Determining angled thrust component

[Zatnikitelman]

In my launcher I'm working on, I've given up trying to make engine gimbaling work for now and will simulate it using invisible thrusters (currently visible for testing purposes). The problem now however, is that I get weird values for what the thrusters should be producing to simulate an angled engine.
Each engine produces 3,370,000 Newtons of thrust.
The gimbaled engine would have had 10 degrees offset each direction.
Thus, my calculations show that is equivalent to 3,318,802.12765 Newtons straight back, and 585,194.358 newtons at a right angle to that.
The 585kN seems high to me. When I set the thrusters to that value, the launcher moves too fast.
Since the pitch is being generated by two thrusters, would this number need to be halved in this case? Or did I just make a mistake somewhere in the math?
Thanks for any help,
Zat.

 

[Juanelm]

Hi Zatnikitelman,

The values you calculated are correct.

If you have two thrusters, their force need to be halved; the net force has to be 585,194.358 newtons.

Are the trusters placed at the same distance from the CG as the engines? If they are not, then the force the thrusters exert must be different (not 585,194.358/2 newtons), in order to create the same torque.

Maybe its just that 10 degrees is to large, or the rotational moment of inertia of the ship is too low.

 

[Hielor]

One of the samples online has engine gimballing in it, I'd suggest you look at that to help with getting gimballing working correctly.

 

[ex-orbinaut]

Post removed. Content or attachment not really very helpful, on second thoughts.

 

[Southwell]

Hey,im not expert but from what I can tell, I agree with Juan elm, If you have your thrust gimballed you can work out the cartesian components through sin and cosine easily. You can see that the line of action that the Real gimballed thrust will take will pass somewhat close to the COG of your vessel. the perpendicular distance multiplied by the thrust will give a disturbance torque, which can be counteracted by the RCS system to a certain degree, yes 10 degrees may be too much. In the Virtualy gimballed vessel I assume that you are applying this perpedicular thrust down near where the main engine is. The perpendicular distance from this thrust and the COG is much larger than the other perpendicular distance thus creating a larger disturbance torque. For example in the xy plane if your thrust is applied from right to left down near the main enginer and the torque will cause the RCS fomo above the COG to fire eliminating the disturbance torque but then adding to the translational thrust in the x direction.

you could try positioning you virtual thrust so it passes through the COG and still hace RCS thrusters acting parrallel above and below