SMO

SMO

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I received my fuel tank kit from Vans today. I am replacing the fuel tanks on my 1987 -4 which I purchased a couple years ago. No instructions or plans were included in the kit. Is this something I have to order separately? I had talked to tech support before ordering to make sure I was ordering everything I needed and no mention was made of this, of course I never thought to ask specifically about this either.

Wonder if there are any plans available on line. I have the "Frank Justice" instructions but he still refers to the plans.

I will call Vans on Monday but meanwhile I thought maybe someone would know the answer to this question.
 
Build

Hi

How do you propose to build the tanks off the wing...... I am struggling to build a new tank after I damaged one when it fell off the jig when painting.
 
You need the plans to get rivet spacing dimensions and final skin trim dimensions since the -4 was not a pre-punched kit.

Lining up your spar attach holes to the existing spar nutplates will be tricky.

The critical fus. attach bracket was "builder located" so you probably will need to get the tank clecoed togther and on the wing before you drill the final location hole for that bracket.

Does anyone in your EAA chapter restore old plane? He might be able to help you with hole transfer tricks to get the new holes to match existing structures.
 
Tip

Once you get the tank built and fitting the wing the way you like you can take a thin piece of plexi glass and cut it to match the upper and lower aft flange of the old fuel tank ( one piece top one for the bottom). You can pick up the mounting holes into the plexi glass by laying it over the old flanges simply seeing the holes and drilling. Then transfer the plexiglass template to the new tank flanges to transfer your holes. Easy money!
Ryan
 
For hole locations......

........I was anticipating pulling the old tanks off, dismantling them and using the pieces to match drill the new tanks. I did this for an elevator I reskinned and it worked out okay.

Of course I have never had tanks off before so maybe there is a "gotcha" I am not aware of. It's not quite clear to me exactly how they attach onto the wing. The F1 Rocket I am building has quickbuild wings with the tanks already installed so this is a new experience for me.

Final drilling the Fuse Attach Bracket when the tank is mounted is a good idea.
 
Gotcha

Hi

The gotcha is the tank sealant......... its glue dont forget. I would have loved to have been able to pull the sins off...... but no way.
 
Use the other side?

Understand the sealant will not allow just drilling the rivets out and disassembly, but perhaps some careful work with the die grinder will get the tanks apart and by matching the outside surface of the old skin to the inside of the new one I can match drill.

Are there any tricks to getting the gas fumes out of the old tanks? I have heard things like pumping car exhaust into them or filling them with water before starting. Need to sort this out.

Steps as I have them in my head are:
1. Mark distance from leading edge to rear of tank using the old tank as a template.
2. Cut old tank apart without stretching the skins (okay, this is the hardest part).
3. Cut off the leading edge
4. Clamp outside surface of old skin to inside surface of new skin and match drill.
5. Do step 4 for each of the top and bottom of the left tank, and again for the right tank.

If all goes as per normal, my plan will need to be adjusted multiple times before completion.
 
I suggested the plexi method above because of the dificulty getting the old tanks apart. Keep in mind if you destroy the old skin trying to get it apart you wont have a template to work with. Good luck.
Ryan
 
You don't need the old skin as a template for the rib rivets.

Build the tanks to the cleco stage, trim the edges to fit the wing nicely, and then use mylar or similar method to transfer the #8 screw hole locations for mounting to the spar and the outer rib. At this time the fus. attach bracket can be clamped to the inner rib and the fus. and drilled.

Then take it apart and do the ProSeal thing....:)
 
Be carefull

Hi

BE careful you measure your skins to ensure they have been cut square before using the template method. I have just received a skin which was cut almost 1/8 out of square, unfortunately is short on one edge which may mean it wont fit round the leading edge and leave sufficient edge clearance or the screws.

If I had taken the edges as a starting point for drilling clearly everything would be off!!
 
Thanks for the tip

I was short shipped a couple ribs and am still waiting for them, so I have not started the building process yet. I don't have any confidence in the "squareness" of the old tanks so I will be carefully measuring each dimension and angle in order to duplicate these. I do have the old tanks off the plane and in my shop now, so am ready to go when the parts arrive.
 
Skin

Well it looks like Vans will be sending me out a new skin as Ken came back to me saying there is no point building on this one.

As I say just double check the dimensions, this faulty skin appears to have been cut buy pinking shears on the top edge as there are witness marks from what appear to be the edge of the blades. I would have expected it to be cut on a guillotine.

Frustrating but when you consider it only the second part I had in my kit which was not right.......... is a pretty good record for Vans quality. The previous skin I had but which I messed up on was perfect........
 
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