Stock Payload Fraction Challenge: 1.0.5 Edition

[MunGazer]

Yeah I know. But aircraft involvement in a space program game with multiple planets that have atmospheres just didn't strike me as "peculiar", especially in a negative way, although I'm sure rkman didn't mean it in a negative way. There are plenty of challenges involving jet planes, but I don't think the idea that a lot of people would enjoy playing with aircraft in a sandbox that is ideal for playing around with them is odd, strange, unusual, etc. What other game can you do this in? I have X-Plane 10. But X-Plane 10 is a steeper learning curve, and lots of hard work to make nice aircraft. KSP makes aircraft creation from concept to finished product more fun and streamlined for a lot of people. To just drop into this thread and say "I find it peculiar" and point out non rockets in a rocket game... it just invited my response featuring a contrasting opinion, but I don't mean any animosity by it nor do I consider rkman incorrect. I just have a different opinion This is a great thread and frankly it is very relevant to a space program.

[Red Iron Crown]

Well being a little bit competitive I have to demand I be moved up the board for I have successfully gotten my Xylol A to lift 41.7 tons of cargo out of a total (stock engineer's report) weight of 161.6 tons, that is 25.80%. I had made a mistake adding up the cargo mass, when I remove the cargo the craft weight is 119.9 tons, so it is 41.7 tons, not 41.825.

To lift 42.7 tons: start with one pair of jet fuel tanks empty, close bays on the runway for good luck or what ever, take off at 30° to 10 km, then at 0° until air speed exceeds 600 m/s then 20° to apogee and then circularize.

I think I might be able to put in an extra ton but pretty sure I won't have enough fuel for return then.

Also I have made a Xylol D with extended cargo bay which has lifted 36 tons.

I'll be happy to move up your entry if you supply some documentation (i.e. pics or video). I can't take text-only entries, sorry, too easy for people to cheat.

[RuBisCO]

Check the pictures again.

[Rune]

Great looking plane, Rune! It's a bit more clipping than I'd prefer but not egregious enough to disqualify you, especially seeing as how it wasn't purpose-built for this challenge. I've added you to the leaderboard.

Thanks! And yeah, if I undid the clipping, and applied a trick or two to reduce drag, plus get rid of superfluous stuff... I would get a better fraction . It has enough fuel to dock and return after all, and empty tanks!

Rune. Still, I like the fact that a "production model" found its way up here.

[RuBisCO]

Looks legit mightyhuhn, added you to the top of the board.

Not sure what causes the editor/flight disparity, it used to be massless parts but I think that has been fixed to a degree in 1.0.

I think the problem is MJ does not account for struts properly.

[Majorjim!]

It remains peculiar that non-rockets dominate in this rocket game.

The top three are hybrids which makes perfect sense. I found this thread quite interesting. I have never thought about payload fractions before. Keep it up chaps.

MJ

[Red Iron Crown]

Check the pictures again.

Perfect, thank you. I've updated the leaderboard and bumped you two spots. I'm still really impressed with that plane, I've attempted a similar one but with all RAPIERs, the math says it should work but I've struggled to keep it stable in the critical 15km-20km acceleration band. I need to rework the wings, I think.

[RuBisCO]

I tried all Rapier, it simply does not perform as well, the turbos help provide acceleration needed below 10 km.

I managed to get it with 36 tons to orbit manually, and I'll admit it was a pain. I use MJ for stability and to control flight angle and it does a near perfect job: all I have to do is dial in the angels when it reaches the right speeds and altitudes in MJ and it does the rest. Perhaps it would fly better with a joystick and not a keyboard.

I do land it manually though, MJ tends to snake on landing.

Edited May 30, 2015 by RuBisCO

[antbin]

I couldn't launch metaphor's 50+% craft, so I tinkered with it to try and make it flyable for a crap pilot like me. Or perhaps I need to try a different day/nighttime for better air density? Anyhow:

* Smaller payload: 52.16t

* Smaller payload fraction: 45.4% (pad mass 114.77t)

* More Skipper fuel

* More aerodynamic nosecone (?)

* Fewer (3) struts, attached from intakes upwards (so draggy bits get staged away)

* Stable under SAS (little wobble)

* Probe core instead of manned pod

* Stageable turbojets (drop after 925m/s)

Not sure if these are improvements, but at least they make it easier for a noob like me to fly.

[[[ .craft file ]]]

Javascript is disabled. View full album

Edited June 2, 2015 by antbin

[Red Iron Crown]

Well done, antbin. You're pretty close to being able to recover that Skipper stage, too. Added to the leaderboard.

[Norcalplanner]

Here's my entry, which is titled "Cheap and Cheerful". Only 21.57% mass fraction, but it gets over 20 tons of payload to orbit for less than 37k funds. It uses a tried and true two stage to orbit design, with a Mainsail on the first stage and a Poodle on the second stage. I really tried to limit drag with this design, using what is supposed to be the best nosecone and not having any control fins. Not nearly as fancy as some other entries, but it works.

