---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Mon 12/10/18: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:08 AM - Re: How to install a hobbs/tach? (A. Dennis Savarese) 2. 11:22 AM - Re: How to install a hobbs/tach? (Looigi) 3. 01:37 PM - Re: Re: How to install a hobbs/tach? (\) 4. 07:44 PM - Re: Re: How to install a hobbs/tach? (Walter Lannon) ________________________________ Message 1 _____________________________________ Time: 04:08:35 AM PST US From: "A. Dennis Savarese" Subject: Re: Yak-List: How to install a hobbs/tach? Oil dilution port is an INPUT to the oil pump. Not an OUTPUT. Find the oil pressure line coming the oil pump and going to the triple instrument in the cockpit. It is a flexible hose. Dennis Sent from my iPad > On Dec 9, 2018, at 11:11 PM, 1906 wrote: > > > Is it possible to install some sort oil pressure switch on these? > My mechanic thought he had it, connected to I believe the oil dilution port but it didn't pick up enough pressure for the switch there... > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=486201#486201 > > > > > > > > > ________________________________ Message 2 _____________________________________ Time: 11:22:19 AM PST US Subject: Yak-List: Re: How to install a hobbs/tach? From: "Looigi" Can I ask a stupid question..... Why would you want to? My Yak is in a syndicate of 9 people, so we need to track flying time so Rob can send each of us his monthly hate mail.... the bill. Given that the Yak needs a lot of time to get the engine oil up to temperature, especially in winter, I didn't want to use an oil pressure switch. I needed to record flight time, not engine time because I didn't want guys to try and save themselves a few cents by short cutting the warm up only to cost us big bucks on engines. I installed a Hobbs and a pressure switch. The Hobbs has its own power supply, through a circuit breaker straight from the master switch and is turned on by a small pressure switch plumbed into the pitot system. There was a convenient unused pipe behind the back seat where some sort of "flight data recorder" once was, and I just plugged into that. When we were doing the bi-annual pitot test, I adjusted the switch to come on at about 60km/h. If this sounds a solution to your problem, I can dig out the details of the switch I used. I hope this helps, Chris Read this topic online here: http://forums.matronics.com/viewtopic.php?p=486211#486211 ________________________________ Message 3 _____________________________________ Time: 01:37:12 PM PST US From: "\"" Subject: Re: Yak-List: Re: How to install a hobbs/tach? At the Collings Foundation, the B-24 Hobbs was hooked up to the landing gea r strut. =C2-With strut extended a switch powered the Hobbs meter. =C2- The FAA seems to be happy with that.Jim "Pappy" Goolsby -----Original Message----- From: Looigi Sent: Mon, Dec 10, 2018 2:23 pm Subject: Yak-List: Re: How to install a hobbs/tach? Can I ask a stupid question..... Why would you want to? My Yak is in a syndicate of 9 people, so we need to track flying time so Ro b can send each of us his monthly hate mail.... the bill. Given that the Yak needs a lot of time to get the engine oil up to temperat ure, especially in winter, I didn't want to use an oil pressure switch.=C2 - I needed to record flight time, not engine time because I didn't want g uys to try and save themselves a few cents by short cutting the warm up onl y to cost us big bucks on engines. I installed a Hobbs and a pressure switch.=C2- The Hobbs has its own powe r supply, through a circuit breaker straight from the master switch and is turned on by a small pressure switch plumbed into the pitot system.=C2- T here was a convenient unused pipe behind the back seat where some sort of " flight data recorder" once was, and I just plugged into that.=C2- When we were doing the bi-annual pitot test, I adjusted the switch to come on at a bout 60km/h. If this sounds a solution to your problem, I can dig out the details of the switch I used. I hope this helps, Chris Read this topic online here: http://forums.matronics.com/viewtopic.php?p=486211#486211 =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin. S - WIKI - - =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin. ________________________________ Message 4 _____________________________________ Time: 07:44:53 PM PST US From: "Walter Lannon" Subject: Re: Yak-List: Re: How to install a hobbs/tach? Looigi; While I have no concern with your choice for activating the Hobbs meter I do have a problem with your choice of power supply. The battery master switch is there to activate the battery master relay which in turn powers the bus. None of the bus load is carried through the switch which is sized for it's primary purpose only. The load you are adding may not be enough to cause a problem but I believe you are breaking a cardinal rule in aircraft electrical practice. Since operation of the entire electrical system depends on the master relay the loss of it's power supply (the switch) means total elec. failure. Any added elec. load should always be taken directly from the bus never from the master switch. Walt -----Original Message----- From: Looigi Sent: Monday, December 10, 2018 11:21 AM Subject: Yak-List: Re: How to install a hobbs/tach? Can I ask a stupid question..... Why would you want to? My Yak is in a syndicate of 9 people, so we need to track flying time so Rob can send each of us his monthly hate mail.... the bill. Given that the Yak needs a lot of time to get the engine oil up to temperature, especially in winter, I didn't want to use an oil pressure switch. I needed to record flight time, not engine time because I didn't want guys to try and save themselves a few cents by short cutting the warm up only to cost us big bucks on engines. I installed a Hobbs and a pressure switch. The Hobbs has its own power supply, through a circuit breaker straight from the master switch and is turned on by a small pressure switch plumbed into the pitot system. There was a convenient unused pipe behind the back seat where some sort of "flight data recorder" once was, and I just plugged into that. When we were doing the bi-annual pitot test, I adjusted the switch to come on at about 60km/h. If this sounds a solution to your problem, I can dig out the details of the switch I used. I hope this helps, Chris Read this topic online here: http://forums.matronics.com/viewtopic.php?p=486211#486211 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ------------------------------------------------------------------------------------- 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.