Starfighter Posted June 8, 2015 Share Posted June 8, 2015 I wonder if anyone can tell me what the "W/T" markings are that appear on British WW II aircraft, such as the Spitfire and Hurricane ? Most of the other stencils are self explainatory, but I've no idea what these signify, and I feel confident that someone will know the answer to this, which has puzzled me for some time. Link to comment Share on other sites More sharing options...
Admiral Puff Posted June 8, 2015 Share Posted June 8, 2015 They indicated that the components on which they appeared were properly bonded to the main airframe. Unbonded components (like rudder, ailerons, elevators) could cause interference with the aircraft's radio(s) if not bonded. Link to comment Share on other sites More sharing options...
brewerjerry Posted June 9, 2015 Share Posted June 9, 2015 Hi W/T .. wireless telegraphy cheers jerry Link to comment Share on other sites More sharing options...
BS_w Posted June 9, 2015 Share Posted June 9, 2015 (edited) "wireless telegraphy"? no sure They indicated that the components on which they appeared were properly bonded to the main airframe. Unbonded components (like rudder, ailerons, elevators) could cause interference with the aircraft's radio(s) if not bonded. Thus, W/T as "wiring throughout" or "wired throughout", which indicates that electrical connection must be realized between the parts stencilled "W/T" Edited June 9, 2015 by BS_w 1 Link to comment Share on other sites More sharing options...
Ed Russell Posted June 9, 2015 Share Posted June 9, 2015 http://www.network54.com/Forum/149674/thread/1316003011/W-T+markings+on+British+planes 1 Link to comment Share on other sites More sharing options...
Starfighter Posted June 9, 2015 Author Share Posted June 9, 2015 At lst, now I know ! Thanks for the info everybody, it's much appreciated. Link to comment Share on other sites More sharing options...
Don McIntyre Posted June 9, 2015 Share Posted June 9, 2015 In American parlance, I think the equivalent term would be "Grounded," but I'm not 100% sure about that definition. Link to comment Share on other sites More sharing options...
BS_w Posted June 9, 2015 Share Posted June 9, 2015 all metal parts of an aircraft must be equipotential, so they must be wired between them or electrically connected.When the aircraft is refuelled on the ground, these masses must be grounded before the fuel hose is placed to prevent a electrical static discharge during refuelling. 1 Link to comment Share on other sites More sharing options...
Selwyn Posted June 9, 2015 Share Posted June 9, 2015 (edited) all metal parts of an aircraft must be equipotential, so they must be wired between them or electrically connected. When the aircraft is refuelled on the ground, these masses must be grounded before the fuel hose is placed to prevent a electrical static discharge during refuelling. In aircraft,electrical bonding prevents static electricity build-up that can interfere with radio and navigational equipment. Bonding also provides lightning protection by allowing the current to pass through the airframe with minimum arcing. Bonding prevents dangerous static discharges in aircraft fuel tanks and hoses. Lack of adequate bonding was probably the main cause of the Hindenburg disaster in the 1930's. Selwyn Edited June 9, 2015 by Selwyn 1 Link to comment Share on other sites More sharing options...
Edgar Posted June 21, 2015 Share Posted June 21, 2015 Yesterday, I found the 1918 specification, and how-to-do-it for the earthing (as it was called, so forget this "wired throughout" idea, since it was nothing of the sort) of all metal objects. On wooden aircraft, brass, or copper, wires were run the length of the fuselage longerons, and wings' leading and trailing edges, and all metal objects had to be attached to them by wires securely soldered at each end; the idea was that everything metallic should be joined together, and to the aircraft's earthing point. This involved items like internal cross-bracing wires, fuel tanks, Scarff rings, etc. Continuity testing was carried out with 2 volt battery and lamp. A carry-over of this can be seen in the metal strips inside the Mosquito fuselage. 1 Link to comment Share on other sites More sharing options...
Darwinism Posted June 21, 2015 Share Posted June 21, 2015 Well, you live and learn - like brewerjerry I always assumed it meant "wireless telegraphy" so was something to do with the radios. Thanks everyone for the info. Link to comment Share on other sites More sharing options...
