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#16
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Quote:
Fans and props often show bad distortion when filmed Actually, what is probably happening is the fan is quite flexible because it's plastic. The ends of the blades are moving faster than the inner portions and are twisted to have a higher angle of attack, thus under greater stress. The airflow over the blade is going to try to straighten out the rear portion more than the front portion (less angle of attack) because the pressure differential is greater toward the rear and generally the blade is thinner. That movement would appear to be toward the front.
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Current Stable
Last edited by mach4; 10-05-2012 at 01:39 AM. Reason: spelling |
#17
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I can do that with a pencil
In the ground picture, what does the shadow say about what's going on with the prop? Sixto 87 300D |
#18
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I suspected there were other forces in play there.
Thanks for the lesson, very interesting what is going on. Mach4 are you a pilot?
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The OM 642/722.9 powered family Still going strong 2014 ML350 Bluetec (wife's DD) 2013 E350 Bluetec (my DD) both my kids cars went to junkyard in 2023 2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles) 2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles) 1998 E300DT sold to TimFreeh 1987 300TD sold to vstech |
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Yes, but not current. Flew for the Navy and also hang gliders.
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#20
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Thanks for the nice lesson. Let me explain what Im seeing
lets take data as fan clutch engaged engine speed at 2000 rpm Because the fan is spinning fast it resembles a disc - If I rev the engine and look at the fan from the side then it appears to flex (bend) towards the engine when looking at the edge. After reading this excellent piece Im going to paint a few marks on the fan blades then try to eyeball it. You learn something every day. Can this phenomenon occur because the fan is not actually set into the shroud - In my car it kind of sits half inside the shroud with big clearance on the sides I have another situation I could never understand - this is with old jap fwd cars, their radiator fans when brand new have straight blades and are pretty quiet too, when they age the blades warp into a potato chip profile and end up kind of flat at the edges - They sound pretty loud at that point and dont move much air despite being at the same rpm as new.
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2012 BMW X5 (Beef + Granite suspension model) 1995 E300D - The original humming machine (consumed by Flood 2017) 2000 E320 - The evolution (consumed by flood 2017) |
#21
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#22
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I'm ditching the mechanical fan all together and going all electric. Cold Tstat + Efan with early trigger worked on the M103 for 30k miles, it'll work on the OM603.
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CENSORED due to not family friendly words |
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