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The SRBs can not be throttled, once ignited, they provide thrust as explained above. SRB ignition takes place some three seconds after main engine ignition, and once they ramp up to full thrust, the shuttle has no choice but to leave the launch pad. For thrust vectoring, SRB nozzles can be gimbaled up to 8 deg in both pitch and yaw axes, a roll moment is created by gimbaling the two SRBs in opposite directions. | The SRBs can not be throttled, once ignited, they provide thrust as explained above. SRB ignition takes place some three seconds after main engine ignition, and once they ramp up to full thrust, the shuttle has no choice but to leave the launch pad. For thrust vectoring, SRB nozzles can be gimbaled up to 8 deg in both pitch and yaw axes, a roll moment is created by gimbaling the two SRBs in opposite directions. | ||
As of May 2015, SRB separation happens automatically once the thrust drops below some threshold to avoid having to drag dead weight. The SRBs are pushed away from the remaining launch vehicle by separation motor burns. These (including the separation animation with still burning SRBs) are modeled in FG, however due to technical issues with the submodel code at high velocities, thrust of the separation motors in the sim is set larger than in reality to provide the same visual separation dynamics. | As of May 2015, SRB separation happens automatically once the thrust drops below some threshold to avoid having to drag dead weight, but there is no provision to manually separate. The SRBs are pushed away from the remaining launch vehicle by separation motor burns. These (including the separation animation with still burning SRBs) are modeled in FG, however due to technical issues with the submodel code at high velocities, thrust of the separation motors in the sim is set larger than in reality to provide the same visual separation dynamics. | ||
The SRBs are implemented as ballistic submodels, i.e. they follow a correct trajectory and ascent with the shuttle, however since (unlike the shuttle) they are not accelerating, they visually fall behind quite quickly. | The SRBs are implemented as ballistic submodels, i.e. they follow a correct trajectory and ascent with the shuttle, however since (unlike the shuttle) they are not accelerating, they visually fall behind quite quickly. | ||
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