1943 L-2 fuel tank question

[N47322]

Hi, I have a 1943 L-2 and my ole girl could use some new fuel tank "sight" glasses in them, the ones in her are so cloudy I can't see how much fuel is in it at all. My question is can I replace these without tanking the tanks out of the wings? Also if I can do it in place where do I get the parts?

Thanks for your help!
Don

[tawadc95]

Re: 1943 L-2 fuel tank question

Get ahold of Dick Huish,if he can't answer you the question does not exist when it comes to l birds.
He is warbug 43.

[n6346m]

Re: 1943 L-2 fuel tank question

Don,
I replaced mine several years ago. Mine were installed pretty much the same way shown on page 21 of the L-2 parts manual. They are held on with a couple clamps and short sections of rubber hose. The sight gauges were easily replaced without removing anything significant. My old sight gauges were made from some kind of plastic that had crazed and turned yellow and cracked. I went to a guy who makes custom neon signs and he made me a perfect match in glass in about five minutes. He was real glad he could be of help and when I told him what they were for he made me an extra set and charged me almost nothing but the cost of the glass and a little propane. That was about ten years ago and of course they still look like new. If you should ever have to remove your wings for any reason don't forget to remove your sight gauges first because if you don't pull the wing out perfectly straight they will hang up and break.

Bob

[n6346m]

Re: 1943 L-2 fuel tank question

Don,
I forgot to mention that if yours are made of glass they can probably be cleaned ok. If they are made of plastic, they're probably history.
Bob

[Hank Jarrett]

Re: 1943 L-2 fuel tank question

I'm not an L-2 person, and know very little about the fuel system in them, but is it normal to have a glass tube full of fuel in the wing root of the cockpit? What happens if something hits the glass and breaks it? The idea of a wing tank pouring raw fuel in the cockpit isn't comforting! Of course a plastic line cracking from old age and failing isn't any better.
It seems to me a glass tube inside a thin flexible plastic tube would be the best option (although not original). If something hit the tube and broke it the plastic tube would contain the leak even if long term exposure to fuel would break the plastic down.
I'm sure there is more to this than I know, but as a safety engineer I tend to look at things and see the worst case problem. I sure don't want to hear about one of you guys doing an imitation of a comet!
Hank

[n6346m]

Re: 1943 L-2 fuel tank question

Hank,
Thanks for your comments. I too was concerned about glass tubes full of gas in the cockpit. After thinking about it I decided that the risk was minimal. The sight gauges in the L2 are recessed in the wing root and have an aluminum bezel around them part of which is behind the glass and part of which is in front of it. The part that is formed behind the gauge is painted with six diagonal lines that turn horizontal (refraction) when fuel is present. Four horizontal bars means four gallons. Pretty clever (i wasn't sure how to spell ingenious) of those guys back then. That entire assembly can be covered with "bank teller window" plastic if you like if you are worried that something will fly around and break the glass during your aerobatic routine.
The sight gauges are mounted in the forward part of the tank just aft of the gas cap. When a couple of gallons have been burned, the sight gauges will no longer indicate anything with the airplane sitting in a three point attitude on the ground, they were obviously designed for level flight. Should you be unfortunate enough to get a leak in that area, be it from broken glass or plastic, leaky rubber or clamp or (most likely) a cracked aluminium tube coming out of the tank, you could fly the airplane in a nose-up attitude minimizing the leak until you get it on the ground. The tanks have a fuel pick-up in both the front and the rear of the tank.
I believe that in a crash severe enough to break the glass (as protected as it is) will also break old plastic and compromise other areas of the tank first.
I probably would have used the plastic tubes if I could have found new ones at the time but after one of them crumbled in my hand when I removed it (good thing left and right are the same, I still had a pattern) I decided that glass was the way to go. Just an opinion.
Bob

[Hank Jarrett]

Re: 1943 L-2 fuel tank question

Makes me feel better. Sounds like you would have to stab the slot you look at the tube through with a screwdriver to break the glass.
I'm just a worrier.
Hank

[astjp2]

Re: 1943 L-2 fuel tank question

Cubs have been flying with glass for decades, no big deal. Tim

[N47322]

Re: 1943 L-2 fuel tank question

Hi guys! thanks for the help so far. Where do I go about buying or making the fuel sight glass for my wing tanks?
Thanks
Don

[n6346m]

Re: 1943 L-2 fuel tank question

Don,
Like I said, if you want to make them out of glass, take a sample of your old one to a person that makes custom neon signs. There are quite a few of them around unless you live out in the boonies like I do.
Bob

[Ron Greene]

Re: 1943 L-2 fuel tank question

Don,

The correct material is Butyrate tubing 3/8 OD.

It is available from McMaster-Carr at www.mcmaster.com

It comes in 6 foot lengths and is heat bendable.
Below is the page from McMaster-Carr and the L-2 drawing is D-335 on Disk 1 if you want to take a look go to www.taylorcraft.org and look at the L-2 blueprints

Part Number: 8565K33 $2.65 Each
Material
Butyrate

Shape
Structural Tubes

Structural Tube Type
Plain Round

Structural Tube Tolerance
Standard

Outside Dia.
3/8" (.375")

Outside Dia. Tolerance
±.010"

Inside Dia.
1/4" (.25")

Inside Dia. Tolerance
±.010"

Color
Clear

Operating Temperature Range
-40º to +170º F

Rockwell R
78

Tensile Strength
6,300 psi

Impact Strength
4.5 ft.-lbs./in.

Specifications Met
Not Rated

Length
6'

Length Tolerance
+1"

[Forrest Barber]

Re: 1943 L-2 fuel tank question

Wow I ahve been meaning to do all that for about 10 years, thanks Ron....there are originals here in Alliance, on tanks too!! Plus a few in a pile of used stuff. The F-21B & up used the same type sight guage.