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Payload shell possible? Because this is ridiculous...


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Hi,

I've been playing Kerbal for several hours straight now and have managed to loft a modest space station into a more-or-less spherical orbit around the planet. Tutorials helped a bunch! I took a screenie on the way up, because I wanted to show the real botch job I did on sturdily securing the stupidly massive payload to the rocket/delivery mechanism.

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I was wondering if it was possible to enclose your payload into some kind of bay or wrap a shell/cowling around it? Perhaps launching something as large as this is a bit much, I don't know... but I'm gonna build a Soyuz and don't particularly want it going up bare ass to the sky :P

Cheers

Daev

Edited by whoshotdk
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I personally like the Procedural Fairings mod to put a fairing (or "shell" as you say) around payloads. However, the fairing itself won't get rid of the wobble. It looks like you could use a few more struts on that payload!

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As Xavven said, Procedural Fairings and more struts are always a good thing :) good job btw on hitting a Circular orbit and lofting a space station so quickly! Might I also suggest a mod called MechJeb. It's a good tool and a capable teacher too!

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The real issue here is that the rocket gets very narrow and then expands again where the payload is attached, causing it to buckle. Also, if SAS is on it actually exacerbates the wobble instead of making things better. Try putting a large probe core lower in the stack and control the rocket from there. Also, try not to use SAS on huge payloads (you can hold F to toggle the SAS for a few seconds if you need it). What happens is your SAS is reacting late because it is trying to damp motion where you're controlling the craft, but the engines are generating most of the torque. If the craft is not stiff enough, SAS control inputs are out of phase with the motion of the rocket.

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There are various add-ons that provide aerodynamic payload fairings for rockets:

- Procedural Fairings

- KW Rocketry

- NovaPunch

Also, just looking at the picture you've posted, whilst I'm tempted to use the "more struts" adage, I'd also advise dividing your payload up further into smaller, dockable subassemblies - the taller and more ungainly a payload is, the more likely it is to flop about even with struts.

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Agreed. You have a weak point - in general smaller diameter parts make weaker joints. You've put one strut but more would be better.

Nice lifter, by the way. Reminiscent of the Russian ones with the flared-out base. You could try part clipping adapters or nosecones on top of the LFBs to smooth it out.

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Procedural Farings mod looks awesome!

I'm very much aware of the weakness in small diameter joints... my initial prototype didn't include that bracket, so the rocket just kinda snapped in half on the launch pad. The reason for that single point of re-enforcement rather than say a symmetrical 4-set was simply that I did not want to clutter my pristine station with explosive-release-node thingies.

Circular orbit at 250k was pretty easy actually as I had a crap-ton of liquid propellant. Having said that, I got my apo/peri's matched to within 1m with only a smidgeon of fuel left...and now of course I'm stuck in orbit with a spent stage-two floating gently away from me - I'm scared its gonna come round the planet and cause problems :D

Thanks for all the suggestions, explanations and kind comments.

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While folks are recommending mods, you might also want to try Ferram Aerospace Research. It vastly improves the stock aerodynamics; without it, your fairing will look pretty but it won't actually do anything to help your rocket get into space. It'll actually hurt, by adding purely cosmetic weight.

With F.A.R. installed, the things under the fairing will be shielded from drag. It also makes spaceplanes fly more sensibly.

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I'm very much aware of the weakness in small diameter joints... my initial prototype didn't include that bracket, so the rocket just kinda snapped in half on the launch pad. The reason for that single point of re-enforcement rather than say a symmetrical 4-set was simply that I did not want to clutter my pristine station with explosive-release-node thingies.
I can't tell if you did or not from the pic, but you don't need to run struts to extra decouplers, they will break automatically when the main stack decoupler is fired. The strut will leave one end behind though, which can be unsightly, so check that end gets left on the launcher and the station is clean.
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Meh, either learn it now or learn it later. If the OP starts early, that's less he has to UNlearn when he switches.

while I agree on the learn sooner thing, its also akin to asking a first grader to solve the general theory of relativity. No, he should at least reach "high school" first, as in, proficient at all the basics, then, run up difficulty.

It needs to be in a fairing. Procedural fairings.

I use Proc. Fairings myself, and I can tell you this much: unless he makes that payload way more rigid, its STILL gonna sway. Ive watched payloads sway during launch and peek out of the Proc Fairings. He needs a good combo of fairing AND stability in the payload.

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Yeah, run struts upward, starting from the lifter body and ending on the payload. That will keep them from leaving bits behind.

Bracket the skinny section with the struts. I would say 3 or 4 should fix the buckling problem.

Mods are not my expertise, but I would say use some caution. I think people have more success figuring out what area of KSP really interests them first, then selecting mods that enhance those areas.

