My large 751 ton payloads are too small to get to space

[Clockwork13]

I am working on my space station, and I am using a powerful booster to escape the atmosphere. Strangely my payload weighing over 750 tons keeps exploding in the atmosphere because it's going like 1200 m/s before it's hardly even half way out of the atmosphere. According to mechjeb, my ship is 751.674 tons and I have 7295 DeltaV total. Guess I'm speeding up to fast...

[MKI]

Is your ship or the final payload (the thing you getting into space, not the whole rocket) 750 tons?

Lower the throttle so you not flying so fast if your ship cannot handle the stress. With fuel gone you accelerate faster. If mechjeb is flying for you, change the acceleration limit so your aren't go so fast early.

Other than that find the structural problem and fix it. When things explode in KSP its either a design flaw or an piloting flaw.

Edited March 28, 2014 by MKI

[problemecium]

^What he said. Whenever I'm lifting something heavy I keep the G-force under 2 to avoid squishing it. It's probably overkill, but you should still keep it low for big stuff to avoid explosions.

[merendel]

Since you've got MJ I'd say open the utilities tab and limit acceleration to 20m/s or so. I tend to do that if I've got a particularly high TWR. I've had a few craft with 2.5 or so on the pad that were OK at launch but were up in the 4-5G range just before stage burnout. If you've got something particularly heavy on top of a small connection your probably going to crush the connector at that speed.

If you post a pic of what your trying to launch we might be able to give you more specific tips.

[KvickFlygarn87]

Use MJ to limit to terminal velocity, helps both structural integrity and delta-v to orbit

Also, GOOD GOD. 750T to orbit? Mind sharing pics and download link.

[Clockwork13]

Well, it's 8 SRBs each with 3200 thrust so I can't slow it down.

[Taki117]

Well, it's 8 SRBs each with 3200 thrust so I can't slow it down.

Well there's your problem! Use fewer SRBs. With that much thrust you're shooting off the pad, and if you are firing your liquid engines as well your TWR is ridiculous! Either cut the number of SRBs, or don't fire your main engines until after you separate them. (If you put your liquid engines on the same stage as your radial decouplers they will fire at the same time you decouple your SRBs)

[Clockwork13]

Well there's your problem! Use fewer SRBs. With that much thrust you're shooting off the pad, and if you are firing your liquid engines as well your TWR is ridiculous! Either cut the number of SRBs, or don't fire your main engines until after you separate them. (If you put your liquid engines on the same stage as your radial decouplers they will fire at the same time you decouple your SRBs)

Well, I was thinking of that, but I want to have as much force as possible. Basically my 8 SRBS usually get me to around 50 km then my liquid boosters get me into orbit and wherever I want to go. Although it might work if I make half of my SRBSs fire in one stage and the next fire in the rest. I'll post the download link soon for those of you who want to try it and have NovaPunch.

[Daddy Cecil]

Did you forget to put a decimal mark in there? Because 8 SRBs isn't going to lift 751 tons a single millimeter.

[Clockwork13]

Did you forget to put a decimal mark in there? Because 8 SRBs isn't going to lift 751 tons a single millimeter.

It's 751 tons. No decimal mark. Each SRB has 3200 thrust though which is plenty to lift the rest of the craft.

[Deathsoul097]

The KW Thor booster? Or are you using Stretchy SRB/Stretchy Parts?

[Daddy Cecil]

Can we get pics of the craft pls?

[Clockwork13]

The KW Thor booster? Or are you using Stretchy SRB/Stretchy Parts?

It's a Nova Punch booster