To continue on where we left off. Let's finish up and install the fuel tank in the fuselage. Although I didn't include it in the pictures let's go ahead and attach our fuel tubing to the tank. I put about 10”-12” of both tubes on, and I'll trim it back later on. Like I said in my last post, I use two different colors of fuel tubing so that I can always identify which tube is which. Pink tubing is fuel delivery/carb and blue tubing is vent tube/muffler. If you use a system like this you'll appreciate it if you've ever had to remove a fuel tank because you've mixed up which tube is which while you're working on the plane.

As we get ready to install the tank let's look at a major point in installing a fuel tank. I see a lot of people that have problems with their engines that they just can't seen to figure out what's wrong. About 7 times out of 10 these problems can be traced back to a fuel problem, and a lot of those fuel problems can be traced to bubbles in the fuel lines. It doesn't take too much get bubbles in the fuel line. All it takes is a portion of the fuel tank in direct contact with fuselage/airframe. Once that happens vibrations from the engine are transferred to the fuselage and then to the fuel tank, and these vibrations can cause bubbles in the fuel, fuel line, fuel foaming, and a bunch of other problems. While this issue can cause lots of problems, it's usually very easy to fix. Isolate the fuel tank from the fuselage. Sometimes this is an easy task and sometimes it's a difficult task depending on the plane, but usually when you are building a kit it's pretty easy. In tank installations like this I prefer to just pack the tank compartment with foam around the tank. Pretty easy do to. You can purchase foam from your LHS or the online hobby suppliers (Tower, Horizon, etc...), but it always seems to me that they are higher priced than they need to be. You can find foam at Wal-mart in the sewing section cheaper than it is at the hobby shop. But if you keep an eye out you can usually find foam for free, and IMHO that's better than paying for it any day of the week. There are a lot of places to watch for foam that you can use but I'll tell you a few that I use. Probably one of the best sources for very high quality foam, check with computer/networking shops in your area. I know this for a fact because my wife and I own and operate a computer/network shop. High dollar computer components and networking items will come packed with some very very nice foam. If you go to these shops and ask them they will probably save up the foam for you and let you have it for nothing. Same thing goes for stereo and TV shops. If you just keep your eye out in everyday life you'll be surprised just how much foam you come across in daily life. When you find it, snatch it up and take it home and store it in your shop. And before you ask, yes I am cheap. We'll not exactly cheap, I just don't like to pay for things that I can get cheaper or for free. With that in mind, let's move on to the installation of the fuel tank.

Picture #1 shows the type of foam that I'm using here. This is a flat sheet of foam that you can find in craft shops. To start with I cut one piece that is as wide as the fuselage and is long enough to start at the top of the firewall, go down the firewall to the tank floor, back along the tank floor to the rear tank brackets we installed, and back up to the top of the fuselage. I know that may sound a bit confusing, but if you look at picture #2 you'll see what I mean. After this piece of foam is in feed the fuel lines through the holes in the firewall (picture #3) and then push the tank down into the compartment, making sure you get it surrounded by the foam so the tank doesn't touch the fuselage (picture #4). Next cut a piece of foam for the side of the tank. This can be worked down the side of the fuel tank using a screwdriver to push it down in place (picture #5). Picture #6 shows what the tank looks like so far, with the foam on one side of the tank. Now do the same thing on the other side of the tank (picture #7). And last we need a small piece of foam for the top of the tank (picture #8). Now we can go ahead and put the tank hatch in place over the tank (picture #9). Picture #10 shows the installed tank in place. You'll notice the fuel lines hanging loose, leave them like this until we install the engine.

Pictures
1. Flat foam used to pad fuel tank.
2. First piece of foam on the bottom, front, and rear of the fuel tank
3. First feed the fuel lines through the firewall.
4. Then insert the fuel tank into the compartment.
5. Push a piece of foam down the side of the fuel tank
6. Tank in compartment
7. Push another piece of foam on the other side of the tank.
8. A small piece of foam will isolate the top of the tank
9. Securing the fuel hatch
10. Final view of installed tank, fuel lines, and hatch.


Until next time

Ken