Definition: BTU (British Thermal Unit) is that 1 BTU,
is equal to the amount of heat required to raise 1
pound of water 1 degree farenheight. This refers diredtly
to raising or lowering temps in water (sensible heat).
When removing latent heat (the heat contained in changing
state ie from water to ice) it takes 140 BTU's per
pound as compared to 1. In other words it will take
140 times the exposure to change the water to ice as
it took to lower it 1 degree in the tank. There fore
if you could measure the temps in you tank you could
then do the math to figure out when you tail or wings
are going to explode Any way have been flying for
3500 hours with many 0-15 degree hours with water and
not had a problem yet. But then again I don't have
a tail tank



At 17:42 29 June 2006, Mike The Strike wrote:
My take is that freezing level in the summer months
out west is around
15,000 feet and that at 18,000 feet it is rarely below
20 degrees F
(about -6 C). If you take the average temperature
between 15,000 and
18,000 as around 26 F (-3 C), it will take a long time
to extract
enough heat out of water to freeze it.

If you're really worried, you could paint your fin
black!