Spraying water into a hot engine

Horse said:
Funny how this works.. You see that VW bus is going forward as is evidenced by the splashing of the water. Usually when a rigid object such as a bus moves forward, eventually the rear end will be where the forward end is. So at some point further along, that rear of that VW bus will be where you see the front at the moment. In the water. Submerged. That poor, poor engine.

Shock cooling is a horrible thing and very real. Be afraid everyone.
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Obviously you've never been under a VW. The cylinders and heads are completely shrouded; they're not out in the road splash. You'd have to drive it, thoroughly heated up, into a deep puddle.
 
gitmo234 said:
You're the one going against physics. Show me or you quit. Here some formulas to get you started. And you'll need the aluminum expansion rate, which is something like .0023 per meter per 40 degrees change, but don't quote me on that. I haven't used it since January

http://formulas.tutorvista.com/physics/thermal-expansion-formula.html?view=simple
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IOWs you don't know either. expansion rates have no bearing until you exceed them, this guy sure as hell didn't do that. even by your charts.
We all know that after a bazillion times of heating and cooling aircraft cylinders will crack, if one time does as you suggested we'd never fly, because we'd be changing cylinders after every time we started the engine.
So your theory doesn't work in practical operation.
Secondly, you can not start an age hardening process with out taking the aluminum to above its critical temp. then quenching prior to allow it to age. other wise our cylinders & cases would be getting harder by the minute.
For those who didn't know, you can heat 2024-T3 to a little over 800 degrees, for 1 hour, remove it from the oven allow it to cool and it will be 2024-O work it as "O" (soft) after working it as required,reheat it as before, quench it, and 24 hours later you will have 2024-T3 part ready to use.
As a working metalsmith in the Navy, I've done that many many times, works great for spinning ashtrays.
OBTW thanks for you tax payers buying us navy guys great equipment.
 
Dan Thomas said:
Obviously you've never been under a VW. The cylinders and heads are completely shrouded; they're not out in the road splash. You'd have to drive it, thoroughly heated up, into a deep puddle.
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Ummm :confused: what ? VWs are completely open on the bottom
 
Dan Thomas said:
Obviously you've never been under a VW. The cylinders and heads are completely shrouded; they're not out in the road splash. You'd have to drive it, thoroughly heated up, into a deep puddle.
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Relook at that picture. I think it qualifies as more than a deep puddle.
 
I've literally owned a metric **** ton of air cooled VWs, here is a decent picture of how the shrouding is -
aircooled-VW-engine.jpg
 
Tom-D said:
IOWs you don't know either. expansion rates have no bearing until you exceed them, this guy sure as hell didn't do that. even by your charts.
We all know that after a bazillion times of heating and cooling aircraft cylinders will crack, if one time does as you suggested we'd never fly, because we'd be changing cylinders after every time we started the engine.
So your theory doesn't work in practical operation.
Secondly, you can not start an age hardening process with out taking the aluminum to above its critical temp. then quenching prior to allow it to age. other wise our cylinders & cases would be getting harder by the minute.
For those who didn't know, you can heat 2024-T3 to a little over 800 degrees, for 1 hour, remove it from the oven allow it to cool and it will be 2024-O work it as "O" (soft) after working it as required,reheat it as before, quench it, and 24 hours later you will have 2024-T3 part ready to use.
As a working metalsmith in the Navy, I've done that many many times, works great for spinning ashtrays.
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I know just fine and as much as I'd love to continue to explain the problems with your examples, it's clearly a waste of time. Proud of you for being a metalsmith though. I'll try to make it simple for you. The answer to the question of whether he damaged it or not isn't a "yes or no". The fact he heard the metal expanding validates he rapidly cooled the engine by spraying it with water. Guess one method we use to increase wear on engine to test it? rapid cooling.

So to keep it simple, imagine a sliding scale. One side is "definitely did not cause damage" on the other side is "definitely did cause damage". Now take in all the unknowns. How old was the engine? how many hours? how has every other student and CFI flown in it? how well was the maintenance? where there already unknown mechanical defects? How much water was sprayed and where? etc etc.

Even with perfect answers it's still possible. The answer falls to the right of center on the scale. "Its entirely possible". Not all or nothing like you claim. I hope this helps you.
 
Oh and to further clarify, one major issue is unequal expansion. That would mean "cold parts" or in this case, parts that were directly sprayed had a different rate than "hot parts", or those who didnt have cold water put directly on them. Parts is probably too difficult to, maybe should say "areas". Like part of a cylinder.
 
SkyDog58 said:
You can lead a horse to the water hose but you can't make him think.
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You can lead a whore to culture, but you cannot make her think.

Jim
Mike Smith said:
Thats a horse of a different color.
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Only if the horse is pulling a donut cart, then it is a horse of a different cruller.

Jim
 
Actually they say: "At all times, caution must be taken not to shock cool the cylinders. The maximum recommended temperature change should not exceed 50°F. per minute."
 
