Matt wrote on Sep 4
th, 2010 at 2:06pm:
The only thing that made sense was Seagull X-ray was somewhere else in the world and at the time the mobile transporters were the only viable option. They were supersonic as well but not Mach 4.
I don't think they are supersonic; the engines look very much like Turbofans which are designed for efficiency at sub-sonic speeds.
A turbofan consists of a gas turbine which drives a large fan. Whilst some of the air passing through this fan passes into the turbine compressors, the bulk actually passes round the OUTSIDE of the engine, This air then joins the outside of the exhaust stream, both increasing the mass of air moved (and hence the thrust) but also acts to muffle the noise from the hot exhaust stream, thus quietening the aircraft.
The problem with designing engines to cope with supersonic flight is tha the airflow has to be slowed down to subsonic speeds otherwise it 'piles up in front of the primary engine fan, rather than passing through. To do that in the case of military aircraft and Concorde, a long inlet tunnel has to be placed in front of the fan which, with carefully-placed baffles, slows down the airflow.
Seagull X-Ray has the tunnel, the Mobile Transporters do not, therefore, although the Transporters can operate at high sub-Mach numbers, they cannot fly supersonically