Shock Cooling

wjmiller3 said:
In the turbo cirrus, which is normalized, you do nothing. Just start your descent and if you need to pull back a few % power to keep the speed down out of the red you do. But at 85% power you can make a 500 fpm descent without changing anything. You are way over tubulence penetration speed though, so if it is rough or IMC I do not do this. If it is rough I will pull it back to about 65-70% and make the descent. That is the beauty of the cirrus normalized system, I can descend from 25,000 feet and not once touch the mixture or the throttle until on approach. The same goes for the climb, mixture full till level off, you lean the mixture to 17GPH fuel flow, and it is set, no matter what altitude you climb to. You just make minor changes(+/-1 GPH) based on CHT.
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Yup :) I bet if you did it at 1000 FPM and just reduced power slightly to stay out of the red (obviously smooth air) those engines wouldn't shock cool blow up and fall off the airplane...right?
 
shdw said:
Yup :) I bet if you did it at 1000 FPM and just reduced power slightly to stay out of the red (obviously smooth air) those engines wouldn't shock cool blow up and fall off the airplane...right?
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All Continental and Cirrus say is keep the CHT's above 240 in the descent. To get the CHT's that low you must almost have to pull it all the way back to idle.

I can say that I once was daydreaming or something, and came on to the approach to DWH at 170kts. Pulled the power WAY back from 85% to 35% and started the descent watching the CHT's, CHT's stabilized at 275......Me and the engine survived, and that was several hundred hours ago on the airframe.
 
MikeD said:
The Continental 520s on the 404 and 421 were touchy, but didn't need to be too babied. Agree that shock cooling has been far overblown by some, and there's no harm in taking care of the engine. But treating it like a frail elderly person is going a bit overboard, IMO.
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IO-520s with the turbo are notorious for not making TBO up here, all the 207s up here are normally aspirated because they kept crapping out, so pretty much everybody removed them (and DA isn't a factor).

I found that about 1" per nautical mile worked real well with the normally aspirated ones, and not going to idle until short short final (e.g. no gliding diving approach.)
 
shock cooling is real. i fly a 421 and 414 and they both cracked engines when i went to 10" and dropped it 5000 feet. careful out there.
 
ryanmickG said:
shock cooling is real. i fly a 421 and 414 and they both cracked engines when i went to 10" and dropped it 5000 feet. careful out there.
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That's the normal "shock cooling exists" story, but what proof do you have that the cooling of the engine is what cracked the "engine"?

Specifically what did the temps do? What kind of indicators are you using? What powre setting were you running at? Where did the "engine" crack? Yadda yadda. Lots of questions I'd have before I'd believe that your "shock cooling is real" story is really a result of "shock cooling" and not a result of something else.

-mini
 
minitour said:
That's the normal "shock cooling exists" story, but what proof do you have that the cooling of the engine is what cracked the "engine"?

Specifically what did the temps do? What kind of indicators are you using? What powre setting were you running at? Where did the "engine" crack? Yadda yadda. Lots of questions I'd have before I'd believe that your "shock cooling is real" story is really a result of "shock cooling" and not a result of something else.

-mini
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temps went high to low. i was uing my gaugesg. the block and 1 sylinder crakz/ i seen it and it doneb roke so believes wut u want.
 
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