payload bay... 39.8/148.33=26.83% on those very suboptimal conditions. I'm polishing it with liberal applications of part clipping to densify the payload, and extra liquid fuel. Screw TWR!

Edit: note I'm using 1.03. In all the important bits, that shouldn't matter, right?

Edit2: does anyone know how to fix that bug with scatterer? Kerbin is "a bit" too blue for my taste when seen from map view.

Rune. I knew it was a good idea to leave free tankage space.

Edited June 23, 2015 by Rune

[Slugy]

I bet you'll be getting a lot more out of that Longsword once you've tweaked it - the drag fixes (especially to the Mk3 cargo bay) should really help.

[Red Iron Crown]

Well, the Longsword outperforms itself, even though the fuel levels are all wrong. 100 more m/s left in a higher 100km orbit, with ~4mT more in the bay and a wonky fuel mixture since now airbreathers suck more fuel. Can I count the unspent fuel? Otherwise, I'm gonna have to enlarge the payload bay... 39.8/148.33=26.83% on those very suboptimal conditions. I'm polishing it with liberal applications of part clipping to densify the payload, and extra liquid fuel. Screw TWR!

Counting unspent fuel is a bit of a no-no, it makes the challenge too easy (just launch with an empty tank as payload, transfer any remaining fuel to it, no real need to match payload to lifter). You could try replacing your fuel payload with ore, it is almost twice as dense as fuel. I'll hold off on adding you to the board if you want to try for a higher fraction (it sounds a bit like you want to see what its real limit is ).

[rocx]

I already posted this in a different thread, this was done in 1.0.3 which I believe is the same as long as you don't use heat shields (which I never do anyway). By chance I picked the same name as Rune, I did so because a Rapier is a sword and it's a long rocket.

7,1675t mass, 2,2475t payload, for 31,36% payload fraction.

Imgur seems to be a bit broken at the moment, so here are the images one by one:

Same as before, except that the FLT-200 has been split into two FLT-100's, one in the payload, one in the rocket.

Burnout as high as possible, more than 1,6 km/s.

Orbit is achieved (on the 10th try)!

The untouched payload is separated.

[Red Iron Crown]

Great entry, rocx, added to the leaderboard. I think you could have squeaked out a bit more by moving your probe core into the payload (permitted by these rules), but it's cool to use an entry made for a similar challenge.

I went ahead and added Rune's entry too, mostly because I will forget to if an updated entry doesn't appear. Beautiful plane, and quite functional, too.

[Rune]

Great entry, rocx, added to the leaderboard. I think you could have squeaked out a bit more by moving your probe core into the payload (permitted by these rules), but it's cool to use an entry made for a similar challenge.

I went ahead and added Rune's entry too, mostly because I will forget to if an updated entry doesn't appear. Beautiful plane, and quite functional, too.

Hehe, now I can improve on myself. 30% fraction, you are my next target, I'm warning you.

Rune. The ore tip is probably the thing I need.

[Rune]

Hehe, now I can improve on myself. 30% fraction, you are my next target, I'm warning you.

Ooookay. Record successfully shattered. The specially tricked-out RecordBreaker snatches back the first place with 53.4/161.2=33.02%. Almost a third of the takeoff weight, and with enough juice to go back to the runway.

The trick was to take out engines, actually. The turbojet was no longer doing as much, and liquid fuel consumption was kinda awful. Now it really struggles to gain height (TWR<0.5 on the runway), but if you do a very shallow ascent, she breaks the Mach barrier at 9kms, and from then on, the RAPIERs wake up and get you to a cutoff speed over 1,300m/s. Low TWR FTW! Even at max-thrust conditions (~13kms), I never went over 1.5, and I broke Mach at 0.6. Thanks for the tip on dense payloads!

Rune. I feel SO validated.

Edited June 24, 2015 by Rune

[Red Iron Crown]

Nicely done, Rune! I've updated your entry in the leaderboard, your craft also has the distinction of the longest name of any entry.