Preheating engines: Airplane engines versus auto engines

Matt W. Barrow wrote:
"Peter R." wrote in message
...
On 12/19/2007 7:56:55 PM, wrote:

Cars typically use 5W30. I used to use 0W30 in my Ford
pickup. Started OK at -35°C. Airplane engines can't use such thin
stuff.
Thanks, Dan, for the education. Unlike some of the hotshot pilots in this
group who apparently were born with this knowledge, I admit to still
having a
lot to learn despite flying twice to three times every week.


FWIW - http://www.reiffpreheat.com/tbo.htm

And some magazine articles at
http://www.reiffpreheat.com/product.htm#Why_preheat

And a blog article about engine moisture after shutdown (and follow-up) at
http://www.reiffpreheat.com/product.htm#Why_preheat (2nd and 3rd down)

As always...YMMV.

Yes, YMMV, especially when based on incomplete information. The first
reference above claims that "The specific heat of oil is at least four
to five times the specific heat of the metals in an engine," which
simply isn't accurate for aircraft. If you count only the steel in the
engine, then this is true, but a significant part of most aircraft
engines is aluminum and its Cp is about twice that of steel and thus
less then 2.5X different from oil rather than 4-5X.

I've read the "expert" commentary from Shell, Lycoming, Continental, and
other companies about this issue and they certainly make arguments that
sound logical on the surface. However, I live in a fairly cold climate
for at least 5 months of the year and have personally had engines that
were cold started at temps often below 0 F and occasionally below -20F
with not a single problem.

So, I still preheat given a choice, but I would not lose a second of
sleep over starting an airplane engine at any temperature at which it
would crank fast enough to start.


Matt