fuel tank attach nutplate?

JimWoo50 · #1 08-21-2009, 05:31 PM

Why a nutplate on the aft side of the rv-6 fuselage fuel tank attach bracket? It's not hard to access so I am thinking about using a drilled bolt and castle nut instead. Has anyone else done this? Also I have wires leading from the front of the cockpit aft past the spar, I think they will be ok under the wing root fairing but it would be nicer if they could be routed through the spar. I am extremely leery of drilling through the spar though; but is there a place on the spar that could be drilled for this? Thanks in advance. Jim.

flion · #2 08-21-2009, 06:46 PM

I can't answer the 'why' but, while the access behind is not impossible, there are fluid lines and wires behind there. Also, a castle nut/bolt combo would be free to rotate which would not be optimum on this joint. Finally, it's real easy to install per the plans; why make more work for yourself?

For my fore/aft wiring, I routed either along the subpanel and through the wing spar web at the junction or along the cockpit side rail and down once past the spar. Static tubing and intercom down the left, lights and wing coax down the right, and fuselage coax, autopilot, and stick switches through the center on my plane. If you omit the subpanel, you will have to find another way to get the wires there...

rvbuilder2002 · #3 08-21-2009, 10:14 PM

Quote:

Originally Posted by JimWoo50

Why a nutplate on the aft side of the rv-6 fuselage fuel tank attach bracket? It's not hard to access so I am thinking about using a drilled bolt and castle nut instead. Has anyone else done this? Also I have wires leading from the front of the cockpit aft past the spar, I think they will be ok under the wing root fairing but it would be nicer if they could be routed through the spar. I am extremely leery of drilling through the spar though; but is there a place on the spar that could be drilled for this? Thanks in advance. Jim.

The design intent is for the tank to pull away in an accident without pulling the inboard end of the rib out of the tank.
The nut plate is intended to capture the bolt so that it acts as a pin. If a bolt with separate nut is used, it has more of a tendency to tilt and jamb tighter when the tank bracket pulls away from the fuselage bracket. This is also the reason the nutplate is specified to be positioned laterally...to help resist the bolt from tilting.