One more bad Voltage Regulator

[Loki]

With over 50K 912's on the market and over 40 million run hours the reg/rec works well and holds up fairly well. No electrical unti is absolutely bullet proof. The big killer is heat and poor wiring. I would not enclose this unit. It was given those fins on the outside to disappear internal heat build up. Enclosing it will not allow any outside heat exchange. Doing something to this engine without ruling out other issues has always caused problems. The temp should be checked before you blame temp as a failure cause. Putting the reg/rec in the cabin over where it is currently would certainly help heat issues, but moving it inside the engine compartment could also do the same.

The worst thing that usually happens to a Rotax engine is its owner.
Fix the cause not the result and that means to star the beginning at "A" then proceed to "B" and don't start at "C".
Do a temp check on the unit first then move on.

Two ways to take care of a heat issue.

Remove the unit from the heat source or remove the heat from the unit.

[todehnal]

There are double spade connector to accommodate the extra B+ wire
All that is needed is to bend the ends up a little, so it fits the space limitation.
Del City has them, among other electronic suppliers. Just google ?double spade connectors?

Tom

[RFSchaller]

Randy

I like your install!

I bought a JD VR as a hedge against failure, and I carry it in my "Aw S#%t" bag for road trips. I made some pigtails to hook it up to the existing connectors, and my plan is to take a piece of 1/4" Al plate and match drill it to the existing mounting holes. Then I will mount the new VR to the plate with one end at a mounting hole and the other end of the VR secured to the plate by a counter sunk machine screw so that the bottom will fit against the existing surface on the firewall. Essentially a way to mate the JD footprint to the Ducati footprint.

I haven't made the plate yet as I plan to do it at annual next month. I'll let you know if it comes out as planned.

Rich

[Mich48041]

I read about the SILENT-HEKTIK rectifier/regulator after Google translated the webpage to English. It seems that the SILENT-HEKTIK has the same mounting footprint as the Ducati and the electrical connector is also the same. So installation should be easy. The cooling fins look to be much higher to give better cooling. The SILENT-HEKTIK claims to be rated for 47 amps, which is more than twice the output of the Rotax dynamo. The voltage output of the SILENT-HEKTIK is 14.2 volts which is also higher than the Ducati 13.8 volts. Although the Ducati keeps my RV-12 battery charged just fine.
Heat is the enemy of electronics. I briefly thought about cutting a rectangular hole in my RV-12 fuselage skin and mounting the Ducati regulator with the fins protruding through the hole. The slipstream should keep the regulator cool. But I am concerned with aesthetics.

[Mich48041]

There is an interesting warning on the Silent-Hektik website:

alternator regulator, whether ours or other brands, and starter batteries must never be in the cockpit or cab be installed!
A lack of cooling, the controller will inevitably go faulty and there is a risk of fire and / or burns and poisoning by sulfur gases and combustion residues.

[WingedFrog]

Originally Posted by Mich48041

There is an interesting warning on the Silent-Hektik website:

In this regard, I wonder what the filling compound used by Ducati is made of. I have seen over the last 7 years three different compounds used. The oldest (from a failed Remos VR my AN&P gave me to play with) looks like a green foam, the one I removed from my failed VR (could be 2012-13 vintage) is rubber-like black and the new regulator I just received from Lockwood seems to have a different compound based on its color and hardness although I have not tried to dig it out yet with only 2 hours on hobbs. I believe the risk of fire in the filling compound is minimum as the heat is on the other side of the PC board but it would not hurt to know more about its composition.

[Hotscam]

The Sikent-Hektik looks the perfect solution.
Double the current and compatible.
Not cheap $200 but they warrant for three years

[WingedFrog]

To follow-up on Mark Truemper remarkable experimental work I mentioned earlier in this thread (http://pointsforpilots.blogspot.com/...2-voltage.html) I finally got to investigate the efficiency of the cooling of the Voltage Regulator by the blast tube.
I fabricated a home made manometer with 1/4" clear vinyl tubing. I shaped the tube in a U with about 2" of water at the bottom and fastened it on a board. One end of the tube is free, the other end is shaped like a pitot with the help of a thick wire. I located the board inside the cockpit in front of the passenger seat and ran two tests with the upper cowl off and the canopy crack open to allow the tube to go into the engine compartment without being crushed.
For the first test I squeezed the pitot between the radiator and the lower cowl duct and then rotated the head to have it facing the air flow to measure the dynamic pressure. I ran the engine between 2000 and 2500 rpm which is the rate we use to start the engine cold and to taxi around the airport.
For the second test I cut a slit into the blast tube, inserted the pitot to face the air stream and sealed the tube around the pitot with electric tape.

Results:

Air pressure in the lower cowl duct: 3/16" (5mm) of water
Air pressure in the blast tube: zero.

I did not try higher rpm rates because the issue, as explained in Klaus Truemper study is cooling of the regulator on ground during taxiing. When flying, the ram air provides plenty of pressure to provide a good flow of air in the blast tube. Klaus relocated his blast tube in the stream of the propeller and he solved his problem of multiple voltage regulator failures.

In the case of the RV-12, the inlet of the duct on which the blast tube is connected is close to the root of the propeller while the opening of the lower cowl duct is facing the middle of the blades.

Conclusion: As some elements of the RV-12 depend on the workmanship, it is difficult to generalize. For example different builders may have adjusted the cooling shroud in a way that creates more resistance to the air cooling the cylinders which may result in a higher static pressure upstream, where the blast tube is connected. More tests like this one would be needed to find out if this absence of airflow in my blast tube in the 2,000 to 2,500 rpm range is common. If it is, it is likely that overheating of the Voltage Regulator is occurring when operating in warm weather with an engine already hot (for example on a refueling stop) and taxiing a long time on the ground. One may imagine that VANs red RV-12 that is used for transition training and demos may have been stressed this way.

What to do?

I think that VANs decision to relocate the regulator inside the cockpit has a good chance to solve the problem. If you (as I) don't like the new location, we have several options:

- Remove the blast tube and let the air flow inside the engine compartment take care of the cooling. There is plenty of air blowing from the radiator at 2,000 rpms, even if it is not cold air it's better than no air at all under an aluminum helmet.

- Relocate the blast tube's inlet into the radiators cooling duct and have the tube inlet facing the air flow (will require a way to disconnect the tube when removing the lower cowl)

- Switch to the JD regulator as shown in previous posts on this thread

- Switch to Silent Hektik regulator as discussed in this thread

[Mich48041]

Relocate the blast tube's inlet into the radiators cooling duct and have the tube inlet facing the air flow (will require a way to disconnect the tube when removing the lower cowl)

Is there any kind of quick disconnect available that can be used to attach the regulator-cooling-shroud 5/8" duct to the radiator's cooling duct?

[todehnal]

I really like the performance stated on the SK regulator. I'm not quite sure that I understand what they are telling me about the installation wiring. It sounds like we need to make some changes, and add some wiring, including a large capacitor. Could one of you electronic gurus put that into a simple form that a novice like me could understand?? Additionally, I did not find a source in the USA for purchase, but it sure sounds good.

Tom