[0.22-0.23.0] Payload Fraction Challenge

[mhoram]

With the arrival of new engines in version 0.23.5 consider this challenge finished and closed. Please do not submit new entries.

Thanks to all participants for their creative crafts.

Some forum-posts suggest that there have been payload fraction challenges a long time ago.

Since they can not be found anymore on the forum, I want to revive them.

Mission Description

Design a rocket with the highest payload fraction and bring it from the launchpad to a Kerbin-orbit with a periapsis of 75km or higher.

Scoring

Calculate the payload fraction as payload mass in orbit divided by total ship mass before liftoff. The higher the value, the better.

Restrictions

• No cheating, debug console, part clipping, infiniglide
  
• No jet engines
  
• No participation of the payload in the ascent
  
  • No engines in the payload (Xenon and RCS also count as engines)
    
  • Fueltanks in the payload must reach the orbit full (LiquidFuel, Oxidizer, XenonGas, MonoPropellant and SolidFuel)
    
  • No excessive usage of torque in the payload (explanation)
    

  [*]Drag coefficient of the payload must be 0.2 or higher

  [*]Stock only with Kerbal Engineer Redux for information and MechJeb for information and autopilot and optionally FAR (with Module Manager)

  [*]KSP V0.22 and V0.23.0

Submissions

A valid submission must contain at least the following information

1. Payload mass
   
2. Ship mass at launch
   
3. Number of stages of the propellant
   
4. Picture of the ship before liftoff (mass of the ship must be visible)
   
5. Picture of the ship after reaching orbit and decoupling the propellant (periapsis altitude, payload mass & resources-tab must be visible)
   
6. Documentation of the drag coefficient of the payload either by displaying it in MechJeb (Vessel -> Drag coefficient) or by submitting the payloads craft file or detailed pictures of the payload must be provided where each individual part (in this case keep the number of low drag parts small) is recognizable
   

If you use launch stability enhancers, then the following additional rules apply:

• The mass of launch clamps has to be included in the ships mass for the calculation of the payload fraction
  
• keep the bottom of the rocket near the ground
  

If you use FAR, then the following additional rules apply:

• Version 0.11 or later of FAR must be used - the version number of FAR must be visible in at least one screenshot
  
• The restriction on the drag coefficient of the payload is lifted because FAR has it's own drag balancing
  
• The usage of Payload-Fairing-Parts of one of the AddOns Anvil Rockets, KW Rocketry, NovaPunch and Procedural Fairings is allowed. Name and version of the used Payload-Fairing AddOn must be stated in the submission
  
• The AddOn parts of the fairings count to the total ship mass but not to the payload mass and must be separated
  
• Editing FAR's config.xml is forbidden
  
• Entries that use FAR, will compete in a separate leaderboard
  

Awards

Classic Staging Master Award Non-Asparagus style rocket

MechJeb Compliance Award MechJeb can bring this rocket into orbit without human interaction

To qualify for this award state that MechJeb was used and submit a screenshot of MechJeb's ascent path editor.

After launch no human interaction is allowed while the periapsis is smaller than 74km.

Leaderboard

Light Category (Payload < 10 ton)

1. 20.05% Sensi (7.89 ton, 12 stages) MechJeb Compliance Award
   
2. 19.79% Seanner (6.74 ton, 12 stages)
   
3. 19.14% mhoram (4.70 ton, 7 stages)
   
4. 18.76% Nao (7.40 ton, 3 stages) Classic Staging Master Award
   
5. 18.67% numerobis (9.33 ton, 8 stages) MechJeb Compliance Award
   
6. 17.22% antbin (9.89 ton, 6 stages) payload drag coefficient < 0.2
   
7. 15.90% JUDUFU (8.97 ton, 5 stages)
   
8. 13.39% Sirine (0.97 ton, 4 stages)
   
9. 12.36% John.E (2.44 ton, 4 stages)
   

Medium Category (10 ton <= Payload < 100 ton)

1. 20.65% Sensi (29.73 ton, 21 stages) MechJeb Compliance Award
   
2. 20.36% Nao (23.72 ton, 7 stages) MechJeb Compliance Award
   
3. 19.50% tavert (18.65 ton, 9 stages)
   
4. 18.76% Kasuha (99.97 ton, 10 stages)
   
5. 18.53% Galaf (36.24 ton, 9 stages)
   
6. 17.05% mhoram (60.90 ton, 5 stages)
   

