How do i test a LFB KR-1x2 in orbit?

[Armarnis]

Hey people, dunno of this kind of questions is to be posted here but since google gave me no results to this, i'll give it a try anyways

so i accepted a contract to test a LFB KR-1x2 while im orbiting kerbin.... OKAY, i thought, cant be THAT difficult, but i cant manage to actually orbit kerbit once i reached space because if i place radial mounted engines above the booster, all i'm able to achieve is spinning my rocket wildly around... so maybe anyone has a good idea for me how i can lift that big boy up? thanks in advance for your time!

Edited January 9, 2015 by Armarnis

[THX1138]

I'm not sure what the difficulty is. Could you post a screenshot of the rocket that spins around?

[Armarnis]

hope these will help:

http://i.imgur.com/J1Khbmb.png

http://i.imgur.com/xymoNQz.png

[DeMatt]

KSP does not currently understand how to use gimballing rocket engines that are "ahead" or "above" the center of mass. If you want to do the puller approach, turn off the gimbals on the engines and rely on reaction-wheel torque to steer your rocket.

That said, in order to fulfill the contract, you merely have to stage the LFB in the proper situation. The contract doesn't say anything about the LFB actually working there, or whether it's been used beforehand. So you can A) fly it up empty, use it as a fuel tank for other engines, or C) light its engines by right-clicking it and selecting "Activate Engine" (thereby saving the stage-activation for the contract).

[cantab]

This is a shortcoming of the SAS, it assumes gimballed engines are aft of the centre of mass, so when they're fore of the CoM it gimbals them the wrong way. The solution is to lock gimbals on such engines and provide alternative control.

Other ways to get the LFB into space:

Activate it without staging and use it during the launch that way, then stage to run the test. Or stage during launch, then edit the staging and stage again to run the test.

Flip it upside down and put it on top of your rocket.

[Armarnis]

hey, thanks for the infos about the gimbals, after locking them in place and playing a bit around with the thrust of the mainbooster i was able to put it up into space and test it there, many thanks to you guys!