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#21
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Preheating engines: Airplane engines versus auto engines
"Matt Whiting" wrote
news Peter R. wrote: On 12/19/2007 12:39:10 PM, "gpaleo" wrote: This is joke post, right???? Yes, it's a joke. You can go back to bed now. No, 6 year-olds should be in school by mid-day, not playing on mommies computer! As a 6 year-old mechanical engineer of some 30 years practice and owner of an IO-540 equiped airplane, I find it somewhat disturbing that the OP was NOT a joke. Anyway, pat on the back - big hug time for the courageous aviator who started his engine at **GASP** 25 F, after careful deliberation on aborting the flight until Summer. Catch my drift?? |
#22
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Preheating engines: Airplane engines versus auto engines
I purchased Fat Albert from an FBO who kept him in an unheated hangar
for 40 years, and never preheated unless it was well below zero (that's in Farenheit, sonny)... Often it was a 3AM panic call from GM who needed engine parts delivered to avoid the assembly plant from shutting down and their truck was already on the way to the airport with the parts....Load the plane, start the engines, hurry down the taxiway checking mags while rolling, swing onto the runway, cob the throttles and go... Elapsed running time from start to takeoff, less than two minutes for the nearest runway, and perhaps three minutes for the furthest... HIs engines routinely went to TBO... While there is nothing wrong with preheat, etc. - there is also nothing wrong with using synthetic oil and preheating only for extreme temperatures... The biggest killer of aircraft engines is dry starts from weeks/months of sitting between starts... Low temperature starts on a well oiled engine have little to no impact on the wear cycle... I use 15W50 in the winter and 100W+ in the summer... I do not preheat unless it is below zero F... My starboard engine has 1700 hours since factory zero and other than the oil burn being ~ 3 hours to the quart, it starts and runs like a new engine... The port engine has 900 hours since a field overhaul and it runs fine... denny |
#23
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Preheating engines: Airplane engines versus auto engines
Why is it that here in the Northeast US seemingly no one preheats their automobile engine before start-up in very cold temperatures? Is the long-term damage the same for both autos and aircraft engines? If so, why do you suppose auto owners don't typically do this? Is it because that most auto owners do not keep their cars very long? -- Peter Lycoming says you can start without preheat down in the teens if you use multiviscosity oil. As others have said, one of the biggest differences from auto use is that aero engines are often flown less frequently so there's less oil hanging around at startup. On the other hand, that's true even in warm weather, though warm oil will be redistributed more quickly. I doubt that you did any harm. Convert all the degrees to Kelvin temps and be comforted :-) |
#24
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Preheating engines: Airplane engines versus auto engines
On Dec 20, 6:04 am, Denny wrote:
The biggest killer of aircraft engines is dry starts from weeks/months of sitting between starts... That's one, but there's another bad one: Short flights, especially in cold weather. byproducts of combustion include water vapor, and some of that squeezes past the pistons and rings when the engine is cold (some when it's hot, too, but much less so) and this vapor condenses in the crankcase and ends up in the oil. If the engine doesn't get hot enough for long enough, the water isn't boiled off and will mix slowly with the oil, breaking it down and combining with sulfur and chlorine and nitrogen to form sulfuric, hydrochloric and nitric acids. These don't belong in your engine. The stuff that's left from these reactions forms sludge and clogs up hydraulic lifters and cakes on the inside of the case and soon enough breaks off and shows up as scary black guck in the filter. The acids cause dissimilar metal corrosion between the crank and cam and their bearings, between the aluminum piston and the steel cylinder and rings, and on valve stems. Bad. Corroded valve stems break and the engine tries to eat the valve heads and gets indigestion. The oil in my little old Continental doesn't get above 120°F on cold days. There's a tank blanket that I need to buy or make to get it up. I just finished rebuilding the thing to fix corroded bearings and seized valve lifters. Dan |
#25
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Preheating engines: Airplane engines versus auto engines
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. -- Peter |
#26
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Preheating engines: Airplane engines versus auto engines
On 12/19/2007 9:40:19 PM, Dave wrote:
What weight of Oil? 20w-50 What brand? Exxon Elite How long before the oil pressure came up? Within a minute or so, I don't remember now. How long since last run? This was Monday, aircraft last flown previous Saturday. Aircraft is flown twice to three times every week. -- Peter |
#27
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Preheating engines: Airplane engines versus auto engines
On 12/20/2007 9:24:28 AM, Paul kgyy wrote:
I doubt that you did any harm. Convert all the degrees to Kelvin temps and be comforted :-) Ha. Thanks, Paul. -- Peter |
#28
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Preheating engines: Airplane engines versus auto engines
On 2007-12-19 12:21:28 -0500, "Peter R." said:
Given any other day, I would have plugged the aircraft back in and scrapped the flight I know what I did has negative long term repercussions on my engine's health I'm sure you must do some analysis in your head to judge the damage inflicted on the engine in this case - otherwise, how could you judge if scrapping a flight is the appropriate thing to do? I'm curious how you quantify the 'long term repercussions'. Have you concluded, for example, that not preheating in this case will: - Reduce the TBO for your engine by 10 hours? - Increase oil consumption by .2 qt/hour? - Increase the risk of a catastrophic in-flight failure by 5%? Clearly those are just some examples, but I would like to understand what you have judged the impact of flying in this case would be. |
#29
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Preheating engines: Airplane engines versus auto engines
"gpaleo" wrote in message news:1198154485.901022@athprx03... "Matt Whiting" wrote news No, 6 year-olds should be in school by mid-day, not playing on mommies computer! As a 6 year-old mechanical engineer of some 30 years practice and owner of an IO-540 equiped airplane, I find it somewhat disturbing that the OP was NOT a joke. Anyway, pat on the back - big hug time for the courageous aviator who started his engine at **GASP** 25 F, after careful deliberation on aborting the flight until Summer. Catch my drift?? Perhaps with your extensive and pontifical experience you cold summarize the findings of Shell, Chevron, and TCM of the percentage of wear that occurs in the first 30 seconds of cold (ie, below 40 degrees) starts? |
#30
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Preheating engines: Airplane engines versus auto engines
"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. -- Matt Barrow Performance Homes, LLC. Cheyenne, WY |
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