Heavy Category (100 ton <= Payload)

1. 18.26% Sensi (111.64 ton, 16 stages) MechJeb Compliance Award
   
2. 18.14% mhoram (180.60 ton, 6 stages) MechJeb Compliance Award
   
3. 16.91% blizzy78 (108.90 ton, 5 stages) MechJeb Compliance Award
   
4. 16.86% Nadrek (126.80 ton, ~17 stages) MechJeb Compliance Award
   
5. 15.32% 700NitroXpress (702.71 ton, 7 stages)
   
6. 11.92% Moar Boosters (495.97 ton, 3 stages) Classic Staging Master Award
   

FAR Category

1. 
   

Melting Pot (rockets that can not be attributed to a single person)

1. 20.11% Nao & Kasuha & numerobis (7.50 ton, 6 stages)
   
2. 19.93% Nao & Kasuha (7.42 ton, 5 stages)
   
3. 16.36% John.E & blizzy78 (2.44 ton, 4 stages) no pictures
   

The Attic (the place where you beat yourself)

1. 18.02% Nao (22.32 ton, 4 stages) Classic Staging Master Award
   
2. 18.02% mhoram (2.70 ton, 6 stages) MechJeb Compliance Award
   
3. 16.10% blizzy78 (117.35 ton, 5 stages) MechJeb Compliance Award
   

Edited April 1, 2014 by mhoram
Closed Challenge

[mhoram]

Here is my proof of concept entry.

Based on my Tangent 6 I present:

• Payload: 60.9 ton
  
• Ship Mass: 357.1 ton
  
• Stages: 5
  

with a payload fraction of 17.05%

Javascript is disabled. View full album

Edited October 28, 2013 by mhoram

[Sirine]

Mechjeb with autopilot? So, pure math challenge.

[mhoram]

Mechjeb with autopilot? So, pure math challenge.

The idea of this challenge is to design rockets with high payload fractions and not to challenge the player's piloting skills.

So I think autopilots should be admitted for players that are not that good with gravity turns.

In my proof of concept entry MechJeb would be unable to bring that payload into orbit (not enough torque). So I expect that the better entries will most likely not use autopilots.

Edited October 28, 2013 by mhoram

[Sirine]

My entry. Manual control.

Payload_Fraction_Challenge.craft

Payload: 0.79 ton

Ship Mass: 5.9 ton

Stages: 0,1,2,3,4

with a payload fraction of 13.39%?

Javascript is disabled. View full album

[antbin]

9.89 ton payload, 57.42 ton total pad mass = 17.22% fraction

Measured with MechJeb in-game (Kerbal Engineer VAB miscounts struts)

Javascript is disabled. View full album

[mhoram]

We have our first entries.

My entry. Manual control.

Payload_Fraction_Challenge.craft

Payload: 0.79 ton

Ship Mass: 5.9 ton

Stages: 0,1,2,3,4

with a payload fraction of 13.39%?

There is a LV-1 engine attached to the payload, but since it is obvious from the placement of the decoupler that it could not be used for the ascent and no ressources of the payload were used, I will accept it.

9.89 ton payload, 57.42 ton total pad mass = 17.22% fraction

Measured with MechJeb in-game (Kerbal Engineer VAB miscounts struts)

Nice design. Please provide one additional screenshot where the periapsis altitude of the orbit is shown - either in map-view mode or with MechJeb. The altimeter at the top of the screen is not enough to verify the Periapsis-requirement.

I think i need to clarify that I count Xenon engines as engines and as such may not be used when placed in the payload. Updated the OP accordingly.

[mhoram]

A minimalistic entry that can be brought to orbit by MechJeb

Payload: 2.7 ton

Ship mass: 14.98 ton

Stages: 6

Payload fraction: 18.02%

Javascript is disabled. View full album

[antbin]

Please provide one additional screenshot where the periapsis altitude of the orbit is shown - either in map-view mode or with MechJeb. The altimeter at the top of the screen is not enough to verify the Periapsis-requirement.

Oops, I forgot to take that screenie. In my defence, 1) MechJeb was set to 75km periapsis, I assumed it worked, 2) The altitude is increasing between the last 2 screenshots - apoapsis is higher than 75.05 km 3) There was 37 m/s of dV left in the nuclear tank before I decoupled it, which is enough to raise periapsis at least 5km. I can run the MechJeb ascent again, if you insist?

