---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 10/09/03: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:33 AM - Re: AeroElectric-List Digest: 28 Mags - 10/08/03 () 2. 05:13 AM - Re: Electronic tacho & mag check (Trampas) 3. 06:43 AM - Re: Solid state relay to replace master contactor (Jim Sower) 4. 06:44 AM - Re: Starter/mag switch (Gary Casey) 5. 11:43 AM - Re: Starter/mag switch (Robert L. Nuckolls, III) 6. 12:55 PM - Strobe head fix (Gilles.Thesee) 7. 04:36 PM - Starter/mag switch (David.vonLinsowe) 8. 05:30 PM - Starter/mag switch (David.vonLinsowe) 9. 09:30 PM - Re: Strobe head fix (Robert L. Nuckolls, III) 10. 10:25 PM - Re: Fuse Blocks, fuses, fusible links and CBs (fellowsw) 11. 11:50 PM - Re: Fuse Blocks, fuses, fusible links and CBs (Scott, Ian) ________________________________ Message 1 _____________________________________ Time: 03:33:57 AM PST US Subject: AeroElectric-List: RE: AeroElectric-List Digest: 28 Mags - 10/08/03 From: --> AeroElectric-List message posted by: Hi Neville I've just made what you want for a friend with a Druine Turbulent. One mag switch is replaced by a DPDT. One half is used as the p-lead contact. The other half is used as a tacho selector. Dont put relays into such an installation. Best regards Villi H. Seemann Sen. Eng. BSEE Telephony Team Infrastructure, Network Phone (+45) 3333 2101 Cell ph. (+45) 2220 7690 FAX (+45) 3333 1130 ----- Original Message ----- From: "Trampas" Subject: RE: AeroElectric-List: Electronic tacho & mag check > --> AeroElectric-List message posted by: "Trampas" > > I have heard of people taking a couple of capacitors and connecting them in > series with the P-leads, then connect both leads, after the capacitors, to > the tach. I am not sure how well this would work with your tach. > > I personally would look for a different system that had the capability to > monitor both p-leads all the time and let you know if there is any > difference. That is an engine monitor which could notify you in flight of > any difference in the RPMs of the left and right mag. > > I am currently working on building such an engine monitoring system. > > Trampas > ________________________________ Message 2 _____________________________________ Time: 05:13:53 AM PST US From: "Trampas" Subject: RE: AeroElectric-List: Electronic tacho & mag check --> AeroElectric-List message posted by: "Trampas" Bob, From what I have heard and seen I would agree that dual magneto failures are rare. My thoughts were if you are building an engine monitor and have the capability to monitor both P-leads then why would you not want to have an active mag warning? My personal philosophy is that an engine monitor should monitor the engine and any related systems. That is the pilot's job is to fly the plane and enjoy the flight. An engine monitor should provide the pilot with the information he needs to fly the plane and enjoy his flight. A lot of this dual mag topic is a philosophical debate. For example I am the type of person that when a headlight burns out on my car, I replace both headlights. They were on the same amount of time, and most likely identical in construction, therefore they will most likely die about the same time. Kind of like spark plugs in that you would not change just the one that wore out first. Therefore if your mags were both overhauled at the same time using the same parts and one failed, then I am of the mind set that perceives the risk of the other one failing has just increased significantly. However in reality just like the head lights the other one may work for several more years, or just a few more hours. Thus it is all about risk management that is in the headlight example the risk of the second one failing, in my mind, is greater than the $5-$10 for a new bulb. Trampas -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Subject: RE: AeroElectric-List: Electronic tacho & mag check --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 02:45 PM 10/8/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Trampas" > >Bob, > >What happens if the points in the mag shorts or a wire breaks, or any other >failure. After all one of the reasons to have dual magnetos is for back up >therefore there is a perceived risk of a mag failing. > >Trampas I think I understand your question . . . we were discussing the value of looking for the rpm readings from two mags to be DIFFERENT . . . I suggeseted that they're either dead-nuts in lock step with each other -OR- one of them is DEAD. Were you suggesting that there should be some provision for ACTIVE mag failure warning? There have been about 250,000 airplanes built in US alone that have never had a mag failure warning system installed. An excellent demonstration of the value of the FMEA . . . and the underlying notions that (1) you're not likely to get dual failures on any single tank of fuel and (2) you'll catch the failed mag at next preflight. Some pilots do a mag-check during taxi to parking so as to get a heads-up about an unperceived failure during the flight . . . it's better to know that a mag has crapped taxiing in than during next pre-flight. An analysis of this very long and rich history of dual-mag engines for flight suggests that an active mag failure warning system is unnecessary. Bob . . . ________________________________ Message 3 _____________________________________ Time: 06:43:34 AM PST US From: Jim Sower Subject: Re: AeroElectric-List: Solid state relay to replace master contactor --> AeroElectric-List message posted by: Jim Sower <... maximum rated surge is only 270 amps ...