VAF Forums

VAF Forums (http://www.vansairforce.com/community/index.php)
-   RV-12/RV-12iS (http://www.vansairforce.com/community/forumdisplay.php?f=73)
-   -   Why do some of the RV-12 VRs die young? (http://www.vansairforce.com/community/showthread.php?t=145841)

E. D. Eliot 01-18-2017 07:54 PM

Why do some of the RV-12 VRs die young?
 
I know that this has been hashed out a lot - but - I can't help but wonder what it about the RV-12 electrical system that is causing some VRs to die quite young? It it inadequate generation source for the electronics and lights that we are running? Is it the VRs themselves - are they undersized? Under built? Poorly built? Should we try, for instance, Ford, GMC, Chrysler VRs? Why only Bugatti and tractor VRs? Seems that those who are flying other types of aircraft with the Rotax 912 don't have this problem. Maybe I'm wrong?

From where I sit with no personal experience and only the VAF as my source of info, it appears that`something must be wrong with the RV-12 'system'. With ?????K Rotax engines flying, why do we have this recurring problem? Carry an extra RV whenever I leave my home airport? Really? Something is wrong - what is it?

JBPILOT 01-18-2017 08:18 PM

Ed - -
 
My best guess is the load being placed on them. I have a lighter load on mine, and over 1,000 hours, and no problem. If you run lights, a second screen, headlights, etc., that heats up the VR. Having the VR in a warm airstream does not help likely. In the air duct to the radiator would be best in my opinion.

DaleB 01-18-2017 11:22 PM

I don't believe a different automotive regulator would be an option. Normal automotive systems regulate the output voltage by controlling the field winding current to the alternator. The Rotax alternator uses permanent magnets, not field coils, so they work completely differently. The regulator is actually a rectifier and regulator.

mcems 01-19-2017 06:50 AM

I agree with John on this. I think its the increase loads put on them with addition of cockpit goodies and lights. I have 760 hours on mine mounted in the original location . I have no lights or extras running. It has had no issues since new in 2009.

Brad Stiefvater
Salem SD

BillL 01-19-2017 07:24 AM

Read these links
 
http://www.vansairforce.com/communit...93&postcount=7

Read the links in this post. It should be required reading for all 12 owners.

It has a temperature vs load chart, and a circuit diagram.

Heat HEAT HEAT

Do what ever is possible to keep that sucker cool. And thermocouple it to ensure it really IS cool. Then it should last 4000 hrs. My Kubota VR (similar) did.

Piper J3 01-19-2017 07:32 AM

Quote:

Originally Posted by mcems (Post 1143148)
I agree with John on this. I think its the increase loads put on them with addition of cockpit goodies and lights. I have 760 hours on mine mounted in the original location . I have no lights or extras running. It has had no issues since new in 2009.

Brad Stiefvater
Salem SD

My 12 has no lights or AP. Ducati bought the farm at just over 100 hrs. John Deere VR mounted in same location now has over 100 hrs. I made a heavy aluminum sub-plate and used thermal paste for better heat dissipation.

rv6ejguy 01-19-2017 08:15 AM

The Ducati part is a marginal design. There have been failures for a long time on these parts where the electrical system is operating near peak current capacity. Rotax does offer an external alternator where more current capacity is required.

John-G 01-19-2017 12:19 PM

Quote:

Originally Posted by rv6ejguy (Post 1143171)
The Ducati part is a marginal design. There have been failures for a long time on these parts where the electrical system is operating near peak current capacity. Rotax does offer an external alternator where more current capacity is required.

I would tend to agree with the above statement regarding the Ducati regulator. IMHO the heat sink fins are marginal at best for the power the unit needs to dissipate for the RV-12, especially one that is loaded with options.

The Silent Hektik unit I picked up is rated for more than double the current loads our RV-12's draw fully loaded. The unit has probably three times as much heat sink fin area compared to the Ducati unit and also has a flat machined aluminum base to aid in transferring heat away from the regulator and into the mounting surface (especially when a good heat sink compound is applied).

