---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 02/04/14: 20 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:33 AM - Re: Essential Bus question (R. curtis) 2. 08:09 AM - Teaching vs. Propagandizing (Robert L. Nuckolls, III) 3. 08:35 AM - Batteries and step down converters (donjohnston) 4. 09:14 AM - Re: Batteries and step down converters (Tim Andres) 5. 09:59 AM - Re: Batteries and step down converters (Eric Page) 6. 10:38 AM - Small Connector for Ray Allen Trim Servo Cables? (Valin) 7. 10:54 AM - Re: Small Connector for Ray Allen Trim Servo Cables? (Robert L. Nuckolls, III) 8. 10:58 AM - Re: Small Connector for Ray Allen Trim Servo Cables? (Eric Page) 9. 10:59 AM - Re: Batteries and step down converters (Robert L. Nuckolls, III) 10. 11:09 AM - Re: Small Connector for Ray Allen Trim Servo Cables? (rparigor@suffolk.lib.ny.us) 11. 11:12 AM - Re: Small Connector for Ray Allen Trim Servo Cables? (Robert L. Nuckolls, III) 12. 11:42 AM - Off the shelf product update (Robert L. Nuckolls, III) 13. 12:13 PM - Relay for OV Protection (Thomas E Blejwas) 14. 01:43 PM - Re: Relay for OV Protection (Robert L. Nuckolls, III) 15. 01:45 PM - Re: Teaching vs. Propagandizing (Richard Girard) 16. 02:15 PM - Re: Teaching vs. Propagandizing (Robert L. Nuckolls, III) 17. 03:02 PM - Re: Teaching vs. Propagandizing (Robert Borger) 18. 06:32 PM - Re: Analyze This (user9253) 19. 06:51 PM - Re: Relay for OV Protection (Thomas E Blejwas) 20. 09:02 PM - Re: Re: Analyze This (Jeff Luckey) ________________________________ Message 1 _____________________________________ Time: 05:33:39 AM PST US From: "R. curtis" Subject: Re: AeroElectric-List: Essential Bus question You also have to take into account that unlike the LyCo's, the Rotax has a five piece crank that is pressed together with nothing but the pressure of the fit to keep it together and aligned. I would imagine the trail of tear s would include a piston seizure that causes the crank to come out of align ment which not only destroys a bearing or two, but gives the various crank sections a chance to beat upon each other. The reason for the multipiece cr ank is so that it can be made shorter by reducing the clearance between the side of the rod, see picture. With so little clearance between the rod and the adjacent crank web the twisted, misaligned crank now has a chance to r eally start beating on the rods, the piston skirts, and any pieces that hav e come loose. Of course the Rotax engineers have reduced clearances between the rotating assembly and the case halves to shave off more weight and by now the bearings are not only being twisted out of their seats but the case webs are being hammered, too. I find this scenerio to be highly unlikely! If this were the case, t hen I would wager that there would be cases of this type of failure during normal operation, due to the stress and vibration created during high power running. Roger -- Do you have a slow PC=3F Try a Free scan http://www.spamfighter.com/SLOW-PCfi ghter=3Fcid=sigen ________________________________ Message 2 _____________________________________ Time: 08:09:31 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Teaching vs. Propagandizing At 08:23 PM 2/3/2014, you wrote: >Bob, You also have to take into account that unlike the LyCo's, the >Rotax has a five piece crank that is pressed together with nothing >but the pressure of the fit to keep it together and aligned. >Rotax engines are just a different animal. Understand. This isn't a study in design philosophies. It's a sifting of the simple ideas in work -> heat -> loss of finish -> more heat -> destruction over time. Temperature rise in mass is a time dependent phenomenon. The parts at risk of failure need to take on energy that begins with a very low value (new, slick surfaces) and builds as the level of destruction advances. Most engines run minutes producing a high percentage of rated power with no more oil on moving parts than that which was used to assemble it. Then there's the notion that destruction of cylinder walls (of significant mass with water on the other side) had anything to do with rod failure that went from start to completion in 10 seconds. I've spend a lot of my career sifting through narratives for the purpose of assembling data bits into a coherent picture of cause and effect. "No piston lube resulted in breaking a rod and pushing the end through the crankcase at 1000 rpm" does not paint a coherent picture. There is MUCH that is not said/known and as such is a poor tool for educating the listener with any better understanding than they get from watching a Hollywood portrayal of fantastic physics. Memorable perhaps but it's akin to telling our kids they'd better behave or the "boggy man is going to get you." We've