Outsourcing my troubleshooting

[Rune]

Yeah, that's one thing I haven't really tested, but I did it that way because in theory that should even out the thrust and keep it in the center of all 6 engines. Otherwise, in my head at least, it would tilt up or down from the uneven thrust profile.

That shouldn't matter one way or the other, since they are spaced 120 degrees. The center of thrust of each pod should go straight through the center of the tricoupler.

Rune. Because trigonometry and stuff.

[Assault Bunny]

If that's the case, then I'll flip one side. Aesthetics are important to me, at least on post booster stage stuff

[Assault Bunny]

I know you'll all be shocked to hear this, but I'm having trouble getting the Longbow into space. To be more accurate, getting it off the launchpad. My launcher is at least 50% duct tape by now, and still it keeps breaking apart.

Craft file: http://www./?fdmpbml2db970oi

Feel free to totally redesign the launcher. Everything from this separation ring here:

downwards can go. Also the solid boosters on the side. Just put a probe and a battery on the last launcher stage so I can get it out of orbit later

You know, I used to think I was a decent designer, but the fact that nothing is working is making me doubt that...

[Ohm Machre]

Don't give up, Assault! It's taken me MANY MANY MONTHS to get even one craft into a stable orbit.

Persevere!

As for the launcher, the bottom weight is not really evenly distributed. It seems to just stack.

Try building a core rocket with three or four Rockomax X-32 tanks, then add three or four more of those same length ones. Also! It's generally better to use the radial truss that's further separated from the body, because during staging, your spent stages will have a GREAT tendency to collide with your active stage, thus ruining an excellent trip.

I have KSPX, so I tend to use two or three Rockomax X-48 tanks for my booster stage. But it's important to NOT hang all of your weight on a single tank as you have here.

The two SRB boosters you have are also in a greatly inopportune place. They're trying to lift ALL that weight from the top instead of what they're really kinda designed to do, which is to support from the bottom. The boosters ALSO add weight to your upper stage, making it harder for your bottom booster stage to fly. Generally, you want to keep your weight all below your separating ring, as it both stabilizes the ship and keeps it pointed upwards.

I've no time tonight to take a look and picturatize it and show you. But! I can look at it first thing in the morn!

- Machre

[Rune]

I'd say just stick a Nova under it (you can find it on the "Zenith family" thread), and strut it to kingdom come. If that SHLV can't get it up... well, I'm not saying it is impossible to take it up, but it sure won't be easy.

[Assault Bunny]

The boosters were an attempt to reduce the load on the bottom sections by taking some of the weight of the ring during takeoff, which they seemed to do. If they added more weight than thrust, then there would seriously be no point to using them ever. The usual fail point is the hydraulic detachment manifolds, hence the strutting to hell. Collision isn't a problem unless they fail, which they usually do. If not those, then the center tanks somehow separate.

Rune, I'm trying to keep it all stock.

[Rune]

Rune, I'm trying to keep it all stock.

Well, the Nova is all stock, to the best of my knowledge. I even have my own re-engineered version of it, the design is that good. More than 100mT to orbit at 15% payload fraction!

[HoY]

I will vouch for the Nova too !! The way you are setup now, unless you are burning all the fuel in your ring through the lower stages, you don't have nearly enough fuel down bottom to get to orbit. Install mechjeb or engineer to check your staging deltaV

[Assault Bunny]

I figured the Nova was a mod, not a build, so my bad. I got the engineer thing, and it turns out the ring weighs 172.691. That's more than a nova can handle it seems...

EDIT: Yeah, having the same issues. Tried the nova anyway, and the fuel tanks stacked on top of each other are somehow separating and crashing into each other.

Edited May 2, 2013 by Assault Bunny
Added evidence

[HoY]

Post the craft for the ring ill build you a launcher later tonight lol

[Assault Bunny]

http://www./?joj26rhsb86avc2

Try to attach as little as possible to the actual craft. I'm fine with bracing it at each of the duct tape points on the underside (see above), but I prefer to keep the end craft as clean as I can

[HoY]

I understand completely. I use quantum struts for that reason exactly!

I'll do it stock tho

[Ohm Machre]

Hey Assault. I'm taking a look at the Longbow as we speak, see if I can't improve the stability.

Start of editing.

First thing I notice is, as it is right now, the CoM is ever so slightly ahead of the center of the whole craft. This will cause the craft to tip. Removing the middle portion did center the CoM properly on your orange tanks.

Wow, this thing is heeeavy at 165.42 tons, according to MechJeb. I see no possible ways to remove the weight, however...

This is how I'm setting up the booster system the best way I can think of at this point. Those two radial decoupler trusses are for the next thing in the pictures.....

...which is this. Hopefully this keeps the booster stages from oscillating into one another. ;D

Time to launch.

Forgot to show my engine layout. Four Rockomax Mainsails on three X-32s, and a core of three X-32, one X-8, and four T-45s.

Well, that is, until it spontaneously exploded.

Literally. It loaded, then the top obliterated itself in a fantastic cascade... all thew while, running at 3 FPS. XP

Unfortunately, there's so many parts it's lagging my computer like mad right now. HoY, by all means, give it a go. This was my only solution..... and I failed. T~T

Edited May 2, 2013 by Ohm Machre

[HoY]

Ohm I won't be able to work on the launcher for another 5 hours, if you have a revision by them throw it up

[Ohm Machre]

Well, I tried.... and my computer nearly DIED. xD

Go ahead and try...

