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General control line discussion => Open Forum => Topic started by: Joe Ed Pederson on December 11, 2021, 04:28:00 PM
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I want to thank Keith Morgan for his posts on how to make a metal fuel tank from scratch! https://stunthanger.com/smf/12-a-building/metal-tank-making/msg544888/#msg544888
I just pressure tested the metal uniflow tank I made and it passed. Since it was my first attempt, I was kinda surprised I was successful. I expected it to leak, but it didn't
The end caps are ugly as sin. The soldering isn't real pretty, but woo! hoo! it's going to work.
I needed a specially shaped tank to go on an Estate model I picked up in September. At first I thought it was profile Smoothie, but it turned out to be a Smootie-looking model by Larry Kruse. The fuselage is extended behind the wing and I'm thinking the horizontal stab and elevator are enlarged. The plans came with it and it has 1/2 inch cheeks on the inboard and outboard of the forward profile fuselage. There's a narrow slot for the fuel tank and I didn't want to enlarge the slot. Brodak has kit for the model in the Dare line of kits (D-304), but I think this one was built from the plans in Model Aviation 1984, plan #453.
Joe Ed Pederson
Cuba, MO
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I want to thank Keith Morgan for his posts on how to make a metal fuel tank from scratch! https://stunthanger.com/smf/12-a-building/metal-tank-making/msg544888/#msg544888
I just pressure tested the metal uniflow tank I made and it passed. Since it was my first attempt, I was kinda surprised I was successful. I expected it to leak, but it didn't
The end caps are ugly as sin. The soldering isn't real pretty, but woo! hoo! it's going to work.
I needed a specially shaped tank to go on an Estate model I picked up in September. At first I thought it was profile Smoothie, but it turned out to be a Smootie-looking model by Larry Kruse. The fuselage is extended behind the wing and I'm thinking the horizontal stab and elevator are enlarged. The plans came with it and it has 1/2 inch cheeks on the inboard and outboard of the forward profile fuselage. There's a narrow slot for the fuel tank and I didn't want to enlarge the slot. Brodak has kit for the model in the Dare line of kits (D-304), but I think this one was built from the plans in Model Aviation 1984, plan #453.
Joe Ed Pederson
Cuba, MO
Congrats Joe Ed!! Wasn't that hard was it? Now, what you need to do it make another one as a spare, and improve on what you did on the first one. That is how to get good at this sort of thing. The biggest thing to work on is getting the fit up of the parts as tight as you can do the soldering goes easier and has a better chance of being sound. You must have been pretty close if you had no leaks on the first test. Build another one now while it is all familiar to you. You never know, you might build another model like it this winter and you will already have the tank made!!
MERRY CHRISTMAS and HAPPY NEW YEAR TO YOU!
Dan McEntee
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I have 4 sets of hard wood forms I use to make tanks, Nice thing is if they are ugly, they go inside and out of sight. LL~ For profiles, paint them and they blend in. H^^
I think I went through three before I got one I trusted and was proud of. Still have some bad parts, not sure why. Reminders to be more accurate I assume. D>K
Yeah, a hardwood block for a form is the way to go for the main body. Each one you make from it will be just like the first. I use 2 by 4 for the most part. The advantage is in being able to use the form with the body wrapped around it to form the end caps. I also have one of Jim Lees handy forming tools for making bends as needed. . By the time you make 3 or four tanks, people tend to "get it" and the results are more pleasing to the eye. Very satisfying item to make and admire when you are finished!
Type at you later,
Dan McEntee
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I made all of my metal tanks since I was a kid. Best part of using the block mold is that you can clamp it in a vice and make some really good end caps. Some of the molds I lost in the fire were 50 years old. Once you get the hang of it you start building tanks to fit the plane instead of planes to fit the tank. I made mine from really thin brass. So thin that I had to put a washer on the vent tubes for support. Probably not the best choice but they were light, they worked and were much easier to solder.