Tom-D said:
Ya think?? just because the aluminum is lighter and has a better thermal expansion rate much better than cast iron? no can't be :)
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Nope, aluminum's coefficient of thermal expansion is double that of cast iron, that's not better, that presents a design challenge compared to iron and steel.
 
We'd do a max of 2deg per sec for DZ ops, that's at a 2500-3k FPM decent, we'd make over TBO on IO550s, doing this 7 days a week.
 
Post #74 by Jesse is by far the best response on how this should of been handled.


Sent from my iPad using Tapatalk
 
It's a different engine type of course, but the Arriel 2B1 engine manual allows for a compressor rinse to happen while running or you need to wait until it cools below ?140*? temp before doing the rinse. I can't remember the exact temp off the top of my head. Normally done after you can touch the eng without getting burned. And they want the engine to "cool naturally".
 
PaulS said:
Nope, aluminum's coefficient of thermal expansion is double that of cast iron, that's not better, that presents a design challenge compared to iron and steel.
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Why wouldn't it better? it will crack less. seldom see a crack in a Honda block or head.
 
gitmo234 said:
I know just fine and as much as I'd love to continue to explain the problems with your examples, it's clearly a waste of time. Proud of you for being a metalsmith though. I'll try to make it simple for you. The answer to the question of whether he damaged it or not isn't a "yes or no". The fact he heard the metal expanding validates he rapidly cooled the engine by spraying it with water. Guess one method we use to increase wear on engine to test it? rapid cooling.

So to keep it simple, imagine a sliding scale. One side is "definitely did not cause damage" on the other side is "definitely did cause damage". Now take in all the unknowns. How old was the engine? how many hours? how has every other student and CFI flown in it? how well was the maintenance? where there already unknown mechanical defects? How much water was sprayed and where? etc etc.

Even with perfect answers it's still possible. The answer falls to the right of center on the scale. "Its entirely possible". Not all or nothing like you claim. I hope this helps you.
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This one occasion did nothing to the engine. thousands of engines are misused more than this every day. start and fly prior to being up to temp, is far worse. You can say that every thing we do to these engines causes their demise- eventually.
but your theory of thermal expansion cracking, never happened here. wasn't hot enough to start, and was only one cycle of the billions it requires cause a cylinder to crack.
 
James331 said:
We'd do a max of 2deg per sec for DZ ops, that's at a 2500-3k FPM decent, we'd make over TBO on IO550s, doing this 7 days a week.
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So what can I tell ya? your easy on engines? others not so much, they still make TBO.
 
Tom-D said:
laugh if you like, but when was the last time you saw a crack Honda block?
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Never, but I've seen a lot of crackheads in Hondas driving around the block-does that count?
 
Omalley1537 said:
Never, but I've seen a lot of crackheads in Hondas driving around the block-does that count?
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your funny. until it is your aircraft engine that is cracked. then you sob,cry, & bit-h like the others here.
 
Dan Thomas said:
Obviously you've never been under a VW. The cylinders and heads are completely shrouded; they're not out in the road splash. You'd have to drive it, thoroughly heated up, into a deep puddle.
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I built and maintained two type one beetles, I forget how many engines I built for them while two daughters commuted to school and college. only time I'd see a cracked block in one was when a rod went thru it.
 
bgdriveway said:
It's a different engine type of course, but the Arriel 2B1 engine manual allows for a compressor rinse to happen while running or you need to wait until it cools below ?140*? temp before doing the rinse. I can't remember the exact temp off the top of my head. Normally done after you can touch the eng without getting burned. And they want the engine to "cool naturally".
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The Alison T-56-14 on the P-# Orion gets a full fresh water wash down in the taxi thru pits upon a return from every low level patrol. full stream down the intake nothing bothers it. TIT @ 1800C drops to about 5-600 then right back to 1800c
 
GlennAB1 said:
When did Honda start making air cooled piston aircraft engines?
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Weren't we talking about aluminum blocks. quit trying to spin it. your theory don't work.
 
GlennAB1 said:
Funny guy, you spun off. We're talking about aircraft engines where weight is more important than automotive engines.
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Your theory doesn't work in either case.
 
Tom-D said:
This one occasion did nothing to the engine. thousands of engines are misused more than this every day. start and fly prior to being up to temp, is far worse. You can say that every thing we do to these engines causes their demise- eventually.
but your theory of thermal expansion cracking, never happened here. wasn't hot enough to start, and was only one cycle of the billions it requires cause a cylinder to crack.
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Now we have authoritative proof. After an in-depth internet examination we have a solid statement that it is impossible this had any consequence.

Maybe you can help the OP out and offer to provide the flight school an Internet X-ray of the engine too
 
Clark1961 said:
now we have the two experts tom and glenn arguing...lmao
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It's actually Tom arguing against myself, Glenn, science, the FAA, and an engine service instruction. I wouldn't be surprised if the next post argues for us to prove the world is round
 
gitmo234 said:
It's actually Tom arguing against myself, Glenn, science, the FAA, and an engine service instruction. I wouldn't be surprised if the next post argues for us to prove the world is round
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Do you have any proof that the world is round?
 
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