Currently the plan is to install my Silent Hektik on the firewall shelf or upper firewall underneath the brake reservoir so the regulator will not have hot air blowing directly onto it from the radiator. Also plan to tap into the air duct in the lower cowl forward of the radiator and run a scat tube to the unit so cool air can blow directly onto the rectifier/regulator.

n233va 01-19-2017 01:36 PM

Correct me if I am wrong, but I believe the Silent Hektik is not available in the US. Tried to find a source a while back but to no avail. Anyone know where to get the Silent Hektit in the US??? On my third regulator. 1st lasted 170 hrs. 2nd lasted about 350.

John-G 01-19-2017 03:23 PM

Quote:

Originally Posted by n233va (Post 1143250)
Correct me if I am wrong, but I believe the Silent Hektik is not available in the US. Tried to find a source a while back but to no avail. Anyone know where to get the Silent Hektit in the US??? On my third regulator. 1st lasted 170 hrs. 2nd lasted about 350.

You are correct about the Silent Hektik not being available in the States .... however, that does not mean it can't be obtained. I ordered mine from a motorcycle shop in England that sells Silent Hektik products. It was ordered through his supplier in Germany and then shipped to me from England. I made no mention of it going on an aircraft, nor was I asked ... just said I was looking for a R4112 Silent Hektik regulator to be shipped to me in the States ... it was not a problem.

There was a small issue with the leads though, apparently the regulators are not available any longer with spade leads on the regulator ... now the regulator comes with wires coming out of the regulator with bullet connectors attached to the wires, not a big deal I'll just cut off the bullet ends and replace them with spade terminals for compatibility with the ends on the Rotax engine's wires.

Return from the future: Fortunately before wiring up the Silent Hektik F-4112 regulator I have with wires comming out of the unit, I noticed a small difference in a couple of the drawings at the Silent Hektik site. Fortunately, I had the presence of mind to filter the Silent Hektik WEB pages through a German to English translator. I was surprised to receive a version of the F-4112 regulator with wires coming out of the regulator ... even though the unit was the same part number as a unit that a photo was posted of here in the VAF forums with the exact same part number but with spade terminals. Apparently, there were variants of the F-4112 regulator at the time the order was placed. To my understanding, all the units with wires coming out of the regulator are wired differently . and NOT what we want as a replacement for the Ducati regulator.

Builders beware!!! Here is the BIG BIG difference. On the standard Ducati regulator reading the terminals from left to right you have G G R +B L C. On the Silent Hektik F-4112 WITH WIRES, the terminals are marked as G G R B L C. Yet the Silent Hektik unit that has the same F-4112 part number but with the spade connectors like the Ducati unit the terminals are marked as G G R +B L C.

The big difference is where the regulator receives it ground from . The F-4112 unit WITH WIRES gets it ground from the B lead (blue) which needs to be connected to the battery's ground terminal however, the RV-12 wiring configuration connects this lead to the battery's positive terminal, not good!!! Yet, the regulator version with the spade leads uses the regulator case as the ground and the +B terminal is connected to the battery's positive terminal, as it is in our RV-12 application.

Im assuming this must have created quite a bit of confusion which is likely why Silent Hektik changed the part number to F-4118 for the regulator with the spade terminals and now the one they recommend on their WEB site as the replacement for the Ducati regulator on Rotax912/914 engines. the F-4118 regulator IS the one we want to install as the direct plugin replacement for the Ducati regulator. The leads are marked as G G R +B L C which is what we want. The F-4118 regulator also has an added feature of a four stepped voltage output ... so it can be used not only on lead acid batteries, but also on ion batteries as well. If you have one of the F-4112 regulators with the spade leads you should be OK just check that the sticker above the terminals says +B and NOT -B. Just be sure NOT to use one of the regulators with the wires because it is NOT pin for pin compatible with the Ducati regulator.


All times are GMT -6. The time now is 11:56 AM.