Installing the wing fuel tank

[shipljl]

I wonder if anyone has directions and or pictures to help me install my wing tank? The right hand wing was disassembled when I got the project and I am unsure how the tank is secured to the spars. Also, is there supposed to be felt between the spars and the tank? Any help would be greatly appreciated!

thanks,

John

[lfries]

Re: Installing the wing fuel tank

Courtesy of Rob Lees Some time ago.

http://www.taylorcraft.org.uk/how_to_replace_a_wing_tank.htm

[Pearson]

Re: Installing the wing fuel tank

John

Each tank is held in place by two steel straps about an inch wide. The straps go around the front of the front spar and the rear of the rear spar. The tightening screws go on the rear side of the rear spar. There is supposed to be felt between the straps and the tank. I am not sure how thick this felt is, but approximately 3/16” before compression. Additionally there are two wires that pass through the inside of the tank. These drag and anti-drag wires do not “hold” the tank in place. But they do limit the movement of the tank.

Before you reinstall your wing tank, chase the threads on the outlet fitting and where the drain valves screws in. Make sure you don’t screw the tap in too far. They are 1/8” NPT threads. The T stands for tapered. If the area around the outlet fitting has not been reinforced the time to do it is NOW. Spend the money, take the time. You will thank me later.

Once you get the threads chased and the outlet area has been reinforced, plug up all the holes and check it for leaks. The guy that reinforced the outlet holes for me checked mine using an inert gas. I cannot stress enough how strongly I feel about the need to have this area reinforced. You will be sorry if you try to get by without doing this.

Next, check the nipples that the drag and anti-drag wires go into. Make sure you have something around the nipples to make sure they don’t push up into the compression strut fittings. Mine had a mix of electrical tape or tiny little electrical wire ties. I would actually install the wires with the tank out of the way, just to make sure everything fits correctly. You will need a spoke wrench to fit the nipples. I forgot what size it is. I know I couldn’t find one at any of the bicycle shops I went to, so I just made one. You need to put some sort of rubber tubing around the wires before you install them to keep them from rubbing on the inside of the tank. Try to use something with a thin wall so the outer diameter stays as small as possible. This will give you more room to adjust the location of the tank after you have the wires going through it.

Lay your reinforced, leak checked, tank in the wing bay on top of the spars. There should be felt pads under each flange at the front and rear of the tank. Mine also had felt pads between the spars and the ends of the tank, but this goes in later. If your felt is bad or missing you need to find something that has a little bit of “give” to it, but that can also support the weight of the fuel without compressing very much. Otherwise the vibration from the engine will shake your tank to pieces. Whatever you use, you need to put enough of it under the forward flange, and on top of the main spar, to bring the top of the tank almost even with the top of the ribs. If the tank sits too low, with the flange too close to the top of the main spar, you will have a difficult time removing the gas cap.

With the tank aligned vertically, you should now be able to install the drag and anti-drag wires through the tubes that make an X through the tank. You did check your nipples before you put the tank in didn’t you? The trick is to get the wires started in their nipples and then put the felt in between the forward and rear of the tank and the spars before you tighten the wires too tight. It is definitely not a fun chore, but not as bad as a root canal. I found it best to install the wires from the aft end of the tank. Before you “nail it down”, make sure you check your outlet hole at the wing root and the fuel drain outlet to make sure you have them where you want them. Generally you want the tank as close to the wing root as you can get it, within the constraints of the drag wires. Once you get the wires tight, you can install the straps.

As one who has had to cut good fabric to remove a leaking wing tank, I suggest you look in the Taylorcraft website for a copy of the 337 I did where you put sheet aluminum over the bay that holds the tanks.

[dennispip]

Re: Installing the wing fuel tank

Veritas Avi: All fuel tanks leak, only a matter of how soon.

[Pearson]

Re: Installing the wing fuel tank

Dennis,

That is why I made mine where I can take them back out without having to do a fabric repair.

[dennispip]

Re: Installing the wing fuel tank

B I N G O Richard...well done!!!

In all fairness, back in the day when they designed these planes, as is well documented in many posts, these planes were expected to be recovered every 3-5 years and everything would be thoroughly inspected at that time. I doubt they ever thought that some of the new coverings we now have would exist and now these planes go for 20 or 30 years without recovering. Your STC is a wonderful way to get in there without near the trouble that otherwise is encountered. You would be a rich man if the fleet was only 100 times it's size!!