conducted similar exercises here on the List with close examination of narratives in the flying rags that I've dubbed "dark- n-stormy-night" stories. In this case: "Better not have your EFIS system rebooting right after start up lest the engine put a rod through the crankcase." The difference between teacher and propagandist is the ability to bring all the simple-ideas in a narrative together for that coherent picture. The puzzle may be ten pieces or 1000 pieces but until they've been fitted into place, the integrity of the narrative is suspect. Remember that math teacher who insisted you write down all the steps for solving a problem? The goal WAS NOT to get to the right answer on one problem . . . the goal WAS to understand HOW to get to the right answer on all problems. Bob . . . ________________________________ Message 3 _____________________________________ Time: 08:35:51 AM PST US Subject: AeroElectric-List: Batteries and step down converters From: "donjohnston" Two totally unrelated questions... 1) To keep my primary EFIS up during engine start, I'm thinking of using a small battery (I will need two since I've got a 24v system). I've seen mention of people using 7ah batteries for this. What manufacture/model battery people are using? 2) I've got one device that is only available in a 12v version. I was going to get this step down converter from Lone Star. http://www.lonestaraviation.com/Step-Down-Conveter-24V-to-13.8-Volts.html Then I ran across this one at 1/5th the cost. http://www.pyleaudio.com/sku/PSWNV480/24V-DC-to-12V-DC-Power-Step-Down-480-Watt--Converter-W-PMW-Technology I'm wondering if it's likely that there is a fundamental difference between the two beyond one of them being for the aviation market. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418075#418075 ________________________________ Message 4 _____________________________________ Time: 09:14:55 AM PST US Subject: Re: AeroElectric-List: Batteries and step down converters From: Tim Andres I think most any of them will run on 12 volts just fine. If so no need to convert it. Here's what I use: http://www.batteriesplus.com/product/46043-WKA12--7F-12V-7Ah-AGM-Battery/566-0/8183-Emergency-Light-Security-Battery/655122-Moose/Z1100-Security-Alarm.aspx Tim > On Feb 4, 2014, at 8:34 AM, "donjohnston" wrote: > > > Two totally unrelated questions... > > 1) To keep my primary EFIS up during engine start, I'm thinking of using a small battery (I will need two since I've got a 24v system). I've seen mention of people using 7ah batteries for this. What manufacture/model battery people are using? > > 2) I've got one device that is only available in a 12v version. I was going to get this step down converter from Lone Star. > http://www.lonestaraviation.com/Step-Down-Conveter-24V-to-13.8-Volts.html > > Then I ran across this one at 1/5th the cost. > http://www.pyleaudio.com/sku/PSWNV480/24V-DC-to-12V-DC-Power-Step-Down-480-Watt--Converter-W-PMW-Technology > > I'm wondering if it's likely that there is a fundamental difference between the two beyond one of them being for the aviation market. > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=418075#418075 > > > > > > > > > > ________________________________ Message 5 _____________________________________ Time: 09:59:19 AM PST US Subject: Re: AeroElectric-List: Batteries and step down converters From: Eric Page What device are you planning to power from such a DC/DC converter that needs a supply capable of 10-20 amps? Lone Star's prices reflect the high cost of TSO compliance testing and, as you suggested, application of the word "aviation" to their products. That said, I'll bet they're high quality. The Pyle... who knows? As long as in-flight failure of the connected device would have no safety implications, I wouldn't hesitate to use the Pyle converter, or indeed any you might find on eBay for even less $, smaller size and lower weight. Perhaps this: http://bit.ly/1frGS3M -or this- http://bit.ly/1eQFmXj -or this- http://bit.ly/LM7x2A Or, if 5A current capacity is enough, this: http://bit.ly/1n8N17Y Search eBay for "DC buck" and you'll get endless hits. I would figure out the peak current draw of your device, double it, and buy a converter with that capability to assure adequate supply without high operating temps. I wouldn't lose much sleep about reliability; if a converter functions out of the box, it's probably unlikely to fail later, assuming it's not driven to absurd temperatures or subjected to mechanical abuse. Eric On Feb 4, 2014, at 9:34 AM, "donjohnston" wrote: > > Two totally unrelated questions... > > 1) To keep my primary EFIS up during engine start, I'm thinking of using a small battery (I will need two since I've got a 24v system). I've seen mention