ROTAX/Ducati Voltage Regulator Connector Issue

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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FastEddieB
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby FastEddieB » Sun Oct 30, 2016 11:42 am

Nomore767 wrote:Short term replacing the VR in its current location gets me flying and is relatively simpler for the ' regular' shop on my airfield.


I may have missed it, but have you totally eliminated the possibility of a bad connection?

At least a few times cleaning the contacts and reseating the plug has taken care of the issue.

As an aside, my VR is pretty close to a (wrapped) exhaust pipe, but given the engine orientation, the flow of air hits the VR first and the pipe is downwind, so to speak.

Image

With my pusher configuration, the air flows right to left in the above photo, and the exhaust has been wrapped.
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Sun Oct 30, 2016 3:25 pm

Eddie

I haven't eliminated anything yet. I'll have the regular shop on my field take a look this week and see if we can figure the exact problem and go from there.

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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Sun Oct 30, 2016 5:39 pm

Roger

In your experience has moving the VR to the cockpit side of the firewall, as per the VANs authorization, reduced the failure rate to 'normal'?

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FastEddieB
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby FastEddieB » Sun Oct 30, 2016 8:33 pm

Nomore767 wrote:Eddie

I haven't eliminated anything yet. I'll have the regular shop on my field take a look this week and see if we can figure the exact problem and go from there.


Not a bad idea.

I was going to suggest pulling the connector and taking a look, but with an S-LSA the AMM very possibly requires certain certification to do so.

Regardless, have them check the connector first. In my experience, that's often the culprit.

And be sure to let us know what they find.
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Tue Nov 01, 2016 9:01 pm

Mechanic at my field determined that voltage regular had failed.

I ordered a replacement voltage regulator from Lockwood today.

I have a call into Vans support regarding the supporting paperwork and any kit they may have so as to relocate the new VR into the cabin under the panel.

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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby FastEddieB » Tue Nov 01, 2016 9:46 pm

Just curious...

...did he devise a way to test it, or was it by way of process of elimination?

I ask because I have two that I don't know for sure if they're good or not. I would not mind sending them out for testing.

Or does someone have a straightforward way to test them myself?
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby MrMorden » Wed Nov 02, 2016 9:41 am

I'm kind of surprised at the number of VR failures seen. On my CT it is mounted on the right side of the engine side of the firewall. So far (knock on wood!) mine has been very reliable. It charges about 13.8V - 14.0V very consistently and has never had any issues. I wonder what it is that cause some to be so troublesome? Is it simply excess heat? I would think mine would be subject to that as well, being under the cowling.
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Wed Nov 02, 2016 4:15 pm

Update:-

My mechanic checked connection to VR and found tight. He looked at Vans wiring for engine as well as Rotax and after some tests determined that the VR has failed.
The volts were 12.5 and drain was 6-7. Loud squeal in headset .

I have ordered a new Ducati VR from Lockwood which is the only one they have for the 912ULS.

My Rotax guy is at Lockwood going through recurrent training and this topic came up in class. Instructor said they felt there should be a bigger capacitor and VR should be relocated.

I have been in contact with Vans Tech Support. They say mine is the first SLSA requesting to relocate the VR. Current production planes have incorporated the relocation. However, earlier ones like mine require a Notification ( not an LOA) and they haven't written one and they don't intend to in the near future.
This means I can o lay replace the VR at the current location. I do have a tube bringing cooling (?) air to VR which I think is part of a VAF mod, but I'm still waiting for Vans to say whether I can use the metal wrap on the exhaust. My mechanic says it would dissipate the heat a bit but we'd have to see if it's authorized.

I do open the oil access door right after each flight to help dissipate the heat and maybe that plus the 'cooling tube' may have given me a longer VR life than others but who knows?

Anyway that's where I am right now.
Last edited by Nomore767 on Sun Nov 06, 2016 1:31 pm, edited 2 times in total.

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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby roger lee » Thu Nov 03, 2016 9:10 am

The key to longevity of a VR is cooling. If you underload or overload a VR it builds heat. It must be in a place with air movement and not around another heat source that adds to it. These VR's are out there on more than 50K engines and haven't had big failure rates. Vans is the worst I've see. If it were me I would either move the VR or wrap the exhaust pipes and I would absolutely turn the 1" air tube into the air stream and not cross ways with it. This last item doesn't need any approval and is huge in getting cool air the the VR.
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Thu Nov 03, 2016 1:12 pm

Good idea Roger thanks.

I'll see if we can get a better air flow down that tube.

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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Thu Nov 03, 2016 5:18 pm

Regarding wrapping the exhaust pipes the word I got from Vans today is don’t wrap the exhaust – 'this is not approved, and won’t be'. They say that 'guys have tried that on other RVs and it can lead to premature failure of the exhaust system".

Just passing this along FYI and I'm bound by Vans since I'm SLSA.

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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby FastEddieB » Thu Nov 03, 2016 5:26 pm

Nomore767 wrote:They say that 'guys have tried that on other RVs and it can lead to premature failure of the exhaust system".




I'd be really curious as to the proposed mechanism for that.

Worst I've heard is the fear that the wrap could make cracks more difficult to catch early.
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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Thu Nov 03, 2016 5:45 pm

That's the word from Vans that I have to abide by.

I have no personal experience one way or the other and I have great respect for the experienced owners and Rotax gurus such as yourself and Roger.

Just passing on the word from Vans

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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby Nomore767 » Sat Nov 05, 2016 9:42 pm

Update:

http://www.vansaircraft.com/pdf/Notific ... -11-03.pdf

Vans have used my SLSA case to write a new Notification regarding relocating the VR for both ELSA/SLSA RV-12.
I made an enquiry to Vans Tech Support the other day about supporting paperwork to allow my Mechanic to relocate the VR on my SLSA RV-12. Even thought they now incorporate the relocation in current builds they said they weren't planning on writing the supporting Notification and I was resigned to simply replace the VR at the old location.

Apparently they took pity on me and relented and now my mechanic will relocate the VR I just received from Lockwood.

Vans say the cooling tube and shroud on the old VR position can be cut and removed .

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Re: ROTAX/Ducati Voltage Regulator Connector Issue

Postby roger lee » Sun Nov 06, 2016 12:30 am

"leads to premature failure of the exhaust system".

This isn't true. Many people have wrapped Rotax exhaust. I have been wrapping them for 12 years without a single issue. They just don't have any real time experience so they are over cautious. Flight Design did with with a fleet approval and it has helped many and they have not had any issues. These exhaust are stainless steel and are not susceptible to the heat or carbonization that plain steel is because of the chrome and nickel content. It prevents up to 70% heat reduction from radiated and convected heat. It helps save wire insulation, rubber engine mounts and hose from early degradation. Overheating can only come from improper application. You are only supposed to over wrap each edge by 3/8", but if you overwrapped by 1/2 the width or by 1" then the pipe could retain too much heat. There are RV12's out there that are using the wrap. I know, I put it there. It will not cause failures when you apply it correctly and with all the owners with wrapped exhaust it's very easy to prove.
Living in denial that they have an issue and not ACTIVELY addressing it just causes owners more grief and money when a fix is so simple.

p.s.
feel free to repost this on the Vans site.
Roger Lee
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