---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 02/16/15: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:19 AM - Re: Re: 12v vs 14v System? (Robert L. Nuckolls, III) 2. 11:20 AM - weird radio trouble (B Tomm) 3. 11:34 AM - Re: weird radio trouble (Earl Schroeder) 4. 11:55 AM - Re: weird radio trouble (Peter Pengilly) 5. 12:54 PM - Re: weird radio trouble (John MacCallum) 6. 01:22 PM - Re: weird radio trouble (BobsV35B@aol.com) 7. 01:43 PM - Re: weird radio trouble (David Lloyd) 8. 03:28 PM - Risks associated with unproven crimp tools . . . (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:19:47 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: 12v vs 14v System? From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: 12v vs 14v System? It's probably too much to ask for standard terms to be applied to electrical systems after all these decades. [Wink] Ain't gonna happen . . . batteries are chemical beasts with no single cell offering anything closed to 12v. So combinations of cells have to be joined until the target 'system' requirements are met. In the case of lead-acid batteries, multiple cells in series were '6-volt', '12-volt' and '24-volt' long before anyone stuck them in a vehicle paired with a generator. Early electrification of boats and railroad cars featured '32-volt batteries' charged at 38 volts. To this day, you can still buy a 32 volt lamp for 'marine' applications. Emacs! Chas Kettering's 1916 Delco-Light plant for rural applications were offered to charge 16 lead-acid cells in series . . . Emacs! This would have nominally been a 32-volt battery charged by a generator and (later a wind-mill) for a system voltage of 38 volts. Just put a new battery in Dr. Dee's little red Saturn. Just for grins, I sucked out most of the electrons in its off-the-shelf condition and got this plot . . . Emacs! With a 5A load, you can see that it started out a closer to 13 volts and tossed in the towel before it about 11 volts . . . with an AVERAGE output of 12 volts. Now, to stuff all those electrons back in at room temperature, I need to charge it at 13.8 volts for a few days . . . but to stoke it back up in hours or less, a charge voltage of 14.2 to 14.8 is called for. Since day-one, vehicles of all stripe have been said to operate at the battery's maintenance voltage (i.e. 14v) while in fact, batteries delivered energy at their label value of 12v (which is a more of an average over the discharge curve of the battery). Now comes the lithium family of cells. If you charge a stack of 4 cells to the maximum rated charge voltage of 4.2 volts per cell, then you'd have to do it at about 16.8 volts. We might call this a '17 volt system.' Emacs! Referring to the family of curves above, the 16.8 volt operation gives you a "15 volt battery". But put the same array of cells into your "14v system" tuned to lead-acid chemistry and you get a "13.5 volt battery" while giving up about 1/2 its max rated chemical capacity. Hence, it's entirely proper and logical to speak of batteries in terms of the manner in which they deliver energy and to speak of systems in terms a nominal operating voltage within which all accessories (including the battery) are obliged to perform to design goals. Bob . . . ________________________________ Message 2 _____________________________________ Time: 11:20:32 AM PST US From: "B Tomm" Subject: AeroElectric-List: weird radio trouble A hangar neighbor did an engine overhaul last fall. The airplane didn't fly for about 5 months. It sat in a hangar the whole time. Now that it's flying again, there's a new weird radio problem that we can't figure out. Initial radio operation (on the ground) is... not stellar but OK (maybe 4/5 for clarity). After airborne for a short time (less than 1/2 hour) communications becomes so poor that radio contact with the tower cannot be maintained. Aircraft is BD4 (aluminum skins) Comm antenna is on top ala Cessna 172 etc The alternator is also new with the engine overhaul. Plane Power internally regulated. At first we thought it was a low battery (sitting for 5 months) or alternator problem but a recently added multimeter reveals 14.5V while flying. The hangar has been very humid at times with condensation forming on all the exterior surfaces. So we are wondering about corrosion or connection issues. But comms on the ground are much better than in the air. That may be just following the trend that initial communications is always better. It seems to deteriorate a little after being airborne. Any ideas? Bevan ________________________________ Message 3 _____________________________________ Time: 11:34:02 AM PST US Subject: Re: AeroElectric-List: weird radio trouble From: Earl Schroeder Putting my money on 'ground' issues on aluminum skins. Even from one skin to the next. Good luck! On Feb 16, 2015 1:25 PM, "B Tomm" wrote: > > > A hangar neighbor did an engine overhaul last fall. The airplane didn't > fly for about 5 months. It sat in a hangar the whole time. Now that it's > flying again, there's a new weird radio problem that we can't figure out. > > Initial radio operation (on the ground) is... not stellar but OK (maybe > 4/5 for clarity). After airborne for a short time (less than 1/2 hour) > communications becomes so poor that radio contact with the tower cannot be > maintained. > > Aircraft is BD4 (aluminum skins) > Comm antenna is on top ala Cessna 172 etc > > The alternator is also new with the engine overhaul. Plane Power > internally regulated. > > At first we thought it was a low battery (sitting for 5 months) or > alternator problem but a recently added multimeter reveals 14.5V while > flying. > > The hangar has been very humid at times with condensation