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02-14-2017, 03:54 PM
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Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
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Ric,
I assume you meant 47,000 microfarad. The easiest place might be near the regulator and tap into the B+ wire from the regulator. No, the 22,000 microfarad capacitor would not have to be disconnected. I do not know if adding another capacitor would help anything though.
Joe
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If one were to install a 47mf 63v capacitor.....would you know where the easiest place to wire into our electrical system? And would the 22mf capacitor have to be removed?
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__________________
Joe Gores
RV-12 Flying
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02-14-2017, 05:39 PM
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Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
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I remember THAT THREAD started by the guy from Arlington. Their "FIX" is akin to putting a penny in place of a fuse. Yeah, the circuit works. But is it safe? In case of smoke in the cockpit at cruise RPM, shutting off the master switch will not shut off the dynamo (alternator) if the alternator half of the master switch has been bypassed. Don't believe me Dick? After the regulator problem has been solved, go flying and at cruise RPM, shut off the master switch and see if electrical power goes off or not. A pilot should have the ability to shut off all electrical power. One could always pull the 30 amp fuse. But when you are coughing and your eyes are stinging from the smoke, will you remember to pull that fuse? Smoke in the cockpit is unlikely. But why take a chance? Fix the problem the right way. Two wrongs do not make a right. Van's Aircraft put a switch in the "C" terminal circuit for a reason.
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Joe Gores
RV-12 Flying
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02-14-2017, 06:25 PM
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Join Date: Jul 2009
Location: Coeur d'Alene, ID/Casa Grande, AZ
Posts: 654
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Quote:
Originally Posted by Mich48041
I remember THAT THREAD started by the guy from Arlington. Their "FIX" is akin to putting a penny in place of a fuse. Yeah, the circuit works. But is it safe? In case of smoke in the cockpit at cruise RPM, shutting off the master switch will not shut off the dynamo (alternator) if the alternator half of the master switch has been bypassed. Don't believe me Dick? After the regulator problem has been solved, go flying and at cruise RPM, shut off the master switch and see if electrical power goes off or not. A pilot should have the ability to shut off all electrical power. One could always pull the 30 amp fuse. But when you are coughing and your eyes are stinging from the smoke, will you remember to pull that fuse? Smoke in the cockpit is unlikely. But why take a chance? Fix the problem the right way. Two wrongs do not make a right. Van's Aircraft put a switch in the "C" terminal circuit for a reason.
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Joe,
See PM
__________________
Ric Dickison
307 (CAB) Phantom
Search and Destroy (Can Tho RVN)
Distinguished Flying Cross Society Member
CH-47 & UH-1H "Driver"
Rotax 9 Series Service IRMT
RV-12 Kit#729 "N312RD" is now a full functioning fun machine!! Thanks Van for fulfilling my dream😎
2018 Dues Paid
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02-15-2017, 07:22 AM
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Join Date: Aug 2015
Location: Lopez Island, Wa.
Posts: 178
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v/r failure
Joe, you mean there should be a switch in the small yellow wire?? When I first started flying this new plane it would not charge all..Van's had no answer, post's were not helping..Arlington repair fixed it so a little hard to find fault..
__________________
Retired Firefighter/Para-Medic
Sold 182 Skyelane
sold Super Cub
Building RV 12 E-LSA
Paid thru 2016, even though exempt
RV 12 completed, waiting DAR
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02-15-2017, 11:25 AM
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Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
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Yes, there is already a switch in series with the small yellow wire. One half of the master switch controls the battery contactor and the other half of the master switch controls the small yellow wire going to the regulator "C" terminal. Shutting off the master switch normally shuts off all sources of electrical power, both the battery and the alternator. The voltage regulator needs battery voltage to be enabled. But once up and running, the regulator no longer needs the battery to continue operating. If a jumper is placed around the regulator half of the master switch, as was done in your plane, the pilot loses the ability to shut off the alternator. Shutting off the master switch during cruise only disconnects the battery. But the alternator will continue running because it is still supplying power to terminal "C". You can test this by shutting off the master switch during cruise and notice that electrical loads keep on working even with the battery disconnected. Also notice that the little green light on the master switch remains lit with the master switch turned off. The guys from Arlington did not find and fix the problem with your electrical system. They just bypassed it. And they created a new problem, the inability to shut off the alternator during cruise. Smoke in the cockpit is one situation where one might want to shut off electrical power. A fuel tank leak is another.
__________________
Joe Gores
RV-12 Flying
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02-15-2017, 12:20 PM
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Join Date: Apr 2010
Location: Tucson, AZ
Posts: 461
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Quote:
Originally Posted by Mich48041
Dual glass panels draw more electrical current which makes the regulator run hotter. Mounting the regulator with heat-conductive grease helps to conduct the heat away. I suggest that Van's add that hint to the plans.
As part of the annual inspection, I suggest that each female terminal of the regulator plug be tested by inserting a male spade connector. If the spade slides in easily, then the female terminal is not gripping tight enough. A loose connector generates heat which speeds up corrosion which generates more heat which, over time, leads to failure.
Some RV-12 owners have discarded the regulator plastic housing and connect each terminal individually.
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I don't think this is the solution. My VR failed and was installed with heat-conductive grease as I thought the firewall would help to cool the VR. As others have noted, the FW gets very hot itself and I wonder if it actually heated the VR more than it was cooled.
