Riveting/Sealing Stiffeners

April 6th, 7th, 8th 2019, 11h

Riveting using the fuel tank sealant is a missy time consuming job.  We decided to tackle half of the stiffeners at a time so that we can be done in one hour while the sealant is still good. The method we used is as follow:

  • Clean very well all surfaces, rivets and clekos with Acetone.
  • Add type to all inside surface we did not want any sealant in.
  • Add a good layer of sealant to the stiffeners.
  • Put the rivets in and add backing type.
  • Rivet
  • Add more sealant to the edges of the stiffeners and the head of the rivets.
  • Remove all type and clean with Acetone.
  • We had a couple rivets that did not go very well, so we replaced them.


Right Fuel Tank Prep

April 5th, 6th, 7th, 2019, 15h

After getting the new z bars for the right wing tank, I went ahead with preparing this tank to catchup to the left one:

  • Drilled the z bars middle holes.
  • Checked the fitting of the fuel skin with the drilled z bar and the baffle,  I had to make some very small modifications.  By the end the filling looked good.
  • Drilled the rest of the lower holes in the 6 z bars
  • Attached plate-nuts to the z bars: drilling holes for rivets, deburring, counter sinking and riveting.
  • Attached the z bars, and checked the fitting again, it looked good.


  • Attached the baffle, and drilled the lower holed for the 7th z bar.
  • Attached plate-nuts for the 7 z bar to the main spar: drilling holes for rivets, deburring, counter sinking and riveting.
  • Attached baffle and the ribs and drilled the rest of the top holes in z bars.
  • Attached the Skin to the ribs and baffle.
  • Drilled the holed in W-423 attachment plate.
  • Matched drilled all Skin holes with the ribs and baffle.
  • Counter sinks the holes in the skin for attachment with baffle.
  • Debbured all holes in the skin, and stiffeners.
  • Smoothed the edge of the skin.
  • Dimpled all holes in the skin and stiffeners.
  • Roughed the surfaced in the skin and and stiffeners for better attachment with fuel sealant.


More Fuel Tank Prep

March 28rd, 29th, 30th, April 2nd, April 4th, 2019, 20h

After further reading on inverted fuel and oil, we decided to go without, given that we are not looking to do extended inverted flight or negative g maneuvers.

So far, we had good progress with the fuel tanks.  However, open fitting the fuel tank with the leading edge, the fit was not good.  I talked with Vans technical support about this, and they mentioned that the z bars connecting the main spar to the fuel tank can bend and that I can extend the holes in the baffle.  However, I was not happy with applying these solutions.  I decided to buy new z bars and a drill press in order to get the holed drilled more accurately this time to get a good fit between the fuel tank and the leading edge.


After drilling the new z bars for the left tank and attaching the fuel tank to the wing.  The fit was perfect.  It was worth it.  Then we moved on to finishing the left fuel tank prep:

  • Drilling, deburring, countersinking and riveting plate nut to the z bars.
  • Drilling, deburring, countersinking and riveting plate nut to the attachment plate between the fuel tank and leading edge.
  • Match drilling the z bars to the baffle and the ribs.
  • Counter sinking the fuel tank sink for the baffle attachment holes.
  • Attaching the fuel tank again and re-checking the fit.  Looks great.
  • Prepping the fuel line and sander attachments


Itching the inner left fuel tank, the ribs and the stiffeners to prep so that the tank sealant adheres well.


Fuel Tank Prep

February 23rd, 2019, 6h

One of the big decision to make here is to decide whether to go with inverted fuel system. It depends on whether I will be doing extended inverted flight and negative g maneuvers.  As well, I need to look into inverted oil, since inverted fuel alone is not enough to do these maneuvers.

In the mean time, while researching these option, I did the other fuel tank prep.  So, I prepared the vent line input in the inner rib:


I added the vent line support in the fuel caps:


As well, I prepared the fuel sanders: