Rocket explodes 40s after launch?

[giddonah]

I had problems with them pitching over, but this is new. I had more on the thing and kept removing fuel tanks to make it lighter and shorter. I'm down to this and it still explodes. This is a pic 1 second before fireworks (there's a fourth tank/engine behind the middle):

[dlmarti]

What does the debug log say was the fault?

[giddonah]

I trimmed it down to just the capsule, parachute, decoupler, one fuel tank, and engine. Blew up.

I loaded another rocket I was having problem with pitch control with, which never blew up. It blew up.

I'm starting to think there might be a bug.

[giddonah]

The pitch control rocket blowing up:

[Vonar]

I think the problem is that you are staging to early, or you have got no struts, and the external engines are ripping off the connectors. Try a redesign with struts. Struts are your friend.

[SRV Ron]

Looks like a tri launcher design that I downloaded, then added additional capability to use for missions to Mun and Minmus. Facts are, my boosters are the same design as yours other then using T-30 engines

Your problem appears to be instability causing excess stress, then failure on the decoupler after 40 seconds of flight. The resulting explosions are caused by the boosters crashing into your center stage.

Try this modification;

1. Mount the decouplers higher on the center tank.

2. Mount the three boosters lower on the decoupler.

3. Add a set of braces from the base of each booster to the base of the center rocket.

4. Add a set of braces to connect each booster together at the base.

5. If using T-45 engines on the boosters, replace with T-30. Since those engines are non vectoring, you will get rid of the stress caused by unnecessary vectoring during powered flight. The T-45 in the second stage is more then sufficient to keep your rocket under control

6. Ditch the fins. The design is stable enough without them.

Edited July 24, 2013 by SRV Ron

[SRV Ron]

Forum is being flaky again.

You can add a second T-400 fuel tank to the center stage, then add a decoupler, LV-909 engine, a T-400 fuel tank, and a thruster tank and set of four thrusters to play with. That addition becomes my Tri Orbiter that can be used to send a Kerbal to Mun or Minmus or land probe packages on them using the thruster package as part of the probe stage.

[Alistone]

Follow above suggestions to reinforce connections. The problem is almost certainly coming from the lost fuel mass. If your radial tanks are 3/4 empty then instead of your engines spnding most of their energy speeding up the own fuel tanks, they are tranferring more force to the main rocket. This extra force can often break connections.

You can also help avoid this by reducing throttle as the tanks have less fuel and by keeping your ascent on the slower side of terminal velocity.

Sometimes a "crush" can occur even in a single column. To avoid this I turn off the tank at the bottom of the rocket and pull fuel from the top instead. This keeps the weight closer to the engine to avoid squeezing the stuff in the middle during the rapid accelerations accomplished outside of the atmosphere.

[giddonah]

What makes me come here for help is that it's happening now when it didn't before with zero change in design.

I took steps though. I did like Ron said. I first moved the decouplers up and mounted the boosters lower. Boom. Added struts. Boom.

[numerobis]

"Crashed into collider" sounds like the old "crashed into water pipe" bug that for example pa1983 sees on long missions: some parts of KSC have their collision meshes end up in the wrong place after a while. No known workaround.

Does it persist if you start a new save?

[SRV Ron]

Noticed your VAB building screen. Found the problem. It is the update causing something. My update froze out icons on the upper right forcing the three finger reboot and forced shutdown. That's after trying to use the existing programs. Time to start from scratch. At least, the Craft files are backed up if they still work.

[SRV Ron]

Went and built your design in the updated program. I did not use the fins but added a T-400 to the center stage. Otherwise, it looks like your design. I also brace the outer stage to each other at the base in a ring.

Flight test: Noticed the new SAS is touchy to use in flight, and weighs 1/2 ton. but none of that annoying searching for the center. The results, no explosion at 40 seconds. Jeb is in orbit, 120,000M by 86,000M with fuel to spare.

It may be best to just rebuild your rocket from scratch and see if it still blows up or not.

[Nurph]

Built the same rocket, did hard and early gravity turns, loops, re-entry effects, full throttle the whole time, no struts. Had absolutely 0 structural failures. Try rebuilding from scratch.

[giddonah]

I went so far as to create a new game/name/flag and built the thing from scratch. 33s and kaboom. Then I revert to launchpad and my rocket just kind of falls apart like it was held together with duct tape and explodes. I then revert again to take this screenshot:

Edit: I just tried adding a T-400 to the center and bracing between the three outer parts in a ring. Go to launchpad and as soon as I hit Shift to prepare for launch the capsule jumps off the top of the rocket and explodes. Didn't even get off the ground.

I'm going to try reinstalling.

Edited July 25, 2013 by giddonah

[giddonah]

Steam>Delete Local Data, then re-downloaded the game and...

35 seconds. Boom.

What the hell is wrong with this?

[mellojoe]

Are you using any mods?

I had a weird bug that would crop up when I had a mod installed wrong. I'd get to the launch pad and one of my thrusters would be sideways on the pad and the rest of the rocket would be half-together, half-in-pieces. Very weird. After deleting that mod, it worked fine. And after I re-installed the mod correctly (just drop the single folder in to the GameData folder next to the Squad folder), everything worked fine.

[giddonah]

Solved!

In Steam Library right click and Delete Local Data

I also had to delete the KSP folder in Steamapps/Common <----

Then re-download the game.

Unless I deleted the folder as well, saved games persisted along with video and audio settings.

That was frustrating...

Thanks to everyone who replied!!!!

[troyn123]

I think it might be a wind resistance thing, tearing stuff loose. 250+ m/s at only 5 km is pretty quick. Terminal velocity at 5km is ~169 m/s. Throttle back, keep your speed lower until you clear more of the atmosphere. Take a look at this chart: http://wiki.kerbalspaceprogram.com/wiki/Kerbin#Atmosphere I think if you just slow your roll a little, it'll work.