of people using 7ah batteries for this. What manufacture/model battery people are using? > > 2) I've got one device that is only available in a 12v version. I was going to get this step down converter from Lone Star. > http://www.lonestaraviation.com/Step-Down-Conveter-24V-to-13.8-Volts.html > > Then I ran across this one at 1/5th the cost. > http://www.pyleaudio.com/sku/PSWNV480/24V-DC-to-12V-DC-Power-Step-Down-480-Watt--Converter-W-PMW-Technology > > I'm wondering if it's likely that there is a fundamental difference between the two beyond one of them being for the aviation market. ________________________________ Message 6 _____________________________________ Time: 10:38:59 AM PST US Subject: AeroElectric-List: Small Connector for Ray Allen Trim Servo Cables? From: "Valin" Hello, Can anyone recommend a good, small, preferably environmentally sealed connector to use on the five conductor cable of 22 AWG wires that run to each of the Ray Allen trim servos? If I werent going to be flying in primer first Id probably just splice the wires together for the entire run. But with paint and control surface removal in the known future Id like to make removal of the control surfaces easier with connectors on these cables. They need to be low volume connectors to fit in the space where theyll be. Thanks, Valin Thorn Lancair Legacy Project Boulder, Colorado BTW, when I try to email in questions to the list nothing comes through for me. So posting directly to the AeroElectric List Forum. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418080#418080 ________________________________ Message 7 _____________________________________ Time: 10:54:23 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Small Connector for Ray Allen Trim Servo Cables? At 12:38 PM 2/4/2014, you wrote: Hello, Can anyone recommend a good, small, preferably environmentally sealed connector to use on the five conductor cable of 22 AWG wires that run to each of the Ray Allen trim servos? If I werent going to be flying in primer first Id probably just splice the wires together for the entire run. But with paint and control surface removal in the known future Id like to make removal of the control surfaces easier with connectors on these cables. They need to be low volume connectors to fit in the space where theyll be. Thanks, Valin Thorn Lancair Legacy Project Boulder, Colorado BTW, when I try to email in questions to the list nothing comes through for me. So posting directly to the AeroElectric List Forum. Not sure what you mean by 'email to the list' Using aeroelectric-list@matronics.com in your address is the only way to post to the list server and in this case, it seems to have worked for you. Why 'environmentally sealed' . . . that opens a huge catalog of choices few of which offer a good return on investment. Consider this: http://tinyurl.com/cmq7epd . . . for reducing the profile on a d-sub to allow threading through the lightening holes on an RV . . . not sure what your cable routing constraints are . . . perhaps a stock pair of D-Sub9 connectors would fit. If you're committed to the environmentally sealed variety heres an exemplar selection http://tinyurl.com/n3auqc4 http://tinyurl.com/k883l97 I think you'll find the rudimentary D-Subs adequate to the task. Bob . . . ________________________________ Message 8 _____________________________________ Time: 10:58:02 AM PST US Subject: Re: AeroElectric-List: Small Connector for Ray Allen Trim Servo Cables? From: Eric Page Weather Pack connectors should do the trick, assuming they fit your space co nstraints. The 5-pin is a bit bulky, but a 2-pin and a 3-pin offset from on e another might work. They're even available as pigtails so you don't need t he crimp tool. http://www.whiteproducts.com/weather_pack.shtml Eric On Feb 4, 2014, at 11:38 AM, "Valin" wrote: > Hello, > > Can anyone recommend a good, small, preferably environmentally sealed conn ector to use on the five conductor cable of 22 AWG wires that run to each of the Ray Allen trim servos? If I weren=99t going to be flying in prim er first I=99d probably just splice the wires together for the entire r un. But with paint and control surface removal in the known future I=99 d like to make removal of the control surfaces easier with connectors on the se cables. They need to be low volume connectors to fit in the space where t hey=99ll be. > > Thanks, > > Valin Thorn > Lancair Legacy Project > Boulder, Colorado ________________________________ Message 9 _____________________________________ Time: 10:59:56 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Batteries and step down converters At 10:34 AM 2/4/2014, you wrote: Two totally unrelated questions... 