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  #1  
Old 11-04-2019, 05:54 AM
Handclutch Handclutch is offline
 
Join Date: Feb 2015
Location: Bendigo, Australia
Posts: 135
Default Silent Hektik failure

My Silent Hektik regulator (F4112) failed last week at around 180 hours. Anybody else had a SK failure?

The failure was quite sudden. I flew a two-hour leg with voltage indications normal before landing for fuel. Voltage was then okay on start-up but shortly after takeoff I got the low-voltage warning (I have the low-voltage warning set quite high to act as a generator failure warning for IFR flight). It worked!

It was a very hot day but the temperature strip on the regulator had maxed at 71? C, less than what I had previously seen on the Ducati. However, it is possible that the SK had seen slightly higher temperatures previously before I modified its cooling system.

Now for something interesting - I did a Google translation of the SK website and found that they don't guarantee the regulator unless you use phosphor bronze crimp connectors. Here is what they say:


Wrong connectors on the 912er alternator connection:
The LiMa connector plugs of the 912 engines are of inferior brass. That's a massive problem for three reasons.
- The brass plugs are not designed for the high currents, with up to 20A, and therefore overloaded and prone to overheating.
- The brass plugs have a low spring force and are therefore not vibration-proof and loosen over time.
- The brass plugs have no surface protection and oxidation then produces brownouts and malfunctions.
For safety reasons, therefore, we only recommend Tyco FastOn tinned phosphor bronze connectors . Everything else is botched.


Could this be a reason why there are so many regulator failures?

Jack
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  #2  
Old 11-04-2019, 06:20 AM
Piper J3's Avatar
Piper J3 Piper J3 is offline
 
Join Date: Nov 2014
Location: Hinckley, Ohio
Posts: 2,564
Default

Interesting?

The Ducati VR?s fail internally. Several folks on this forum have dissected and found poor soldering technique.

Incorrect material for spade lugs wouldn?t explain why direct replacement with John Deere VR works well. My JD has been operating fine for over 400 flying hours.
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  #3  
Old 11-04-2019, 01:53 PM
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rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,665
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Quote:
Originally Posted by Handclutch View Post
It was a very hot day but the temperature strip on the regulator had maxed at 71? C, less than what I had previously seen on the Ducati. However, it is possible that the SK had seen slightly higher temperatures previously before I modified its cooling system.
What are the details regarding how it is installed and how it is being cooled?
Van's recommended?
Personal design?
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Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Hubbard, Oregon
Van's Aircraft Engineering Prototype Shop Manager
FAA/DAR
RV-6A (aka "Junkyard Special ")
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  #4  
Old 11-09-2019, 05:28 AM
Handclutch Handclutch is offline
 
Join Date: Feb 2015
Location: Bendigo, Australia
Posts: 135
Default

Scott, personal design evolved/modified over time. When I bought the aircraft it was the standard set up for that time. Duct from cowling opening to engine shroud/plenum with cooling tube tee'd in and then connected to the cooling cover over the regulator.

My first effort at improvement was installing a stainless steel heat shield on the no 4 exhaust. It follows the curve and stands off by about 0.5".

After Vans ditched the shroud/plenum I took the opportunity at the five yearly hose replacement to get rid of it. I then aimed the forward end of the cooling tube directly at the cowling opening, the theory being that it would push more air onto the regulator.

There was always the question of whether the cooling cover over the regulator wasn't allowing the fins to do their job especially after shutdown. Towards the end of last summer (southern hemisphere) I removed the cooling cover but left the tube directing air at the fins. At the same time I installed a small baffle in front of the regulator to deflect at least some of the hot air coming off the radiator.

The recent hot day(around 100?F) was the first time these modifications had been put to the test. I was pleased with the outcome - the regulator ran cooler than with the original set up.

It may still not be as good as the newest Vans design but, as I am not into fibre glass, it will be staying the way it is. It's definitely an improvement, although that didn't help the Silent Hektik. There is the possibility of course that with the SK I simply got a crook one - no manufacturer gets it right 100% of the time.

Jack
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  #5  
Old 11-09-2019, 07:58 AM
bobg56 bobg56 is offline
 
Join Date: Nov 2018
Location: Peachtree City, GA
Posts: 204
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I have a Ducotti regulator mounted on the inside. It is on the pilot side against the firewall, I drilled holes and installed nut plates. I used 1/4" 12 point bolts and added washers to the back side to keep it off the firewall a bit so as not to pick up heat transfer. It is easy to change out and I keep a spare in the map box. During summer ops I have used a laser thermometer to see what temperature it was running at. The highest reading I got was in the 120's F. This is with an OAT in the 90's....heat is the enemy, even with blast tubes when you shut down it is baking under the cowl. I think the max operating temp. is in the 170's. I have only 80 hours since I relocated it, time will tell...also I pinched the blade connectors to make sure I got a tight fit, that can be an issue if they are loosely connected.
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