Greetings,

I have two questions regarding the fuel tank installation.

I am currently on step 37b for those with a 4*40 instruction booklet. I was told by friends to install a 10oz tank instead of the recommended 8oz tank. This was due to me using a OS .46AX. Would it be easier if I went ahead and installed the 10 oz fuel tank now before I install the tank floor so I will not have to modify the F1 entry to insert the fuel tank? Should I be concerned about the future of having to remove the fuel tank and then have to enlarge the F1 entry in the future?


Also, the plans do not call for a location to drill through the firewall for the fuel inlet line and the muffler pressure line. These both need to be drilled through the firewall, correct? What are some suggestions of where to drill through the firewall? Also, if I wanted to have a re-fueling mechanism besides using the muffler pressure line are there any standard market fuel tanks that has another fuel line designated for refueling only? Maybe I could make a side fuel entry through the fuselage side?


Thanks for any ideas and help.

I started with a 10 oz tank and had to remove it a couple years later to replace the internal lines. I cut the tank to get it out and replaced it with an 8 oz. I still get at least 10 minutes of run time. One thing I have noticed about smaller tanks- the run time is shorter, but the engine runs more consistent from full to empty.
I try to get the tank at the correct height in relation to the spraybar. Drill the holes so the fuel line has a straight shot to and through the firewall.
Have fun with it, MIkeB

I have a 4*40 kit but haven't started on it yet. I was wondering about a hatch for the tank as tanks and fuel lines do need to be replaced about once a year it seems.

A straight shot thru the firewall to the remote needle valve is the best idea. Some engines, not all, will run better with a droop in the fuel lines as they run thru the firewall.

A hatch is not a bad idea. It would be very simple to just make a section of the top sheeting in front of the canopy into a hatch. But tanks are inexpensive and it never hurts to have spares, so I'd just buy an 8oz. And MIkeB makes a good point about more consistent running.

You didn't say what brand tank you have, but I know Sullivan, DuBro, Great Planes and Hayes tanks all have a third hole on the stopperand end cap, or nipple for a third fueling line. You just have to punch the rubber stopper or the third nipple (did I type that?) the rest of the way through.

I've had a tank and the same fuel tubing in one of my planes for over 20 years!
What am I doing wrong? Sullivan tank, 6 oz, Royal 45 engine. Maybe this will be the year that I wished I had changed it! Ron

I've had problems with most of my Sullivan tanks. I do have one that has lasted almost 2 years but I've had others that leaked too much. Same for fuel lines. Maybe it is back luck? I know that the rubber stoppers get hard and brittle from age.