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#31
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Preheating engines: Airplane engines versus auto engines
"Matt W. Barrow" wrote
news "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? May I humbly pontificate that proper starting of engines (incorporating the, appropriate for the temps and engine, oil) at 25F will NOT impact their respective TBOs to any statistically significant degree. I have many examples of this at the airports where I have been based and I follow this practice on my own plane. |
#32
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Preheating engines: Airplane engines versus auto engines
gpaleo wrote:
"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?? He never said anything about "killing" his engine. He is certainly worrying more than necessary, but that is no worse than your overly melodramatic and condescending response. Actually, your response was worse as his was made from ignorance and yours was intentional. Matt |
#33
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Preheating engines: Airplane engines versus auto engines
"gpaleo" wrote in message news:1198177392.30618@athprx03... "Matt W. Barrow" wrote news "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? May I humbly pontificate that proper starting of engines (incorporating the, appropriate for the temps and engine, oil) at 25F will NOT impact their respective TBOs to any statistically significant degree. Well, your holiness, no one said anything about TBO. I have many examples of this at the airports where I have been based and I follow this practice on my own plane. Since you blew in with your qualifications at the forefront, answer the question and don't change the subject and go off on tangents (like TBO). Also, see the references in my later reply to Peter R., and be aware that anecdotal stories are pretty much useless. |
#34
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Preheating engines: Airplane engines versus auto engines
Matt W. Barrow wrote:
"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. Yes, YMMV, especially when based on incomplete information. The first reference above claims that "The specific heat of oil is at least four to five times the specific heat of the metals in an engine," which simply isn't accurate for aircraft. If you count only the steel in the engine, then this is true, but a significant part of most aircraft engines is aluminum and its Cp is about twice that of steel and thus less then 2.5X different from oil rather than 4-5X. I've read the "expert" commentary from Shell, Lycoming, Continental, and other companies about this issue and they certainly make arguments that sound logical on the surface. However, I live in a fairly cold climate for at least 5 months of the year and have personally had engines that were cold started at temps often below 0 F and occasionally below -20F with not a single problem. So, I still preheat given a choice, but I would not lose a second of sleep over starting an airplane engine at any temperature at which it would crank fast enough to start. Matt |
#35
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Preheating engines: Airplane engines versus auto engines
Matt Whiting wrote:
Tauno Voipio wrote: Peter R. wrote: --- clip clip -- 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? Here in the north of Europe We'll pre-heat our cars if possible, if the temperature goes below +5 C (whatever it is in F, around 40?). You can force an engine to start even at -30 C, but it means that the poor thing runs some time practically dry of lubrication. Really? Where does all of the oil disappear to that was there when the engine was shut down? Matt The lubrication is based on fluid between the metal surfaces. When the oil thickens enough, it will not get to the small spaces between the metal surfaces. -- Tauno Voipio |
#36
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Preheating engines: Airplane engines versus auto engines
Ο "Matt W. Barrow" έγραψε στο μήνυμα ... "gpaleo" wrote in message news:1198177392.30618@athprx03... "Matt W. Barrow" wrote news "gpaleo" wrote in message news:1198154485.901022@athprx03... "Matt Whiting" wrote news .................................................. ............................... 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? May I humbly pontificate that proper starting of engines (incorporating the, appropriate for the temps and engine, oil) at 25F will NOT impact their respective TBOs to any statistically significant degree. Well, your holiness, no one said anything about TBO. I see what you mean. I intended to convey the idea that no damage would occur to the engine resulting from the cold-ish starts within the time period to overhaul. Do find some inner peace, my son ;-)) (the holy-ness kicking in). |
#37
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Preheating engines: Airplane engines versus auto engines
"Tauno Voipio" wrote in message ... Matt Whiting wrote: Tauno Voipio wrote: Peter R. wrote: --- clip clip -- 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? Here in the north of Europe We'll pre-heat our cars if possible, if the temperature goes below +5 C (whatever it is in F, around 40?). You can force an engine to start even at -30 C, but it means that the poor thing runs some time practically dry of lubrication. Really? Where does all of the oil disappear to that was there when the engine was shut down? Matt The lubrication is based on fluid between the metal surfaces. When the oil thickens enough, it will not get to the small spaces between the metal surfaces. -- Tauno Voipio Research will tell you the oil is allready there and being cold and thick it tends to go nowhere and in fact does its job rather well. Many engines are started a far colder temps regularly and suffer no damage and make TBO. Far,far worse to let an engine sit. |
#38
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Preheating engines: Airplane engines versus auto engines
Isn't some of the problem with cold starts not necessarily oil related but
related to piston scuffing against the cylinder walls? The aluminum pistons have a greater coefficient of expansion than the steel cylinders and the pistons should become a looser fit at colder temps. I'm not sure how the rings fit into the temperature equation. -- Best Regards, Mike http://photoshow.comcast.net/mikenoel "gpaleo" wrote in message news:1198154485.901022@athprx03... "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?? |
#39
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Preheating engines: Airplane engines versus auto engines
On Thu, 20 Dec 2007 19:39:17 GMT, Tauno Voipio
wrote: Matt Whiting wrote: Tauno Voipio wrote: Peter R. wrote: --- clip clip -- 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? Here in the north of Europe We'll pre-heat our cars if possible, if the temperature goes below +5 C (whatever it is in F, around 40?). You can force an engine to start even at -30 C, but it means that the poor thing runs some time practically dry of lubrication. Really? Where does all of the oil disappear to that was there when the engine was shut down? Matt The lubrication is based on fluid between the metal surfaces. When the oil thickens enough, it will not get to the small spaces between the metal surfaces. Preheating a car at +5C is just ridiculous if you are using the proper weight of motor oil. I might use a block heater if the temperatures went below -20C, but not higher than that. Try using a good 10W30 oil between +5 and -10, and perhaps a 5W30 below that. You won't damage anything, and your engine will last longer than the body panels on the car! -- Jay (remove dashes for legal email address) |
#40
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Preheating engines: Airplane engines versus auto engines
20w-50 Close enough Exxon Elite Thattle do... How long before the oil pressure came up? Within a minute or so, I don't remember now. Watch this like a hawk on cold starts of any kind...15 secs is marginal, 10 secs max preferred... No pressure, shut it down.... How long since last run? This was Monday, aircraft last flown previous Saturday. Aircraft is flown twice to three times every week. 2 days since last? No worries mate! Fly on..... (remember, I am not an AME...but I do listen a lot.. fortunate to have a few near whom I believe to be knowledgeable in this area.. including a reputable engine builder / overhauler..) Cheers! Dave |
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