1) To keep my primary EFIS up during engine start, I'm thinking of using a small battery (I will need two since I've got a 24v system). I've seen mention of people using 7ah batteries for this. What manufacture/model battery people are using? What is the input voltage requirement for your electro-whizzies. Many contemporary products now use switch-mode power supplies with a wide range of acceptable inputs . . . typically 0-32 volts. If your devices are of this generation, then you don't need brownout protection in a 28v system . . . starter inrush drain won't pull your bus below 10 volts and the glass will stay powered up. The problem arises when a device with a 10v minimum input voltage sees a drop to 7-8 volts during starter inrush events. 2) I've got one device that is only available in a 12v version. I was going to get this step down converter from Lone Star. http://www.lonestaraviation.com/Step-Down-Conveter-24V-to-13.8-Volts.html Then I ran across this one at 1/5th the cost. http://www.pyleaudio.com/sku/PSWNV480/24V-DC-to-12V-DC-Power-Step-Down-480-Watt--Converter-W-PMW-Technology I'm wondering if it's likely that there is a fundamental difference between the two beyond one of them being for the aviation market. What is the device you're fitting with the down-converter and what are its input demands? Bob . . . ________________________________ Message 10 ____________________________________ Time: 11:09:37 AM PST US Subject: Re: AeroElectric-List: Small Connector for Ray Allen Trim Servo Cables? From: rparigor@suffolk.lib.ny.us Hi Valin We were going to use D-sub connector with no shell, use Goop to hold wires to connector and heat shrink together (this was one of Bobs ideas, I am pretty sure he has instructions for this). Since we have an inspection cover close to the servo, insteads of using a connector we just stagger soldered wires and heat shrunk, leaving a service loop to allow us to unsolder if servo ever needed replacement or removal. In addition we marked on a white piece of heat shrink which wires you would want to connect to a 9 volt battery to jog to a somewhat neutral position to get you home in the event the pitch circuit failed. Details: http://www.europaowners.org/main.php?g2_itemId=30484 Ron Parigoris ________________________________ Message 11 ____________________________________ Time: 11:12:38 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Small Connector for Ray Allen Trim Servo Cables? >They need to be low volume connectors to fit in the space where theyll be. > >Thanks, If you've got a really tight size restriction, then there are some pretty compact but still well enclosed connectors from Lemo http://tinyurl.com/p4ycw9p I used these on a couple of programs at Beech . . . but they come in so many assembly options that nobody stocks many ready-to-install combinations. Both times I needed 4 and 5 wire connectors, they were ordered in from a Lemo distribution facility that custom assembled to the desired option. Cost about $40 each half plus back shells and 6 week lead time. Nice connectors tho . . . Bob . . . ________________________________ Message 12 ____________________________________ Time: 11:42:51 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Off the shelf product update A few weeks ago we were discussing several design goals that would benefit from the incorporation of solid state relays. At that time I cruised the offerings on eBay and purchased this item http://tinyurl.com/l2v72uf Emacs! This is a DC/DC solid state relay rated for switching up to 60 volts at 100 amps. I selected the 100 amp rated device based on the notion that mos-fet transistors rated for the greatest currents tend to have the lowest On-Resistance ratings. I've used many 'oversized' transistors in a task not because I needed some 'headroom' for reliability . . . but because I wanted the lowest practical on-resistance which in turn produces the simplest heat rejection problem. When the first relay arrived, I biased the critter up on a 20A constant current supply and it exhibited a voltage drop on the order of 5 volts . . . obviously unsuited to the task at any current level. Wrote to the seller who was wanting to see schematics on how I had wired it up . . . but who didn't have a clue as to how it was supposed to work. I finally lodged a complaint with eBay for merchandise not as advertised. The seller responded with an offer to replace it and I received the second part directly from the factory yesterday. This part does perform much better . . . only 0.5 volts drop at 20A and probably less than the advertised 1.0 volt drop at 100A. I closed the 'gripe' with the eBay seller. This discovery demonstrates the designers unwillingness to 'bootstrap' the gate supplies to his power FETs for the purpose of achieving the lowest