These units have been in use by the British Military for the best part of 50 years now. This unit was originally supplied with a Cooking Outfit, Trailer Mounted, No.4 Mk2 (NSN 7360-99-130-5642) - a Sankey Field Kitchen, the ubiquitous ones found in-tow behind Land Rovers and Bedford Lorries. They follow this lineage: Mk1 - Gasoline Powered from a central pressure source (a modified Hydra Burner). Mk1 Modified - Adapted to burn Propane only (remove vapouriser, pilot/preheat burner and change main jet to propane). Mk2 - Propane only from new. This example is a Mk1 Modified, it shares the NSN with the Mk2, it is 7360-99-132-3576. It can be identified by the clip beneath the burner controls, in-use it would be slotted in under a retaining strip at one end and dropped over a slotted pin, the clip then slides to lock it in place. Other tell-tales are redundant holes for supporting the vapouriser tube and preheating burner. The Cooks Trailers were supplied with 8 of these 50,000 BTU (14.5Kw) Burners. Two beneath ovens and four beneath cooking-stations for Pans/Pots/Skillets etc. The remaining two burners had dual functions: the were "hot" spares for any of the other burner units, to be swapped in case of failure; or for auxiliary/standalone use on separate frames for whatever purpose. They were recommended as being fed from a 0.7Bar supply but it was fairly quickly standardised to 1Bar, to ensure commonality with the No.5 Field Cooker. So, what we have here is a Burner, on a standalone frame, boiling a 6-Gallon Pan/Dixie Just lit, gas just cracked open, giving it time to allow the mass of cast iron to warm up gently/thoroughly. Burner controls: The square spindle poking out through the gland packing is the gas valve; The square spindle above and to the right operates the air control shutter. Open the gas valve as far as required and then adjust the air to give the cleanest burn. Throttle back on the gas as required. As can be seen, it is a conical venture, this aids the mixing process, the draught of the burner also helps combustion. When up to temperature the response rate can be a little slow to change but it is a supremely stable burn at whatever heat output. Burner in place on the support frame. A trickle of gas and air 1/2 open, a nice stable medium-heat. Deliberately giving it too much gas, allow it 10 seconds to stabilise flowrates.... And you have full flat-out power! Air fully opened, any more gas and you get yellow flames (remember it's a 1Bar instead of 0.7Bar supply). Boiled 6 gallons in short order (no, I forgot to time it..) A dumpling or duff will be coming up in the near future.... Alec.