[mhoram]

Oops, I forgot to take that screenie. In my defence, 1) MechJeb was set to 75km periapsis, I assumed it worked, 2) The altitude is increasing between the last 2 screenshots - apoapsis is higher than 75.05 km 3) There was 37 m/s of dV left in the nuclear tank before I decoupled it, which is enough to raise periapsis at least 5km. I can run the MechJeb ascent again, if you insist?

Thanks for the explanation.

Setting MechJeb to 75km brings me usually to a periapsis of 74.95 km.

According to the screenshots there would have been enough fuel left to bring your ship to a 75km periapsis.

For future submissions I will request the screenshot with periapsis, but in this case I will not insist on it.

[Nao]

So.. an unusual entry.

Academia 2, no-asparagus rocket. 4 stages and zero fuel lines: 18,02% payload fraction

1) On launch pad 123,83t

2) In 75x75km orbit with 14kg propellant left

3) Payload decoupled 22,32t

There is a lot to improve, and of course using asparagus staging would help a lot, but the design idea was to remain simple and efficient while not using fuel lines (like they do on normal rockets).

[mhoram]

Academia 2, no-asparagus rocket. 4 stages and zero fuel lines: 18,02% payload fraction

Now this is an incredible rocket. Congratulations on the design!

I will add an award for non-asparagus style rockets.

[Galaf]

Here's the CROSS:

Javascript is disabled. View full album

It has 9 stages, including the LV-N which is attached to a docking port. I let Mechjeb fly this until ~55km before I switched over to smart A.S.S. and set it to 5 degrees above the horizon.

Achieves a payload fraction of 36.24/195.61 = 18.52% Also delivers a fully functional cargo: An orange tank with a mechjeb unit, 4 solar panels, reaction wheels and a docking port. Why not use it to start off a space station?

You could probably squeeze out the FL-T200's by playing around with the engines and flight path, but I can't be bothered. Abusing cubic struts and 48-7S's is another possible improvement, but I consider that cheaty even if the rules would allow it. Even with those tweaks, I think it's impossible to hit a 20% payload fraction.

[Nao]

Welcome to the forums , nicely done. The 48-7S are indeed ridiculous, I'm not touching them unless i really have to, but 20% is doable. I could be wrong but i think some versions ago (0.16-0.18?) we got well into the twenties with similar challenge.

[tavert]

You probably need another rule that the payload must consist of >= 0.2 drag coefficient parts. With 48-7S's and a payload of RCS blocks, or if those are forbidden even when unfueled then aircraft cockpits, 20% should be quite possible. Standard-drag I'm not so sure what it'll max out at, will give it a shot shortly.

[Kasuha]

533.01 t on the ground, 99.96 t in orbit. 18.75% if I'm not mistaken.

I used payload's torque and a bit of battery charge. Does it still count?

No mechjeb or other calculator, steered manually. Probably could be improved using them.

Javascript is disabled. View full album

[SRV Ron]

An untweaked experiment. I don't have the stats on weight but this design placed a full orange tank plus thruster pack, controller, and docking port, around Mun with a small expenditure of RCS fuel to trim the orbit.

The tweak, to do your challenge and find the right center stage size to have all its fuel gone at the 100K desired orbit. Currently, that core stage has sufficient fuel left to do a Mun high orbit.

I'll also play with this mini design some more. I may be able to get the center, upper stage, and probe into a lower orbit with all fuel left in the core stage.

Not quite in orbit

Guess these won't work due to the use of NovaPunch fuel tanks and engines.

Edited October 30, 2013 by SRV Ron

[mhoram]

Here's the CROSS:

Achieves a payload fraction of 36.24/195.61 = 18.52%

Quite the accomplishment!

I could be wrong but i think some versions ago (0.16-0.18?) we got well into the twenties with similar challenge.

Has anyone a link to the old payload fraction challenges? I could not find any of them in the forum, so I thougt that they disappeared with the forum-reset.

You probably need another rule that the payload must consist of >= 0.2 drag coefficient parts. With 48-7S's and a payload of RCS blocks, or if those are forbidden even when unfueled then aircraft cockpits, 20% should be quite possible. Standard-drag I'm not so sure what it'll max out at, will give it a shot shortly.

After seeing Nao's entry I was also thinking about this issue.

Since in the spirit of the challenge payloads should be exchangeable, I will add a rule that the payload must have an average drag coefficient of 0.2 or higher.

