Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: MachFly on October 31, 2010, 05:43:12 AM
-
I'm trying to find out what does "ata" mean on the 109's power setting? I understand that it's basically the same as manifold pressure but I'd like to know the exact meaning of the letters, is it an acronym, abbreviation, something in German, or something else.
I'm just curious.
Thanks
-
METRIC MANIFOLD PRESSURE
The idea behind the metric system was that all (metric) nations should adopt common measuring standards for concepts such as manifold pressure. Some hope!
Whilst German aviators measured MAP in Atmospheres (Ata), Soviet aviators decided to measure MAP in decimetres of Mercury (dmHg), and Italian aviators decided to measure MAP in kilogrammes force per square centimetre and could not even agree if the abbreviation for that was C or C2. Americans refused to give up inches of Mercury (inHg) and the British refused to give up pounds per square inch of boost (PSI boost). Meanwhile metric engine designers everywhere measured MAP in millimetres of Mercury (mmHg).
Confused yet?
Well it certainly makes real operating manuals confusing because the engine was rarely designed to run at 'round numbers' in the system of measurement the aviators of different nations insisted on using in the cockpit. All the following are equal in different cockpits:
1.000 Ata (Germany)
29.92 inHg (US)
760.0 mmHg (metric engine designers)
0.000 PSI boost (UK)
1.033 C or C2 (Italy)
7.600 dmHg (USSR)
So we see that 1.0 C in an Italian cockpit is only 0.97 Ata in a German cockpit or slight negative boost in a British cockpit or 28.96 inches in an American cockpit.
MAP - Manifold Absolute Pressure.
ata - Atmospheres Absolute
Manifold air pressure is in atmospheres (ata), 1 atmosphere being 30 inches of mercury.
You Happy Yet...I have a headach...... :rolleyes:
-
Small detail to add: The "t" in ata is the abbreviation for technisch - so ata is the abbreviation for Atmosphäre, technisch, absolut, literally translated: atmosphere, technical, absolute.
-
I see, thanks