Hey,

I've got a tank whose clunk won't stay at the back of the tank. It's got medium (5/32" i.d.) tygon with a pretty big nickel-plated brass clunk on the end of it. If you tilt the nose down more than 20 degrees, the clunk shoots forward. To get it to go back, you have to hold the nose up about 70 degrees and shake it like it owes you money. As soon as the clunk goes forward and the nose is up a bit, that starts your 40 second countdown to empty UAT.

I can't be the first guy to experience this. What have you guys done about it?

Easy fix.

Instead of a full length of Tygon from the stopper to the clunk you can use solder a piece of brass tubing onto the clunk, then just use a short piece of Tygon to connect that at the stopper. The Tygon will allow the clunk to move up and down and side to side, but the brass tubing should be long enough to prevent the clunk from turning around in the tank.

Actually, you don't even have to solder anything. Just attach a length of brass tubing to the clunk with a short piece of Tygon. Then use another short piece of Tygon between the tubing going through the stopper and the length of brass tube you've connected to the clunk.

Dang!

Duh..... why couldn't I think of that?? You guys are awesome!! Thanks!

I usually solder a length of brass tubing onto the clunk as Kevin described. On a couple of planes I cut a short length of plastic straw (from McDonalds or Burger King) and slid that over the tygon clunk line.

Joe

so what clunks does everyone suggest using? This is about all i have come up with thru my search for large heavy clunks.

http://www.dreamworksrc.com/catalog/...roducts_id=534

Thomas

That clunk is good, the G forces will help keep it down in any case.

I've used the Dubro Large Clunk many times with good results.
http://www3.towerhobbies.com/cgi-bin...?&I=LXAHF0&P=7

For flat rectangular tanks I prefer the Sullivan Super Clunk because it allows fuel pick-up closer to the bottom of the tank. See link in above post.

Joe

thanks guys. these will be going in some jettech fuel cells i my large YA F-18. so i think the sullivan superclunks will be best.

I also used the brass tube with about a 1 inch piece of tygon.I had problems with the tubing not wanting to stay straight and centered in the tank.The brass tubing will also add to the clunk effect.I had to use the small clunks to get them to fit through the BMV tank hardware,but with the brass tubing it seems to move up and down with more athourity than just the tubing and clunk.

instead of using lots of different tubing and stuff and wire to keep all together
just use festo pun 6-h tubing
then go for a felt fuel clunck HD and all your problems go away..
cost less also!