Author Topic: STUNT PLUMBING ? (Read 2421 times)

Greg L Bahrman · « **on:** July 13, 2006, 10:52:51 AM »

Hi All,
I need help.... I want to use a dubro plastic, clunk, uniflo tank (6 oz.) in my full bodied ship. I want to know what is the correct way to do the plumbing from the tank to the outside of the ship. I would like to be able to fill the tank from the outside of the ship without removing the cowl each time to pinch off the line to the venturi etc. Is there a proper way ?? and how should the plumbing on the outside look. Thank you!!

Bill Little · « **Reply #1 on:** July 13, 2006, 09:05:15 PM »

Quote from: Greg L Bahrman on July 13, 2006, 10:52:51 AM

Hi All,
I need help.... I want to use a dubro plastic, clunk, uniflo tank (6 oz.) in my full bodied ship. I want to know what is the correct way to do the plumbing from the tank to the outside of the ship. I would like to be able to fill the tank from the outside of the ship without removing the cowl each time to pinch off the line to the venturi etc. Is there a proper way ?? and how should the plumbing on the outside look. Thank you!!

Since I have used the set up you are referring to, and seen the ones in Mr. Werwage's and Mr. Hunt's planes, I will tell you how I do it.

The uniflow line is hooked to a piece of 1/8th" copper tubing (bent in an "L") that is placed high (above the tank) on the inside fuselage side. I dump the overflow through the bottom.

I do not understand why you would have to pinch off the fuel line to fill a tank. There is a fuel line, an overflow line and a uniflow line. Fill through the uniflow, then cap the overflow before flying. I have never had to remove the cowl (nor does anyone else I know) to fuel the plane.

(??)

Bill <><

Greg L Bahrman · « **Reply #2 on:** July 13, 2006, 09:27:01 PM »

WOW, Or should I say Phew !! That's great Bill. I thought I had to worry about the engine filling with fuel while filling the tank. Worries unfounded. I assume that the uniflow points forward and I guess it doesn't matter much which way the overflow points as it will be capped anyway?...Thanks Bill ! !

Ron King · « **Reply #3 on:** July 14, 2006, 01:43:45 PM »

Greg,

I have attached a couple of pictures to show how I set up a clunk tank for uniflow.

Tank: I bind and solder a short piece of tubing to the clunk and use a Dremel disk to trim the edge about 1/8" behind the fuel pickup. Then I use two pieces of fuel line to connect this "super" clunk to the fuel feed and uniflow tubes. If you set up the fuel lines correctly, the clunk will be pushed lightly against the outside edge of the tank and will ride up and down as you are flying. The angled tube is the overflow. Expect a nice consistent flight, with about two - three laps of lean running at the end of the tank.

Plumbing: The uniflow tube will exit the aircraft on the inboard side near the top of the fuselage (It's obscured under the exhaust stacks on my Mustang.). The bottom tube is the overflow and it's always capped after you fill the tank. The uniflow tube should be pointed forward, although I have talked to some who differ on this. I point the overflow forward as well simply because it looks better.

Fueling trick: When you fill your tank, rotate the prop backwards until it stops against the compression. This closes the transfer port on the crankshaft and you will never flood your engine while you are fueling.

Hope this helps.

EDIT - Corrected info.
EDIT 2 - Reloaded the pictures. Sorry about that.

Ron

Bill Little · « **Reply #4 on:** July 14, 2006, 05:35:13 PM »

Quote from: Ron King on July 14, 2006, 01:43:45 PM

Greg,

I have attached a couple of pictures to show how I set up a clunk tank for uniflow.

Tank: I bind and solder a short piece of tubing to the clunk and use a Dremel disk to trim the edge about 1/8" behind the fuel pickup. Then I use two pieces of fuel line to connect this "super" clunk to the fuel feed and uniflow tubes. If you set up the fuel lines correctly, the clunk will be pushed lightly against the outside edge of the tank and will ride up and down as you are flying. The angled tube is the overflow. Expect a nice consistent flight, with about two - three laps of lean running at the end of the tank.

Plumbing: The uniflow tube will exit the aircraft on the inboard side near the top of the fuselage (It's obscured under the exhaust stacks on my Mustang.). The bottom tube is the overflow and it's always capped after you fill the tank. The uniflow tube should be pointed forward, although I have talked to some who differ on this. I point the overflow forward as well simply because it looks better.

Fueling trick: When you fill your tank, rotate the prop backwards until it stops against the compression. This closes the transfer port on the crankshaft and you will never flood your engine while you are fueling.

Hope this helps.

EDIT - Corrected info.

Ron

Hi Ron,

Exactly how I do it, or used to do it.

Now I point the overflow down! This just helps to keep some fuel off the plane.
On some planes, I extend the overflow down through the cowl (fuel tubing) and have a plug underneath the plane so that the overflow squirts straight down. Got that from Mr. Werwage.

