---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 03/05/08: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:55 AM - VOR Diplexer (Terry Frazier) 2. 08:12 AM - RG-400 vs. RG-142? (Dr. Andrew Elliott) 3. 09:30 AM - Re: VOR Diplexer (Dawson, Bill) 4. 11:06 AM - static system leak check procedure (Ken) 5. 11:41 AM - Re: static system leak check procedure (Ralph E. Capen) 6. 12:11 PM - Re: Starter Choice (Peter Pengilly) 7. 12:33 PM - Re: RG-400 vs. RG-142? (Robert L. Nuckolls, III) 8. 01:16 PM - Re: Starter Choice (Robert L. Nuckolls, III) 9. 02:08 PM - z16 rev L (Bill and Marsha) 10. 04:20 PM - Re: static system leak check procedure (Carlos Trigo) 11. 05:26 PM - Status of the small strobe wiring experiment. (Robert L. Nuckolls, III) 12. 05:59 PM - Re: z16 rev L (Robert L. Nuckolls, III) 13. 06:04 PM - Re: static system leak check procedure (Bill Bradburry) ________________________________ Message 1 _____________________________________ Time: 07:55:35 AM PST US From: "Terry Frazier" Subject: AeroElectric-List: VOR Diplexer I'm building an RV7A with one SL-30 radio and inside the wingtip antennae. I'll probably use the Sport Aircraft design for the antennae. Question is, can I use a diplexer "backwards" to feed the one VOR with two antenna feeds to both boost signal and reduce shadowing effects? Would a standard diplexer work, or would I need something special? Thanks in advance, Terry 7A Panel Wiring ________________________________ Message 2 _____________________________________ Time: 08:12:53 AM PST US From: "Dr. Andrew Elliott" Subject: AeroElectric-List: RG-400 vs. RG-142? I know that has been discussed before, but I want to be sure. Are there any significant downsides to using RG-142 for aircraft antenna applications where the cable will not be regularly flexed (except for normal vibration)? I am somewhat leery of using a solid core coax. Andy Elliott, Mesa, AZ N601GE (reserved) 601XL/TD, Corvair, building... ________________________________ Message 3 _____________________________________ Time: 09:30:32 AM PST US Subject: RE: AeroElectric-List: VOR Diplexer From: "Dawson, Bill" You are talking about diversity reception. Google that term and lot's of things pop up. I use it a great deal with wireless mics. Go to this website for starters... http://www.lectrosonics.com/WPapers-Magazines/ReceptionTechniques/Recepti onTechniques.htm The problem is, the antennas can not be tied together as the signal one picks up will not be in phase with the other antenna. The result is a reduced signal and in some cases complete cancel of the signal. So how do the dual antenna receivers do it? They constantly sample the antennas and *switch* to the antenna with the most signal. Bill -----Original Message----- From: owner-aeroelectric-list-server@matronics.com on behalf of Terry Frazier Sent: Wed 3/5/2008 7:51 AM Subject: AeroElectric-List: VOR Diplexer I'm building an RV7A with one SL-30 radio and inside the wingtip antennae. I'll probably use the Sport Aircraft design for the antennae. Question is, can I use a diplexer "backwards" to feed the one VOR with two antenna feeds to both boost signal and reduce shadowing effects? Would a standard diplexer work, or would I need something special? Thanks in advance, Terry 7A Panel Wiring ________________________________ Message 4 _____________________________________ Time: 11:06:44 AM PST US From: Ken Subject: AeroElectric-List: static system leak check procedure I started to do a preliminary static system leak check and noticed that it only takes about 500 feet of static vacuum to make the ASI read about 100 knots. 10 or 20 thousand feet would peg the ASI pretty firmly. Is the pitot side subjected to the same vacuum as the static side of the system to prevent altimeter damage or is that not a concern? It seems prudent to check for obvious leaks before taking the plane to the radio shop. thank you Ken ________________________________ Message 5 _____________________________________ Time: 11:41:43 AM PST US From: "Ralph E. Capen" Subject: Re: AeroElectric-List: static system leak check procedure I did a similar test with the ASI removed and its fittings plugged to verify the integrity of the rest of the system up to 20000ft. Then I put it all back together and verified the leakdown integrity. -----Original Message----- >From: Ken >Sent: Mar 5, 2008 2:02 PM >To: aeroelectric-list@matronics.com >Subject: AeroElectric-List: static system leak check procedure > > >I started to do a preliminary static system leak check and noticed that >it only takes about 500 feet of static vacuum to make the ASI read about >100 knots. 10 or 20 thousand feet would peg the ASI pretty firmly. Is >the pitot side subjected to the same vacuum as the static side of the >system to prevent altimeter damage or is that not a concern? It seems >prudent to check for obvious leaks before taking the plane to the radio >shop. >thank you >Ken > > ________________________________ Message 6 _____________________________________ Time: 12:11:12 PM PST US From: "Peter Pengilly" Subject: RE: AeroElectric-List: Starter Choice Frank & Jim, Thanks for your advice - do nothing is an option! Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of J. Mcculley Sent: 04 March 2008 23:47 Subject: Re: AeroElectric-List: Starter Choice Peter, I have over 500 flight hours on my O-360 with a skytec permanent magnet starter and not one moment of problem with just an Odyssey 17 AH battery and a B&C SD-8 permanent magnet alternator. Jim ------------------------------------------------------------------------ ---------- Peter Pengilly wrote: I am changing the engine on my One Design. I am removing an O-320-E3D and fitting an IO-360-B1B (180 hp regular compression). I will be fitting an Odyssey 17ah battery. The 320 has a B&C starter that has been used for around 100 hours, it also has 122 teeth on the starter ring. The 360 has a Sky-tec PM starter (and is brand new and is painted bright red) and a 149 tooth starter ring. The airplane is fitted with a B&C SD-8 generator so cannot guarantee a fully charged battery every time. I have heard stories that permanent magnet starters and Odyssey batteries do not get on, and that starting is often slow, especially the first couple of blades. All things being equal I would swap the starter and the starter ring, but that's not possible as the part numbers of the starter rings between the two engines are different - I don't know the precise differences, and I would have to paint the old starter ring. To be able to use the B&C starter on the new engine B&C recommend I change out the ring gear, or return the starter for overhaul ($310 plus shipping from Europe ). And will have to change something on the old engine. So my questions is, am I right to be concerned about the long term abilities of a Skytec PM starter and the Odyssey battery to provide reliable starting? Does anyone have any experience with this combination? Regards, Peter ------------------------------------------------------------------------ ---------- ________________________________ Message 7 _____________________________________ Time: 12:33:01 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RG-400 vs. RG-142? At 09:00 AM 3/5/2008 -0700, you wrote: >I know that has been discussed before, but I want to be sure. Are there >any significant downsides to using RG-142 for aircraft antenna >applications where the cable will not be regularly flexed (except for >normal vibration)? I am somewhat leery of using a solid core coax. Then use the stranded version, RG-400. RG-58 in the lengths we common use for small airplanes does not present a significant performance impact. However, the materials from which RG-58 is made and the technology behind the design of the coax is now over 60 years old. See: http://www.aeroelectric.com/Pictures/Curves/coaxloss1.pdf Consider a 10' run of coax from GPS receiver to antenna. RG58 offers an attenuation of about 35db/100'; RG-400/142 is about 24db/100'. 10' runs reduce to 3.5 and 2.4 db for a difference of 1.3 db . . . delta that is impossible to observe and difficult to measure at that frequency. With respect to materials, RG-400/142 are double- layer, silver-plated shield and fabricated from modern cousins to Teflon. It's the best we know how to do . . . today. Bob . . . ________________________________ Message 8 _____________________________________ Time: 01:16:20 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Starter Choice At 10:19 PM 3/4/2008 +0000, you wrote: >I am changing the engine on my One Design. I am removing an O-320-E3D and >fitting an IO-360-B1B (180 hp regular compression). I will be fitting an >Odyssey 17ah battery. The 320 has a B&C starter that has been used for >around 100 hours, it also has 122 teeth on the starter ring. The 360 has a >Sky-tec PM starter (and is brand new and is painted bright red) and a 149 >tooth starter ring. The airplane is fitted with a B&C SD-8 generator so >cannot guarantee a fully charged battery every time. Size of the alternator certainly influences how well your battery is charged at shutdown. But judicious stewardship of stored energy from the battery after to back off the throttle for approach to landing can go a long way toward mitigating the effects. From an energy perspective, cranking an engine takes perhaps 5% of the total energy stored on your battery. If you use say 20% off the top during descent and taxi to parking, cranking performance from 100% charge versus 80% charge would not be terribly noticable. > > >I have heard stories that permanent magnet starters and Odyssey batteries >do not get on, and that starting is often slow, especially the first >couple of blades. All things being equal I would swap the starter and the >starter ring, but that s not possible as the part numbers of the starter >rings between the two engines are different I don t know the precise >differences, and I would have to paint the old starter ring. To be able to >use the B&C starter on the new engine B&C recommend I change out the ring >gear, or return the starter for overhaul ($310 plus shipping from Europe). >And will have to change something on the old engine. >So my questions is, am I right to be concerned about the long term >abilities of a Skytec PM starter and the Odyssey battery to provide >reliable starting? Does anyone have any experience with this combination? This question stands on a whole lot of variables both in the observed performance of your as-installed starter/proposed battery -AND- the as-installed/ demonstrated battery of those who would hope to advise you. Let's consider another approach