forming on all > the exterior surfaces. So we are wondering about corrosion or connection > issues. But comms on the ground are much better than in the air. That may > be just following the trend that initial communications is always better. > It seems to deteriorate a little after being airborne. > > Any ideas? > > Bevan > > > * > > > * > > ________________________________ Message 4 _____________________________________ Time: 11:55:43 AM PST US Subject: Re: AeroElectric-List: weird radio trouble From: Peter Pengilly What type of radio? On 16 Feb 2015 19:33, "B Tomm" wrote: > > > A hangar neighbor did an engine overhaul last fall. The airplane didn't > fly for about 5 months. It sat in a hangar the whole time. Now that it's > flying again, there's a new weird radio problem that we can't figure out. > > Initial radio operation (on the ground) is... not stellar but OK (maybe > 4/5 for clarity). After airborne for a short time (less than 1/2 hour) > communications becomes so poor that radio contact with the tower cannot be > maintained. > > Aircraft is BD4 (aluminum skins) > Comm antenna is on top ala Cessna 172 etc > > The alternator is also new with the engine overhaul. Plane Power > internally regulated. > > At first we thought it was a low battery (sitting for 5 months) or > alternator problem but a recently added multimeter reveals 14.5V while > flying. > > The hangar has been very humid at times with condensation forming on all > the exterior surfaces. So we are wondering about corrosion or connection > issues. But comms on the ground are much better than in the air. That may > be just following the trend that initial communications is always better. > It seems to deteriorate a little after being airborne. > > Any ideas? > > Bevan > > > * > > > * > > ________________________________ Message 5 _____________________________________ Time: 12:54:26 PM PST US From: John MacCallum Subject: RE: AeroElectric-List: weird radio trouble You don=99t say whether it=99s a transmit or receive issue? You also say contact with the tower, so do you mean local comms with a control tower or do you mean Air Traffic Control which is usually remote. If on receive the Radio is a little scratchy and only readability 4 for a local control tower there may be something wrong with the Antenna or the feed line or the radio. If you have more trouble receiving the further you get away from a local station, ie a local Tower with weak reception and the Tower has trouble hearing you, look at the Antenna and the Feedline, check them for connections and check the SWR. If Radio receives ok and the Antenna/feedline is ok but the Tower has trouble hearing you at a distance then it=99s most likely the Power output from the Radio. Most SWR Meters will also tell you what the output power is so you can check that as well. Older model Radios usually somewhere around 10 watts and the newer stuff 25 watts. Cheers John MacCallum VH-DUU RV 10 # 41016 From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Peter Pengilly Sent: Tuesday, 17 February 2015 6:54 AM Subject: Re: AeroElectric-List: weird radio trouble What type of radio? On 16 Feb 2015 19:33, "B Tomm" wrote: A hangar neighbor did an engine overhaul last fall. The airplane didn't fly for about 5 months. It sat in a hangar the whole time. Now that it's flying again, there's a new weird radio problem that we can't figure out. Initial radio operation (on the ground) is... not stellar but OK (maybe 4/5 for clarity). After airborne for a short time (less than 1/2 hour) communications becomes so poor that radio contact with the tower cannot be maintained. Aircraft is BD4 (aluminum skins) Comm antenna is on top ala Cessna 172 etc The alternator is also new with the engine overhaul. Plane Power internally regulated. At first we thought it was a low battery (sitting for 5 months) or alternator problem but a recently added multimeter reveals 14.5V while flying. The hangar has been very humid at times with condensation forming on all the exterior surfaces. So we are wondering about corrosion or connection issues. But comms on the ground are much better than in the air. That may be just following the trend that initial communications is always better. It seems to deteriorate a little after being airborne. Any ideas? Bevan ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List tp://forums.matronics.com _blank">http://www.matronics.com/contribution ________________________________ Message 6 _____________________________________ Time: 01:22:40 PM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: weird radio trouble Was the radio working acceptably before the engine work? Old Bob In a message dated 2/16/2015 1:35:01 P.M. Central Standard Time, n233ee@gmail.com writes: Putting my money on 'ground' issues on aluminum skins. Even from one skin to the next. Good luck! On Feb 16, 2015 1:25 PM, "B Tomm" <_fvalarm@rapidnet.net_ (mailto:fvalarm@rapidnet.net) > wrote: A hangar neighbor did an engine overhaul last fall. The airplane didn't fly for about 5 months. It sat in a hangar the whole time. Now that it's flying again, there's a new weird radio problem that we can't figure out. Initial radio operation (on the ground) is... not stellar but OK (maybe 4/5 for clarity). After airborne for a short time (less than 1/2 hour) communications becomes so poor that radio contact with the tower cannot be maintained. Aircraft is BD4 (aluminum skins) Comm antenna is on top ala Cessna 172 etc The alternator is also new with the engine overhaul. Plane Power internally regulated. At first we thought it was a low battery (sitting for 5 months) or alternator problem but a recently added multimeter reveals 14.5V while flying. The hangar has been