Preventing lower stages from blowing up?

[robly18]

Hello. I am a proud kerbonaut who has sent around 10 successful missions(Not saying out of how many). But the reason many of my missions fail is the lower stages. Most of the times, here's what happens:

1-The ship blows up before launch. I add more struts, repeat until enough struts. Go to 2.

2-The ship now launches, but collapses into itself upon liftoff. Add struts. Repeat until enough. Go to 3.

3-One of the boosters dislodges sometime after launch, and procceeds to collide with the rest of the ship tearing it apart. Add more struts. Repeat until ragequit.

So yeah. If anyone could help, I'd appreciate it. Here's the picture of one of my most recent ships that I've been attempting to fix:

[Serratus]

Less struts. Don't take off with full throttle.

EDIT:

Engine exhaust can destroy the tank it is next to. Don't burn along the body of Your rocket. Like those side-mounted tanks You have there.

Edited August 22, 2012 by Serratus

[Naiba]

You might want to try connecting the radial tanks and boosters together so they don't wobble around all over the place.

Also try launching at lower thrust, you might be suffering from too much power, crushing your rocket against the atmosphere like a tin can.

[robly18]

Just so you know, I launch at full thrust but upon launch only the solid boosters and the toroidial are turned on. Only after the solid boosters are decoupled the other thrusters get to thrust. I'll try moving and removing some stuff around anyways, thanks.

[Zephram Kerman]

It might be exhaust heating, but more likely a wobbly attachment problem. The mission report after you 'end flight' will tell you what went wrong. If the first malfunction is 'exploded due to overheating' then it's the exhaust thing. If it is 'structural failure between...' then you need to find a different way to connect those two parts. Sometimes a connection is almost perfectly rigid, sometimes it's like a bowl of spaghetti, and I've never been able to figure out what makes the difference.

By the way, it's usually ok to launch with full thrust. My designs actually run all engines, often including the lander stage, in order to help with the Goddard problem.

[segaprophet]

This doesn't blow up -

I would advise connecting each major component to each other one with at least 2 struts on either end. Also don't overstress the rocket by firing 100% of your lower stage engines/SRBs at once, but stage them out a little bit.

[EndlessWaves]

I couldn't tell from the picture so I rebuilt your machine in KSP without the struts and gantries and tinkered with it.

1. The collapsing on the launchpad problem isn't a lack of strength and weight but a bending problem - you've got all that weight. A long stick with weights attached to the sides isn't very stable even if those weights are even distributed. Moving the big fuel tanks down to the aerospikes are just above the ground and the boosters are resting on it will cure almost all launchpad wobbling.

2. The large decoupler is rather weak currently and that seemed to be causing the non-wobble collapses. Replace with the small one (and three or four struts in the gap between the tanks to increase stiffness).

3. I never came across this problem. Given those large tanks seem to be fixed attachments rather than on decouplers it shouldn't be bending enough for impact or large enough stresses from a single SRB per decoupler. Possibly resonance built up from a good launchpad wobble?

I couldn't correct the first stage tipping so like you I ended up with far too many wagglers to brute force it. It's possible your orbiter/lander is a bit too heavy for the rocket and this is another weight distribution issue but winglets are a good enough fix to continue experimenting with that layout.

I've attached the end result, It's the same basic design with the suggested fixes from above but I made a couple more tweaks like moving the winglets down a stage (they're just dead weight when you exit atmosphere) and I had to improvise a top part as it wasn't in your picture.

[ATTACH]31752[/ATTACH]

[robly18]

Thanks for all the help. I'll be tinkering a bit more and following your advice. If you want I can give you my .craft file, but it requires zoxygene.