My log entries have been kind of slow this week.  Working with tank sealant is not very conducive to taking photographs.  Earlier in the week, Tami and I were able to install 3 tank ribs in one session.  So if you are keeping count, that means I have 5 of the 7 tank ribs riveted and sealed.  That leaves the two outboard ribs.  Therefore, I started working on the vent line and capacitance senders so I could rivet the LAST TWO ribs.

With capacitance fuel senders, you run the wire wrapped along the vent line so the instructions tell you to notch the snap bushing in order to make room for the 18 AWG wire.  It doesn't take much of a notch to fit the wire through the snap bushing.  I just used the Dremel tool and a small cutter bit to remove the small amount of material.

For my vent line, I measured the offset between the root rib and the next outboard rib.  Based on my vent fitting location, I needed to make a approximately a 2" off-set between the vent fitting and the hole in the next rib.  I decided to make this a 60 degree, 2" off-set.  This involved a new skill as I haven't had to use the tubing tools I bought for the project up to this point.  Again, I kind of made the off-set a math (trigonometry) problem to see where I needed to make my bends.  Three tries later, I had my 2" off-set.

After I checked my fit in the tank, I used the flare tool to put a flare in the vent tubing (don't forget to put on the AN sleeve and nut on the tubing before making your flare.)

Here is a picture of the outboard end of the fuel tank, the vent, and the fuel filler flange.  When making the T-714 clip, make sure that it will hold the vent line about where the bottom of the filler flange is (the vent line needs to be at the high point of the tank).  That way, you won't have to do any exotic tubing bends in the tight space to keep your vent fitting secure AND high in the tank.  As you can see, the vent line comes right out of the snap bushing and right into the T-714 clip.  I had to modify the vent clip as it was originally to long (low).  I cut it off, deburred the end, and re-bent it to hold the vent line.  (If you remember, the rivet that holds the skin, fuel filler flange and vent clip gave me some trouble during installation so I had to hurry and make another clip before the tank sealant cured>>  ARGHH).

This is a picture of where I am trying to correct a tubing length issue.  I did not allow enough room for the AN ELL fitting on the in-board rib.  I had to trim about a 1/2" off, debur, and re-flare.  This flaring tool works GREAT!!!  I had no problem getting it into this somewhat confined space.

I could have just moved the tubing over in the tank, but I had all of my capacitance sender wires wrapped around the vent line and it was just easier to cut and re-flare.

Everything looks good.  When I re-installed the in-board rib, I had near perfect alignment.  WooHooo!!!

This picture kind of back tracks in the actual sequence of how things were actually worked today.  These are the insulating washers that you put between the rib and the capacitance sender plates.  When they were manufactured, the washers were not cleaned up with the excess molding material (in the Navy, we called this "Irish Pennants">>  Don't grade me on my spelling).  I didn't want this stuff to eventually flake off and get into the fuel line.  It is some pretty tough stuff, but I am not taking chances.  Besides, it looks better after the washers were cleaned up.

To clean the edges up, I took an X-acto knife and scraped the edges of the washers.  The bottom two are what they looked like after I was done.  It is all about "piece-of-mind" by trying to ensure some quality of construction.  For goodness sake, it is just an airplane.

Attaching the wire to the outboard sender was a piece of cake.  You have plenty of wire you can pull out to move the plate around to get on the screw and nut to tighten everything up.  When I got the wire/lug attached to the outboard sender plate, I mounted it to the rib so that I could final measure the wire to the inboard sender.

Okay, now the trick...   When you attach your inboard sender plate, the wire from the outboard sender is cut to length.  That doesn't give you a whole lot of room to move the plate around so that you can get on the screw and nut to tighten it up.  Additionally, the inboard sender has two lugs that are attached to the plate.  One from the outboard sender and one from the BNC coax connector on the inboard rib.  What I did to obtain enough room to attach the lugs to the inboard sender plate was remove the outboard plate from the rib so that I could pull a little wire through to the inboard sender plate.  You can get about 4-5" of extra wire on the inboard side to attach everything together.

This is a picture of the inboard side.  As you can see, there are several extra inches of wire that will allow me to attach the inboard plate.

