Originally Posted by
henra
pic snipped.
This looks like the Jet nozzle to me (and I fail to find another one on the other side). I would not expect this to be on the lower side of a VLO aircraft.
I very much doubt it. In order to lift this thing onto the truck and get it onto the RCS pole it will require a crane to do the job. Considering the position is directly opposite the RCS pole flange/connector, which will be somewhere near the centre of gravity, then I suspect it's simply an opening which allows hooking it up to a crane.
BAE Replica was mounted upside down for RCS testing. It also had very small exhausts. Most RCS testing is performed on prototype shapes and models which are not to scale and therefore don't always have the exact same features as a full scale, finished aircraft.