possible on-resistance . . . hence the lowest possible heat dissipation. This product is offered by many eBay sellers and I've found a few bad-reviews . . . but for the most part, these critters seem to operate as advertised. But we can do better . . . I've got a 20A package I'm working with that is in a plastic enclosure and requires NO heat-sink. But it wont sell for $13 either. I can recommend the product offered on eBay for situations where the MINIMUM drop on the order of 0.5 volts is not a stumbling point. At $13, its a good value. I would not operate it at much more than 20A for the same heat-rejection issues we've been deliberating here on the list for bus power steering diodes. I'm going to throw the SSR in the goodies-bin and move on . . . might have a place I can use it on my truck someday. Bob . . . ________________________________ Message 13 ____________________________________ Time: 12:13:35 PM PST US Subject: AeroElectric-List: Relay for OV Protection From: Thomas E Blejwas In modifying Z-07 or Z-19 for my Viking engine, I will add over-voltage protection for the Viking-supplied, internally regulated, 40A alternator by ND. Based in part on Bob's demonstration in the literature of a type 70 contactor opening under simulated o.v. conditions, I'd started to plan on such a relay/contactor instead of spending over $200 on an EV200 or similar. But since the relay is not in the starting loop, could I use a stout auto relay instead? I recently became aware of the Picker 7150 (now sold by Waytek) that has ratings of 75V switching voltage and 150A for continuous load and breaking. It has 3/8" quick tabs for the load, but connectors for #8 wire are available from Digikey. Advantages would be weight (2.1 oz.) and electrical draw (2.9W). Are there potential problems? Btw, I'm not concerned with it surviving an o.v. event, since it would cost $20 or so to replace. Thanks in advance for any feedback. Tom Sent from my iPad ________________________________ Message 14 ____________________________________ Time: 01:43:49 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Relay for OV Protection At 02:12 PM 2/4/2014, you wrote: In modifying Z-07 or Z-19 for my Viking engine, I will add over-voltage protection for the Viking-supplied, internally regulated, 40A alternator by ND. Based in part on Bob's demonstration in the literature of a type 70 contactor opening under simulated o.v. conditions, I'd started to plan on such a relay/contactor instead of spending over $200 on an EV200 or similar. But since the relay is not in the starting loop, could I use a stout auto relay instead? I recently became aware of the Picker 7150 (now sold by Waytek) that has ratings of 75V switching voltage and 150A for continuous load and breaking. It has 3/8" quick tabs for the load, but connectors for #8 wire are available from Digikey. Advantages would be weight (2.1 oz.) and electrical draw (2.9W). Are there potential problems? Btw, I'm not concerned with it surviving an o.v. event, since it would cost $20 or so to replace. Thanks in advance for any feedback. Tom Give it a try! The ratings are good. http://tinyurl.com/kwlvfj2 I note that they come with built in coil suppression that appears to be a plain vanilla diode. Your "high-risk" features are centered more on the connectors and crimps than on the relay. Of all the S700-3 switches 'smoked' by strobe systems, I don't think we've seen any evidence of contact's ill suited to the task. We've seen terminals overheat and do the precipitous slide to smoke and fire, also compression joints across plastic housings (tabs held by rivets) and even some 'teeter totters' that annealed and deformed . . . but the contacts looked fine. What we're learning here is the value of gas-tight integrity for made up joints . . . they appear far more vulnerable to abusive electron flows than the actual controlling contacts. With 3/8" fast-on tabs, you might consider drilling them for #6 screw and using ring terminals to attach. I think I'd go for a soldered-on non insulated ring terminal too. With due diligence to your made up joints, odds for success are quite good. Now for the caveats . . . this is a plastic enclosure and a runaway IR alternator ALWAYS goes into self destruct by putting something on the order of 200 volts on its own field winding - and nearly as much on the b-lead disconnect relay. The only concern I have is for the possibility of internal-eternal fire getting outside the housing . . . this was not a concern with the metal housed Model 70. Bob . . . ________________________________ Message 15 ____________________________________ Time: 01:45:49 PM PST US Subject: Re: AeroElectric-List: Teaching vs. Propagandizing From: Richard Girard Bob et al, It's been seven