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while I agree on the learn sooner thing, its also akin to asking a first grader to solve the general theory of relativity. No, he should at least reach "high school" first, as in, proficient at all the basics, then, run up difficulty.

I've only been playing a month or so, and I've got probes, stations and landers at every planet and SSTO spaceplanes that are solid and stable enough that if you deliberately flip them into supersonic spins you can fairly reliably pull them out of it intact (eventually...). Just the stock parts, and they're fun to fly; struggling for control in the thin air at 25,000m at Mach 4 just before you kick the rockets in is always a hoot.

http://i1378.photobucket.com/albums/ah120/craigmotbey/imagejpg1_zps9e3153eb.jpg

Your mileage obviously varies, but personally I find it easier to fly when things behave as I expect them to. That happens with F.A.R.; it doesn't with stock. It's still a very forgiving flight sim. I honestly don't understand why you think F.A.R. has such an effect on the difficulty.

I use Proc. Fairings myself, and I can tell you this much: unless he makes that payload way more rigid, its STILL gonna sway. Ive watched payloads sway during launch and peek out of the Proc Fairings. He needs a good combo of fairing AND stability in the payload.

Yup. As everyone says: struts. At least four. That will detach when the decoupler goes if you start them from the lower stage.

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To everyone suggesting Procedural Fairings: you do realize it is PURELY cosmetic?

It only gets some use besides looking cool if you are also running FAR, otherwise they do NOTHING (besides looking cool). And when I say nothing, I mean that they add some mass to your rocket, but don't drecrease drag and most importantly, YOUR PAYLOAD CLIPS THROUGH.

So basically, procedural fairings is not in any way a solution to OP's problem: what he does need is MOAR STRUTS. Or Kerbal Joint Reinforcement, if he's ok with modding.

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From the pic supplied, You need a set of struts at the narrow part, where the bend is. A symmetrical set of six would do. Also, the command pod you are using is notorious for being aerodynamically unstable in the atmosphere. No mods would be needed, given the clipping you are using, for that design to work.

The SAS would be better, but not critical, located on the booster.

OPPS! bug in the forum double posted.

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you don't need to run struts to extra decouplers, they will break automatically when the main stack decoupler is fired. The strut will leave one end behind though, which can be unsightly, so check that end gets left on the launcher and the station is clean.

What I had was a decoupler on the station only. This decoupler was joined straight to the stack with a single (actually 4 overlapping really) strut. Are you saying I could omit the decoupler from the station part and that the strut will decouple itself without one? Sorry I dont quite understand what you mean.

Thanks

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Meh, either learn it now or learn it later. If the OP starts early, that's less he has to UNlearn when he switches.

+1.

And to add to his point.

It is better to learn good habbits then learn bad ones and have to unlearn them later. I can tell you now it is easier to teach someone who has no experience in the subject, then it is to teach someone who has learned all the wrong things.

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The fairings from Procedural Fairings can also be structural, which is relevant to OPs problem. The key is to put a second fairing base on top of the payload, facing down. The payload is then stiffly braced from top and bottom and all problems are solved...at least until the fairings are jettisoned :(. But, by then the problem is reduced because usually space engines don't make that much thrust. Nevertheless OPs rocket looks pretty extreme and could still benefit from a redesign as per other posters' suggestions.

Untitled.jpg

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The fairings from Procedural Fairings can also be structural, which is relevant to OPs problem. The key is to put a second fairing base on top of the payload, facing down. The payload is then stiffly braced from top and bottom and all problems are solved...at least until the fairings are jettisoned :(. But, by then the problem is reduced because usually space engines don't make that much thrust. Nevertheless OPs rocket looks pretty extreme and could still benefit from a redesign as per other posters' suggestions.

Learned something new myself... yeah! +1

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What I had was a decoupler on the station only. This decoupler was joined straight to the stack with a single (actually 4 overlapping really) strut. Are you saying I could omit the decoupler from the station part and that the strut will decouple itself without one? Sorry I dont quite understand what you mean.

Thanks

Basically yes. This arrangement will work fine, the struts will vanish when the cupola is decoupled from the engine.

14641785441_e64b47de88_o.png

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The fairings from Procedural Fairings can also be structural, which is relevant to OPs problem. The key is to put a second fairing base on top of the payload, facing down. The payload is then stiffly braced from top and bottom and all problems are solved...at least until the fairings are jettisoned :(. But, by then the problem is reduced because usually space engines don't make that much thrust. Nevertheless OPs rocket looks pretty extreme and could still benefit from a redesign as per other posters' suggestions.

http://i682.photobucket.com/albums/vv182/lsos/Untitled.jpg

Holy crap, if this is true I may have to start using procedural fairings instead of the KW fairings...

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