Javascript is disabled. View full album

Edit: Whoops, just noticed the requirement to use the mass figures in the map mode screen. I took the opportunity to revise the craft slightly, with an even pointier fairing and a tweaked ascent profile. Missed getting a shot of the craft on the pad, but the mass fraction increased just a tiny bit to 21.69 percent. Here's the revised design.

Javascript is disabled. View full album

Edited June 3, 2015 by Norcalplanner
revised design with proper mass screens

[Red Iron Crown]

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.

[maccollo]

Maybe you should throw in a separate category for cost/payload fraction? It would be interesting to see performance and cost effectiveness of various designs side by side.

[RuBisCO]

This one was specifically designed from the get go to achieve the highest mass fraction while still retaining enough fuel and flight capacity to land back from orbit.

The Xylol 3 is a small improvement on the Xylol 1&2, having the extended cargo bay of the Xylol 2, but with more aesthetically pleasing bow and stern and re-designed and strut re-enforced tail fin. It comes with an external docking port (open/closes with cargo bays custom09), RCS and air brakes.

The Xylol 3RB is a cut down version with Xylol 1 cargo bay, removal of external docking port, RCS, airbrakes, 4th landing gear and some struts which make the wings uncomfortably wobbly at times while shimming off 0.6 tons.

Javascript is disabled. View full album

You can remove my previous record, this is my last attempt with the Xylol as their is no chance I can beat the 2-stagea: that thing is a monster.

http://www./download/8g6o128l5lxa736/Xylol+3.zip

[Red Iron Crown]

Bumped you up a spot on the leaderboard, RuBisCo. That plane gets more impressive with each iteration, well done!

[NikkyD]

I have a question about the 50% winner...

He has 850 m/s on the upper stage, that would require him to make 1600 or more speed (horizontal) with the lower stage which is something that i havent seen any jet engine do yet. The mark is usually 1400 and then you switch to closed cycle or stage.

Antbins version looks more realistic but its 45%

[zarakon]

I have a question about the 50% winner...

He has 850 m/s on the upper stage, that would require him to make 1600 or more speed (horizontal) with the lower stage which is something that i havent seen any jet engine do yet.

1600 orbital speed, which means around 1400 air speed

[NikkyD]

I am talking about the air speed. Just build a simple rapier + fuel + ram intake and fly it. Only with the good nose cone can i get that fast, ram intakes blow up.

[Red Iron Crown]

I did a little test, ~1600m/s of surface speed is possible:

But it's not even really necessary. Orbital speed at the altitude metaphor's entry used is only about 2290m/s, subtract the 850m/s the rocket stage has and only 1440m/s orbital speed is needed or about 1265m/s of surface speed (ignoring gravity and drag losses). It is plausible to me that the RAPIERs reached significantly faster than 1265m/s enabling the upper stage to complete the insertion, so the entry will stand.

[Slugy]

I've been playing with space planes today, and have a Skylon inspired one I'm pretty pleased with (apart from the random yaw, probably induced by engines on the end of wings and KSP physics).

For this run it's carrying ore into space and is not fully fuelled, 35288 Kg at launch, 14000 Kg of which is cargo (or 14100 Kg if we count the struts as KSP seems to be doing): giving 39.75% (or 39.96%) payload fraction.

Most of the run is done with only the nose intake and the inline ones open, the shock intakes on the engines are opened briefly at high alt, if temperature allows: It gets quite warm

Engineer gets quite confused about how much fuel is there too.

Javascript is disabled. View full album

- - - Updated - - -

I do like the style of the longsword - it looks like a proper cargo plane

Edited June 4, 2015 by Slugy

[Red Iron Crown]

That's an incredible fraction for a single stage plane, Slugy, most impressive. Added your entry to the leaderboard.

[Slugy]

That's an incredible fraction for a single stage plane, Slugy, most impressive. Added your entry to the leaderboard.

Cheers, I was genuinely surprised when I did the numbers: after the first test flights I was pretty sure it would be quite good

Two things I forgot to mention: it was quite easy to get the engine thrust so high (>550 each) that they would overheat very quickly. That's not a problem I've had before. Also that building speed and thrust whilst dipping as low as 7km can work, although that's not how I flew this one (see first point ...)

EDIT: Also wing and canard angle is really important.

And EDIT 2: Nice job testing the Rapier - I know this plane gets to ~1400 ground speed.

Edited June 5, 2015 by Slugy

[RuBisCO]

I've been playing with space planes today, and have a Skylon inspired one I'm pretty pleased with (apart from the random yaw, probably induced by engines on the end of wings and KSP physics).

Try using a tail fin that is mostly static, like the Delta-Deluxe Winglet, the less fish tailing the better performance.

[Slugy]

Try using a tail fin that is mostly static, like the Delta-Deluxe Winglet, the less fish tailing the better performance.

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 ...

[RuBisCO]

Slugy,

Try tail planes instead of canards. The problem maybe that SAS and MJ can't handle the increased instability of canard configuration. I personally have found all my tail plane crafts more stable then canard ones.

Canard

Conventional : Tail planes

If roll is the problem use smaller roll controlling ailerons, while I generally have several ailerons set for pitch I have the smallest ones set for roll.