Sorry Nao, antbin and Kasuha, but you will have to resubmit your rockets with changed payloads in order for the results to be compareable - of the other entries so far I am quite sure that the payloads contain only 0.2+ drag parts.

533.01 t on the ground, 99.96 t in orbit. 18.75% if I'm not mistaken.

I used payload's torque and a bit of battery charge. Does it still count?

Nice job!

Battery usage is no problem because it does not change the mass of the payload.

Allowing torque in the payload will effect the usage of gimbal-free engines. Gimbal free engines usually have the advantage of lesser weight compared to gimbaling engines. Excessive usage of SAS modules in the payload allows the penalty-free usage of better engines - I would like to prevent this.

I will have to come up with a good ruke of thumb for this problem. But for the moment I think 7 SAS modules for a 100 ton payload seems excessive.

As far as I can tell, at the top of the payload is a part with a drag coefficient < 0.2? Please have a look at the new rule about drag.

[mhoram]

An untweaked experiment. I don't have the stats on weight but this design placed a full orange tank plus thruster pack, controller, and docking port, around Mun with a small expenditure of RCS fuel to trim the orbit.

The tweak, to do your challenge and find the right center stage size to have all its fuel gone at the 100K desired orbit. Currently, that core stage has sufficient fuel left to do a Mun high orbit.

Please be advised that this is a stock-only challenge: I do not intend to maintain a non-stock-leaderboard.

And the desired orbit is 75km.

[numerobis]

You probably need another rule that the payload must consist of >= 0.2 drag coefficient parts. With 48-7S's and a payload of RCS blocks, or if those are forbidden even when unfueled then aircraft cockpits, 20% should be quite possible. Standard-drag I'm not so sure what it'll max out at, will give it a shot shortly.

Damn you, I was about to submit that I got 18.5 flying by hand, and I'm a terrible pilot. My intended payload was a cockpit and a bunch of seats.

[Kasuha]

Allowing torque in the payload will effect the usage of gimbal-free engines. Gimbal free engines usually have the advantage of lesser weight compared to gimbaling engines. Excessive usage of SAS modules in the payload allows the penalty-free usage of better engines - I would like to prevent this.

I will have to come up with a good ruke of thumb for this problem. But for the moment I think 7 SAS modules for a 100 ton payload seems excessive.

I'm not the only one who uses torque on payload. And to be honest what I used was total overkill, I used them to fine-tune the weight and then I had to be careful with it to not break the ship.

As far as I can tell, at the top of the payload is a part with a drag coefficient < 0.2? Please have a look at the new rule about drag.

There was no such rule when I was building that payload. The only part with drag < 0.2 is Standard NC at the top which weighs 0.1 t and I used it for aesthetic reasons.

[tavert]

It's not a big deal if it's just a tiny fraction of the payload, but it would make a substantial difference if the whole payload is made up of low-drag parts. You have to draw the line somewhere.

[mhoram]

It's not a big deal if it's just a tiny fraction of the payload, but it would make a substantial difference if the whole payload is made up of low-drag parts. You have to draw the line somewhere.

You are right, that the line has to be drawn, but in a comprehensible way.

I think that accepting submissions where the payloads drag coefficient deviates at most 1% from 0.2 is reasonable. This allows the usage of low drag parts in a limited manner. (e.g. 4 Thruster Blocks per 20 ton payload or 1 Nose Mk7 per 20 ton payload) In the process of coming to this conclusion, the drag-values of Nao's and Kasuha's entries were accepted.

The requirement that the drag coefficient has to be documented in the submission will be necessary, because rebuilding the payload of each submission to get the drag coefficient is much work for me and easily achievable by the submitters.

Edited October 30, 2013 by mhoram

[Kasuha]

Okay, I redid my entry so it's "clean". 1 SAS module and the cap is avionics package which has 0.2 drag.

533.02 t on ground, 99.97 t in orbit. 18.75539% - 18.76% if you round up on second decimal digit.

Javascript is disabled. View full album

It was a tough battle, the ship got 100 km apoapsis first but then dipped to the atmosphere again while circularizing. I bet it's possible to do it better using some tools. In my opinion 20% should be possible using the right design.

Edited October 30, 2013 by Kasuha

[Sirine]

OP, please explain "No excessive usage of torque in the payload", I do not understand this.

What is "Torque", and where do they actually helping in the fraction value?

How many torque value is consider excessive?