Help my esparagus staging?

[staf7]

Whenever i try to lift off with this rocket test my ship turns uncontrollably and just explodes i can't figure out whats wrong

http://imgur.com/a/CPgbd#0

theres an album first photo shows what happens and the other two show the setup

(i know i don't have SAS in those photos but i added later and it still doesn't work)

[I_Killed_Jeb]

It's because from what I can tell, you have your fuel draining asymmetrically - at the penultimate asparagus stage, you should have two boosters 180 degrees from each other. With your design, as soon as you fire your rocket you'll shift your center of mass, causing the rocket to uncontrollably torque. Additionally, I'm not sure what you're trying to accomplish with this setup, since there are no engines under your radial boosters you're not gaining any sort of TWR advantage.

[austin4050]

It's because from what I can tell, you have your fuel draining asymmetrically - at the penultimate asparagus stage, you should have two boosters 180 degrees from each other. With your design, as soon as you fire your rocket you'll shift your center of mass, causing the rocket to uncontrollably torque. Additionally, I'm not sure what you're trying to accomplish with this setup, since there are no engines under your radial boosters you're not gaining any sort of TWR advantage.

I must agree with this guy! I has to be your fuel not flowing correctly, sometimes when you load the craft most commonly struts are wrongly placed and this could also mis-place fuel-flower-things. So just double check all of those pipelines before you start again.

[I_Killed_Jeb]

Here, this is what your fuel lines should look like with proper asparagus staging. As you drop the outermost stages you maintain symmetry and a centered CoM.

BTW, your outer layer of tanks are not placed in a straight line towards the center tank (look carefully). Additionally, there's a good chance this rocket will tear itself apart in its current configuration if you add engines to your radial tanks (which is the point of asparagus)

Edited November 7, 2013 by I_Killed_Jeb

[700NitroXpress]

It looks like your staging is dropping one tank at a time and you should be dropping two. Another reason is that the blue decoupler can fail under enough force from the rockets, the red decoupler should always be used to avoid this. You could also get rid of all of the RCS components because you never need RCS on anything unless you're docking the craft, use SAS for turning. Also, you should add an SAS component because I don't see one on your craft and that could also cause it to be hard to control. I would put a large SAS ring right on top of the orange fuel tank and a small SAS ring on top of your lander can. You already have solar panels, but adding two electric generators wouldn't hurt either.

Edited November 7, 2013 by 700NitroXpress

[celem]

Yep, those stages are dropping single tanks. Co-ordinate opposite pairs to drop together, if your fuel lines are done right they will be hitting 0 together anyway. As other's have said, you probably want an engine on every single stack, otherwise it will struggle to move all that fuel.

Personally i'd keep some of the RCS, though you do have a lot. Add some of those rcs thrusters in 4-symmetry way way back on the main fuselage. Having it all up front isnt especially effective. With rcs setup right you can use it in combo with sas to launch even quite unstable rockets.

I'd also strongly suggest moving the control surfaces (fins) off the external tanks. As it stands you will drop 3-pairs of tanks and then be without control in the tail of your rocket. Since this will almost certainly occur below 9km its a problem. Especially while you are staging incorrectly with single tanks they will actually push you off course as you will have asymmetrical winglets.. Put the fins on the centre column and you will have use of them for much longer.

I_Killed_Jeb has done an excellent image for you above. Thats how your fuel should flow, 2 winding paths rather than 1 spiral.

Edited November 7, 2013 by celem

[SRV Ron]

Asparagus stages need to be dropped in balanced pairs. They have engines attached under them. You appear to be using drop tanks. Those work best in interplanetary burns. In addition, you need at least one SAS under the control module since once you get off center, your design will swap ends.

Here is what a three step asparagus looks like. Note how staging is set up.

This mini design will swap ends if you are not careful in how fast you make an orbital turn. The problem is in flying through the atmosphere.

However, when properly set up, the design can be very efficient;

Note the use of a SAS ring next to the control module. Only one is needed.

[Monkeh]

If you want 8 symmetry tanks and asparagus staging you'll need to have a couple of things:

1) Perfect symmetry. Your shots show the outer tanks not lining up with the inner tanks. This is very important. Draw a mental line from the middle of your central tank out through the first layer and on to the second. It should be a straight line that moves through the centre of each outer tank. Your third picture shows imperfect symmetry.

2) Dropping the right tanks at the right time. The way to think about this is to imagine that each outer tank feeds EVERY inner tank connected to it or the tank it's connected to. Having four tanks on each side of your central one means you should pick a tank and attach it to the next one along. Connect that one to the next one along and then once more and then the fourth one should be connected to the tank on the inner ring next to it. Next you connect the first inner one to the one next to it, that one to the next one, and again and then that one into the middle tank. Repeat for the opposite side. Sort out your staging and BOOM! You got poifect asparagus staging and a whole load more delta v. Make sure you go in the opposite direction as you connect them on each side so the tanks you drop are also on opposite sides of your rocket and you keep a nice weight symmetry. The diagram up there illustrates this quite well.

Once you get your head round this it really helps a lot.

This one of mine had 15 mainsails to start with

Dropped 8 on the first staging

Then 4

Then 2

All along it kept the symmetry and stayed straight.

Then it landed

Then it became a rover/base builder

Whoops, that was a bit too many pictures...ah well.

Good luck.