that takes advantage of a demonstrated experiment using your equipment. What are the risks of leaving the present starter in place and going ahead with the installation? EVERY starter system benefits from wound-field starter motors in terms of cranking under worst case conditions. However, there are thousands of PM starters in service where users report satisfactory performance to their needs. I'll suggest that if time and costs to get your new engine installed are to be minimized, there's little risk in leaving the system configured as you've described. In fact, I'll suggest there is an advantage for leaving the configuration alone. You have a significant task for changing out the engine and getting everything tight and tuned up. Why not get these tasks done while being sensitive to starter performance for the purpose of answering your own question . . . and then having some experimental data to share with the rest of us? Bob . . . ________________________________ Message 9 _____________________________________ Time: 02:08:09 PM PST US From: "Bill and Marsha" Subject: AeroElectric-List: z16 rev L Question for Bob. I am doing my final wiring checkout on my soon to be complete Pulsar lll Rotax 912 project. I came across a revision L to Z16. Question, Was their a specific problem for the change to the alternator disconnect ckt? and would you recommend changing from version k to rev. L and why. Thanks Bill ________________________________ Message 10 ____________________________________ Time: 04:20:16 PM PST US From: "Carlos Trigo" Subject: RE: AeroElectric-List: static system leak check procedure By the way, can somebody explain how is a static leak check performed? Carlos > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list- > server@matronics.com] On Behalf Of Ken > Sent: quarta-feira, 5 de Maro de 2008 19:02 > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: static system leak check procedure > > > I started to do a preliminary static system leak check and noticed that > it only takes about 500 feet of static vacuum to make the ASI read about > 100 knots. 10 or 20 thousand feet would peg the ASI pretty firmly. Is > the pitot side subjected to the same vacuum as the static side of the > system to prevent altimeter damage or is that not a concern? It seems > prudent to check for obvious leaks before taking the plane to the radio > shop. > thank you > Ken ________________________________ Message 11 ____________________________________ Time: 05:26:18 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Status of the small strobe wiring experiment. Neal's strobe parts have arrived. I've decided to shift the emphasis to a lab experiment. My good ol' Luna Pro-F flash light meter died years ago and I've had no good reason to replace it until now. Just picked up a much younger replacement off of Ebay. We'll wire one tube with 15' of 20AWG Beldfoil and the other with 22AWG twisted trio and see what the difference is between light output of the two tubes. I'll also get some waveforms for both the flash-tubes and the 14V DC input power. We can convert these measurement to total energy numbers. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 12 ____________________________________ Time: 05:59:34 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: z16 rev L At 04:04 PM 3/5/2008 -0600, you wrote: > Question for Bob. I am doing my final wiring checkout on my soon to be > complete Pulsar lll Rotax 912 project. I came across a revision L to > Z16. Question, Was their a specific problem for the change to the > alternator disconnect ckt? and would you recommend changing from version > k to rev. L and why. Thanks Bill It's a cleaner way to do it. The previous configuration will function as advertised but it's better to interrupt the energy flow as close to the source as possible. Bob . . . ________________________________ Message 13 ____________________________________ Time: 06:04:51 PM PST US From: "Bill Bradburry" Subject: RE: AeroElectric-List: static system leak check procedure Carlos, check out the following website... http://www.kilohotel.com/rv8/rvlinks/ssec.html Bill B -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Carlos Trigo Sent: Wednesday, March 05, 2008 7:16 PM Subject: RE: AeroElectric-List: static system leak check procedure --> By the way, can somebody explain how is a static leak check performed? Carlos > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list- > server@matronics.com] On Behalf Of Ken > Sent: quarta-feira, 5 de Maro de 2008 19:02 > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: static system leak check procedure > > > I started to do a preliminary static system leak check and noticed > that it only takes about 500 feet of static vacuum to make the ASI > read about 100 knots. 10 or 20 thousand feet would peg the ASI pretty > firmly. Is the pitot side subjected to the same vacuum as the static > side of the system to prevent altimeter damage or is that not a > concern? It seems prudent to check for obvious leaks before taking the > plane to the radio shop. > thank you > Ken ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-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/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-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.