Left Tank Sealant

Today I continued working on the initial parts of sealing the tank.  I finished the filleting of the stiffeners and was able to get the end rib vent tube and fuel senders attached torqued and sealed.  They turned out pretty well.

I also worked on the fuel caps and was really excited for this part since they are so cool.  It turned out to be fine, but I am not super happy with the finish.  After a paint job, it will look perfect, but until the paint job, you can see minor scratches where the thin nose squeezer yoke was on the rivets.   I should have shot all of these instead of squeezing the ones close to the edge..  Rebekah's tank cap will look much better.  ;-)

I also decided to take the skin off the skeleton and work on deburring, countersinking and dimpling of the skeleton in preparation for the wings.  Typically this is done after the tanks but I had time and wanted to work on something else and it enabled me to get the skeleton all cleaned up.  Dimples in the ribs and countersinks in the spar.

Sealing Left Tank stiffeners

Today was my first day using the sealant.  Went fairly well, but it takes a long time.   I sure hope I get more efficient with this.   Here I am getting ready to go !  and a view of my sealing set up..

I was able to mix 2 batches of 33 grams each.  (30g of sealant and 3g of catalyst)  The first batch was used to insert the rivets "wet" by filling the dimple with the sealant, then buttering up the stiffeners and lowering them over the rivet heads and back riviting the stiffeners.

The second batch was used to encapsulate each rivet head and start putting fillets down the sides of the stiffeners.   I was able to get the flat side of the stiffener with the wood sticks I had, but the flange side will need to wait for a better solution.  The sealant was getting to thick for my taste with the size sticks I was using.

I also worked on closing up some of the tooling holes on end rubs, added the nose stiffener to the outboard end rib and attached the fuel drain.  Will finish working on the inboard end rib and attaching fittings tomorrow.

Left Tank Deburred, Dimpled, Scuffed

Today I spent about 3 hours taking the left tank apart and deburring each hole on each side of the skin and the ribs, then dimpling, and scuffing in preparation for the Pro-Seal.

I also cleaned the parts and got ready to proseal.  Leveraging other sites and forums I think I am ready to begin the Pro-Seal.  MEK, Gloves, Syringes, Popsicle sticks, Tape, Scale...   Here goes..

Tanks Continued

Since family is in town, I am not able to move to fast on the plane this week.  I was able to get a bit of soldering practice in on the capacitive sender BNC jacks.  Haven't soldered much, but think with the bit of practice first the final result turned out satisfactory.  I also fitted the vent tube in the tank.  I don't have a flaring tool, so will hopefully be able to borrow one when the time is right.

I also got a surprise from Bekah..  The Bob Archer wingtip antenna.  This guy goes in the fiberglass wingtip and can be used for VOR, ILS and Localizer.  Mounting is critical with this antenna, some people have good results, some marginal, but they work great in RV's.  I am going to have HID lighting in the wing tips as well, so will need to see if there is any noise that interrupts the Nav signal with the lights on.  Landing lights will only be on a fraction of the time when I would be depending on the Nav signal.  (IFR Night Approach)..  If there is any interference, then the right landing light will remain off until airport is in sight.

Capacitive Senders

I was able to test fit the Capacitive Senders for both tanks.  These guys are the way to go if you want a flop tube since there is no float to get in the way in the fuel pick up bay in the wing.  Those who use flop tubes need to relocate their float into the second bay where it needs to come in from the rear through the baffle if that makes sense. 

The capacitive senders are separated from the aluminum tank with UMAH washers that allow the electrical single to be measured through the gasoline.  More gas more signal, so the fuel guages are pretty accurate with this method.  Of course they have their own challenges upon install.   Per the instructions I cut back where they interfered with the bottom skin stiffeners on the outer bay ( you can see this in the right pic).  Sorry the pics are so bright, that is some reflective aluminum with the flash.  There are two capacitive plates in each tank, and everything is test fit in both tanks.

Tank End Ribs and Trap Door

I had mistakenly primed the nutplates that go inside the tank in the beginning of my work with the wings.  Not realizing at the time that the nutplates are internal to the tank.  You can't have anything inside the tank primed because it may flake off or interact in some way with the fuel.  So my order of extra nutplates arrived and I was able to rivet the end ribs attachment plates on.  Also I installed the right wing trap door into the second rib from the root of the wing.

Right Leading Edge Final Assembly

Rebekah and I spent a couple hours in the shop today putting together the right leading edge for the last time.  Turned out pretty well.   Now there is nothing standing in the way of the tanks.  After Thanksgiving, focus will be on the tanks until complete..

I also torqued both fuel pickups and safety tied the flob tube..

Right Leading Edge Prep

No pics today, but the right LE Prep looks just like the left leading edge which I posted a few weeks ago.  I was able to finish the deburring and dimpling on both skin and ribs, also cleaned scuffed and primed the skin.  Before final assembly of the Leading Edge, I will take and blot some additional primer on the ribs where the holes have been match drilled.  The original primer has been removed where the match drilling took place.  Bekah and I plan on going to work on leading edge #2 tomorrow.  Freeing up even more clecos.

Fuel Tank - Trap Doors

Tonight I was able to work on the trap doors..  It's little things like this that take a long time and you never realize.  These guys as I said earlier keep the fuel in the inner most fuel bay in the wing where the fuel pick ups are, so that when you are turning (especially on final) the fuel doesn't run to the outside of the low wing and...  ut oh...

Anyway, these are done at this point, apart from the trimming that will happen when I actually install them on the inner tank ribs.  You will see them installed later on.  I also worked on one of the Leading Edge/Tank attach strips.  Drilling and dimpling for the nutplates.  Many people here get pillowing of the tank skin compared to the leading edge skin.   I have a theory on that.  The nutplates are straight and for the 3/4 inch or so they try to straighten the curve of the tank skin right near the leading edge.   I am going to bend my nutplates a bit hopefully to pull the skin into the curve so you don't get pillowing between the nutplates.  We will see if that works..

