fuel tank question
 

I have always used foam for isolating the fuel tank from the airframe, but was wondering if anyone has ever used the small cell bubble wrap for that purpose? Lacking the foam, I was experimenting with some bubble wrap I had on hand, which seems to me should work. I was just wondering if anyone else had tried it and what were the results..???

I use mouse pads. I would think that bubble wrap, even small cell, would be too flexible and have problems fitting through some bulkheads.

I have sometimes used no wrapping at all without any problems. Modern glow fuel has anti-foaming additives to help.

Bubble wrap is a bad choice. It doesn't dampen vibration; it only spreads shock over a larger area. The bubbles don't hold air forever either, so if you are using it to create a snug fit the tank will eventually rattle around.

A problem I have with foam rubber is that it soaks up fuel over time. Is there any type of foam rubber that is not prone to that?

If that's happening there is a tank problem. I'd say that's indicative that your stopper and lines need to be replaced more often.

Same here. No foam and no issues. And when I break a motor in on my test stand (I still
prefer in-flight break-ins), no foam around the tank, vibrates a bunch, but not a single problem with properly feeding the engine.

Kurt

To me that is the biggest pain with IC engines, the stupid fuel tubing and tank stoppers. I have split more tanks and had more spills from loose stoppers than I can remember. I have many times tightened the stopper so much because I had a loose one that I split the fuel tank. That was the beauty of the old Hayes fuel tanks. They were so simple to set up, the stopper was only large enough to pass the pickup line through it and it would snap into the fuel tank, no guessing or ever coming loose.

I agree. I have a plane more than 20 years old, with no padding around the tank (no room for it) and have never had a problem with it. I do sometimes put foam around a tank, but that's just to keep it in place, not to prevent foaming.

I like to use 1/8" polyethylene foam. If it's a snug fit usually you can get one wrap around it. If the space is larger just add more wraps.

If it's a large plane I would put Velcro on it an strap it down.

i'll usually glue small pads of foam to the fuselage's interior in key places around the where the tanks sits. it absorbs vibration and helps hold the tank in place and looks much neater than wrapping the tank.