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Page 31-06 step 4

DonFromTX

DonFromTX

Well Known Member
I installed my magnetic switches for the wing pins, like a good little boy got the meter out to watch them work their magic. Problem was, their magic escaped!
I ran a search, and see that many have had problems with the mysterious magnetic fields in these switches. Everythng is installed and aligned exactly according to plans, still no joy. The fuse is on its side, does that make a difference?
I never much liked the switches anyway, am considering just shorting across the wires and ignoring their function. I don't think I will ever try to take off without the wings on anyhow :p .
 
In going over and over it, I noticed in one illustration, number 4 I think, the hole for the switch is much larger, large enough for the switch to poke thru and get closer to the magnet.
Did I miss some step that called for that hole to be drilled out much larger?
 
Don,

Do a search in this forum on "magnetic switches" and read all the entries. Lots of good ideas. You just need to work the clamps into the right position. Test them one at a time with an ohmeter.
 
Wing pin switches

Don,
I drilled a hole for the switch to stick through. Although doing that was not in the plans, my switches operate as intended. You might try mounting the switch parallel with the magnet or try hints that others have posted in the past. It is unlikely that a RV-12 would take off without the wings. :D
But it is possible that a pin could work its way out over time if the latching mechanism failed. If that happened while flying in turbulence . . .
Accidents happen sometimes due to a sequence of circumstances. It is better to get those switches working properly.
Joe
 
Will work...

It should be noted that some of the posts by the earliest builders are no longer relevant because Van's issued a revision which included new brackets which moved handle magnet closer to the switch. Later kits were corrected.
If installed exactly per the plans, the switches will work as they are supposed too. I did not drill a bigger hole to move the switch closer to the magnet. It is important to expose the magnetic field slowly by filing a small amount (1/32 inch) off the steel handle in a trial and error procedure until the switch makes. If you take too much steel off the handle or move the switch too close, then the switch will make alright, but there is the possiblitly that it could make even if the plunger is out of its hole, IMHO.
Here is a shot of what mine looks like:
[url=http://tonytessitore.smugmug.com/RV-12Project/Finish-Kit/9229733_jnRJi#638819922_p4qV7-A-LB][/URL]

The only issue I have encountered after initially adjust the switches is that the armrest is not real sturdy and it flexes a bit when a passenger leans heavily on it which causes a momentary "Bad Spar" alarm on the Dynon and in the headsets. Then the passenger gets big eyes :eek:. Since the alarm system relies on the armrest being rigid to within 1/32 of an inch, it could be designed a little sturdier.

Tony
 
Spent FAR too much time on this problem

Finally after fiddling with the reed switches for days now, I found the problem! Seems it is all in that "cushioned clamp" we are to use. Notice in the first photo, the nature of the clamp is to put the switch down too far, a little tweaking of the clamp, and presto, it all works like it is supposed to! Hope this saves someone else the troubles I had. It is the nature of the switch to NOT work if it is trying to "see" the magnet thru the steel handle.
k1t6w3.jpg
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Then after tweaking, see how much higher the switch will be positioned.
fw67p2.jpg
[/IMG]
 
I had to shave off the rubber on the right side of the metal band (as shown in your second picture above) and that moved the sensor a nice bit closer.
 
Yeah, that was going to be my next trick if this did not work. I also shaved 1/8 off the pin handles, that helps a lot too. Once I straightened the clamps, everything worked perfectly.

Bill_H said:
I had to shave off the rubber on the right side of the metal band (as shown in your second picture above) and that moved the sensor a nice bit closer.
Click to expand...
 
I tried all these tricks but it just came down to the clamps affecting the relay seeing the magnetic field (or not, in this case). Instead of trying to fiddle around any longer with those steel clamps, I made some from scrap aluminum. I put a piece of silicone tube over the relays to cushion it from the clamp and the relays worked exactly as if the clamp wasn't there.
Before it worked great with the switch in place held by my fingers but then refused to see the magnetic field once it was held by the cushioned clamp.
The aluminum clamp fixed this issue and even gave me some leeway to decide if I wanted it more or less sensitive. I had to tone them down a bit to not trigger before the pin was in place on both sides.

IMG_5695.JPG

Sorry, the image is a little blurry as the camera can't focus so close to the object.
 
I wondered how my magnetic reed switches worked with steel cushion clamps, so I checked mine and they are made of aluminum. In fact every cushion clamp with black rubber on the whole airplane is made of aluminum. Steel clamps must have been been put into your kit by mistake.
 
I think these switches are a classic case of clever over-engineering. I would have much preferred using the same type of mechanical switch used for the stall warning. Easy to adjust and reliable - that's all that was needed here.
 
Free up a Dynon input

I think these switches are a classic case of clever over-engineering.
Click to expand...
Switches are a good idea for those that remove their wings after every flight. But for the majority of us who rarely remove the wings, safety wiring the pins in place will suffice. Doing that will free up a Dynon General Purpose input for something useful like indicating that the flaps are deployed or the canopy is not latched.
Joe Gores
 
Mich48041 said:
Switches are a good idea for those that remove their wings after every flight. But for the majority of us who rarely remove the wings, safety wiring the pins in place will suffice. Doing that will free up a Dynon General Purpose input for something useful like indicating that the flaps are deployed or the canopy is not latched.
Joe Gores
Click to expand...
I think that switches are actually desirable, just not these switches. The same functionality could be had with micro-mechanical switches like the one used in the stall warning. Easy to install and nearly foolproof to configure. The magnets and reed switches are a too clever solution to a simple problem, in my opinion, and their complexity and finickiness will ultimately lead some builders into less than optimal solutions.

And as you say, it's possible that they could have been provided as an option left to the builder to decide whether they are needed or not, although I'm not sure what issues offering that choice would have caused for liability concerns and E-LSA certification.
 
Last edited:
The Cushion Clamps are the problem

I just spent the last two hours doing step 4, the testing of the reed switches. I was concerned after reading all what was posted on this tricky step and, sure enough, once everything was in place according to instructions, nothing was working. Reading the many postings on this issue did not clarify a lot what the issue is as there is a mix of problems mentioned, including those related to the first kits that got a retrofit later. I got a good lead when I read that it was useful to position the reed switch without the clamp. This allowed me to find out that the switch was kept too far from the arm rest by the cushion clamp. I just removed the rubber on both sides of the clamp where it contacts the arm rest and I reshaped the clamp to fit flat against the arm rest and lo and behold, this did the trick for both sides!
I saws that some enlarged the hole and even pushed the switch housing through the hole: no need to do that in my case. I just removed the 1/8 inch of casing indicated in the instructions so that the top of the casing aligns with the center of the hole of the switch. For the rest I followed the instructions.
I hope this will settle the questions raised about the engineering of this safety device: the only problem is the clamp and it is easy to fix.:D
 
Those darn clamps

Now this last post sounds like a good fix. I too spent hours testing and messing with the reed switches. Thanks for all the prior posts giving me ideas to get the system to work. I drilled the hole and pushed the switch through and got it to work but I am glad another remedy has been discovered.

Thanks everyone for all the helpful posts.
 
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