Edgar Posted June 21, 2015 Share Posted June 21, 2015 Sorry, I should have been more explicit, but it's a four-page folder of close-fitting typing; the wiring of the wings was for two-seater aircraft, and was quoted as being, " In order to increase the conducting surfaces, and consequently the electrical capacity of aircraft for wireless telegraphy purposes." 1 Link to comment Share on other sites More sharing options...
ben_m Posted June 21, 2015 Share Posted June 21, 2015 That is not evidence that the WW2 RAF stencils were an abbreviation of 'wireless telegraphy', even if that which was purpose of earthing in 1918. From the quoted sentence "In order to increase the conducting surfaces, and consequently the electrical capacity of aircraft for wireless telegraphy purposes." It sounds like they were using all these connected metal parts as the aerial? Or maybe, as radio communication to and from aircraft only started in 1917, maybe the author (or the engineers instructing them) didn't fully understand the technology. Either way the description does not fit with the WW2 wireless telegraphy technology (using independently insulated aerial). Edgar mentions the mosquito. I am not an expert on radio interference, but I do not believe that earthing together all the metal pieces of a mostly wooden aircraft such as a mosquito, would have a significant effect on radio interference, particularly in comparison to, the amount of electromagnetic noise created by the 24 spark plugs. Ian Thirsk (Head of Collections, RAF Museum), the internet leads me to believe, stated in a book on the mosquito, that it stood for 'wired throughout'. I have one of his books, but have failed to find a reference in the time available. The description 'wired throughout' matches with the actual physical earthing connections that the ground crew working on an aircraft would need to be reminded of. Link to comment Share on other sites More sharing options...
Edgar Posted June 21, 2015 Share Posted June 21, 2015 (edited) You are perfectly welcome to believe that the Ministry of Munitions, Technical Department - Aircraft Production were too incompetent to know what they were producing, but, when they issued an instruction leaflet, saying that "The following specification for wireless earths," I prefer to think they might possibly have known what they were talking about, and it certainly wasn't aerials. This is what Ian Huntley (who worked at Fairey, and would have seen these stencils on a regular basis) said:- Edited June 21, 2015 by Edgar 1 Link to comment Share on other sites More sharing options...
ben_m Posted June 21, 2015 Share Posted June 21, 2015 Why does that quote imply w/t is an abbreviation of "wireless telegraphy"? It doesn't even mention that term. It mentions bonding wire, so W/T could equally be an abbreviation of 'wired throughout'. Link to comment Share on other sites More sharing options...
Ptmvarsityfan Posted June 21, 2015 Share Posted June 21, 2015 Because W/T was the abbreviation for wireless telegraphy used by the RAF cheers, paul Link to comment Share on other sites More sharing options...
Black Knight Posted June 21, 2015 Share Posted June 21, 2015 When I was in in the early 1970s we used the abbreviation R/T, and the sets we trained on, ex-Lancaster radios, were marked R/T. Link to comment Share on other sites More sharing options...
Dave Batt Posted June 21, 2015 Share Posted June 21, 2015 (edited) We are I think referring to a period when not all aircraft had radios, and many relied on morse rather than voice for transmissions over any distance. Regarding the need for proper earthing, anyone else old enough to remember the way the TV picture would flicker when a cheapo motorbike went by? Edited June 21, 2015 by Dave Batt 3 Link to comment Share on other sites More sharing options...
brewerjerry Posted June 22, 2015 Share Posted June 22, 2015 (edited) When I was in in the early 1970s we used the abbreviation R/T, and the sets we trained on, ex-Lancaster radios, were marked R/T.Hi Most likely, radio sets would be marked R/T, W/T in ww2 was morse personally I think the w/t ( wireless telegraphy ) marking was probably was put on when the electrical circuits were bonded, but the W/T was used as it was a WW2 term used by the radio mechanics who would service the system, and easily find the point on a particular aircraft. Cheers Jerry Edited June 22, 2015 by brewerjerry 1 Link to comment Share on other sites More sharing options...
Mitch K Posted June 22, 2015 Share Posted June 22, 2015 We are I think referring to a period when not all aircraft had radios, and many relied on morse rather than voice for transmissions over any distance. Regarding the need for proper earthing, anyone else old enough to remember the way the TV picture would flicker when a cheapo motorbike went by? And crawling all over cars wiring earthing jumpers and chokes onto every last miserable bit of wire in the hope of ensuring you could hear what was on the radio, rather than just static... 3 Link to comment Share on other sites More sharing options...
sloegin57 Posted June 22, 2015 Share Posted June 22, 2015 From A.P. 3083, Section 4 Chap. 3 Paras 39 to 43, "Standard Technical Training Notes - Electrical Fitters", July 1946 :- HTH Dennis 1 Link to comment Share on other sites More sharing options...
brewerjerry Posted June 22, 2015 Share Posted June 22, 2015 Hi An interesting read of ww2 recollections http://www.telegraph.co.uk/history/Britain_at_War_Readers__Memorie/3241851/Britain-at-War-RAF-reflections.html He refers to his trade as wireless operator/mechanic in 1942, and still uses the term wireless in june 1944. Seems as you say, trades used the term wireless, but tech writers used radio. Maybe its one of those things we will never realy know . Cheers Jerry Link to comment Share on other sites More sharing options...
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