Engines don't accelerate craft

[cranachan]

I have attached two radial engines (the 120kN ones) to the top of a craft and when trying to land on the moon they do nothing, and by that I mean 0g's of force. If I undock the docking nodes one or two of the parts docked to them it suddenly starts accelerating violently. It's not a thrust problem as they detached parts add up to a tonne at most and kerbal engineer shows the the TWR is 6 for the mun. Is this just a limitation of the physics engine (i.e. needing to update the craft by undocking things) or an I doing something wrong?

Any help is appreciated

Edited April 1, 2014 by cranachan

[sjwt]

If you could post pictures of your craft and the .craft file it would make helping out much easier.

[Xaiier]

If there's something below the engines it can block them. Even a small part down in the line of thrust can prevent any thrust from being applied.

[Red Iron Crown]

Are the engines actually burning when you have no acceleration, i.e. can you see the exhaust effects?

[capi3101]

Usually this happens when something is blocking the thrust. Open up your flight log after you thrust and see if something is taking damage - if it is, that's what's causing your problems. Try extending them out on girders and see if the problem persists.

[cranachan]

Usually this happens when something is blocking the thrust. Open up your flight log after you thrust and see if something is taking damage - if it is, that's what's causing your problems. Try extending them out on girders and see if the problem persists.

Solved it, just had to move the engines so that the nozzle is no where near any parts. Thanks very much