Anticept Posted February 3, 2014 Report Share Posted February 3, 2014 Well there's another problem with diodes, they drop voltage. I don't know how much voltage a modern diode drops, but the ones i was familiar with would drop .7 volts, which is quite significant in a 12 volt system! EDIT: this isn't universal. Seems this is for silicon diodes, germanium drops .3. It is also apparently variable, if you pump a lot of current, the drop goes up. If you have equipment on while installing or removing a battery, you have bigger problems . It isn't as big of a problem with modern electronics, but older systems were somewhat sensitive to voltage levels bouncing around. Link to comment Share on other sites More sharing options...
Runtoeat Posted February 3, 2014 Report Share Posted February 3, 2014 Voltage drop would be a bad thing - especially with our anemic Rotax charging system. Link to comment Share on other sites More sharing options...
Anticept Posted February 3, 2014 Report Share Posted February 3, 2014 I just checked with someone who knows this stuff. .7 is for silicon, .3 for germanium, and there are others. Also, the drop will increase if you are conducting a lot of amperage. By the way, one thing i find goofy with our sbs battery installation: they use one size terminals. In car batteries, there are two different post sizes. The LED warning light is your best bet for polarity checking. You shouldn't have the master on while changing your battery anyways. Link to comment Share on other sites More sharing options...
Jim Posted February 3, 2014 Report Share Posted February 3, 2014 All the electronics I design has protection diodes. One way to avoid the voltage drop is to first route the current through an easily replaced fuse and then place a zener diode between the power and ground. The zener will cause the fuse to blow if either the maximum voltage is exceeded or the polarity is reversed. Link to comment Share on other sites More sharing options...
Runtoeat Posted February 4, 2014 Report Share Posted February 4, 2014 Jim, I figured there was something that could be put inline on a power supply. Voltage spike or reversals can and do happen. Do you have any part no's and/or simple diagram showing where the zener is placed to protect for reverse voltage? Link to comment Share on other sites More sharing options...
Anticept Posted February 4, 2014 Report Share Posted February 4, 2014 My CTLS already comes with main breaker. I would not like to fuse the main power because it is another point of failure.The zener is placed in parallel to the loads (after the breaker/fuse and before the rest of the electronics/loads) and grounded in reverse bias. The breakdown voltage should probably be around 16-18 volts in a 12 volt system. If you put the battery in backwards or the voltage gets too high, it will only be incorrect for a very brief amount of time because the majority of power will shunt through the zener unrestricted, and pop the breaker/fuse. Link to comment Share on other sites More sharing options...
Jim Posted February 4, 2014 Report Share Posted February 4, 2014 What Anti said. Link to comment Share on other sites More sharing options...
Runtoeat Posted February 5, 2014 Report Share Posted February 5, 2014 Neat. Thanks. Link to comment Share on other sites More sharing options...
FastEddieB Posted February 15, 2014 Author Report Share Posted February 15, 2014 Update: Sigtronics has shipped the repaired intercom - total with shipping was about $105. Horizon in Knoxville bench tested the encoder and it was fine. That plus the transponder repair came out to about $143, and Karen picked them up today and will be home with them Sunday. I'll be so lucky if that was the extent of the damage. Let's hope! Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 16, 2014 Report Share Posted February 16, 2014 Eddie, it seems this adventure has kept you on the ground for far too long! Link to comment Share on other sites More sharing options...
FastEddieB Posted February 16, 2014 Author Report Share Posted February 16, 2014 You think??? Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 16, 2014 Report Share Posted February 16, 2014 I'm right there with you, after my surgery I got to make two flights, then got sick with a respiratory infection for a week and a half, and now have my plane in pieces while doing the Matco wheel and brake upgrade. I have not flown in almost a month. Link to comment Share on other sites More sharing options...
Anticept Posted February 16, 2014 Report Share Posted February 16, 2014 Eddie, it seems this adventure has kept you on the ground for far too long! You think??? No wonder he's been around a lot. He needs to hurry up and fix his plane so we can stop hearing him talk Link to comment Share on other sites More sharing options...
opticsguy Posted February 16, 2014 Report Share Posted February 16, 2014 I made my own oil cooler fix. It raises my oil temp about 20F over doing nothing, without the issues of blocking the coolant radiator. I took a piece of sheet metal, folded over an edge and slid it between the two radiators. Here's a pic with it in partially removed.. It kept me at 180F during final in 50F weather, instead of 130-140F. Much less risk of coolant overheating. Pic with it in place. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 16, 2014 Report Share Posted February 16, 2014 It looks like that covers a LOT of the oil cooler. Great idea. Link to comment Share on other sites More sharing options...
opticsguy Posted February 17, 2014 Report Share Posted February 17, 2014 it covers about half of the oil cooler. If it's below 0C/32F, my oil may not be warm enough so I may still need tape. My CT has great cooling. If I don't block the oil cooler I will get below 124F on final if the air is below 40F. Most don't have this issue. Link to comment Share on other sites More sharing options...