> But wouldn't it still be ideal for an alternator relay that can be easily shut off for overvoltage> chaskuss@bellsouth.net wrote: > --> AeroElectric-List message posted by: -- Jim Sower Crossville, TN; Chapter 5 Long-EZ N83RT, Velocity N4095T ________________________________ Message 4 _____________________________________ Time: 06:44:07 AM PST US From: "Gary Casey" Subject: Re: AeroElectric-List: Starter/mag switch --> AeroElectric-List message posted by: "Gary Casey" <> That's a great idea - except that I don't think you don't need a triple pole switch. Use a double pole switch on one mag to run the mag and starter. Another double pole switch runs the other mag and also switches the tach. Should work, right? And doesn't really add much complexity. Gary Casey ________________________________ Message 5 _____________________________________ Time: 11:43:29 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Starter/mag switch --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:42 AM 10/9/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "Gary Casey" > >< can be used to swap tach sensing to the opposite > mag when it is in the OFF position. It doesn't matter which > mag you do this with. > Bob . . .>> > >That's a great idea - except that I don't think you don't need a triple pole >switch. Use a double pole switch on one mag to run the mag and starter. >Another double pole switch runs the other mag and also switches the tach. >Should work, right? And doesn't really add much complexity. If you want to enable starter with R mag OFF and L mag ON then it takes a dedicated pair of poles as I've illustrated. If you consider it sufficient to disable the starter button only when R mag is ON, then yes, a pair of two pole toggles will do it. Running the starter through both mag switches was to minimize probability of inadvertent starter operation with the airplane parked. This is a TINY order of probability so yes, if you can give up the airplane-parked, starter-lockout then http://www.aeroelectric.com/temp/elect_tach2.gif is the schematic. If you want to retain the parked-airplane, starter- lockout, then one 3-pole switch is needed as shown in http://www.aeroelectric.com/temp/elect_tach.gif Bob . . . ________________________________ Message 6 _____________________________________ Time: 12:55:34 PM PST US From: "Gilles.Thesee" Subject: AeroElectric-List: Strobe head fix --> AeroElectric-List message posted by: "Gilles.Thesee" Hi Bob and all, A friend just asked me a question about the suitable material for the strobe head on his homebuit. Can silicone be used to re-seal the glass lens to the transformer/plastic base of the head ? If so, what grade is best ? Thanks, Gilles Thesee ________________________________ Message 7 _____________________________________ Time: 04:36:53 PM PST US Subject: AeroElectric-List: Starter/mag switch From: "David.vonLinsowe" --> AeroElectric-List message posted by: "David.vonLinsowe" Hi Bob, Twice the rpm with the electronic ignition is because the mag is putting out one pulse per rev and the E.I. puts out two. The EIS can be configured for either one pulse or two, but it can't change in mid stream. It was also recommended that I use the mag as the primary rpm sensor because of the response time of the EIS. It can detected potential mag problems by way of an erratic rpm reading. Thanks, Dave Snip >What do you think about the idea of using a triple pole switch for the >left mag and starter and add a circuit to switch to the EI tach info >when the mag is off? The EI tach info will have twice the rpm, but I >don't see that as an issue. Is there a better way? not sure about the "twice the rpm" statement but yes, most electronic tachs work best while watching only one of two mags at a time. A third pole on one mag switch can be used to swap tach sensing to the opposite mag when it is in the OFF position. It doesn't matter which mag you do this with. Bob . . . ________________________________ Message 8 _____________________________________ Time: 05:30:07 PM PST US Subject: AeroElectric-List: Starter/mag switch From: "David.vonLinsowe" --> AeroElectric-List message posted by: "David.vonLinsowe" Hi Jim, Actually this setup is even simpler, only two switches. The left mag switch is three position with the full up position momentary, that's the starter circuit. It's been working great for the last 300+ hours. I switched to electronic ignition on the right mag and still no problems. The problem is when you do away with the mechanical tach and don't have two mags. When you do a mag check