The fuel tank area in my Decathlon is wide and flat; the 'floor board' has some holes in it, some of which go out of the plane and some go into an empty well in the side of the fuse. I'm not able to strap the tank using the holes in the floor however. It is a flat bottom tank. The manual says to use silicon on the firewall part of the tank, and some toward the rear. I'd like to use some foam. I also would like something not terribly permanent in case there is a problem. I don't have a camera, sorry.

Also the throttle linkage runs right through the center of the firewall about an inch from the floor boards. Is it ok to mount the fuel tank above this by installing it on blocks? The engine is mounted at 135 degrees (45 degrees short of completely inverted). I'm not sure how things are supposed to line up, but from what I remember there is a rule about the level of the tank and the level of the carb or something.

any suggestions?

thanks.

For the most part I "float" my tanks surrounded with foam rubber and no part is cemented to the fuselage or a frame or the firewall. That can result in foaming and lean runs. You can make a foam rubber gasket that helps to seal the opening in the firewall. Just be sure the fuel lines are free and not bent excessively or squeezed once installed

Sometimes I add cross-braces to help secure the tank in place.

Thanks. I dont like the idea of a permanent install. Ill try to find a way to wrap it in foam and clamp it down. All my other planes had a cutout to snugly fit the tank, this ones going to be spending most of its life vertical or inverted so i want to get it right.

Small cup hooks and a few rubber bands with foam under the tank. Bands not to tight and crossed over the tank.

I use the foam from shipping packages and wrap the tank in one or two rolls of it, or cut it into several sheets that will jam the tank into place. then I make a strap out of some stick or sheet balsa to hold it in from the rear.

Hi!
Use soft foam! Never hard white foam from packing boxes.

I use sill seal foam from the local hardware store to wrap the tank. Then CA a stick of 1/4" x 1/4" balsa to hold the tank in place. If or when you want to remove the tank you can just break the balsa stick and remove the tank.

Stop at your local Agway, Tractor Supply, etc. store and ask for Vet Wrap, nice foamy self stick stuff for wrapping batteries, receivers, and sheep's feet. Best stuff to protect whatever needs protection.

It is important that you wrap your sheep's feet.

Absolutely, you will never see a sheep fly without it...

You can also use a mouse pad.

Another related question: the directions had me install the nylon tube for the throttle linkage before installing the fuel tank. The engine is mounted at 135 degrees (45 degrees short of completely inverted) and the throttle linkage needs to be in the center of the firewall, about an inch off the floor boards, which is in the way of the fuel tank. It would be great to mount the tank on a block above the throttle linkage, but I know there's a requirement for the level of the center of the tank and the carb - what is that, and how does it change when the engine is inverted? Also am I free to move the tank as far aft as I'd like?

thanks. In my language sheep feet translates to leg of lamb, and wrapping sheeps feet in something soft would be a pita and is called a gyro. yumm!!!

I cannot believe that the plans showed the throttle linkage going down the center of the tank area. Definitly must change that. The tank should be as close to engine as is possible and center of tank should be in line with carb needle valve,vertically. It's not nessacery to wrap in foam but do secure it in some way but not in permanent manner not glued. The linkage is usually running down the side of fuse directly off servo arm and can be bent after passing through firewall to connect to throttle arm.