Bill <><

Ron King · « **Reply #5 on:** July 15, 2006, 12:05:39 PM »

Quote from: Bill Little on July 14, 2006, 05:35:13 PM

Hi Ron,

Exactly how I do it, or used to do it.

Now I point the overflow down! This just helps to keep some fuel off the plane.
On some planes, I extend the overflow down through the cowl (fuel tubing) and have a plug underneath the plane so that the overflow squirts straight down. Got that from Mr. Werwage.

Bill <><

That is exactly how we used to do the Nobler plumbing.

Thanks for the idea. Since I had to refinish the Mustang the overflow hole has been filled. I could mount that overflow on the bottom now.

Take care,

Ron

Steve Helmick · « **Reply #6 on:** July 16, 2006, 03:39:57 PM »

I've noticed that Howard has a vertically bent tube similar to the Uniflow inlet, for the overflow. It points down, but it's up high, where he can see that it's been un-capped for fueling, capped for flying.

He hooks a tubing onto it from a little glass jar, squirts the overflow into the jar. At the end of the day, he dumps the jar back into his gallon jug...I asked.

This prevents mess on the model and flying field, environmentally friendly, saves $. We all should get onto this trick. I would, however, suggest use of a poly bottle or just an 8 oz clunk tank, purchased at a swap meet. There's also no reason that a longer hose couldn't be run straight back into the top of the gallon fuel jug.

Steve

Doug Moon · « **Reply #7 on:** July 16, 2006, 10:22:13 PM »

Or,

You could just plumb it like the instructions say and go without uniflow all together.

I install the overflow in the tank to the top, just as the instructions say.

Then a tube that passes just pass the stopper and stops. Or I have it go in and do a 180 and point to the front of the tank.

Then the pick up line just as the instructions say.

I run pressure to the middle or 180 tube and go from there.

As far as filling. I run a three pass throughs on the side of the fuse.

One is the overflow. And one if the pressure from the muffler, then a uturn piece of tubing to the third pass through that goes to the tank pressure line. Unhook and fuel from there.

It is simple, straight forward, and works like a champ.

Bill Little · « **Reply #8 on:** July 17, 2006, 06:03:45 PM »

Quote from: Steve Helmick on July 16, 2006, 03:39:57 PM

I've noticed that Howard has a vertically bent tube similar to the Uniflow inlet, for the overflow. It points down, but it's up high, where he can see that it's been un-capped for fueling, capped for flying.

He hooks a tubing onto it from a little glass jar, squirts the overflow into the jar. At the end of the day, he dumps the jar back into his gallon jug...I asked.

This prevents mess on the model and flying field, environmentally friendly, saves $. We all should get onto this trick. I would, however, suggest use of a poly bottle or just an 8 oz clunk tank, purchased at a swap meet. There's also no reason that a longer hose couldn't be run straight back into the top of the gallon fuel jug. Steve

Hi Steve,

That's an idea I have seen several flyers use.

But since I am pretty lazy ( ** ) And I *might lose a total of an oz. during a contest to overflow, I just unplug the piece of tubing that sticks out the bottom of the cowl and let it rip.

Anyway, castor oil and alcohol doesn't do much harm to the environment. At least it didn't when we got dosed with it as a kid.

Bill <><

Jim Thomerson · « **Reply #9 on:** July 17, 2006, 06:52:22 PM »

When you are setting up an airplane, you may want to make some shortcut which will make the airplane harder to deal with when out flying. Don't do it! Been there, done that.

Bill Little · « **Reply #10 on:** July 17, 2006, 08:34:17 PM »

Quote from: Jim Thomerson on July 17, 2006, 06:52:22 PM

When you are setting up an airplane, you may want to make some shortcut which will make the airplane harder to deal with when out flying. Don't do it! Been there, done that.

Hi Jim,

If you mean running the fuel overflow tubing down through the bottom of the cowl, nothing could be simpler.

We don't have any appearance points around here at local meet (I do NOT agree with that!) so a 1/2" of tubing stiking out the bottom doesn't hurt a thing, and guarantees that I don't get any raw fuel on the finish when filling. I don't know, I just borrowed it from Mr. Werwage.

Bill <><

RC Storick · « **Reply #11 on:** July 24, 2006, 08:14:27 AM »

If I get one more report on this thread it will be gone. Pictures were lost sorry.

Author Topic: STUNT PLUMBING ? (Read 2421 times)

Greg L Bahrman

STUNT PLUMBING ?

Bill Little

Re: STUNT PLUMBING ?

Greg L Bahrman

Re: STUNT PLUMBING ?

Ron King

Re: STUNT PLUMBING ?

Bill Little

Re: STUNT PLUMBING ?

Ron King

Re: STUNT PLUMBING ?

Steve Helmick

Re: STUNT PLUMBING ?

Doug Moon

Re: STUNT PLUMBING ?

Bill Little

Re: STUNT PLUMBING ?

Jim Thomerson

Re: STUNT PLUMBING ?

Bill Little

Re: STUNT PLUMBING ?

RC Storick

Re: STUNT PLUMBING ?