DTsang
08-23-2011, 10:37 PM
It seems that a widely spread understanding of German wwii manifold pressure unit "ata" might be wrong.
various sources, including this one:
http://forum.1cpublishing.eu/showthread.php?t=22308
show the following conversion:
1 Ata = 29.92 inches Hg = 760mm Hg
But a few sources suggests that "ata" or "at" refers to "technical atmosphere", while "atm" refers to standard atmosphere.
1 ata=1 kg/cm²=0.96784 atm=735.559mm Hg
http://www.sensorsone.co.uk/pressure-measurement-glossary/at-technical-atmosphere-pressure-unit.html
http://books.google.com.hk/books?id=vai7wiq5HIYC&pg=PA87&lpg=PA87&dq=technical+atmosphere+ata&source=bl&ots=_It295NiZ5&sig=6hr9Xvhma41Y7Lo_Vqele_4uyI8&hl=zh-TW&ei=2SJUTsTsJMjmmAWYtcGaDg&sa=X&oi=book_result&ct=result&resnum=5&ved=0CEkQ6AEwBA#v=onepage&q=technical%20atmosphere%20ata&f=false
these 2 sources are good, but seems not conclusive.
more about these 2 units in wikipedia:
http://en.wikipedia.org/wiki/Technical_atmosphere
http://en.wikipedia.org/wiki/Atmosphere_%28unit%29
Read between the lines there is another argument: standard atmosphere as a unit is adapted in 1954, after wwii, so the wwii unit "ata" is much less likely to be standard atmosphere.
I think more direct and conclusive evidence, say a unit conversion equation in a wwii German aircraft engine manual, is needed to confirm this, but I could not find it.
Any comments everybody? Anybody familiar with German wwii aircraft engines?
various sources, including this one:
http://forum.1cpublishing.eu/showthread.php?t=22308
show the following conversion:
1 Ata = 29.92 inches Hg = 760mm Hg
But a few sources suggests that "ata" or "at" refers to "technical atmosphere", while "atm" refers to standard atmosphere.
1 ata=1 kg/cm²=0.96784 atm=735.559mm Hg
http://www.sensorsone.co.uk/pressure-measurement-glossary/at-technical-atmosphere-pressure-unit.html
http://books.google.com.hk/books?id=vai7wiq5HIYC&pg=PA87&lpg=PA87&dq=technical+atmosphere+ata&source=bl&ots=_It295NiZ5&sig=6hr9Xvhma41Y7Lo_Vqele_4uyI8&hl=zh-TW&ei=2SJUTsTsJMjmmAWYtcGaDg&sa=X&oi=book_result&ct=result&resnum=5&ved=0CEkQ6AEwBA#v=onepage&q=technical%20atmosphere%20ata&f=false
these 2 sources are good, but seems not conclusive.
more about these 2 units in wikipedia:
http://en.wikipedia.org/wiki/Technical_atmosphere
http://en.wikipedia.org/wiki/Atmosphere_%28unit%29
Read between the lines there is another argument: standard atmosphere as a unit is adapted in 1954, after wwii, so the wwii unit "ata" is much less likely to be standard atmosphere.
I think more direct and conclusive evidence, say a unit conversion equation in a wwii German aircraft engine manual, is needed to confirm this, but I could not find it.
Any comments everybody? Anybody familiar with German wwii aircraft engines?