years since I saw that engine at Lockwoods. At the time I didn't think to take pictures, however I have a request in to Dean Vogel, there, to see if I can get one or two pictures of it. I've had the misfortune to blow up an engine or two over the last 50 years. The first was an Alfa Romeo four cylinder that blew a head gasket. I had just had the engine rebuilt after I over revved it and spun a rod bearing. The book said to re-torque the head every 1300 miles. I had a date and thought I could get it the next morning. Sure enough, white steam began pouring out of the exhaust a block from her house. The trip odometer said the engine had 1317 miles on it. The fellow I sold the car to did the same thing. Dave, as I recall, got a little over that but did not reach 1400 miles. Alfa was quite serious about the 1300 mile re-torquing. I was 19 and it made an impression on me that the manufacturer generally knows his product. Back to the Rotax. First, your assumption that it would idle at 1000 rpm. It's a geared engine that idles at 1800 to 2200. Kinetic energy increases at the square of the speed, does it not? So we have around 4 times the energy from the idle speed you used as an example. Rotax piston fits. As I said, somewhere back, the allowable piston to cylinder fit for a 912 is .0000 to .0009". It is perfectly acceptable to have a size on size fit up. Even at .0009" it does not take much to seize a piston. When I examined the damage, one of the things that impressed me was the absence of metal discoloration or burned oil on the parts, in this case break in lube. This is why my recreation of events concentrated on the failure of the built up crank. I just didn't see the damage signature that I've seen in a typical rod failure event. What there was, was a lot of impact damage. If I'm lucky enough to get a picture or two, I'll pass them along. Rick On Tue, Feb 4, 2014 at 10:08 AM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com> > > At 08:23 PM 2/3/2014, you wrote: > >> Bob, You also have to take into account that unlike the LyCo's, the Rotax >> has a five piece crank that is pressed together with nothing but the >> pressure of the fit to keep it together and aligned. Rotax engines >> are just a different animal. >> > > Understand. This isn't a study in design > philosophies. It's a sifting of the simple > ideas in work -> heat -> loss of finish -> > more heat -> destruction over time. > > Temperature rise in mass is a time dependent > phenomenon. The parts at risk of failure > need to take on energy that begins with a > very low value (new, slick surfaces) and builds > as the level of destruction advances. > > Most engines run minutes producing a high > percentage of rated power with no more oil > on moving parts than that which was used to > assemble it. Then there's the notion that > destruction of cylinder walls (of significant > mass with water on the other side) had > anything to do with rod failure that went > from start to completion in 10 seconds. > > I've spend a lot of my career sifting > through narratives for the purpose of > assembling data bits into a coherent picture > of cause and effect. "No piston > lube resulted in breaking a rod and > pushing the end through the crankcase > at 1000 rpm" does not paint a coherent > picture. > > There is MUCH that is not said/known > and as such is a poor tool for educating > the listener with any better understanding > than they get from watching a Hollywood > portrayal of fantastic physics. Memorable > perhaps but it's akin to telling our > kids they'd better behave or the "boggy > man is going to get you." We've conducted > similar exercises here on the List with > close examination of narratives in the > flying rags that I've dubbed "dark- > n-stormy-night" stories. In this case: > "Better not have your EFIS system rebooting > right after start up lest the engine put > a rod through the crankcase." > > The difference between teacher and propagandist > is the ability to bring all the simple-ideas > in a narrative together for that coherent > picture. The puzzle may be ten pieces or > 1000 pieces but until they've been > fitted into place, the integrity of the > narrative is suspect. > > Remember that math teacher who insisted > you write down all the steps for solving > a problem? The goal WAS NOT to get to the > right answer on one problem . . . the goal > WAS to understand HOW to get to the right > answer on all problems. > > > Bob . . . > > -- Zulu Delta Mk IIIC Thanks, Homer GBYM It isn't necessary to have relatives in Kansas City in order to be unhappy. - Groucho Marx ________________________________ Message 16 ____________________________________ Time: 02:15:21 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Teaching