Date:         Sat, 15 May 1999 08:25:22 -0500
Reply-To:     John Rodgers <inua@ROADRUNNER.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Rodgers <inua@ROADRUNNER.COM>
Subject:      Re: Burning Magnesium Engine Case
Comments: cc: Roger&Zoe Ann Banker <Vantaztik@aol.com>

-- [ From: John Rodgers * EMC.Ver #2.5.02 ] --

Roger&Zoe Banker said:
  >>Magnesium contains its own oxygen, so once it gets started it will burn
from the inside, and is very difficult to deal with.<<

While magnesium alloy in the engine case may or may not have sufficient
oxygen bearing compounds to sustain a fire, Magnesium, once hot enough, has
such an affinity for oxygen that it  is capable of breaking the chemical
bond between an oxygen molecule and its companion chemicals. Case in point:
Burning magnesium is so chemically active that when placed in a pure C02
(carbon dioxide) environment it's flame will not be snuffed out like
ordinary fire when shut off from oxygen, but it  will separate the O2
molecule from the C (carbon) atom and consume the O2 molecule in sustaining
its own flame. Great plumes of pure carbon black or soot are produced when
the carbon is released from the CO2. An oxide of magnesium  is the magnesium
product from the reaction.

Underwater magnesium flares use the same principle, utilizing the breakdown
of water to produce the oxygen for combustion.

In World War II aircraft engine cases, especially the ones on the bombers,
were constructed of magnesium alloy. Many a bomber lost its wing and crashed
due to an engine fire that could not be put out. The fire suppression
systems could handle oil and fuel fires but if the fire got the engine case
hot enough to burn, with the rushing stream of air from flight supplying
oxygen to the fire, it was impossible to extinguish. The burning engine
produced somuch heat that it simply melted or burned through the aluminum
wing structure. With the resulting structural failure, the plane of course
crashed.

Magnesium  fires are  extremely difficult  to bring under control, and
really are  best left to the professionals.

John Rodgers
"88 GL Driver in New Mexico