Volkoff Posted January 21, 2014 Posted January 21, 2014 (edited) This may be a silly question, but what unit of measurement would I use to describe my manifold pressure on my LaGG-3? i doubt that we use inches, so what do we use? MJ Edited January 21, 2014 by =69.GIAP=MIKHA
Emgy Posted January 21, 2014 Posted January 21, 2014 (edited) it's mmHg. (millimetres of mercury) Conversion ata, mmHg, inHg: http://www.ww2aircraft.net/forum/engines/ata-inches-hg-26858.html#post734728 Google also has a good unit conversion feature, the syntax looks like "800 mm of mercury in in of mercury" (Layman alert!) But there are other factors in comparing, IIRC the standard British gauges compared manifold pressure to outside air pressure at whichever altitude, while German gauges compared manifold pressure to a preset (1 ata: normal pressure at sea level). IIRC! Edited January 21, 2014 by Calvamos 1
Volkoff Posted January 21, 2014 Author Posted January 21, 2014 (edited) it's mmHg. (millimetres of mercury) Conversion ata, mmHg, inHg: http://www.ww2aircraft.net/forum/engines/ata-inches-hg-26858.html#post734728 Google also has a good unit conversion feature, the syntax looks like "800 mm of mercury in in of mercury" (Layman alert!) But there are other factors in comparing, IIRC the standard British gauges compared manifold pressure to outside air pressure at whichever altitude, while German gauges compared manifold pressure to a preset (1 ata: normal pressure at sea level). IIRC! Ok, great! Thank you very much for the help. So, if I look at the manifold pressure gauge and my needle is on the eight, I have a manifold pressure of 800 mmHg and if my needle is at ten and one half I have a manifold pressure of 1050 mmHg, etc? MJ Edited January 21, 2014 by =69.GIAP=MIKHA
JtD Posted January 21, 2014 Posted January 21, 2014 The British (and Japanese) gave boost in excess of sea level pressure, not in excess of current altitude outside pressure. So 9lb boost is the same amount of boost at sea level and 20000 feet. I don't recall anyone doing it differently in WW2. 1
Emgy Posted January 21, 2014 Posted January 21, 2014 JtD thanks for the correction. Mikha yes that's correct.
Volkoff Posted January 21, 2014 Author Posted January 21, 2014 (edited) JtD thanks for the correction. Mikha yes that's correct. Thanks a lot, Calvamos. It was really nice of you to explain it. MJ Edited January 21, 2014 by =69.GIAP=MIKHA
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