Uniflow tank question

[Bill Morell]

I have a GRW 4 oz. wedge tank with all tubes forward facing. Is it alright to have Uniflow and the overfill plumbed to exit out the side of the fuselage? I know I read somewhere about wanting? the Uniflow to be facing into the wind.  Just don't want any problems with this if I can avoid it. First Uniflow I have used.

[Larry Fernandez]

I have a GRW 4 oz. wedge tank with all tunes forward facing. Is it alright to have Uniflow and the overfill plumbed to exit out the side of the fuselage? I know I read somewhere about wanting? the Uniflow to be facing into the wind.  Just don't want any problems with this if I can avoid it. First Uniflow I have used.

Yes Bill, you want the uniflow vent facing the airflow. the overflow vent doesn't matter as it gets capped off.
Its a good idea to have the overflow vent facing down, so that the fuel doesn't dribble down the side of the plane, ruining your beautiful paint job.

Larry, Buttafucco Stunt Team

[Dan McEntee]

   Hi Bill;
      After I determine tank location and how it will mount, I put two tubes through the fuselage. One is for the overflow, and will stick out about 1/2" on each side. The side with the tank will get a piece of fuel line that runs from the over flow tube on the tank to the fuselage tube, and of course the other side gets capped after filling. The other tube is in from of that. it sticks out 1/2" on the tank side like the other, but the inboard side is long enough to get bent into an elbow so it will face forward. Another piece of fuel line runs from the uniflow tube on the tank to the outboard side of this tube. I mount these tubes high on the fuselage, above the tank level. You can usually reach the fill/uniflow tube with a pressure line from the muffler if need be, and if you want to try pressure on a standard tank mode just switch the cap and the pressure line. If you are using straight suction, you can add restrictions to a piece of fuel line and attach it to the tube facing forward to vary how much natural pressure is applied to the tank. This makes everything easy to reach when filling a tank, and you don't have to worry about siphoning.

    Good luck and have fun,
     Dan McEntee

[Bill Morell]

Thank you Larry and Dan. Originally I was going with a standard wedge but I followed the construction article a little too closely and after gluing in the motor mounts with epoxy I can't get it in because of the vents. Learning that not everything in 1953 was exactly accurate as published.

[Randy Cuberly]

Thank you Larry and Dan. Originally I was going with a standard wedge but I followed the construction article a little too closely and after gluing in the motor mounts with epoxy I can't get it in because of the vents. Learning that not everything in 1953 was exactly accurate as published.

I would like to add one thing to the information already given.  If the uniflo vent is facing into the airstream some engines (most) will tend to richen on windy days when going into the wind.  If this occurs one solution is to simply use muffler pressure to the uniflo vent.  Another possible solution is to attach a piece of fuel tubing to the uniflo vent and run it inside the cowling.

Having an engine go very rich going into the wind on very windy days can be very exciting!!!  Not fun!

Under normal conditions with low wind the effect is usually hardly noticeable.

Randy Cuberly

[Trostle]

I would like to add one thing to the information already given.  If the uniflo vent is facing into the airstream some engines (most) will tend to richen on windy days when going into the wind.  If this occurs one solution is to simply use muffler pressure to the uniflo vent.  Another possible solution is to attach a piece of fuel tubing to the uniflo vent and run it inside the cowling.

Having an engine go very rich going into the wind on very windy days can be very exciting!!!  Not fun!

Under normal conditions with low wind the effect is usually hardly noticeable.

Randy Cuberly

Another solution to minimize the effect of the engine tend to richen going into the wind is to use decreasing sizes of brass tubing in the uniflow vent tubing to 1/32" diameter.  The vent still functions as a vent but will minimize the effect of going into the wind.  And that 1/32" tube can be squeezed to have an even smaller opening.  However, is the wind still causes problems, the simple solution is to just go to muffler pressure on the vent tube.

Keith

[Bill Morell]

Thank you Randy and Keith. This should keep me entertained for awhile!

[eric rule]

Hi Bill;

Here's what I use to exit the uniflow and overflow vents through the fuselage sides.
Just epoxy the steel plate to the inside of the fuselage and hook up the tubes to the tank using flexible fuel tubing.

Like all ideas, this is just one way to do the job. There are as many good ideas out there as there are flyers.

Eric

[Bill Morell]

Thanks Eric, talk to you tomorrow.