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Bolt Head Rubbing on Wire Bundle Hold-Down Plate

Piper J3

Well Known Member
My friend?s RV-12 built by Synergy as an E-LSA has a rod-end bolt head rubbing on the wire bundle hold-down plate beneath it. We put Teflon tape on top of the plate and it didn?t solve the problem. The wire hold-down plate is raised up because of so many wires ? main wire harness, ADS-B antenna Coax, Comm Coax, AOA tubing, etc.

Anybody else seen this? Suggestions?



 
When I installed ads-b in antenna coax cable, i had the same problem, lots of wires/tubes in a small area. I ended up adding another nylon block just forward of the block you show, and added a 3rd screw to hold everything flat. When done, I was confident the bundle would not interfere with primary flight controls and nothing would chafe the bundle.
 
When I installed ads-b in antenna coax cable, i had the same problem, lots of wires/tubes in a small area. I ended up adding another nylon block just forward of the block you show, and added a 3rd screw to hold everything flat. When done, I was confident the bundle would not interfere with primary flight controls and nothing would chafe the bundle.

Any change you have photo of new Nylon block?
 
The block came from Van's with the ADS-b in install kit. I milled it slightly to better accept all tubes/wires. I'm opening up the plane next week for condition inspection, will get a pic then.
 
Jim,
There was a running change along the way to the upper nylon systems block. The earlier -12's both the upper and lower blocks were the same part# F-1276C. After the change the upper block is part# F-1276D and it has a larger cut out for the wire bundle. I found that even after installing the ADSB-in coax in the bundle the wires could be arranged carefully and the F-1276D top block could be installed without that upward bulge I see in your picture. Even so, it will be a rather tight fit but it should work.
Also the F-00049 Wire Cover Plate in your photo is poorly shaped and bent.

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If everything is installed correctly there should be no rubbing but it will be very close. You may want to dissasseble and reinstall according to plans.
 
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Also, what is that large black cable in your picture? I don't recall anything like that being in the bundle. There isn't room for anything extra in that system block.
 
Jim,

I had the same problems as you. I have a VOR antenna coax added to the mix of wires. I removed the flaperon mixer, wire cover and wire block covers. I was able to widen the slot in the nylon wire blocks to give me a little more space (1/8”) for the wires. I did this with the wires removed from the slot. I took a piece of hacksaw blade and angle notched out the left and right side of the slot. I did this to both the front and back nylon wire bocks.

You have another problem you missed. I can see in your picture that your flaperon mixer arm is also rubbing. I removed the flaperon mixer arms. (Section 21). I removed just enough material from the the bottom legs of the “U” arm (Only in the area of concern) to clear the wire cover plate (.040”). I polished the legs so that if they ever touched the wire cover, gulling would not be a issue.

It is important to try to line up all the wires going between the wire blocks so that they are all in single file, do not allow wires to cross each other. they should lie parallel to the floor (height left and right are the same). Re-bend the wire cover to cover the wires between the bocks. I added a .020” aluminum angle over the cover of the forward block to stiffen it. The leg of the angle is on the forward side. I The can email you a picture. I am unable to post pics.

What I did is totally experimental and was not Van’s approved, so do it at your own risk. Good luck.
 
I think this is one part of the kit where Vans really missed the boat. There isn't any reason the clearance in this critical spot should be so prone to rubbing. Why wasn't the flap mixer designed to sit at least an inch higher?
 
I think this is one part of the kit where Vans really missed the boat. There isn't any reason the clearance in this critical spot should be so prone to rubbing. Why wasn't the flap mixer designed to sit at least an inch higher?

My guess is they did not anticipate ADS-B and AOA during original design...
 
In order to make a little more space for your wire bundle you could remove the nylon spacer and trim away some of the spacing tab, on both sides of the wire run, allowing a bit more width. Just leave a little to cushion the aluminum tubing or cut that tab all the way out and put a vinyl tube sleeve over the aluminum fuel line for chafe protection.
 
Does anyone else find this kinda disturbing that this came out of Synergy?

Are we 100% sure that this came out of Synergy? Did they build E-LSA's? Was the area in question due to the original builder or was something added/done subsequently?
 
Airplane was built in Eugene, OR by Synergy as special order E-LSA. They agreed to build as Experimental. Airplane was delivered 2-1/2 years ago to new owner here in Ohio. No owner modifications made. There were several other (large) discrepancies which I will not divulge. Suffice to say, I would never have Synergy touch my airplane...
 
Here is the Synergy quality workmanship running wires / pneumatic tubing under the flaperon mixer...




 
I see a lot of crossed wires that were under the metal wire cover. I would undo the wire ties and re-arrange the wires so that none of them cross in this section. This will gain you a lot of space. You might not need to widen the slots. The nylon cover may still be a problem because it has become deformed. A new nylon cover or stiffener may be necessary. Good luck!
 
Aren't most of those wires going to the trim motor on the horizontal flap? I see some coax for an ADS-B antenna and static vent tube.

Why would 2 pair of those wires be twisted, other than to prevent RF on the coax shield?
 
The static tubing does not go through this area.

The AS pitot tube passes through here to the ADHRS in the tailcone.

The large white cable contains the all the wiring for the AST trim motor.

The two brown coax cables are for the com radio antenna and the ADSB-in antenna.

One twisted pair are the OAT going to the ADHRS. Several wires are for the AP roll servo. One each wire for the fuel tank sensor, the eyeball panel light, the canopy open warning, the wing locking pins warning.

Also,the ELT wires and phone cable for it's remote.

Yep, lots of important stuff to organize.
 
More on Synergy quality workmanship. We just found this under baggage floor. Maybe return to Synergy for credit?

 
To be fair I know a British Airways mechanic who has a great collection of cleco's with Boeing and Airbus logos. All removed from airliners in service.
 
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