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  #61  
Old 12-16-2014, 04:01 PM
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WingedFrog WingedFrog is offline
 
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Originally Posted by rgmwa View Post
I wondered about that option too. However the air in the duct flows past the oil cooler and runs up against the coolant radiator, so I imagine that the air in at least parts of the duct could get quite warm, which is not what you want for air going to the regulator. At least the air coming from the engine shroud inlet should be cool. Perhaps the best option would be to graft a fibreglass stub onto the side of the shroud inlet at an angle that would direct air smoothly into the conduit. Shouldn't be too difficult.
I doubt that the air upstream from the coolant radiator is warmed by either radiators. The air passes partially in front of the oil radiator, a small amount is sucked/pushed through it, cooling the oil and venting against the exhaust but I doubt there is any significant warming of the air flowing downstream to the coolant radiator. My plan is to pass the blast tube through an elongated hole into the main conduit and fasten it inside the conduit against the wall with its opening oriented forward. The fastening can be done with tie-wraps passing through slits in the fiberglass wall and probably a helping of the same silicon caulk I used for the initial installation of the blast tube. A better solution would be to create a scoop in fiberglass with an adequate stub to connect the blast tube but I prefer to test the results of this minimally invasive set-up before doing something more permanent.
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  #62  
Old 12-16-2014, 07:54 PM
Jim T Jim T is offline
 
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This thread, it seems to me, begs the question: Are there better, heavier duty, regulators out there that would solve this problem? A John Deere regulator has been mentioned, so it looks like others are thinking about this as well.

Maybe a better regulator, combined with the new location. Of course now that dual Skyviews are on the table that might tax the system even more.

Jim
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  #63  
Old 12-16-2014, 09:32 PM
RFSchaller RFSchaller is offline
 
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Maybe I'm whistling past the graveyard, but I have three Phoenix summers on my 12 with no issues. I plan to maintain the original configuration until failure (hopefully not in my dwindling lifespan) and then try a John Deere regulator in the same spot. After all -- nothing runs like a Deere!
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  #64  
Old 12-17-2014, 07:51 AM
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WingedFrog WingedFrog is offline
 
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Originally Posted by RFSchaller View Post
Maybe I'm whistling past the graveyard, but I have three Phoenix summers on my 12 with no issues. I plan to maintain the original configuration until failure (hopefully not in my dwindling lifespan) and then try a John Deere regulator in the same spot. After all -- nothing runs like a Deere!
You are right, Rich, the issue is far from being settled. What seems to be clear from the research paper from Grenoble is that there is a need for cooling that goes beyond just convection. The initial solution by Vans with the blast tube made sense and I would like to understand under what rationale they rushed to this relocation solution. Some basic tests need to be made about the volume of air flowing through this tube and what could affect it. Although the temperature under the cowl raises after engine shut down, I don't believe that this is an issue because after shut down the regulator is off, not generating any heat. Even the need to use a conductive paste between the regulator and the firewall shelf is not clear as the regulator is filled with foam on the bottom side which means that heat dissipation from the bottom is very limited (another good initial call by VAN's instructions).
As the saying goes: before acting on this issue, it is urgent to wait and I am with you.
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  #65  
Old 12-17-2014, 08:20 AM
cactusman cactusman is offline
 
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Quote:
Originally Posted by WingedFrog View Post
You are right, Rich, the issue is far from being settled. What seems to be clear from the research paper from Grenoble is that there is a need for cooling that goes beyond just convection. The initial solution by Vans with the blast tube made sense and I would like to understand under what rationale they rushed to this relocation solution. Some basic tests need to be made about the volume of air flowing through this tube and what could affect it. Although the temperature under the cowl raises after engine shut down, I don't believe that this is an issue because after shut down the regulator is off, not generating any heat. Even the need to use a conductive paste between the regulator and the firewall shelf is not clear as the regulator is filled with foam on the bottom side which means that heat dissipation from the bottom is very limited (another good initial call by VAN's instructions).
As the saying goes: before acting on this issue, it is urgent to wait and I am with you.
When mine goes into paint, I plan to relocate mine and redo the panel with that carbon fiber overlay....I was wondering if in addition to ensuring the ground is proper and the proper use of heat dissipation silicone....perhaps the use of a CPU style cooler and lower amperage fan could be used on top of the the reg when mounted up side down using the wiring for the avionics fans?

