jwingnut1

I am building a Goldberg eagle 2 and I recently purchased my fuel tank (8oz as recommended). The area where the tank is installed is much larger than the tank itself. The manufacturer recommends that I should use padded foam to prop the tank up to the appropriate height. I thought that it might be better to use canned foam, such as "great stuff" foam to fill in the area and give the tank a custom fit. If I cover the inside with plastic I should be able to remove the foam without much fuss should I decide to install a bigger tank in the future. But I'm unsure how the foam will react to nitro fuel. I've had a bad expierience with stirofoam and gasoline[:'(] I haven't purchased any fuel yet so I am unable to run any tests.
Has anyone tried this and if so what was the outcome?

Thanks for your input!

JustErik

The purpose of the foam is to prevent the transmission of engine induced vibration from the airframe to the tank. Using soft foam packed loosely around the tank is the best way to achieve this. The substance you're referring to, I believe, dries very hard. I would do a poor job of insulating the tank from the vibes. I'd suggest going with the recommend foam instead of the expanding stuff.

As far as how it would react to glow fuel, unless you have a leak or rupture, they should never come into contact with each other. If it does, the effect on the foam is the least of your worries. I'd be more worried about all the fuel that will soak into your airframe. Lots of folks like to coat the tank area with a thin film of epoxy to help protect this area should a leak occur.

outdoorhunting

Hey, JustEric, If you use the foam, keep in mind that it swells big time & if you put too much in an area it will split your airframe & damage it severly!! The best idea would be to just use the regular sheet foam rubber & wrap it. Also, it depends on how critical weight is on your plane when you balance it. Good luck !!

Campgems

I've been using the flat sheets of swim noodle stuff. I buy it from the same bin. The stuff is supper light. It is easy to cut to size and if you want, you can cut lightening holes in it for even less weight and more viberation isolation. I use it to back tank, receiver and batteries. I also latch onto the foam sheating like they package dishes and stiff in. It is usually card stock or slightly heaver in thickness and again it is supper light weight. With it, you can crumple it like paper to pack an area. Neither of these foams will absorbe fuel in the case of a leak, nor are they attacked by the nitro. I cut a chunk and put it in a jar of fuel for a couple days to see how it held up. No problems at all.

I've pulled down some old airplanes that had foam rubber around the tank, and that stuff weighed a ton. It also breaks down over time and is a royal pain to clean up after. The closed cell stuff like the swim noodles is really the best way to go in my mind.

Don

mclina

If your tank area is that roomy, why not install a 10oz tank? Definitely wrap it in foam sheets - do not use the expanding foam-in-a-can for reasons already stated.

bbbair

Listen to the post above, they are all correct.

As to putting a bigger tank in an Eagle 2 - WHY? [] My Eagle used the 8oz tank with a 40 engine and I would have 20 minute flights. Then after landing I still had fuel left.

IF you do put in a larger tank you will foul up the balance of the plane, and the handling characteristics... The Eagle is a trainer - use it as such, once you graduate from the Eagle you can start modifying to you heart's content.

Good Luck!