Mobile Runway Destroyer
A device invented by the Devil incarnate! First encountered at Thorney when in the winter of 67 I was authorised as a MRD operator. This being the first engine I was allowed near after leaving Halton, certainly the first ground running I experienced, it was my first experience of the downward cascade principle. Very simple in operation, it started with the Chief was handed the responsibility for the implementation of the MRD, he delegated to the sergeant who told the corporal who selected a J/T (yours truly) to actually be the operator, it couldn't go any further down as you had to be a fitter to run it.
The Derwent , as possibly some of our readers who possibly experienced the Meteor in their early existence may remember, had a very manual starting procedure if the grey cell remembers. First open the LP cock, press start button, at 15% rpm open HP cock and observe JPT rise to ensure no overtemp, at about 33% slowly advance throttle again observing JPT rise whilst attempting to pass the resonance RPM band as quickly as possible whilst not overtemping to achieve 72% idle Rpm. After that it was easy, all you had to do was communicate with the Bowser driver over what was usually a very bad I/c and co-ordinate your operations.
As has been mentioned the MRD was very good at melting snow, which then refroze as ice, which the MRD was yet again very good at removing, generally in big sheets as the jet blast got under it putting anyone or any thing in the vicinity in danger of being dealt some severe damage! If in an attempt to avoid these happenings by changing the attitude of the jet pipes,( which was done if you were lucky by nitrogen pressure acting on a jack or if unlucky by a hand hydraulic pump in the cabin of the MRD ), you could also lift some fairly big chunks of tarmac as well which needless to say did not go down well with the powers that be and in fact it was after a couple of bouts of tarmac relaying that the MRD was banned at Thorney, as was shown later it was in fact safer to land on the snow than try to clear it.
The other party trick with the MRD was to catch the bowser driver by surprise with a swift burst of power, especially if on an icy surface, and send the whole contraption off in reverse with the MRD pushing the bowser, legend has it that some of the virtuosos could steer it in reverse by use of differential throttle, not something I tried being merely a beginner in the dark art of MRD operation.