This shows the inboard tank bay.  As you can see, the last thing that I will connect for the capacitance senders is to solder the lead to the BNC connector.  Sequence was important here.  If you soldered the BNC first, then you would not be able to pull any extra through to land the lugs on the inboard sender plate.

Once the inboard plate lugs were screwed on and tightened, the instructions have you put tank sealant over the screw, nut, lugs and wire to kind of seal everything up.  It also has you put a dab of sealant on the head of this screw.  I fully encapsulated everything and made sure the tank sealant was not touching anything on the tank creating a ground path circuit.  These senders will not work if one of the plates is grounded (connected electrically) to the tank.

With the inboard rib hardware almost in place, one last thing I wanted to check before riveting and sealing the inboard rib was the range of the flop tube.   I wanted to make sure there was not any possible orientation(s) that would result in a hang-up of the flop tube.

Normal flight, the flop tube rests in the bottom corner.  It physically cannot get lodged under and between the sealed plate nuts and stiffener.  No problem.

This orientation represents "knife-edge" flight with right wing down.  Flop tube does not rub or hit anything.  No hang-up concerns.

This picture is inverted flight.  The inspection hole strap prevents the flop tube from banging up against the plate nuts as it re-orients to the top of the tank.  I couldn't physically push, pull, or otherwise tug on the the flop tube to put it in a position of getting hung up on any of the plate nuts.  No concern in this orientation...

Just a close up of the flop tube near the inspection hole plate nuts (inverted).  As you can see, there is no possible way that the flop tube can get hung up on the plate nuts.

This orientation is knife edge flight with right wing up.  This was coming from being previously inverted.  The flop tube has not re-oriented itself as of yet.  Again, even if the flop tube moved to the the other side of the tank, the anti-hang-up strap on the inspection hole would prevent it from chafing up against the plate nuts.  When I continued rotation to normal flight, the flop tube immediately repositioned itself to the bottom of the tank.  No concerns here either...

Physically pushing the flop tube over, I could not get it to reach the trap door.  Additionally, it can not get lodged between the end of the stiffener and the rib.  Van's instructions (as vague as they are here) have you put a anti-hang up bracket that is angled down from the rib web to the aft stiffener (where the flop tube is at in the picture below.  I didn't put that anti-hang-up bracket in as it does not seem to serve any real purpose here that I can see.

So far, so good...  No concerns.

Again physically pushing the flop tube over, I also could not get it to reach the rib hole I covered with scrap aluminum. 

I didn't take the next two pictures showing the flop tube anti-rotation device, however, a discussion came up on this in the Yahoo group after I had finished my tank.  One builder was having a hard time keeping the ell fitting from rotating when the flop tube would reposition.  Supposedely, Van's had recommended to other builders with the same problem, to install a anti-rotation device for the flop tube.  I didn't find anything on the prints or instructions that told me to install an anti rotation device, so this must be something that Van's has been recently recommending.

I can't remember who had posted these, but he did a nice job, so I added hid pics to my log entry.  Looks simple enough as long as you don't already have your tank sealed.

I imagine that if the flop tube ell started rotating (if not restrained) that it could result in a tank leak at that fitting.

I borrowed a multimeter from work (I ordered a Fluke 177 from rhinotoolshop.com and it is supposed to be here next week.  They had the cheapest prices on Fluke DMM's I could find on the net).  Before getting to far on the tank, I wanted to make sure that the capacitance plates were isolated from the rest of the tank.  The "OL" is good.  That means there is a high resistance between the tank skin and the capacitance plates.

Next, I wanted to ensure that the two plates were electrically connected together and had a LOW RESISTANCE.  The meter reads 0.5 ohms which is low.  When I checked the resistance of the test leads, they read 0.5 ohms.  So if I subtract the resistance of the test leads from the indicated value, the resistance between the plates is 0 ohms.  THAT IS GOOD.

Today, was enjoyable.  I just took my time thinking things through and enjoying the "building process".  The weather was COOL (unlike Seattle>>  Sorry Dave P.  Little warm out there???).  I am getting burnt out working with tank sealant.  I am with Dan Checkoway....  TANKS SUCK.