Clunk Tanks

[donchandler]

  Are clunk tanks in stunt being reconfigured internally or used out of the package?

[Glenn (Gravitywell) Reach]

Hi Don.  If you mean the tin tanks, I don't think they are being modified.  One simply purchases the configuration one needs and goes from there.  I am only a sport pilot and could be wrong though.  Hopefully one of the big dogs will comew in and give the definitive answer.

[Rob Killick]

Hi Don ,

Methinks that there are a few post  here , that give a good detailed description and set up for a plastic (Sullivan) uni-flow clunk tank set up .

Just do a search on this site ...

Best of luck ,

Rob K.

[Greg L Bahrman]

This is what works for me. clunk goes to motor. Next line is the uniflow or you can leave it open or you can put muffler pressure to it (I do). The third line with the bent tube is the overflow and it is directed to the top of the tank. The line that goes to the motor should be to the outside of the circle and in the middle of the tank. Having fun in the sun.

[FLOYD CARTER]

I hope Don doesn't mean tin clunk tanks!  You can put a clunk in a tin tank, but you can't get into it to change or fix the tubing after a while.  The plastic tanks, round or square, seem to work well configured as uni-flow.

Floyd

[Tim Wescott]

This is what works for me...

Why the retainer between the clunk and uniflow?  Is it to drag the uniflow around, or to limit the travel of the clunk?

[W.D. Roland]

Don
Sure glad you asked this, I was almost ready to.

My biggest question on this is what alignment with the spray bar works best.

My guess is center of tank in line with spray bar although in R/C I have found it way less critical( with clunk)
Than a hard tank in C/L.
Whole different set of flight requirements conditions though.

Working on something that would be a whole lot better with the short fat clunks than a hard tank.
Packaging/capacity is the problem.

Need at least an idea of location and then leave 'some' room for adjustment.


Don, I would think that the uniflow  line has to be and stay submerged.

Greg, Muffler pressure works good on C/L stunt?
That would be nice as then 'Choking'(priming) the engine can be done by putting finger over exhaust outlet to plug it while flipping.


David

[Greg L Bahrman]

My biggest question on this is what alignment with the spray bar works best..........Different motors and different setups are not all the same.

My guess is center of tank in line with spray bar.......I start with the center of the tank on the center of the engine, it's a good ballpark position and adjust from there until the engine runs the same upright and inverted.


Need at least an idea of location and then leave 'some' room for adjustment. I would think that the uniflow line has to be and stay submerged......yes........Also you will have a warning as the tank empties as the uniflow tube is exposed the engine will sound different.

Greg, Muffler pressure works good on C/L stunt?......It works for me. In fact I like it a lot. Some like it and some don't. So don't listen to all your friends, try it both ways and decide for yourself. Some love it and some hate it. Again some setups (meaning plane, motor and tank) work well with pressure and some don't. When using muffler pressure the 2-4 break is a little softer than without it. If your flying in the wind and the uniflow tube is pointing forward (most planes I've seen are) the engine will cycle between rich and lean depending on if your flying into the wind or downwind. Using muffler pressure eliminates this problem because the tank does not see a pressure change. Some swear by the metal tank and some swear by the plastic tank. I don't feel strongly about either I just use what works best at the time. This plane started out with a metal tank and eventually I found this setup worked best on this plane. It might not work great on another plane. So try not to become dedicated to one type of tank. I have planes with metal tanks and they work great also. Try both and use the one you like. Have fun.......IMHO

[billbyles]

I hope Don doesn't mean tin clunk tanks!  You can put a clunk in a tin tank, but you can't get into it to change or fix the tubing after a while.  The plastic tanks, round or square, seem to work well configured as uni-flow.

Floyd

Floyd, I have been building "tin" clunk tanks since the late fifties when Ed Southwick taught this "kid" of 12 or so how to build a clunk tank.  It takes a matter of a couple of minutes to take the back off of the tank to modify the tank or change the tubing.  However, I have two airplanes with clunk tanks that I built in 1995 that have never been apart and have never had a problem with the tank.  I use the Prather "pink" tubing which I understand is now available through Brodak.

To get the back off of the metal tank I just gently heat the back cover with a propane torch while pushing on the edge of the rear cover.  It takes less than a minute to get the cover off, and not much more than that to solder it back on.

[Dallas Hanna]

Floyd, I have been building "tin" clunk tanks since the late fifties when Ed Southwick taught this "kid" of 12 or so how to build a clunk tank.  It takes a matter of a couple of minutes to take the back off of the tank to modify the tank or change the tubing.  However, I have two airplanes with clunk tanks that I built in 1995 that have never been apart and have never had a problem with the tank.  I use the Prather "pink" tubing which I understand is now available through Brodak.

To get the back off of the metal tank I just gently heat the back cover with a propane torch while pushing on the edge of the rear cover.  It takes less than a minute to get the cover off, and not much more than that to solder it back on.

Just a little bit more work and you can change the internal clunk tube as often as required.   No need to take the back off, just unscrew the front cap.

HH

[Greg L Bahrman]

Excellent idea, really nice. Thanks for sharing but a little far out for the equipment I own or should I say don't own...

[Bill Little]

Are clunk tanks in stunt being reconfigured internally or used out of the package?

Hi Don,

I think it has been answered, but just in case............   I have used clunk tanks quite a bit, and I *plumb* them for uniflow.  There is no real *need* to raise or lower the tank since the uniflow tube can be twisted to compensate.  By loosening the cap and twisting it up or down, it acts like moving the whole tank.  I have ran clunks with simply a feed and overflow on profiles, and made an adjustable plate for it to be fastened to.  They work very well, many times, when a metal tank with enough capacity will not fit in the area given in the fuselage.

One set up is to solder the uniflow line to the pick up.  This keeps the uniflow line in the same location at all times, relative to the pick up.  A *Y* is fabricated with the pick up soldered to it.

Mongo

[donchandler]

 ;WoW! Thanks to everybody. My question certainly got answered. I was refering to the plastic tanks and was wondering about configuring it like a metal uniflow tank, I had visisons of the flexible tubing turning over on itself.

Thanks again to all.

[Greg L Bahrman]

 <;WoW! Thanks to everybody. My question certainly got answered. I was refering to the plastic tanks and was wondering about configuring it like a metal uniflow tank, I had visisons of the flexible tubing turning over on itself.

Thanks again to all.>

Hi Don,
My planes that have clunk tanks I always hang with the nose up. Yes it can happen if you hang it nose down. Had it happen on one of my RC ships.......Grins

[Garf]

I also use steel clunk tanks. I don't need or use uniflo. The only problem I have had was after a yard dart maneuver.

[Gene O'Keefe]

I set mine up like Greg Bahrman - never had a problem with them working.

 Geno

[billbyles]

Just a little bit more work and you can change the internal clunk tube as often as required.   No need to take the back off, just unscrew the front cap.

HH

Ed Southwick & I did that back in the late fifties until we realized that we never did need to change out the tubing.  So we simplified the tank construction by not having a removable pickup tube.

[Brian Massey]

Just a little bit more work and you can change the internal clunk tube as often as required.   No need to take the back off, just unscrew the front cap.

HH

Back when I bought Supersonic 100 fuel in quart cans I always saved the tops of the cans and used the screw caps as the top of my next fuel tank; and yes, you then had instant access to fix a clunk problem. Since fuel now comes in plastic jugs, I'm looking at pint and quart cans of thinner etc. as a good source of screw caps.

Brian