vs. Propagandizing At 03:40 PM 2/4/2014, you wrote: >Bob et al, It's been seven years since I saw that engine at >Lockwoods. At the time I didn't think to take pictures, however I >have a request in to Dean Vogel, there, to see if I can get one or >two pictures of it. >If I'm lucky enough to get a picture or two, I'll pass them along. Great. If he could also expand the narrative to explain the sequence of events along with photos of the participating features . . . Bob . . . ________________________________ Message 17 ____________________________________ Time: 03:02:46 PM PST US Subject: Re: AeroElectric-List: Teaching vs. Propagandizing From: Robert Borger Gents, This thread should probably be on the Rotax list, but sometimes we take what we can get where we can get it. I too have attended Lockwoods 91X class and have seen the engine and heard the story from Dean. There was also a second story related which involved loss of oil due to vibrational damage to an extended fitting to mount the oil pressure sensor. A fitting was inserted between the oil pressure sender and the engine case. The fitting was put in place to add a pressure switch to illuminate a light should the oil pressure drop below the switch pressure set point. Now you have a classic mass on a spring with the sender hanging out on that extension. I dont remember how long that arrangement held up but I dont believe it was very long before the extension piece broke, the gentlemans low oil pressure lamp illuminated and the contents of the oil sump were dumped overboard. Again, the report was that the engine probably didnt run longer than 10-20 second before it seized once the oil was gone. I cant speak to the accuracy of the 10-20 seconds without oil before seizure not having been there in either case. But the takeaway point was that the Rotax 91X engine requires continuous lubrication and that any interruption in that lubrication would be detrimental to your engine. BTW, I have moved my oil pressure sender off the engine and onto the firewall using a length of SS braided pressure line. Saves vibrational stresses on the sender and the fitting to the engine. One of the many things I like about my Grand Rapids EIS 4000 is that it stays up during engine start and the default page shows oil pressure so I know immediately upon engine start if theres oil pressure. Just my 2 and worth at least half that. Blue skies & tailwinds, Bob Borger Europa XS Tri, Rotax 914, Airmaster C/S Prop (50 hrs). Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP 3705 Lynchburg Dr. Corinth, TX 76208-5331 Cel: 817-992-1117 rlborger@mac.com On Feb 4, 2014, at 3:40 PM, Richard Girard wrote: Bob et al, It's been seven years since I saw that engine at Lockwoods. At the time I didn't think to take pictures, however I have a request in to Dean Vogel, there, to see if I can get one or two pictures of it. I've had the misfortune to blow up an engine or two over the last 50 years. The first was an Alfa Romeo four cylinder that blew a head gasket. I had just had the engine rebuilt after I over revved it and spun a rod bearing. The book said to re-torque the head every 1300 miles. I had a date and thought I could get it the next morning. Sure enough, white steam began pouring out of the exhaust a block from her house. The trip odometer said the engine had 1317 miles on it. The fellow I sold the car to did the same thing. Dave, as I recall, got a little over that but did not reach 1400 miles. Alfa was quite serious about the 1300 mile re-torquing. I was 19 and it made an impression on me that the manufacturer generally knows his product. Back to the Rotax. First, your assumption that it would idle at 1000 rpm. It's a geared engine that idles at 1800 to 2200. Kinetic energy increases at the square of the speed, does it not? So we have around 4 times the energy from the idle speed you used as an example. Rotax piston fits. As I said, somewhere back, the allowable piston to cylinder fit for a 912 is .0000 to .0009". It is perfectly acceptable to have a size on size fit up. Even at .0009" it does not take much to seize a piston. When I examined the damage, one of the things that impressed me was the absence of metal discoloration or burned oil on the parts, in this case break in lube. This is why my recreation of events concentrated on the failure of the built up crank. I just didn't see the damage signature that I've seen in a typical rod failure event. What there was, was a lot of impact damage. If I'm lucky enough to get a picture or two, I'll pass them along. Rick ________________________________ Message 18 ____________________________________ Time: 06:32:03 PM PST US Subject: AeroElectric-List: Re: Analyze This From: "user9253" Most aircraft are wired so that starter motor current comes from the battery, through the master contactor, then through the starter contactor to the starter motor. Then if the starter contactor sticks closed, the pilot can break the circuit by shutting off the master switch. I modified Jeff's circuit (attached). Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=418101#418101 Attachments: http://forums.matronics.com//files/starter_circuit_194.pdf ________________________________ Message 19 ____________________________________ Time: 06:51:20 PM PST US Subject: Re: AeroElectric-List: Relay for OV Protection From: Thomas E Blejwas Thanks Bob. I particularly appreciate the caveat. If the runaway can really get to 200V in 5 ms, then I will have a hard time evaluating the potential risk. Tom Sent from my iPad > On Feb 4, 2014, at 2:42 PM, "Robert L. Nuckolls, III" wrote: > > > At 02:12 PM 2/4/2014, you wrote: > > In modifying Z-07 or Z-19 for my Viking engine, I will add over-voltage protection for the Viking-supplied, internally regulated, 40A alternator by ND. Based in part on Bob's demonstration in the literature of a type 70 contactor opening under simulated o.v. conditions, I'd started to plan on such a relay/contactor instead of spending over $200 on an EV200 or similar. But since the relay is not in the starting loop, could I use a stout auto relay instead? I recently became aware of the Picker 7150 (now sold by Waytek) that has ratings of 75V switching voltage and 150A for continuous load and breaking. It has 3/8" quick tabs for the load, but connectors for #8 wire are available from Digikey. Advantages would be weight (2.1 oz.) and electrical draw (2.9W). Are there potential problems? Btw, I'm not concerned with it surviving an o.v. event, since it would cost $20 or so to replace. Thanks in advance for any feedback. > > Tom > > Give it a try! The ratings are good. > > http://tinyurl.com/kwlvfj2 > > I note that they come with built in coil > suppression that appears to be a plain vanilla > diode. > > Your "high-risk" features are centered more on > the connectors and crimps than on the relay. > > Of all the S700-3 switches 'smoked' by strobe systems, > I don't think we've seen any evidence of contact's > ill suited to the task. We've seen terminals overheat > and do the precipitous slide to smoke and fire, also > compression joints across plastic housings (tabs > held by rivets) and even some 'teeter totters' that > annealed and deformed . . . but the contacts looked > fine. > > What we're learning here is the value of gas-tight > integrity for made up joints . . . they appear > far more vulnerable to abusive electron flows than > the actual controlling contacts. > > With 3/8" fast-on tabs, you might consider drilling > them for #6 screw and using ring terminals to attach. > I think I'd go for a soldered-on non insulated > ring terminal too. With due diligence to your made > up joints, odds for success are quite good. > > Now for the caveats . . . this is a plastic enclosure > and a runaway IR alternator ALWAYS goes into self > destruct by putting something on the order of 200 volts > on its own field winding - and nearly as much on the > b-lead disconnect relay. The only concern I have is > for the possibility of internal-eternal fire getting > outside the housing . . . this was not a concern with > the metal housed Model 70. > > > > Bob . . . > > > > ________________________________ Message 20 ____________________________________ Time: 09:02:01 PM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: Re: Analyze This I chose the "non-traditional" approach because:=0A1. Contactor sticking is exceedingly rare=0A2. I did not want cranking to be dependent on 2 contacto rs=0A3. It allows for more choices when selection a master relay=0A=0A=0A =0A=0A________________________________=0A From: user9253 =0ATo: aeroelectric-list@matronics.com =0ASent: Tuesday, February 4, 2014 6:31 PM=0ASubject: AeroElectric-List: Re: Analyze This=0A =0A=0A--> AeroEle ctric-List message posted by: "user9253" =0A=0AMost airc raft are wired so that starter motor current comes from the battery, throug h the master contactor, then through the starter contactor to the starter m otor.- Then if the starter contactor sticks closed, the pilot can break t he circuit by shutting off the master switch.- I modified Jeff's circuit (attached).=0AJoe=0A=0A--------=0AJoe Gores=0A=0A=0A=0A=0ARead this topic o nline here:=0A=0Ahttp://forums.matronics.com/viewtopic.php?p=418101#41810 1=0A=0A=0A=0A=0AAttachments: =0A=0Ahttp://forums.matronics.com//files/start - - - - - - - - - - - - -Matt Dralle, List Admin. ==== ------------------------------------------------------------------------------------- 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.