Shock cooling - and related damage. is it a myth?

teejayevans said:
Well that’s how they are manufactured, doing the opposite by freezing the cylinder, heating the head in an oven so when they equalize it’s a permanent fit. So I can at least imagine it happening but yes, maybe adding some super cooled precipitation might do it.
We need data on cracked cylinder heads, I’m betting they show up on turbocharged planes flown high.
Click to expand...
One of the clues is "where" they crack.....they don't crack where the cold is applied "outside"....they tend to crack in the roof of the "inside" of the exhaust port...on the inside.
 
Bobanna said:
Finally. How can we under-estimate the time-tested importance of "johnson (wagging)" on such a forum?
Click to expand...
If the johnson is cooled rapidly shrinkage results. Never heard of one cracking though...
 
Zeldman said:
I once tried to pee outside at -60f.

Talk about serious shock cooling if you know what I mean....
Click to expand...

Tried? C'mon... when you've gotta go? You go. The worst part is stripping off the gloves so you can dig through the five layers of clothing to get to it, and then hoping you can stretch it far enough to clear those five layers of clothing!

We routinely ride snowgos in -30 and lower temps. One learned item is how to keep the beer from freezing, because we drink beer when we ride. The next problem is making sure that once you open it you can finish it before it freezes. And then you can revisit the comments in line 1!
 
Stewartb said:
Tried? C'mon... when you've gotta go? You go. The worst part is stripping off the gloves so you can dig through the five layers of clothing to get to it, and then hoping you can stretch it far enough to clear those five layers of clothing!

We routinely ride snowgos in -30 and lower temps. One learned item is how to keep the beer from freezing, because we drink beer when we ride. The next problem is making sure that once you open it you can finish it before it freezes. And then you can revisit the comments in line 1!
Click to expand...
be an astronaut.....one word......Depends. o_O
 
Clark1961 said:
If the johnson is cooled rapidly shrinkage results. Never heard of one cracking though...
Click to expand...
Technically it is referred to as fractured and yes they are not a pretty sight.
 
I did not hear the hammer dropping... but this thread definitely got shock cooled

Sent from my SM-G935V using Tapatalk
 
Checkout_my_Six said:
ya but....not for 20,000 hrs. :confused:

and....I imagine your stick and rudder skills must be stellar....along with your button pressing impressions. o_O
Click to expand...
Obviously you have nothing factual to back up the low blow.

I’m not even sure why you would say that.
 
Interesting thread. It brings up a couple questions for me:
1. Has anybody ever seen shock cooling cited in an NTSB report as the probable cause of an accident?
2. Has anybody ever seen shock cooling discussed in a POH? If so, what was the maximum allowable cooling rate specified by the manufacturer?
Thanks,
Mike
 
Lycoming publishes that the maximum recommended temperature change should not exceed 50 degrees F per minute.
 
I baby my engine and do my best to respect it. I generally try to plan ahead and reduce power slowly for a smooth 500 fpm descent. No danger of 'shock cooling' there, and it's easy on the plane, pilot and passengers. But if I need the plane to come down more quickly for some reason, so be it.
 
The POH for my C-T182T is silent as to shock cooling. Lyc TIO-540-AK1A
It does mention that on extended let-downs to keep cowl flaps closed (unless hot conditions) so as to keep CHT at approximately two-thirds of the normal operating range (green arc: 200 degF to 500 degF).
 
You must log in or register to reply here.
Back
Top