Clunk Tank Internal Tubing

[Richard Koehler]

Last year I started using a clunk tank on my new Banshee and I'm wondering how often the internal tubing should be changed?  Anyone have any experience with this type of tank setup?

[Tim Wescott]

Always replace the tubing before it starts causing problems.

I've seen answers here ranging from "mine have been trouble free for ten years now" to "I change mine every year".

Come to think of it, I should change my clunk tank tubing...

[Brett Buck]

Last year I started using a clunk tank on my new Banshee and I'm wondering how often the internal tubing should be changed?  Anyone have any experience with this type of tank setup?

   I have been running the same clunk tank with the same tubing for about 15 years now. We made a bunch of metal clunk tanks where it was permanently installed. I wouldn't worry about it. If you are worried about it, carry a spare tank.

    Brett

[Randy Cuberly]

I'm flying a twelve year old airplane right now with a metal clunk tank.  The thing sat around for about 7-8 years and then was pressed into service this past year after myKA10 was badly damaged in a car incident.  Still working great.  Best setup I've used.  I have no idea how it's plumbed inside beyound guesses.  Bob Whitely built it in 2000 and he doesn't remember.  When I get another airplane flying I'm going to pull it apart to see how it's set up because it works so well with a PA65 on a pipe.  It's uniflow of course with no pressure.

Randy Cuberly

[johnt4051]

I am one of those people who will tend to ignore all the horror stories and hand-wringing about potential problems until I actually see it happen.  But in this case, I have seen (er, let us say, experienced) a number of instances where clunk tank tubing disintegrated.  Usually on an official flight.  So, I would recommend changing it once a year.
  This means that I am overdue to change the tubing in the tank of my profile stunter.  Then again, maybe the others are right.  It's a pain, so I think I'll just let it go ... 

[dirty dan]

The answer depends entirely on tubing used. If one is silly enough to use surgical tubing it ought be changed frequently. Two or three times a year seems about right.

If using tubing supplied with Hayes tanks--the black tubing which reminds one of Veco and Du-Bro tubing of years past--it must be changed at least once a year. In all the times I have suggested use of 3-ounce Hayes tank for Pukey Profiles running a 20FP this is probably the first time internal tubing addressed. And if I remember correctly this is the style of tank John Thompson was referencing upstream a bit.

Good quality silicone tubing will no doubt last as long as the tank, per Brett's comments.

Dan

[Michael Massey]

Voice of experience.  Last year at the Meet n' Meat, my new Nobler (with a trusted older clunk tank) gave me wild and unpredictable engine runs, fuel consumption issues and quit mid flight.  The cause was the silicon tubing clunk that was in the process of disintegrating inside the fuel tank.  The silicon tubing was probably 2 to 4 years old but I don't know for sure.  Once replace, all was good.

So the short answer for me, change the tubing every couple of years.  It is a small cost in time and money but the rewards can be significant.

[Michael Massey]

By the way, I use Sig 10/10/10 fuel so nothing out of the ordinary.

[FLOYD CARTER]

I'm going to stick with the group that says, "change tubing".  Nearly everything on my planes can be replaced (except bellcrank).  Fuel tubing, especially.  It's really sad to miss out on a contest due to a split fuel hose!

Floyd

[Lynn Weedman]

Floyd,
Periodic maintenance is your friend.

I'm an engineer that works with the full size war fighters on a daily basis and I have to tell you, maintenance it the key to a sound fuel system for your aircraft.
It could make the difference between loosing your favorite flying airplane or crashing it......

Lynn Weedman

[Richard Koehler]

Thanks for the info guys, see my next thread

[Allan Perret]

I'm flying a twelve year old airplane right now with a metal clunk tank.  The thing sat around for about 7-8 years and then was pressed into service this past year after myKA10 was badly damaged in a car incident.  Still working great.  Best setup I've used.  I have no idea how it's plumbed inside beyound guesses.  Bob Whitely built it in 2000 and he doesn't remember.  When I get another airplane flying I'm going to pull it apart to see how it's set up because it works so well with a PA65 on a pipe.  It's uniflow of course with no pressure.

Randy Cuberly

Randy or Brett: 
Would the internal plumbing for a metal clunk tank be any different than a plastic clunk tank ?

[Randy Cuberly]

Randy or Brett:  
Would the internal plumbing for a metal clunk tank be any different than a plastic clunk tank ?

I can't think of any reason why it should.  None of mine have been.  You do want, of course, to make sure everything is exactly the way it should be prior to buttoning the thing up...it's a pain in the "you know what" to make changes.

I would add that all of my metal clunk tanks are of rectangular configuration No triangular shapes on the outboard portion...that would be defeating in my opinion.

I've used several different methods of positioning the uniflo line, including a rigid line for it, as well as attaching it to the single clunk, and using double clunks, and all seemed to work well.

Randy Cuberly

[Brett Buck]

Randy or Brett: 
Would the internal plumbing for a metal clunk tank be any different than a plastic clunk tank ?

     No, aside from the fact we could solder the uniflow and overflow tubes to the inside of the tank, instead of having them free to flop around or be moved intentionally. You do want to smooth out the corners or edges on the clunk to reduce the tendency for the clunk to dent and pound its way through the side of the tank.

    Brett