Right Tank - Catching up to the left tank

The thing about wings is you have to do two of everything. Tonight I opened up the end rib and drilled the fuel pick up/access cover, countersunk the rivets around the baffle, installed the fuel cap and drain, as well as some other misc items on the right tank. Now I have to tanks that are 95% of the way ready for the pro-seal treatment..

Next step is to work on the fuel tank "trap doors" and just a couple more items on the tanks. Also, I decided to rivet the right leading edge before going onto sealing the tanks, freeing even more clecos and getting the little bit of satisfaction that comes with a finished part before diving into the tanks for good.  Plus this works out better in regards to timing of Thanksgiving which is next week.

I will talk more about the trap doors, but basically they allow fuel into the inboard fuel bay of the tank and slow its retreat out of that bay.  So if you are using the left tank, and turning left on final, you don't want all your fuel to run to the outside of the tank, away from the fuel pick up tubes..  Good idea right?  Also, if nothing else, this build has taught me something about piloting even in certified aircraft.  If both tanks are equal fuel, on approach, you should select the tank that is outboard of all turns (since most turns are always the same direction on any given approach).  i.e. the tank that is on the high wing so fuel is always running towards the pick ups.  ;-)

Right Tank Match Drilling

Match drilling is the same as reaming out the holes.  Each pre-punched hole is undersized and when you align the skin on ribs etc. you match drill making sure both the hole is true and even between both pieces.  This takes away stresses in the airframe and makes sure each hole is as perfect as possible.

I was able to match drill the right tank Z brackets and skins just like I did on the left tank.  Pics are below.  This tank didn't seem to line up on the spar as easily so am worried about how it will turn out down the road.  Basically in airplane building you end up doing so much work, then when its all done and riveted it better line up.  If after I get this tank done the Z brackets don't line up for bolting on..  then I am in trouble..  It has happened to other builders so I am nervous and trying to be careful here.

Even More Tank Prep

I have the left tank completely ready for the Pro-Seal treatment except for the final Deburring and Dimpling, oh, and then scuffing and cleaning.  See, it is never over.  Always more to do.

Here are some photos of the last bit of work on the left tank, final drilling the tank screw attach holes to #19

Here is the fuel drain at the lowest point in the Tank.   Also, a picture from inside the tank, you can see the flop tube anti-hang up strip attached to the second most rib and the inner most tank stiffener.

Also, here is a look at the "final" right and left fuel pick ups.  Flop tube pictured on the right, standard on the left.  I went with both options for a couple of reasons.  One, is weight..  Two flop tubes would have weighed more, and you really only need one if I decide I want sustained inverted flight options on the engine.  Second is reliability; the flop tube moves and the standard pickup doesn't (need I say more?)  I will manage fuel such that the flop tube tank is always used first.  On my fuel selector valve I am going to label it as such:   LEFT TANK - AERO/RIGHT TANK - NORM

Continued Tank Prep

Ok, hit a bit of a snag on the right tank so focused today turned back to the left.   Basically I drilled the root Z bracket off center by about 1/32nd " when compared to the other wing.  It might not have been noticed if I wasn't building the wings both at the same time.  (here is one reason why you might consider building both together)   So an order from Van's should be here shortly with a new Z bracket, some wire and other goodies, but till then back to the left wing.  Note to builders if you drill your Z brackets using similar methods:  The baffle near the top root of the wing is so close to the spar that cleco's will hit the spar and possibly off center the leading edge.  You don't need to ask me how I know this.  ;-)  (It shows it in the plans but is not obvious)

Just the same, lots of Good Looking progress today ! 

Deluxe Fuel Cap drilled for initial fitting:

Complete tank angle attachment with Flop tube inserted. (temporarily)

Right Tank

Begun work on the Right Tank (Rebekah's Tank)..   Oh, and I did get her to commit to filling her tank too.  That's cool, I fill my tank..  She fills hers.  Works for me.  ;-)

After final work was complete on the ribs, I went to initial assembly then through the same process as with the left tank.   Drilling the baffle/Z brackets using the Checkoway method is next.

On this tank, I drilled the leading edge attach angle prior to initial assembly.  Here you can see the holes, and the angle attached with clecos.  Also, I will have to drill out the angle for the 3 skin rivets that will come through and interfere with the attach angle.


While I was at it, I worked on the left tank attach angle.  Here it is different because the flop tube needs to go through the angle on this wing.  So a large hole drilled in the middle allows for the tube to be inserted.

Left Tank Match Drill and Countersink

I pulled the tank from the Spar and match drilled all the holes.  Using tons of clecos to make sure it was as tight as possible.

Reminder !   If you use Dan's type method for drilling the baffles, make sure at this point you match drill the Baffle to the internal tank ribs.   If you remember, we drilled the baffle to the Z brackets but never to the ribs..  This could cause some serious issues during final assembly...

I also was able to countersink the skins where the baffle is connected.  This makes for easier final assembly as the baffle just slides in with the Pro-Seal gouped all over. 

Operation "Free the Cleco's" ( Left Leading Edge final assembly)

Bekah and I spent a few hours saturday morning trying to liberate clecos so that I had enough to work through both tanks.  I figure the left leading edge was a good place to get some from.  I won't do the right leading  edge for a while since I think I have enough clecos now to work through the tanks.

I also took the time to drop a few rivets into the countersunk spar flange under the tank.  These single rivet holes at the end of the ribs don't get used to hold the skin on so I was able to close them up now with a rivet.