25 July 2013

Wings: Fuel tanks. Prepping for sealant, capacitive probes fabricated and locking caps.

I decided to redo my fuel tanks.  See here for why.  The entries specific to the redone tanks are here.

Here are the tank stiffeners, J-stiffener and fuel cap flanges placed in the skins.  I'm tracing around these parts so I know to what extent I should scuff the interior of the skin for sealing.  I'll do the same for the ribs separately.  Since the interior of the tank skin isn't going to be primed (well it can't, really), I want to preserve as much of the alodine as possible.

Using my new nut plate jig for the capacitive probes I fabricated.

Match drilling the VA-141 finger drainer flange to the inboard tank rib.

Below is the inboard tank rib showing the location of the optical fuel level sensor I'll be using as a redundant low fuel warner.  I placed it about 1.75" from the bottom of the tank at that location.  A quick, back-of-napkin, entirely inaccurate calculation suggests this will correspond to a bit more than 5 gallons, which ain't much.  If the warner goes off, it's either time to switch tanks to a hopefully fuller one and/or find a place to put down of my own choosing.

The anti-rotation plate is visible on the left.  Also, there is an additional hole at the top which is for the BNC connector that will be used to connect to the capacitive probes.  I've decided to use both the capacitive probes and the floats as redundant fuel level indicators.  This is for two reasons 1) in case one fails and 2) in case my capacitive probes end up being non-functional or not satisfactorily accurate.


And locking caps which fit the stock flanges (I verified this with Robin at Newton SPRL prior to purchasing).  Left image:  Locking cap with universal flange on left.  Right image:  Caps swapped.  I will be using the setup on the right.  And I guess I'll have surplus caps and flanges.


And why not get a "Remove Before Flight" keychain for the associated keys?

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