Payload Fraction Challenge Reboot

[quasarrgames]

Since the payload fractions for jets and rockets has changed in 1.0, i'd like to reboot the challenge for largest payload fraction.

How large a fraction can you get?

Rules are simple, no cheats or mods that are cheaty.

Please indicate which mods you used (if any), your starting and payload mass, and provide a screenshot please.

Have fun!

Leaderboards

Stock Rockets:

Requia: 25.5%

Stock Jets:

rocx's Longsword 2: 31.36%

Modded Rockets:

Modded Jets:

I will submit my own entry shortly

Edited June 23, 2015 by quasarrgames

[Requia]

Stock rocket (KER and KER and Mechjeb for all to avoid using the part were used) 25.5%

Initial mass 766.77 tons. Payload mass 195.92 tons.

http://imgur.com/a/Laofu launch instructions and

.7 tons of the payload was useful, probe core, 2 reaction wheels, and a battery.

I should upload the craft file but I'm not sure where?

[rocx]

My first try in 1.0.3: the Longsword 2, powered by 1 RAPIER. 7,1675t takeoff mass, 1,685t payload mass, 23,51% payload fraction. As I had quite some fuel left at the end, this can and will be improved.

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Requia, which part of your rocket is the payload? I don't see anything that can separate, and in the original challenge the payload has to be a separable, inactive part.

Edited June 23, 2015 by rocx

[ColKlonk]

With RSS rockets I'm getting a ratio of approx 20:1.. for about a 300Km orbit, which I think is normal for RL if I'm not mistaken.

[rocx]

A slightly improved version, with an FLT-100 moved to the payload. Still the same 7,1675t mass, but 2,2475t in payload now, 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.

As an interesting side note, this rocket has a delta-v capacity of 2911,5 m/s, and I had 64,2 m/s left at the end, so that means minimum delta-v to orbit in 1.0.3 is less than 2850 m/s.

Edited June 23, 2015 by rocx
Requia pointed out my delta-v calculations were wrong

[Requia]

Requia, which part of your rocket is the payload? I don't see anything that can separate, and in the original challenge the payload has to be a separable, inactive part.

There's a stack seperator in the middle of the 14400s.

http://i.imgur.com/SO9H4zh.png (look closely, it didn't separate very far).

[rocx]

Very hard to see indeed!

[Requia]

As an interesting side note, this rocket has a delta-v capacity of 2911,5 m/s, and I had 64,2 m/s left at the end, so that means minimum delta-v to orbit in 1.0.3 is less than 2850 m/s.

According to KER it has 6000.

It ends up depending on how much LF you use before getting too high/fast I think. The 2911.5 number assumes that ou only use the 40L of LF in the LF only tank, the 6000 assumes the oxidizer is payload.

- - - Updated - - -

the heck do you even fly this thing? I thought a practical test so I could see the final fuel, but my thrust drops off to fast as I climb, so I never reach supersonic.

[rocx]

According to KER it has 6000.

It ends up depending on how much LF you use before getting too high/fast I think. The 2911.5 number assumes that ou only use the 40L of LF in the LF only tank, the 6000 assumes the oxidizer is payload.

- - - Updated - - -

the heck do you even fly this thing? I thought a practical test so I could see the final fuel, but my thrust drops off to fast as I climb, so I never reach supersonic.

Hm, right, I miscalculated the delta-v, making a spreadsheet for an airbreathing rocket is a difficult thing. Anyway, half the oxidiser in the FLT-400 is removed, so I have 40+90 liquidfuel units, or 650kg, for the jets, and 45+55+90+110 = 300 rocket fuel units, or 1,5 tons. This gives me 2987,4 m/s airbreathing and 783,4 m/s rocket delta-v, so 3770,8 total, so delta-v to orbit is 3706,6.

The way to fly it is to go diagonal pretty much right from the start. TWR at zero speed is barely over 1, so build up sideways velocity to increase engine thrust. Then aim for a 20 degree angle at 6000 m and keep it. Throttle slightly back at max Q to avoid blowing up parts. Over 15km go as horizontal as possible without flipping, and a flame-out speed over 1,6 km/s should be achievable. Burn full throttle in rocket mode to 65 km apogee, and then burn lowest throttle to 70,5 km (without throttle the rocket tends to flip in the atmosphere that's left at 30 km). And most important: try and retry a lot.

[Requia]

Er, that last proof shot was of the wrong payload according to the KER mass display, I actually launched again, this one is less invisible too: http://i.imgur.com/0UgCUL2.png

[Frank_G]

My entry: Moray Delta II Stock SSTO spaceplane.

The fully fueled craft weighs 111.3 tons and can carry additional 41.5 tons to an 85 km circular orbit, resulting in 2.68 : 1 craft : payload ratio. This is equal to 35.3% of the launch weight. The craft can be downloaded from my craftfile thread.

Detailed mission report with visible stats as follows:

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[selfish_meme]

Um http://forum.kerbalspaceprogram.com/threads/116729-Stock-Payload-Fraction-Challenge-1-0-4-Edition

[Frank_G]

Ok... thought a reboot would be the actual thread. Thanks for pointing me there.