Stock Payload Fraction Challenge: 1.0.5 Edition

[Red Iron Crown]

Val, before I add your entry, do you want to make a recovery attempt to get on the Recoverable board?

[Val]

[quote name='Red Iron Crown']Val, before I add your entry, do you want to make a recovery attempt to get on the Recoverable board?[/QUOTE]Oh. I actually have to perform it? Then yes, I'll make a recovery attempt tomorrow.

Luckily I did quicksave, so I can continue where I left off. But I'll probably not make a video. I suspect it'll take a long time to deorbit.

[tewpie]

Nice job Val, that's incredibly close to the 1.0.4 fraction. Now I have to get cracking ;)

Red Iron Crown: is engine stacking allowed or not? I have a feeling this actually matters now.

[Right]

Congrats Val! Should be no problem recovering.

Tewpie, is engine stacking the same as clipping two engines on top of eachother?

[tewpie]

[quote name='Right']Tewpie, is engine stacking the same as clipping two engines on top of eachother?[/QUOTE]

Not the same. This is mounting an engine on the exhaust end of another engine and then offsetting it to the side to avoid the exhaust.

[Red Iron Crown]

[quote name='Val']Oh. I actually have to perform it?[/QUOTE]
Yes, I'd like to avoid debate about what can be recovered or not, a challenge entry should demonstrate. :)

[quote name='tewpie']This is mounting an engine on the exhaust end of another engine and then offsetting it to the side to avoid the exhaust.[/QUOTE]
I believe this practice is a bit too exploitative of the aero model and over-penalizes engines with no bottom nodes, so I'm going to update the rules with a "Additional stacks must be attached radially" kind of rule. Apologies to anyone working on designs using this technique.

[tewpie]

[quote name='Red Iron Crown']I believe this practice is a bit too exploitative of the aero model and over-penalizes engines with no bottom nodes, so I'm going to update the rules with a "Additional stacks must be attached radially" kind of rule. Apologies to anyone working on designs using this technique.[/QUOTE]

Ok, but clipping reversed nose cones into the backs of engines is ok? Cause that's what Val did in his entry :)

[Red Iron Crown]

[quote name='tewpie']Ok, but clipping reversed nose cones into the backs of engines is ok? Cause that's what Val did in his entry :)[/QUOTE]
It's part of the same stack. It's the additional engine exhaust area without additional frontal area that I am trying to keep in check.

[tewpie]

[quote name='Red Iron Crown']It's part of the same stack. It's the additional engine exhaust area without additional frontal area that I am trying to keep in check.[/QUOTE]

Ok, so I can attach anything to the backs of engines (say a toroidal fuel tank), as long as it's not another engine, right?

[Red Iron Crown]

What advantage is to be gained from attaching a fuel tank to the back?

[tewpie]

[quote name='Red Iron Crown']What advantage is to be gained from attaching a fuel tank to the back?[/QUOTE]

It's more stable to have an engine pulling a stack instead of pushing it. You can also jettison fuel tanks easier in multistage designs this way.

Also the backs of engines can be used as free attachment points for axial air intakes (rotated 180 degrees and offset forward).

Also you can attach an engine + air intake without any fuel tanks with a radial mount point (which can be shielded from drag by offsetting it into a cargo bay).

[Red Iron Crown]

[quote name='tewpie']It's more stable to have an engine pulling a stack instead of pushing it. You can also jettison fuel tanks easier in multistage designs this way.[/quote]
Have you tried this in 1.0.5? I think the exhaust would destroy the tanks.

[quote]Also the backs of engines can be used as free attachment points for axial air intakes (rotated 180 degrees and offset forward).[/quote]
That is fine.

[quote]Also you can attach an engine + air intake without any fuel tanks with a radial mount point (which can be shielded from drag by offsetting it into a cargo bay).[/QUOTE]
Not sure what you mean by this, can you show me an example?

[tewpie]

[quote name='Red Iron Crown']Have you tried this in 1.0.5? I think the exhaust would destroy the tanks.[/QUOTE]

The fuel tanks would be offset to the side.

[quote name='Red Iron Crown']Not sure what you mean by this, can you show me an example?[/QUOTE]

Like this:

[IMG]http://i.imgur.com/UwrBLvO.jpg[/IMG]

[Red Iron Crown]

[quote name='tewpie']The fuel tanks would be offset to the side.[/quote]
Then you're making a new stack that isn't attached radially. So, no.



[quote]Like this:

[url]http://i.imgur.com/UwrBLvO.jpg[/url][/QUOTE]
Separate stacks must be radially attached. The stacks in that pic are attached axially.

Would it be clearer if I phrased the rule as "No use of the offset tool to create new stacks of axially attached parts"?

