Part randomly breaks off (OJ tanks)

[thepackett]

I've been working on a launcher to get 5 OJ tanks (one central, and four radially mounted) worth of fuel into orbit, and I've accomplished it, except that one (radially mounted), and only one tank persistently falls off. There is next to zero shudder or shake in the ship when it happens. Only the middle engine has gimbal on, and everything is symmetric. The entire structure is linked with struts in such a method as to prevent any oscillation. The tank that persistently falls off is only on one side of the ship, and falls off later in the launch, when nearing space (I've seen when the struts break), which is odd because all the engines are turned <66% maximum power to prevent overheating, unlike the rather violent takeoff. It's as if the connection and all the struts for that one tank only just say "I'm done" and break. None of the other tanks fall off, no matter how much stress I put them under.

I'm sure there's no way to fix this, it has to be in the engine, but are there any other tips and tricks to keep parts from falling off like this?

Edited October 6, 2013 by thepackett

[MrPopcup]

This happened to me a while back in .20, I was experiencing this problem when I wanted to put a huge part of space station into orbit ( 100~ tons ) in one launch to 400 km, I was on 90% throttle all time and it kept breaking AFTER quitting from the first layer of the atmosphere, I put more struts from the lower tank to the upper one, then from the upper to the middle and did the X shape around every tank, still, problem occours after exiting, I found the fix is just lower your throttle down until you reach 1.20 TWR, TWR is how much your rocket produces thrust to lift itself , anything above 1 CAN lift it, so lower it until it barely adds speed, then after reaching 15 km or 20 km throttle up to your normal acceleration.

this is by far the best solution, If this didn't work with you ( also with struts and stuff like that ) then you might want to re-install the game.

[Starwaster]

as you're nearing space you've burned so much fuel (and therefore mass) that your TWR is much higher than at takeoff. press F3 at that point and see what max Gs you've sustained. Because you're at the point in your flight when you need to have throttled back alot. If using mechjeb or any tool thatnreports acceleration, keep it at 20m/s (not a hard and fast number but it sounds like that craft needs it)

edit: also how are the tanks physically connected? just radially to each other? or is there a part in between? if so which part is it? And by OJ you mean the large orange tank?

Edited October 6, 2013 by Starwaster

[thepackett]

edit: also how are the tanks physically connected? just radially to each other? or is there a part in between? if so which part is it? And by OJ you mean the large orange tank?

I'm currently using the thick and short I beam as it has two connection points and has given me the best results so far. I also have 4 struts on each tank connecting it to the center tank, and 4 struts connecting each radial tank to the adjacent radial tank.

And yes, Kerbals have mastered the art of turning orange juice into rocket propellant, hence the name OJ for the large orange tanks

Also, both Starwaster and MrPopcup, I will go try that launch method now, I will come back with results!

[Skorpychan]

I can confirm that acceleration Gs are a pain in the ass with the big tanks. My lifter had the nasty habit of just shedding one at inconvenient moments during launch, until I added more struts.

[Starwaster]

I'm currently using the thick and short I beam as it has two connection points and has given me the best results so far. I also have 4 struts on each tank connecting it to the center tank, and 4 struts connecting each radial tank to the adjacent radial tank.

And yes, Kerbals have mastered the art of turning orange juice into rocket propellant, hence the name OJ for the large orange tanks

Also, both Starwaster and MrPopcup, I will go try that launch method now, I will come back with results!

ok dont see a problem with those beams, I've used them that way myself. (my concern in asking is that I've noticed recently that lots of stock parts have no defined breakingTorque or breakingForce defined which IS a problem)

and I agree about the tanks; disregard the warning in the description they are totally edible!

[thepackett]

Some sound advice and 600 parts later: The Dawn of Victory

It even had half a orange fuel tank left over, plus the five large canisters of RCS I piled on top of it

Thank you for the advice!

I can confirm this as an effective method to get massive quantities of orange juice into orbit!