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  #1  
Old 03-20-2018, 08:40 AM
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Vlad Vlad is offline
 
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Location: NJ
Posts: 7,497
Default Educate me about vacuum pump

I just got a nice gift a set of clean low time vacuum driven gyros (thanks JohnR) and I need a pump and associated plumbing. How long usually vacuum pump last? Used or new? Please educate me.
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  #2  
Old 03-20-2018, 09:04 AM
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dlloyd3 dlloyd3 is offline
 
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Went thru about 10 of 'em in the Bo. About 600 on the average. Two failed under 100 hours. Seems like one went 1200 hours.
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  #3  
Old 03-20-2018, 09:12 AM
terrye terrye is offline
 
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Location: Vancouver, BC, Canada
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Default Vacuum pump

Well, the wet vacuum pump in my Cessna 150 has lasted over 30 years that I have owned it, and maybe longer than that. On the other hand I have heard that dry vacuum pumps are prone to self destruct at any time up to around 500 hours.

Either pump has a main rotor with several vane slots in it. In the case of the wet pump, the vanes are steel and the pump is lubricated internally with engine oil. The discharge line from the pump goes into an oil/air separator with the oil being returned to the engine sump and the air discharged overboard. The dry pump was an "improvement". The vanes are self lubricating carbon/graphite and thus the pump is "dry", that is it needs no lubrication from the engine oil and needs no oil/air separator. BUT, the vanes are more fragile and do not last anywhere near as long as the wet pump.

After understanding this I decided both technologies were obsolete and I'm making my RV-9A fully electric with EFIS displays.
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  #4  
Old 03-20-2018, 09:42 AM
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RV6_flyer RV6_flyer is offline
 
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1st one in the RV lasted between 700 and 800 hours. 2nd one lasted almost 2,000 hours. Third one was removed working with between 600 & 700 hours.

I overhauled the 1st vacuum pump and still have it sitting on the shelf. If you want it, it is yours.

Vacuum system removed from my RV-6 less than a year ago to upgrade to two G5s and GMU 11.

Both gyros sold through VAF. Not much of a market for vacuum stuff in the experimental world.
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  #5  
Old 03-20-2018, 10:23 AM
noelf noelf is offline
 
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Location: Cary, N.C.
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Vlad, I removed the vacuum system from my Cessna 150 that I recently purchased and installed the Garmin G5 AI and HSI units. I do not know if the pump was working, but you can have it and the vacuum regulator and filter if you want them.

I will be in Mount Holly next month for several weeks and I can bring them up there if you want. The 150 is in a hangar at Flying W.
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  #6  
Old 03-20-2018, 06:02 PM
BobTurner BobTurner is offline
 
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The graphite vanes should be good to TBO/2000hrs, but, as others have said, they are very sensitive to FOD. Anything that can impede their smooth sliding along the wall can break a vane. Make certain you clean everything (gyros, hose, pump) prior to installation. Early failures are often blamed on small carbon chunks from the previous failure getting sucked into the pump.
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  #7  
Old 03-20-2018, 07:16 PM
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FORANE FORANE is offline
 
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Location: East TN
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Get a sigma tek. they are built way better with a metal vane holder and vanes that are strong like carbon fiber. compare that to the fragile carbon like pencil lead vane holder and vanes in a different brand such as rapco.
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  #8  
Old 03-20-2018, 07:48 PM
RVDan RVDan is offline
 
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From the Malfunction database that I revised a few years ago the dry pumps have an MTBF of about 500 to 600 hrs. That said, If you decide to go head with a vacuum system, I have some of the other components, like fittings, filter and regulator if you need them.
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  #9  
Old 03-20-2018, 08:34 PM
sibriggs sibriggs is offline
 
Join Date: Nov 2014
Location: Concord, NH
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Default Vacume system :-(

Vlad, I used vacuum systems (gauges, pumps, gyro's) for years. My advice would be to sell the items you got and use the moneys to help buy an electronic replacement, G5 or similar. You'll spend a bit more but it will pay off in the long run and be much more reliable and provide additional flight info.

Steve
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  #10  
Old 03-20-2018, 10:02 PM
Rallylancer122 Rallylancer122 is offline
 
Join Date: Aug 2013
Location: Oconto, WI
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Quote:
Originally Posted by sibriggs View Post
Vlad, I used vacuum systems (gauges, pumps, gyro's) for years. My advice would be to sell the items you got and use the moneys to help buy an electronic replacement, G5 or similar. You'll spend a bit more but it will pay off in the long run and be much more reliable and provide additional flight info.

Steve
Ditto what Steve said. Most people consider dry pumps to be on borrowed time after 500 hours, but it's not uncommon for them to fail before that. I was at an AOPA seminar a couple years ago and they threw up a stat that something like 1/3 of all vacuum pump failures in IMC are fatal. That was enough to convince me they weren't worth messing around with.

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