very humid at times with condensation forming on all the exterior surfaces. So we are wondering about corrosion or connection issues. But comms on the ground are much better than in the air. That may be just following the trend that initial communications is always better. It seems to deteriorate a little after being airborne. Any ideas? Bevan ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List tp://forums.matronics.com _blank">http://www.matronics.com/contribution ________________________________ Message 7 _____________________________________ Time: 01:43:24 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: weird radio trouble First, suggest checking the coax cable from the antenna to the radio and also the BNC connectors of both ends which might have a broken shield connection or cold solder joint. The coax cable should be checked to see if it got pinched, nibbled on by mice, cut, water in the dielectric, etc D ------------------------------------------------------------------------- ------- ----- Original Message ----- From: BobsV35B@aol.com To: aeroelectric-list@matronics.com Sent: Monday, February 16, 2015 1:21 PM Subject: Re: AeroElectric-List: weird radio trouble Was the radio working acceptably before the engine work? Old Bob In a message dated 2/16/2015 1:35:01 P.M. Central Standard Time, n233ee@gmail.com writes: Putting my money on 'ground' issues on aluminum skins. Even from one skin to the next. Good luck! On Feb 16, 2015 1:25 PM, "B Tomm" wrote: A hangar neighbor did an engine overhaul last fall. The airplane didn't fly for about 5 months. It sat in a hangar the whole time. Now that it's flying again, there's a new weird radio problem that we can't figure out. Initial radio operation (on the ground) is... not stellar but OK (maybe 4/5 for clarity). After airborne for a short time (less than 1/2 hour) communications becomes so poor that radio contact with the tower cannot be maintained. Aircraft is BD4 (aluminum skins) Comm antenna is on top ala Cessna 172 etc The alternator is also new with the engine overhaul. Plane Power internally regulated. At first we thought it was a low battery (sitting for 5 months) or alternator problem but a recently added multimeter reveals 14.5V while flying. The hangar has been very humid at times with condensation forming on all the exterior surfaces. So we are wondering about corrosion or connection issues. But comms on the ground are much better than in the air. That may be just following the trend that initial communications is always better. It seems to deteriorate a little after being airborne. Any ideas? Bevan ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List tp://forums.matronics.com _blank">http://www.matronics.com/contribution List href="http://www.matronics.com/Navigator?AeroElectric-List">http://www. matronics.com/Navigator?AeroElectric-List ms.matronics.com/">http://forums.matronics.com tp://www.matronics.com/contribution">http://www.matronics.com/contributio n ________________________________ Message 8 _____________________________________ Time: 03:28:40 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Risks associated with unproven crimp tools . . . A few days ago I received some wire segments off of an airplane that experienced burned p-lead shields, melted insulation around center conductors AND even failure of toggle switch. The problem manifested in the airplane when the toggle switch(es) failed open after 100+ hours of service. Only after second failures of switches did more detailed examination reveal melted insulation over outer jacket of p-lead shields as well as melted insulation around center conductor. This had the 'smell' of a sneak-path ground consisting of (1) a poor architecture of the p-lead wiring and (2) high resistance in the starter current ground path. The jumper between forest of tabs ground on fire wall hand been fabricated with a less than ideal crimp tool. Emacs! I did some voltage drop tests across the crimp joints and found pretty high . . . about 2.5 millivolts at only 10 amps! Emacs! Cross-sectioned crimp joints examined under the microscope showed numerous areas of 'failure to achieve gas tight' across the face of the cut. Emacs! My findings suggest some value in replacement of all terminals applied with this tooling. I am also concerned with the corrosion ring around the hole in the terminal . . . this should at worst be slightly darkened tin plating. The degree of corrosion and pitting of the mating surface suggests that this terminal was not made-up with sufficient force to achieve gas-tightness in the joint. If you don't have access to a hydraulic tool and proven die to install a terminal, then consider soldering your terminals on per the article at: http://tinyurl.com/qh4k7ko Interestingly enough, it was failure of magneto p-lead switches that brought the deficiency to light. Emacs! As you can see above, the phosphor bronze rocker strut that held the moving contact was burned in two. The fixed contact is in great shape but structure that supported the moving contact fused. The moving contact was free to rattle around inside the switch. If you use welding cable for your fat-wires, the weld shop where you bought the wire can probably sell you terminals and install them with proven tools. Finally, make sure all mating surfaces for bolted up joints are clean, smooth and torqued down right smartly on assembly. This is an excellent example of a case where marginal joint(s) took perhaps years before degrading to the point where smoke and/or failure to perform manifested. Bob . . . ------------------------------------------------------------------------------------- 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.