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I bought a welding tool, I think, that has wide jaws that is great for bending the tabs on end caps. Similar to this one. https://www.amazon.com/MIDWEST-Seamer-Tong-KUSHN-POWER-Comfort/dp/B00REG7CD6/ref=sr_1_54?keywords=wide%2Bblade%2Bpliers&qid=1639311900&sr=8-54&th=1 I can bend 4 of the 5 tabs with it. I also solder the uni flow tube on top of the pickup tube. and don't forget, 1/2 inch from the pickup tube end. I put one too close and it drove the engine crazy.
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I bought a welding tool, I think, that has wide jaws that is great for bending the tabs on end caps. Similar to this one. https://www.amazon.com/MIDWEST-Seamer-Tong-KUSHN-POWER-Comfort/dp/B00REG7CD6/ref=sr_1_54?keywords=wide%2Bblade%2Bpliers&qid=1639311900&sr=8-54&th=1 I can bend 4 of the 5 tabs with it. I also solder the uni flow tube on top of the pickup tube. and don't forget, 1/2 inch from the pickup tube end. I put one too close and it drove the engine crazy.
Those are often called duck bill pliers by some. Vice Grip has a version of the same thing. I have bought similar at Harbor Freight also. When making tanks I use whatever gets the job done, like lineman pliers, smooth jaw needle nose pliers, anything that helps you make the bend where you need it. Jim Lee's special tool can even be used on the ends to make bends on narrow sections.
Check out some of Al Rabes writings and videos that show how he made dunny tanks from manila file folders to make sure things fit properly and then used that as his pattern for cutting sheet metal.
HAPPY HOLIDAYS!!
Dan McEntee
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Check out some of Al Rabes writings and videos that show how he made dunny tanks from manila file folders to make sure things fit properly and then used that as his pattern for cutting sheet metal.
Got that from the man himself. Now I do it for batteries and just about anything I have to fit first. Another way to get the end caps bent is to use a small press. You have to make a female mold of your block (wood is fine) then press the tank mold into the female to make the bends. Best to trim the corners first. With thin tank metal a drill press is probably enough or a small arbor press. Makes very professional end caps but, lineman's pliers work pretty good as well. (We called them side cutters or dikes but that is not PC anymore).
Ken
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and don't forget, 1/2 inch from the pickup tube end. I put one too close and it drove the engine crazy.
Thanks for that little piece of experience. I put the uniflow tube much closer to the end of the feed line than 1/2". So, if It drives the engine crazy, I'll have a clue on fixing the problem.
Thanks,
Joe Ed
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Once you get the hang of it you start building tanks to fit the plane instead of planes to fit the tank.
Ken,
Yes, I have a shoebox full of new and used metal fuel tanks, and most of them aren't what I would consider the best arrangement for the location of the feed and uniflow and vent tubes. On profiles with engines with the needle valve assembly (NVA) in the venturi, I want the feed line coming out of the bottom of the tank about on third of the way back from the front of the tank, and close to half the way toward side of the fuselage, and angled toward the NVA so the fuel line has just about a straigh shot to the nipple on the spray bar. And if it's one of my OS FPs or LAs with remote needle valves I want to the feed line coming out the top of the tank a third back from the front of the tank and at the best angle to get the fuel line to the NVA.
Feed lines that come out of metal tanks pointed at the glow plug drive me crazy. On engines with the NVA in the venturi, how are you supposed to get the fuel line from the front outboard extreme corner of the tank to the NVA without having the fuel line touching the muffler or going across the exhaust port (If like me you don't use mufflers on the old engines)?
Yes, it will be quite useful to be able to build my own metal tanks to match the model and NVA arrangement (in the venturi or remote).
Joe Ed Pederson
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Hey Joe,
You're welcome.
The hardest part of making
metal tanks is learning that it
isn't hard.
Did the sliding main seam make it
easier for you to get a tight fit?
In my experience, that's the
important trick.
Merry Christmas everyone !
Cheers! - K.