[Right]

[quote name='Red Iron Crown'][quote name='tewpie']Also the backs of engines can be used as free attachment points for axial air intakes (rotated 180 degrees and offset forward).[/QUOTE]
That is fine.[/QUOTE]

Well hang on a second... I thought the rules especially prohibit engine clipping. And rightly so I think. You can reduce tail drag quite a lot by unrealistically clipping tails cones on rear engine nodes.

[quote name='tewpie']Ok, but clipping reversed nose cones into the backs of engines is ok? Cause that's what Val did in his entry :)[/QUOTE]

I don't believe he did. He attached the "Small Nose Cone" on the back, no clipping or rotating.

[tewpie]

[quote name='Right']I don't believe he did. He attached the "Small Nose Cone" on the back, no clipping or rotating.[/QUOTE]

Pretty sure a non-clipped small nose cone in the back will explode from exhaust.

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[quote name='Red Iron Crown']Would it be clearer if I phrased the rule as "No use of the offset tool to create new stacks of axially attached parts"?[/QUOTE]

Are you saying anything laterally offset attached axially is a new stack? What about offsetting engines for CoM thrust balance? This is overly broad I think.

[Val]

I've added my recovery to the imgur album in my entry post.

A video (~10 min) of the recovery is uploading and will be ready in an hour.

[HR][/HR][quote name='tewpie'][quote name='Right']Tewpie, is engine stacking the same as clipping two engines on top of eachother?[/QUOTE]Not the same. This is mounting an engine on the exhaust end of another engine and then offsetting it to the side to avoid the exhaust.[/QUOTE]KSP aerodynamics treats it the same, whether you offset the engines on top of each other or offset the rear engine to the side.

[quote name='tewpie']Pretty sure a non-clipped small nose cone in the back will explode from exhaust.[/QUOTE]No it does not.

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[TD][URL="http://i.imgur.com/T9KJJCQ.png"][IMG]http://i.imgur.com/T9KJJCQ.png[/IMG][/URL][/TD]
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[Red Iron Crown]

[quote name='Right']Well hang on a second... I thought the rules especially prohibit engine clipping. And rightly so I think. You can reduce tail drag quite a lot by unrealistically clipping tails cones on rear engine nodes.[/QUOTE]
I'm trying to strike a balance between overly litigious rules and avoiding the worst exploits. Rapierspikes and equivalents I do not consider very exploitative.

[quote name='tewpie']Are you saying anything laterally offset attached axially is a new stack? What about offsetting engines for CoM thrust balance? This is overly broad I think.[/QUOTE]
What I am trying to avoid is engine exhaust area being added without corresponding frontal area. Offsetting an engine a little bit to center the CoT is fine (though usually I see rotation used for this). Offsetting to avoid the exhaust of another engine in the same axial stack is not.

[Red Iron Crown]

I have added Val's updated entry (now with 100% more recovery!) to the leaderboard. Well done, that's a high bar you've set.

[Val]

[quote name='Red Iron Crown']I have added Val's updated entry ([B]now with 100% more recovery![/B]) to the leaderboard. Well done, that's a high bar you've set.[/QUOTE]Yay. Thank you.

And lol, I wish I had thought of using that line as my edit comment.

[tewpie]

[quote name='Val']I've added my recovery to the imgur album in my entry post.

A video (~10 min) of the recovery is uploading and will be ready in an hour.

[HR][/HR]KSP aerodynamics treats it the same, whether you offset the engines on top of each other or offset the rear engine to the side.

No it does not.

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They do explode if you use gimballing on your engines, which you do on the mk8 but probably not in your test video (I can't tell). They don't explode on your mk8 because you clipped the nosecones into the gimballed engines. In any case, I don't care one way or the other, as long as it's made clear rapierspikes with [B]CLIPPED [/B]nosecones are fine (or not). Edited November 21, 2015 by tewpie

[Red Iron Crown]

They are fine.

[Right]

Okay doke, thanks for clarification.

[tewpie]

Prepping my entry.. recovery takes a LONG time ;P

[Val]

[quote name='tewpie']They do explode if you use gimballing on your engines, which you do on the mk8 but probably not in your test video (I can't tell). They don't explode on your mk8 because you clipped the nosecones into the gimballed engines. In any case, I don't care one way or the other, as long as it's made clear rapierspikes with [B]CLIPPED [/B]nosecones are fine (or not).[/QUOTE]I did actually have Gimbaling enabled on the test craft and I took it all the way to orbit with no exploding.

[U]But you are right[/U]. If I do full yaw and full pitch control inputs at the same time, it does explode. That is just not something I've ever had to use while the engines were thrusting, so that's why I didn't catch it.

[quote name='Red Iron Crown']They are fine.[/QUOTE]Maybe change the rule, while my entry is the only one on the board, using them? I can make a new one without Rapier-spikes.

That way there'll be no ambiguity regarding offsetting stuff connected to the rear node of engines. Edited November 22, 2015 by Val
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