I am installing the fuel tank in my new Sig Kadet LT-40. Is there any problem with securing it to the plane with a velcro strip? I will then use foam on the sides and top to fill the gaps.

Mr Meyer,

You want to make sure the fuel tank is very secure. I have never seen that plane with the wings off so I do not know if it has its own hold built in for the correct tank.

Lets say it does not.

I do not think velcro is a good idea but I suppose it depends on how its applied.
I would look for a way to secure it with a light ply strip.
Do use the foam around it whatever method you choose. One of the things that does is keep the engine from vibrating the tank so much. You want to isolate it from all sides of the plane if possible. That is one reason I do not see velcro as a viable option.
Vibrating RC fuel causes foaming....air bubbles....problems.

You can probably pack it tight with foam then you need to secure it from sliding back with something sturdy. It will be heavy when its full, you do not want it sliding back and tearing or dissconnecting a line. Not to mention having your center of gravity go crazy.
I promise having your CG change in flight is no fun.

I bet you can download a manual for that plane if you look...or just find the PDF, save the page for reading and save your ink.

Good luck
Michael

Get the largest tank that will fit comfortably with a 1/4 inch gap around it (I think it was a 12oz on my LT-40) then pad on all sides, top and bottom with foam. Finally glue in a light ply back brace behind the foam-padded tank and between the fuselage sides. As Michael said, you don't want a heavy fuel tank sliding back in your fuselage during flight.

Cheers,
Neil.

I have successfully held the back end of many larger tanks in securely with large industrial velcro, and battery packs as well. If you have room for two servings, you'll be good to go. You may want to look inside of any large IMAC plane, you would be amazed at how many of us are using velco to hold in 20 to 32 oz. tanks. My test is, if you can pick the fuselage up by the tank, then it is most likely strong enough.

That being said, do not us light weight velcro, with only one serving, you may regret it. If you can't pull it out with the velcro attached, then you are most likely okay. For smaller planes like yours, I usually opt for a light ply brace, with foam glued onto it. I make a notch support glued to fuse, and fasten it with a couple of small (servo) screws for easy removal in the field. As sure as you glue it in, you will drop a clunk, have a fuel line leak or need to pull the tank for some reason, and have problems doing so.

Good luck with your LT40, it is a great, rugged, reliable trainer.

Mindwarp is right with the foam installation. Mike and I wrote at the same time, so you get twice the info.

I guess its optional but I would either screw the light ply to some existing wood. Usually a fuse former at the back of the space for the tank. Put foam between that and the tank too.

Its not set in stone but I think access to the fuel tank from the rear is a needful thing.
Otherwise you end up removing the engine to access the rubber seal of the tank to remove its insides.
Your fuel pick up clunck can fall off..lines crack.

The fuel clunk attches to the metal or platic tube inserted through the rubber seal in the front. Pressure nipple beside You want to make sure that pick up line inside the tank is clear of he rear of the tank. Close but not touching. Hold the plane or the tank depending on where you are and see that the clunk moves freely form top to bottom, side to side without biding on the back of the tank. Each day before I fly I flip my planes around to listen for a free moving clunk.

Here is a pic of my Avistar instructions. They explain better. This is typical for all planes....several optional ways of doing these lines are in use. This is basic.

By the way the "Caution" you cant read say's not to bend the pressure tube up so much it touches the tank or fuel flow might be interrupted...do not overtighten the stopper plates or damage to the tanks might occur.

Good luck
Michael

One of the nice things about the LT-40 is that it has a removable hatch above the fuel tank. Makes tank maintenance easy, and doesn't require removing the tank through the fuselage.

Well OK then

For your next planes fuel tank install you now know another option or two.

Sorry if you took that last message as criticism, belittlement of your posts, or a pedantic reply Michael - that was absolutely not how I intended it to be read. I'm a firm believer in "the more knowledge the better" and completely agree with everything you said in your post. I was merely trying to add to the 'knowledge pool' so that you and other readers not familiar with the LT-40 would have a better understanding of where Mr Meyer was coming from.

Cheers,
Neil.

when I use velcro to secure a tank or anything I use a ring of velcro around the tank and around a secure fixture in the plane. horizontal shear forces are harder to pull the tank out whereas a strip of velcro pulls out easier if force is applied perpendicular to the strip,

I've crashed a plane that had the tank secured with velcro. The entire piece of wood the tank was mounted to pulled out, but the tank was still firmly attached to the wood. The only thing I would add about attaching with velcro is to mention that you still need to cushion the tank with foam to keep it from foaming up.

yeah, I wouldn't bother with velcro. Just foam it up.

And the easy tank hatch will make a difference. My Superstar doesn't have one. But today with a little exacto and CA it does

Here is what I did - and it seems to work very well. I cut a piece of 1/4" latex foam to the exact size of the fuel compartment. I then velcroed the front of the fuel tank to the foam, that way it is separate from the wood and the vibrations of the plane should be dampened by the foam. I then put pieces of 1/2" foam down each side of the tank and held them firmly in place with a piece of 1/4" latex foam spacer. I then epoxyed a piece of 1/2" X 1/"2 hardwood at the back of the tank to keep it from sliding backwards. Finally, I used small pieces of 1/2" foam between the front of the tank and the firewall. I appreciate everyone's help and I hope this helps someone.