[shipljl]

Re: Installing the wing fuel tank

Thanks for the responses, it really helps. I have a couple of specific questions.

1. What thickness should the steel straps that hold the tank in place be?
2. How are the steel straps tightened? The photos from Robert Lees don't show the area back of the rear spar where they are tightened. Do you just bend a right angle in the two ends and put a long machine screw through and tighten it?
3. I have two extra brackets (shown in the attached photo). Are they used in the tank installation? On the left wing, they are just placed between the front and rear spar right next to the root rib, top and bottom and screwed to the spars (see the second photo). Do I just put them in the same way on the right wing with the tank?

[Pearson]

Re: Installing the wing fuel tank

John,

Those parts shown in your pictures do not look like the straps that were used to hold the tanks on my airplane. My only experience with all this is what I learned on my airplane only. Those may be used on a earlier or later model, but they look like a homemade part to me. I would be very leery of screwing anything into the spar to hold the tanks in place. I don't know. That may be the way they did it at the factory at one time. But it looks like poor engineering to me.

The straps on my plane were flat strips of steel. They had soft bends (1/4" radius) at each spar and a sharp 90* bend at the middle of the back side of the rear spar. Where the two ends came together at the 90* bend, each side had a hole in it for a long machine screw to draw the two ends together.

I will see if I have any pictures that show the straps. I know I have pictures of cutting out the fabric and the aluminum. But I don't recall taking any of the straps. I bet Rob Lees blog would have better pictures than any I might have.

[Robert Lees]

Re: Installing the wing fuel tank

John:

I have also not seen those items before (having fixed fuel tanks on both my pre- and post-war Taylorcraft).

But strangely, the pre-war one (the subject of the blog to which Lloyd refers) had what appeared to be home-made aluminium strips of about 0.040" thickness by about 1" wide.

The post-war Taylorcraft that I fully refurbished had steel straps of about the same thickness but only about 1/2" wide, but these had a "machine screw" (like what to which you refer) to perform the clamping action behind the rear spar.

Unfortunately, no photos. But the ends of the steel strapping, behind the aft spar, were bent double to allow the machine screw to pull the ends together.

I attach a schematic.

Rob

[Pearson]

Re: Installing the wing fuel tank

John,

My straps had only a single 90* bend on each end. I think it was a #10 machine screw about 3" long. Whoever put it all together used square nuts. I guess that helped keep the 90* bend in the one side. I guess if you really wanted to keep the 90* bend going in both ends of the strap, you could drill out the hole in another square nut and run the screw through so the nut would be just under the head. That would help keep the screw from pulling the bend out of the strap as you tighten.

I doubt if this would be considered an approved method, but whoever put my wings together used expanding spray foam as a cushion at the front and rear of the tanks. I was afraid it might hold moisture against the spar and scraped it all out. I forgot what I used, but replaced the foam with something else to help cushion the tank between the spars.

Robert,

I am surprised! We finally found something you didn't have a picture of. I think your blog is one of the best documented restorations of a Taylorcraft I have ever seen.

[Robert Lees]

Re: Installing the wing fuel tank

< snip>
Robert,

I am surprised! We finally found something you didn't have a picture of. I think your blog is one of the best documented restorations of a Taylorcraft I have ever seen.

Well...I've not found a photo of it yet

I may well do, but it was quicker to sketch what I remember.

[Pearson]

Re: Installing the wing fuel tank

Rob,

I feel like that first avitar in your last post. I could have sworn I had pictures of my fuel tank straps. I searched hi and low but couldn't find them.

[Ron Greene]

Re: Installing the wing fuel tank

I have attached a diagram and parts list from the L-2 parts list, probably not exactly like the model B but gives you an idea.

Wing Tank.pdf

Wing Tank 2.pdf

[Ryan]

Re: Installing the wing fuel tank

Here are photos when I took my wings apart showing the fuel tank straps. These were on a 15 rib truss style wing for what it is worth. My other wing was a stamped post war wing, and in eyeballing the other they appear to be the same...

Ryan

[shipljl]

Re: Installing the wing fuel tank

Thank you all for the information and pictures. I believe I now have enough info to install the tank the way it is supposed to go in.

But first, I will have the NPT fitting reinforced and the tank leak checked again afterward.

thanks,

John