FastEddieB Posted February 20, 2014 Author Report Share Posted February 20, 2014 Great news! I went out to the hangar today and reinstalled the repaired intercom. I had already reinstalled the transponder and encoder. On reinstalling the panel and hooking it up, everything worked. Pulled the plane out of the hangar and it started right up, and the charge on the new battery looked fine. Assuming no further hidden damage, I'm out only just under $250 in repairs, not including my time. Whew! Too windy and cloudy to fly today - hope to tomorrow. Photos and commentary to follow. Link to comment Share on other sites More sharing options...
FastEddieB Posted February 20, 2014 Author Report Share Posted February 20, 2014 Some photos and comments: 1) I printed out a photo of the correct battery cable orientation and taped it to the battery box: If nothing else, hopefully it will remind me to check. 2) Every plane I've owned has in some cases had me praising the designers for making things simple, and other times cursing them for making things hard*. In the Sky Arrow, one very nice feature is that the panel is held in place with 2 10mm nuts and I can have it out in less than 5 minutes. Everything running into it is easily unplugged/disconnected: The blue hoses are the pitot and static, making it easy to blow them out if water gets in. Here it is on the bench: This allows: Ready access to the rudder pedal adjustment assembly and heater valve and other items in the pilot's footwell for routine maintenance: Easy access to the encoder and intercom: And easy access to all the instruments and switches and breakers - much less aggravation than any prior plane I've owned. Oh, and the new LED landing light is really bright: When I do get to fly, I'll let you all know how it goes. *On the Sky Arrow they mounted the voltage regulator in a location nearly unreachable by normal human hands - it took us 3 hours to remove the old one, using all sorts of mechanic's tricks and specialty tools - and swearing. The new one got relocated to a much easier to reach location, with more air flow to boot. Link to comment Share on other sites More sharing options...
FastEddieB Posted February 20, 2014 Author Report Share Posted February 20, 2014 I'd say landing light*. But for me, not planning on night flying, really more of a recognition light. Oh, and I do have a headlight Velcro'd to the panel in front of me, were I ever to find myself in the dark and have panel light failure. *but I do get the reference! Link to comment Share on other sites More sharing options...
FredG Posted February 21, 2014 Report Share Posted February 21, 2014 Glad to hear the good news. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 21, 2014 Report Share Posted February 21, 2014 awesome Eddie! Link to comment Share on other sites More sharing options...
WmInce Posted February 21, 2014 Report Share Posted February 21, 2014 All good news Eddie. Glad for ya'. Link to comment Share on other sites More sharing options...
Runtoeat Posted February 21, 2014 Report Share Posted February 21, 2014 Eddie, I really like the Sky Arrow's setup for instrument panel removal. Especially the ability to get to the rudder pedal system for inspection/repair. Good news that your "oh sh*t" battery fiasco ended up being a minor cost to fix. I've learned that anything that costs me less than $500 to fix on my CT is a welcome event. Andy and Eddie, I feel your pain, my CT has been in the repair shop since the end of December and due to the ice and snow, I haven't been able to fly it home for the last three weeks. Last nite, we had snow combined with lightening and thunder, followed with heavy rain. This comes after getting another 5" of snow a few days ago which put is near 7 feet for the winter and temps in the low singles during the day and below zero overnight for all of January and most of February. We're 3 feet over the winter average and there's more winter left. It's been a strange winter for lower Michigan. OpticcsGuy, a nice and simple way to control cooling. Agree that very low ambient would still require one to add some tape to the radiator. Link to comment Share on other sites More sharing options...
FlyingMonkey Posted February 21, 2014 Report Share Posted February 21, 2014 My A&P had to go to Florida this week, but I'm hoping to have the CTSW back in the air Saturday. Link to comment Share on other sites More sharing options...
FastEddieB Posted February 21, 2014 Author Report Share Posted February 21, 2014 I flew her!.6 and 3 landings.First two pretty bad, third OK - easy to get rusty.And......I guess I shouldn't be surprised, but when I pushed down on the tail during the preflight, it went down noticeably easier.I guess losing 10 lbs from the nose at quite a distance ahead of the main gear makes a difference.I think I noticed it on landing as well, with the nose feeling just a bit lighter.I will post the W&B change shortly, and I did run through "what-if" loadings with heavy rear passengers and the rear limit is still safe. Here you go: But as I said, I had looked forward to the weight savings without really considering that I might feel it in any way.Always learning! Link to comment Share on other sites More sharing options...
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