---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Tue 06/26/12: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:22 AM - Crowder Spinner (Ahmed M. Ragheb) 2. 11:43 AM - Is there an over-priming hydraulic lock monster? (Elmar & Manuela Hegenauer) 3. 01:21 PM - Re: Is there an over-priming hydraulic lock monster? (Brian Lloyd) 4. 05:19 PM - Re: Is there an over-priming hydraulic lock monster? (Rob Rowe) 5. 07:58 PM - Re: Re: Is there an over-priming hydraulic lock monster? (cjpilot710@AOL.COM) ________________________________ Message 1 _____________________________________ Time: 03:22:11 AM PST US From: "Ahmed M. Ragheb" Subject: Yak-List: Crowder Spinner Does any one know of a Crowder spinner or parts for sale? Med N53CJ ________________________________ Message 2 _____________________________________ Time: 11:43:10 AM PST US From: Elmar & Manuela Hegenauer Subject: Yak-List: Is there an over-priming hydraulic lock monster? Numerous times I have read about the possibility to get a hydraulic lock by over-priming. Today I have pulled the primer line on my CJ and measured the exact amount of gasoline per priming stroke at 20 degrees Celsius ambient temperature. I have repeated the test 60 times and each time it was almost exactly 7.15 ml per stroke. In the past I was told one needs at least 120 ml of any kind of fluid per cylinder to evoke the infamous hydraulic monster. So here comes my question, either I did something wrong or is it nearly impossible to cause a solid hydraulic lock by over-priming? Your opinion on this matter is highly appreciated. cheers Elmar ________________________________ Message 3 _____________________________________ Time: 01:21:52 PM PST US Subject: Re: Yak-List: Is there an over-priming hydraulic lock monster? From: Brian Lloyd On Tue, Jun 26, 2012 at 2:40 PM, Elmar & Manuela Hegenauer wrote: > I have repeated the test 60 times and > each time it was almost exactly 7.15 ml > per stroke. > > In the past I was told one needs at > least 120 ml of any kind of fluid per > cylinder to evoke the infamous hydraulic > monster. > > So here comes my question, either > I did something wrong or is it nearly > impossible to cause a solid hydraulic > lock by over-priming? > > Your opinion on this matter is highly > appreciated. > There you go, trying to apply science and engineering to understanding the airplane. That will just NOT do! ;-) -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 brian@lloyd.com +1.767.617.1365 (Dominica) +1.916.877.5067 (USA) ________________________________ Message 4 _____________________________________ Time: 05:19:12 PM PST US Subject: Yak-List: Re: Is there an over-priming hydraulic lock monster? From: "Rob Rowe" That also tallies with the 8cc stated capacity of the YAK primers, so unlikely you'll ever solid lock a cylinder through over priming. However 6 or 7 primes worth could still get you the best part of 40cc into the lowest cylinder, which would increase the compression by about a third. Apparently it's that iterative shock that leads to the Russian plug cores blowing (as well as mishandling them). Don't know if the same holds true for Chinese plugs. So while better than bending a rod it's still a scary ride on 8 cylinders with one open to the atmosphere ... the power is usually only slightly down but the vibration is extreme. Happened twice on my -52 in the first couple of years of ownership, then fitted a manifold drain 12 years ago without further re-occurrence. Now while that was probably more oil than fuel related it makes sense, having addressed the oil risk, not to replace it with another fuel one. Given engines start / run on vapour anyway, not liquid fuel, I always leave the manifold open after priming until the bulk of the excess drains out ... usually starts first time and avoids the iterative risk IMHO. Rob R. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=376686#376686 ________________________________ Message 5 _____________________________________ Time: 07:58:00 PM PST US From: cjpilot710@AOL.COM Subject: Re: Yak-List: Re: Is there an over-priming hydraulic lock monster? In the some 2,000 hours of operating a M-14 (over the last 17 years) I've never needed more than 6 pumps (I usually just pump 4 times) of the primer to get a M-14 started. No where does one need to pump 20 times, or did I read that wrong. A hydraulic lock by over priming? Very un likely. Jim "Pappy" Goolsby In a message dated 6/26/2012 8:19:19 P.M. Eastern Daylight Time, yak-list@robrowe.plus.com writes: --> Yak-List message posted by: "Rob Rowe" That also tallies with the 8cc stated capacity of the YAK primers, so unlikely you'll ever solid lock a cylinder through over priming. However 6 or 7 primes worth could still get you the best part of 40cc into the lowest cylinder, which would increase the compression by about a third. Apparently it's that iterative shock that leads to the Russian plug cores blowing (as well as mishandling them). Don't know if the same holds true for Chinese plugs. So while better than bending a rod it's still a scary ride on 8 cylinders with one open to the atmosphere ... the power is usually only slightly down but the vibration is extreme. Happened twice on my -52 in the first couple of years of ownership, then fitted a manifold drain 12 years ago without further re-occurrence. Now while that was probably more oil than fuel related it makes sense, having addressed the oil risk, not to replace it with another fuel one. Given engines start / run on vapour anyway, not liquid fuel, I always leave the manifold open after priming until the bulk of the excess drains out ... usually starts first time and avoids the iterative risk IMHO. Rob R. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=376686#376686 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.