and turn it off you also loose the rpm info. Hence the need to switch over to the electronic ignition for rpm info when the mag is off. Dave Subject: Re: AeroElectric-List: Starter/mag switch --> AeroElectric-List message posted by: Jim Sower I like to keep it simple. I have two toggle switches for ignition and a push button starter. Just a theory ... Jim S. ________________________________ Message 9 _____________________________________ Time: 09:30:58 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Strobe head fix --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:54 PM 10/9/2003 +0200, you wrote: >--> AeroElectric-List message posted by: "Gilles.Thesee" > > >Hi Bob and all, > >A friend just asked me a question about the suitable material for the strobe >head on his homebuit. > >Can silicone be used to re-seal the glass lens to the transformer/plastic >base of the head ? >If so, what grade is best ? Electronic grade (does not smell of vinegar). Bob . . . ________________________________ Message 10 ____________________________________ Time: 10:25:49 PM PST US From: "fellowsw" Subject: RE: AeroElectric-List: Fuse Blocks, fuses, fusible links and CBs --> AeroElectric-List message posted by: "fellowsw" > What would you suggest for a feed to the flap motor. I thought I read > something about this is one particular animal that can nuisance trip. If > you were to recommend a CB application how would you power that off say > the main bus/fuse block? I would prefer to keep the ALT FLD CB the only > breaker on the panel, if practical. FEMA is good concept but .... with many flap systems, the motor will draw more current than the flap system is designed to take if you extend the flaps when the speed is a little over the flap extension speed limit. In this case a breaker in reach is very handy because you can slow the plane down, reset the breaker and safely extend the flaps. If you have a remote fuse in such a case, a good pilot will reconsider runway length and conditions and go to another airport in case the approach speed is too high with only partially extended flaps. Of course most POHs don't give you any guidance for runway lengths with no or partially extended flaps. Under the best of circumstances this is not much fun when a breaker will let you do it the way you originally wanted to do it. I of course have no personal experience with this but have heard those dark and stormy night tales. ________________________________ Message 11 ____________________________________ Time: 11:50:39 PM PST US Subject: RE: AeroElectric-List: Fuse Blocks, fuses, fusible links and CBs From: "Scott, Ian" --> AeroElectric-List message posted by: "Scott, Ian" doesn't everyone practice flapless landings? I certainly do. Ian -----Original Message----- From: fellowsw [mailto:fellows.w@ewcapital.net] Subject: RE: AeroElectric-List: Fuse Blocks, fuses, fusible links and CBs --> AeroElectric-List message posted by: "fellowsw" > What would you suggest for a feed to the flap motor. I thought I read > something about this is one particular animal that can nuisance trip. If > you were to recommend a CB application how would you power that off say > the main bus/fuse block? I would prefer to keep the ALT FLD CB the only > breaker on the panel, if practical. FEMA is good concept but .... with many flap systems, the motor will draw more current than the flap system is designed to take if you extend the flaps when the speed is a little over the flap extension speed limit. In this case a breaker in reach is very handy because you can slow the plane down, reset the breaker and safely extend the flaps. If you have a remote fuse in such a case, a good pilot will reconsider runway length and conditions and go to another airport in case the approach speed is too high with only partially extended flaps. Of course most POHs don't give you any guidance for runway lengths with no or partially extended flaps. Under the best of circumstances this is not much fun when a breaker will let you do it the way you originally wanted to do it. I of course have no personal experience with this but have heard those dark and stormy night tales. ---------------------------------------------------- RSL COM has an extensive and competitive range of local and long distance call packages. We also offer converged multimedia and data services through our own state-of-the-art integrated voice & data network. Visit http://www.rslcom.com.au to find out more. This message is for the named person's use only. Privileged/confidential information may be contained in this message. If you are not the addressee indicated in this message (or responsible for delivery of the message to such person), you may not copy or deliver this message to anyone. In such case, you should destroy this message, and notify us immediately. Any views expressed in this message are those of the individual sender, except where the message states otherwise and the sender is authorised to state them to be the views of any such entity. ----------------------------------------------------