I have noticed that there is a lot of heat coming off that firewall and indeed my center lower console (where the red cube and rudder cables go) is extremely hot - to the degree that I am considering some kind of additional insulation blanket.

I heard from Mike S that the demo/trainer did blow a lot of these regs as well - so I expect they did do some testing with the newer location.

Last edited by cactusman : 12-17-2014 at 08:27 AM.
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  #66  
Old 12-17-2014, 08:21 AM
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rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by WingedFrog View Post
I would like to understand under what rationale they rushed to this relocation solution.

Some basic tests need to be made about the volume of air flowing through this tube and what could affect it.
Rushed?
The design that was abandon was in place since the introduction of the RV-12 (4 + years?)

You assume tests were not made.....?
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  #67  
Old 12-17-2014, 09:06 AM
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Rick_A Rick_A is offline
 
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Quote:
Originally Posted by Jim T View Post
This thread, it seems to me, begs the question: Are there better, heavier duty, regulators out there that would solve this problem? A John Deere regulator has been mentioned, so it looks like others are thinking about this as well.

Maybe a better regulator, combined with the new location. Of course now that dual Skyviews are on the table that might tax the system even more.

Jim
I wonder if the regulator that B&C sells (designed for use with their alternators) would work? The B&C external regulators are rock solid but probably larger than the regulator that is supplied by Vans. They are designed to be mounted on the cold side of firewall
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  #68  
Old 12-17-2014, 12:01 PM
RFSchaller RFSchaller is offline
 
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John,

How did you notice the hot firewall? It's tough to reach in the wheel well.
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  #69  
Old 12-17-2014, 12:22 PM
cactusman cactusman is offline
 
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Quote:
Originally Posted by RFSchaller View Post
John,

How did you notice the hot firewall? It's tough to reach in the wheel well.
lol - and I am not nearly that flexible either!

No - I got one of those cheap laser thermometer pointer things when I noticed how hot the center got while running it up in shorts and sandals - no carpet.

It's frequently 90+ when I point it at the firewall or center console even after a while at higher altitudes and at cruise with all the vents open - point it at the vent and get 55, point it at the firewall near the center console - 91.

With the carpet in place and at altitude it doesn't seem too bad and of course in the desert with that greenhouse canopy I thought it was just typical. There are a few threads here talking about it, and I think I saw someone put a vent/fan in the red cube well......

I wonder if anyone has thought about or done cowl flaps for the 12?

Last edited by cactusman : 12-17-2014 at 12:25 PM.
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  #70  
Old 12-18-2014, 09:08 AM
h&jeuropa h&jeuropa is offline
 
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Location: Kalamazoo, MI
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Couple of comments from long time Rotax 914 owner / operator in my Europa.

If you look at the photo of the regulator / rectifier on the Contrails website, the two diodes (MR2510) that make up half the bridge rectifier are soldered to a copper plate located at the bottom left corner of the photo. The plate is at +12 so it cannot be attached to the Ducatti enclosure which is at ground potential. What happens over time is that the solder connection fails due to thermal stress and so the bridge rectifier no longer functions. Often times the solder will reattach when the regulator cools and will function properly until it is heat stressed again, hence the intermittent nature of the failure. Interesting to note that the thermal photos do not show a hot spot near the diode location which affirms that they do not have a good thermal path.

My understanding is that a certified installation has no choice but to replace the regulator. In an experimental installation, you can add a pair of external diodes in parallel to the internal ones (anodes connect to GG and cathodes to +B/R). Its actually easier to use a bridge rectifier. I have done this and have over 500 hours on my Ducatti.

As shown on the Contrails website, the Ducatti is heat stressed especially when operating near its specified limits of 240 watts (20 amps). It really needs cooling air. I have temperature indicating strips on my Ducatti, ignition modules and external bridge rectifier heat sink and inspect them during preflight.

Aside to Rick, the Rotax engine has a dynamo which requires a regulator / rectifier. The B&C LRC3 regulator does not provide rectifier function. The PMR1 seems to, but B&C does not recommend it. There are shunt rectifier / regulators used on motorcycles but these also will not work with Rotax. The german Schenke regulator rectifier used by Contrails seems to be more robust but is not readily available in the US.

Jim Butcher
Europa XS, Rotax 914, GRT Sport EFIS
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