Engine out practice

"Matt Whiting" wrote in message
news
Jay Honeck wrote:
The issue with shock cooling isn't the rate of cooling per se, but
rather stress induced by differential cooling.

Actually, I think it is the rate of cooling *and* the differential
cooling -- if it exists at all. Like you, I am skeptical -- but am I
willing to bet $25K on it? Nope.

How does the rate affect things? I have a masters in structural
engineering and work for a materials company so don't be afraid to get
technical. :-)

Matt

By implication, a fast cooling rate would cause *more* differential cooling,
since the cylinders cool from the fins inward. The faster the cooling, the
higher the delta-T between the internal and external surfaces of the
cylinders. The higher the delta, the more internal stresses on the cylinders
due to the different growth between the hot and cold surfaces.

But you already knew that and were just being difficult, eh?

KB

Kyle Boatright wrote:
"Matt Whiting" wrote in message
news
Jay Honeck wrote:
The issue with shock cooling isn't the rate of cooling per se, but
rather stress induced by differential cooling.
Actually, I think it is the rate of cooling *and* the differential
cooling -- if it exists at all. Like you, I am skeptical -- but am I
willing to bet $25K on it? Nope.
How does the rate affect things? I have a masters in structural
engineering and work for a materials company so don't be afraid to get
technical. :-)

Matt

By implication, a fast cooling rate would cause *more* differential cooling,
since the cylinders cool from the fins inward. The faster the cooling, the
higher the delta-T between the internal and external surfaces of the
cylinders. The higher the delta, the more internal stresses on the cylinders
due to the different growth between the hot and cold surfaces.

But you already knew that and were just being difficult, eh?

It is a subtle point maybe, but an important one. It isn't the rate of
cooling that matters. It is a difference in rate between two locations.
Faster cooling doesn't necessarily a greater differential, it all
depends on how the cooling is done.

In some materials and at some temperatures, the rate of cooling can
change the fundamental material properties. That is a different issue
than what is involved with engines.

Matt