[Assault Bunny]

So while I was waiting, I decided to take the Artemis (which I had previously gotten into Mun orbit, and with a backup save determined I couldn't land the damn thing properly) back to Kerbin and try to land it. Once I hit atmo it went into an uncontrollable spin (ASAS trying to kill me as usual), and I burned up the last of my fuel stabilising it manually. I assumed poor Jeb was doomed at this point, when I discovered that THE PLANE WAS GLIDING! Seriously, I could hold altitude, and even climb! After a few minutes of gliding (with my housemate's head exploding as he watched) I managed to get it over solid ground and eventually land. So I tried out the rover function, which worked well until it went too fast and blew the tires. I put the landing gear back down to let it taxi itself out, and found it was going faster, which I assume to be the fault of a slight downhill. For funsies I tried taking off again.

I'm currently flying it. This is hilarious, and makes little sense, but it's all kinds of fun

[Ohm Machre]

See? There ya go, then, haha! ;D

Things have worked out.... in one way.

[HoY]

One nova couldnt handle it??? 2 Novas it is!

[Assault Bunny]

I also tried that briefly, but 1: it exploded on the launchpad, shock, and 2: I didn't trust the separation rings I put below the nukes to work properly. Also it looks like you changed something at the bottom of the ring tanks

[HoY]

Yes I switched to cubic strut clustering for the nukes, I couldn't attach the I beam properly to the 3-way splitter. I've only gotten it to 50k but it breaks apart when the last set of radial tanks seperate. Lots of screenshots, but no time to work on it sadly I'm currently on vacation with my family till Sunday and can only really work on it after they go to sleep, and its on my old pc that is kinda choking on the part count lol.

I have it at the point where all it would take for me to fix it is the addition of 4-6 quantum struts lol. But stock struts don't work the way I need them to do to fix this problem. The docking port wasn't built centered so I can't easily build the launcher in the middle, but with quantum struts I can put a brace structure on that port.

I had a couple free hours today but I used them working on a reusable VTOL ssto tanker to bring an orange tank and large mono tank to orbit for use on my Laythe mining base.

One last edit. I noticed while camera paning around in the van that the internals of the ring itself aren't built completely mirrored to each other. The CoM looks right but when the engines start firing the fuel will drain to one side, if I saw what I think I saw. Have you put this into orbit with hyper edit and tested it out with your spaceplane attached? The thrust lines work out ok?

Edited May 3, 2013 by HoY

[Assault Bunny]

My copy of KSP is very vanilla, so I have next to no add-ons. The internals are mirrored, except for one tank of plain jet fuel slightly off center on the bottom section. Really the difference should be negligible.

In other news, I've been working on the launcher and I've come up with this:

Really, there's no reason it shouldn't work, but one of the first stage rockets keeps separating for no good reason, sometimes before I launch, sometimes after. I'll keep trying till I have to get ready for work.

Is anyone working on the Dragunov?

[HoY]

Those extra tanks ontop of the novas are way overkill and drop your twr extremely low. You can theoretically get it into orbit like that but it will take ages and several attempts because low twr ends up with tumbling end over end, especially with so much DRAG so far ahead of the thrust. I'd drop those tanks personally and work out another way to get that extra support where you want it.

Yes it was the jet fuel tank I was looking at, why not have it symmetrical also? Surely you could use both at some point lol.

And was that a yes about testing it with hyper edit? With as much time as your having sunk into this project it would be beneficial to be sure it's a working model first

One more thing,, I saw you used the larger structural girders,, those do work but if you use the smallest ones they become invisible. Just look at the bottom of the core stage of the nova launcher, those engines are attached the same way

Edit: I see what you did. You took his entire nova craft file and used it like that. Everything from the 2.5m stack decoupler UP is his test payload, not part of the actual Launcher, your meant to remove the top bit and place the remains under your own payload

[Assault Bunny]

I only have the one jet fuel tank in the centre because otherwise the tanks would clip about halfway or more through each other. Considering how much the structure flexes as it is, that's asking for an explosion. I don't know what hyper edit is, let alone have it to use it. I know the CoM is more towards the top section, but remember it's only supposed to be used to haul the Dragunov elsewhere.

Right, that makes more sense, considering that section was a bunch of fuel and no engines. I should point out I've only gotten to 22km up by the time I'm down to the centre rockets.

Oh son of a... That means I need to redesign the bracing system again. *sigh*

[HoY]

Hyperedit is a mod that lets you edit orbits. Launch your ring with no launcher, just clamps. Open hyperedit while its on the pad and edit the orbit, once your in space you can test the thrust line to make sure it doesn't pull up or down

Alternatively you can enable Hack Gravity in the alt-f12 menu and just test it at ground level possibly, but I'd do it in a vaccume

[Assault Bunny]

So after a lot of tweaking and random asymmetrical fuel tank explosions, I've managed to get the Longbow launcher stable enough to get it into orbit. Almost. The trouble occurs in the final stage when the launcher is down to the core rockets, and due to the CoM being slightly towards the top of the ring, the entire structure tries, and succeeds, to snap in half, right above the large decoupler (which I don't intend to use, I just left it on because it houses the probe parts and propellant). Also by itself the Longbow doesn't fly straight, pulling up with the engines on. Or down, can't remember. Not straight anyway.

http://www./?fdmpbml2db970oi

At this point I'm out of ideas to fix it, apart from scrapping the whole thing and starting again from scratch. Also, it seems to think it's a spaceplane, as whenever I end the flight to reset, it gives me the button for the spaceplane hanger instead of the VAB.

I've also made a few more tweaks to the Dragunov design, switching out the poodles for 45s and the front most rocket tank for plain jet fuel.

http://www./?xt3zz7oim6doove

It flies fine, till about 18km when the fuel drain changes the CoM too much and the ASAS starts foaming at the mouth. Again, no idea how to fix this.

I also used the debug menu to turn off gravity and dock the Dragunov to the Longbow without the launcher. As I suspected, together the CoM seems to be fine, though I have effectively no steering, so yet another problem to solve.