I am flying out of Southern Arizona and of course temps are pretty off the charts in the summer. Nothing odd in terms of power usage installed. Just an SV with lighting package. Landing light is set to flashing during pattern work, off otherwise.
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02-15-2017, 08:20 PM
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Join Date: Nov 2016
Location: San Francisco, CA
Posts: 51
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Hi Macpara,
I just went through the Rotax class in Tucson. There were 4-5 RV12 owners there and 13 of us total. We talked about Van's having the highest VR failure rate of the aircraft Mfg's. I also talked to another Rotax instructor and they seem to be on the same page. Since I'm kinda new at this I have been trying to learn everything I can.
Here is what I learned. Heat is the killer. Anything 170F+ is too hot. Heat is either caused by too low a current draw or too large a current draw. Heat is also caused by mechanical heat from surrounding objects. This is our problem.
Here is an easy fix that I found out that seems to be working for the RV12's that have started doing it this way.
First put a 1/4" to 3/8" spacer under the VR and the shelf to give it an air gap. No more heat conduction from the hot metal shelf or a firewall. Make sure the VR has its own ground wire. The 3/4" hose that is in the air intake on top of the engine works more like a suction which pulls in all the hot air from the #4 exhaust pipe and of course any heat build up in the metal shelf adds to that heat. heat doesn't get dissipated it gets added to. Now just pull the flex tube from the VR just a tad further into the air tube and turn the opening toward the fresh air intake opening. You can silicone this back in place facing forward and or add a piece of safety wire through the intake tube around the flex tube to keep it facing forward. This now becomes cooler air being FORCED over the VR and out the bottom edges that help keep hot air away. Some of the owners said they had used exhaust wrap on the #4 exhaust pipe to reduce heat. From what I have been able to gather from other RV12 owners that have done this is they no longer have any more issues as the VR stays much cooler and the heat is swept away. I did mine right after the class and put some temp strips on it to check the VR temp. Temps stayed below 150F. Doing this little mod keeps the heat of the metal shelf out of the VR with the air gap and cool forced air flows over the VR.
So from what I have been able to learn is the VR's aren't the issue as this would be a major problem worldwide. Using another VR sounds like just a bandaid when the fix is so simple and it's all about cooling.
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02-16-2017, 04:25 AM
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Join Date: Nov 2009
Location: Jackson Ohio
Posts: 139
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Vr mod
Could you post a picture of your setup the next time you have your cowling off, thanks.
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02-16-2017, 07:39 AM
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Join Date: Aug 2015
Location: Lopez Island, Wa.
Posts: 178
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Heat
O.K. but what about those of us that had newer RV12'a that put the VR under the panel in the cockpit...don't really like to run cold air to cockpit..and it is not hot under the panel...why do these VR's get so hot..car VR's do not get hot and rarely fail....if I can figure out the wiring difference I'm going to put in the John Deer one I bought a long time ago..certainly prior to ordering another Ducati at $170.00 and trying to chase warranty with Rotax which is difficult.
__________________
Retired Firefighter/Para-Medic
Sold 182 Skyelane
sold Super Cub
Building RV 12 E-LSA
Paid thru 2016, even though exempt
RV 12 completed, waiting DAR
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02-16-2017, 09:20 AM
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Join Date: Oct 2006
Location: St Louis, MO
Posts: 323
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Quote:
Originally Posted by Jolly
Hi Macpara,
I just went through the Rotax class in Tucson. There were 4-5 RV12 owners there and 13 of us total. We talked about Van's having the highest VR failure rate of the aircraft Mfg's. I also talked to another Rotax instructor and they seem to be on the same page. Since I'm kinda new at this I have been trying to learn everything I can.
Here is what I learned. Heat is the killer. Anything 170F+ is too hot. Heat is either caused by too low a current draw or too large a current draw. Heat is also caused by mechanical heat from surrounding objects. This is our problem.
Here is an easy fix that I found out that seems to be working for the RV12's that have started doing it this way.
First put a 1/4" to 3/8" spacer under the VR and the shelf to give it an air gap. No more heat conduction from the hot metal shelf or a firewall. Make sure the VR has its own ground wire. The 3/4" hose that is in the air intake on top of the engine works more like a suction which pulls in all the hot air from the #4 exhaust pipe and of course any heat build up in the metal shelf adds to that heat. heat doesn't get dissipated it gets added to. Now just pull the flex tube from the VR just a tad further into the air tube and turn the opening toward the fresh air intake opening. You can silicone this back in place facing forward and or add a piece of safety wire through the intake tube around the flex tube to keep it facing forward. This now becomes cooler air being FORCED over the VR and out the bottom edges that help keep hot air away. Some of the owners said they had used exhaust wrap on the #4 exhaust pipe to reduce heat. From what I have been able to gather from other RV12 owners that have done this is they no longer have any more issues as the VR stays much cooler and the heat is swept away. I did mine right after the class and put some temp strips on it to check the VR temp. Temps stayed below 150F. Doing this little mod keeps the heat of the metal shelf out of the VR with the air gap and cool forced air flows over the VR.
So from what I have been able to learn is the VR's aren't the issue as this would be a major problem worldwide. Using another VR sounds like just a bandaid when the fix is so simple and it's all about cooling.
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Will take this description and run with it. A pic or two, when convenient, is helpful to visually confirm your suggested changes. What is the material and design of the spacer? Thank you!
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