Stock Payload Fraction Challenge: 1.0.5 Edition

[tewpie]

Scarab Mk6c (.craft)

Payload Fraction: 153/271.03 = 56.45%

Pretty much the same as before, without any engine clipping, size 2 tri-adapters for even lower drag, and tweaked flight profile.

Will probably have to switch to external payloads for the next one.

Edited January 7, 2016 by tewpie

[Nefrums]

Well done!

I'm not sure external payloads is better. Cargo bays add wight but they also have better drag than external cargo.

The wings you have at the back, wouldn't it be better to offset them apart rather than angling them?

I'll try adding another 120 ore in my ship and see it it makes orbit. that should give 56,50% 

 

 

[Red Iron Crown]

Added your new entry to the board, tewpie, well done!

[Nefrums]

I made some calculations on my ship in order to improve it,  but the number did not add up.

The weight I calculated that the ship/payload should have did not match the screenshots I had taken.

Luckily I had a save with the payload just deployed in orbit.

 

Can someone please explain this to me?   Is KER displaying the wrong mass???  Or have I missed something.

 

Edited January 7, 2016 by Nefrums

[Nefrums]

Here is two more,   The ship mas before and after payload is detached.

 

The mass clearly decreases with 64330 kg....

so payload fraction should be 56.44% 

@tewpie you only are only 0.01 % ahead..     

 

 

Edited January 7, 2016 by Nefrums

[tewpie]

There's a bug in KER where the actual fairing walls are not counted towards mass.  So your payload fraction is less than 56.44 because you're using the runway KER mass as total mass which is also lower than what it should be.  The mass in SPH should be accurate.

Edited January 7, 2016 by tewpie

[Nefrums]

Never mind that old mk12 ship, here is the new mk13!

I stuffed Jeb among the cargo to keep track of it with his mechjeb 

Payload fraction 56.63%

 

 

[Red Iron Crown]

Updated the leaderboard with your latest entry, Nefrums. You keep squeaking just a little bit more from it.  

[tewpie]

Drake Mk2 (.craft)

 

Payload Fraction: 165.80 / 286.43 = 57.88%

External payload design.  I spent quite some time trying to get a balanced CoM for both takeoff and landing, and then finally realized it's actually more efficient to just use parachutes and have a perfect CoM balance for take off.

[Nich]

Made my first SSTO with over 50% payload fraction.  Really proud of this one.

121.99t takeoff

62.025t payload

50.84%

 

 

[Red Iron Crown]

@tewpie I owe you a big apology, I somehow missed your most recent entry. Sorry for that.

I'll take a look at yours and Nich's entries tonight.

[adsii1970]

I tried to download the silent patch so that I could participate in this challenge but got this error code: Error code: 2F173/H

[Red Iron Crown]

11 minutes ago, adsii1970 said:

I tried to download the silent patch so that I could participate in this challenge but got this error code: Error code: 2F173/H

It's just the most recent version of KSP. Check that you have 1.0.5.1028, if you do you're fine.

[Nefrums]

@tewpie how could i have missed your entry!?!  And it have been here for like a month...

All other challenge are on hold untill I beat you in this one ;-)  

Next entry is the 58% one...

[Red Iron Crown]

@tewpie Congrats on setting a new record with that innovative design! I've tried external payload designs but could never get it balanced for reentry, your solution neatly sidesteps the problem altogether. 

@Nich Congrats on cracking 50%! You know you're chasing every last gram when the tailfin is that small.  

Added you both to the leaderboard, well done. I again offer my humblest apologies to tewpie for the delay in reviewing the latest entry.

[Nefrums]

As promised:

Stingray Mk14:

Payload fraction 58.00%

It was really hard getting that last 0.1 percent..

 

[Red Iron Crown]

Added your entry to the leaderboard, Nefurms, well done!

[Majorjim!]

On 04/27/2015 at 2:34 PM, Red Iron Crown said:

Make sure you have the Silent Patch!

When was this released? I cannot open your link.

[Red Iron Crown]

8 minutes ago, Majorjim said:

When was this released? I cannot open your link.

Released Nov 11, 2015, two days after 1.0.5. It was a hotfix, your build should be 1.0.5.1028. See bottom of this announcement, I'll add it to the OP: 

 

[Majorjim!]

Just now, Red Iron Crown said:

Released Nov 11, 2015, two days after 1.0.5. It was a hotfix, your build should be 1.0.5.1028. See bottom of this announcement, I'll add it to the OP: 

 

OK so a while ago. I think I have it then. Thanks.

Edited February 29, 2016 by Majorjim

[Streetwind]

I'm always intrigued to see the payload fraction difference between spaceplanes and rockets.

IRL, spaceplanes are vastly disadvantaged due to the fact that speed achievable with jet engines is about the same, but orbital velocity is 3.5 times that in KSP. Which is why we haven't built any real contenders yet. Of course, rockets lose payload fraction too, with 3%-4% being considered standard nowadays.

Which makes me curious: if you took a mod like Sigma Dimensions, and started scaling Kerbin up to 2x, then 3x, then 4x and so on - at which point, using stock parts only, would spaceplanes and rockets be in parity? Perhaps that could be a challenge in its own right. A payload fraction challenge with rules identical to this one, just on a resized planet. I'm sure Nefrums wouldn't be shy to try his hand at it...

[Nefrums]

16 hours ago, Streetwind said:

I'm always intrigued to see the payload fraction difference between spaceplanes and rockets.

IRL, spaceplanes are vastly disadvantaged due to the fact that speed achievable with jet engines is about the same, but orbital velocity is 3.5 times that in KSP. Which is why we haven't built any real contenders yet. Of course, rockets lose payload fraction too, with 3%-4% being considered standard nowadays.

Which makes me curious: if you took a mod like Sigma Dimensions, and started scaling Kerbin up to 2x, then 3x, then 4x and so on - at which point, using stock parts only, would spaceplanes and rockets be in parity? Perhaps that could be a challenge in its own right. A payload fraction challenge with rules identical to this one, just on a resized planet. I'm sure Nefrums wouldn't be shy to try his hand at it...

The thing is that you would still get significantly better payload fraction by using jet engines as the first stage.

If you build the first stage from jet engines you would add about 30% mass to your ship. If you build the same stage from chemical engines you would add about 200% mass to your ship.

I made stock ships with ~3% payload fraction in RSS, using jet engines.  Se RSS Moon Landing using stock parts.   Stock chemical rockets only get about 1% payload fraction to LEO, due to the reduced isp of stock engines compared to IRL rocket engines.

This do not have a real world application as SRBs/chemical engines make a much cheaper first stage then jet engines. And IRL it is cost to orbit rather than payload fraction that is important.

 

 

[Streetwind]

Oh neat, I hadn't even seen that challenge before. That's gonna be an interesting read for later today.

[Nich]

Ya the GE9x is pretty close to the goliath and cost 60-120 million a pop vs 2500 kredits.  Staging off one or two of those would kill your budget.  Hard to put a number on whiplash/panther type engines as these are developed by military R&D budges when spread across a very small number of engines they essentially cost billions per engine.  If the saber engine does end up working maintenance alone would end up costing $100,000 or more an hour to operate.

[Ferdoni]

Here is my entry!

98 tons on the pad, 30 ton in orbit, 31% payload fraction  unfortunately as the pictures shows not recoverable