How do you secure your fuel lines to the tank filter and fittings, and fuel pump?

Do you use metal clips, extra tube to clamp the original tube, or not bother?

If you use fuel tube, where do you get stuff with a big enough bore to fit over the tube?

Also, which tube do you use for which connections? (e.g. Tygon throughout, Tygon from tank to pump with 4mm pipe from then on, etc.)

It seems to me that life is made much more complicated by different sized fittings. It would be great if manufacturers would come up with a standard so that a single type of tube could be used throughout. The BVM UAT is an example. These fittings are much bigger than any I have on any other part of my models!!

i use only Festo fittings on the up & down stream of the pump. With 4 mm festo connections and pipes.
with, when necessary, in case of a BVM UAT, a reduction 6-4 mm

up to now i didn't have any leakage...

for the tanks if not possible to use festo connection (with screw) i use small brass tube (for example in dubro tanks) with a external diameters of 3 or 4 mm...

tygon i never used up to now...

btw, i think that with a festo reduction 4-6, on the 6 mm side is possible to connect tygon tube...

[sm=surprised.gif]

Wrap twice with .020 stainless safety wire and twist ends to tighten not to cut tubing.
Darryl Usher

I run the UAT 6mm line direct to the pump using a piece of 4mm on the pump nipple first then sliding the 6mm over it. Never even used anything to secure it and have hd no problems. Tygon from the tanks to the UAT and 4mm from the pump exit to the motor.
V..

Thanks for your suggestions.

What about inside the tank? Is tygon too flexible? I've heard that it will go soft in fuel and may fall off the tubes. I'm not sure if i'll be able to get 4mm tube on the Orbit clunk.

[sm=thumbup.gif]I agree with Darryl. I use soft-temper stainless steel wire on any connection with a barb, including inside the fuel tanks. McMaster-Carr part number 8860 K11. $6.00 for a life time supply.

I use the small zip ties on all fittings inside the tank and out.

Small zip ties or wire and tygon inside the tanks is fine. I like the Dubro heavy clunks for positive fuel delivery.
V..

on my harpoon, I used saftey wire and spring clamps on plumbling. and i found those white, plastic, loop/clip, glue on, tube and wire hanger dodads at homedepot... velcro holds main tank in place with an easily removable padded triangular block of wood zap-glued in, to keep tank from shifting forward.

D.Kid I noticed the neat fitting/vent through fuse fitting you have. I made one for a plane but very clunky, what is yours made of/from?

Thanks,

Bart

if i remember right, i think it is a dubro or a sullivan kit to convert jug caps to a fueling jug.

I use safety wire on ALL connections other than Festo. It is a pain to do the airlines, but after many memories of chasing leaks in Rhom-Air equipped pattern airplanes 20 years ago, I think that it is worth it! The solution to this pain was a tool that I developed. I took a "cheap" screwdriver like the ones that are used for promotional purposes and drilled a hole in the tip. I found a piece of brass tubing that would fit over the end when it was smashed into an oval shape. I then re-smashed the tubing into a round shape along it's length except for the last 1/2 inch or so. This way, the tubing is locked on the screwdriver. The brass tubing holds the wire in place while it is twisted. This tool makes the safety wire thing easy to do and it is easy to get into tight places.

The pictures show how to use it.

Tailwinds,

John

Straight surgical hemostats are the best I have found for installing safety wire. Got plenty between my and my kids trips to the ER. Just ask after stitches...they throw them away!

got the idea from kevin green, here is what he said about it, > I bought a package of Dubro fuel can fittings. (The ones that enable you to convert a container top into a fuel can top.) There is one brass piece in the package that has threads in the middle and barbed nipples on each end. Take this piece and two brass nuts and put them aside.

Get a drill that will enable the brass piece to pass through the fuselage and drill a hole where you desire the vent to exit. Get a thin piece of ply (1/16" works well here) and glue it to the inside of the fuse, centering it over the hole you just drilled. When the glue has cured (I used Flex Zap) drill through the ply with the same drill you used earlier.

Get the brass fitting and the nuts---Put thread locker on the threads of the brass fitting and thread one nut onto the brass fitting, stopping not quite half way to allow for the thickness of the fuselage and the ply backing plate. Place the brass fitting with the one nut secured with thread locker into the hole you drilled, accessing from the inside of the plane. Put thread locker on the brass fitting and then thread the other nut onto the fitting from the exterior of the plane. Tighten the nut snugly against the fuselage.

There you have it---A nice fitting that does THREE things!!!
#1) Obviously, a vent and overflow for fuel tank.
#2) The nipple on the exterior will allow you to connect a ground run tank that also serves as an overflow container to catch excess fuel that is vented out during refueling. (I don't waste a drop!!!)
#3) The nipple will allow you to connect a plug made from a piece of fuel line and a Great Planes fuel plug. (The Great Planes fuel plug is the same plug that BVM uses with the UAT.) This will seal the system and help to prevent fuel spillage and fuel vapors from stinking up your transport vehicle.

I like doing the vent this way as it is very secure and won't get lost inside of the fuselage or won't get pinched off in the airflow. Also, I like the three benefits as described above. I use the large Tygon tubing to connect the tank to the vent fitting.

here's another good use for hemostats.. when installing those hard to put on lines, insert the hemos in the line about 3/16" , then pry open with a screwdriver and leave it that way for 5 mins. then remove the screwdriver and hemos and install the line quick. it will shrink back tight. then safety with your saftey wire tools of choice.. there's mine in the pic too.. back in the good ole days i used to brag that i could knit a sweeter with those plyers. hehe

If your vent is in the top of your fuel tank, and the vent fitting is on top of your plane, then won't you lose fuel while flying inverted?
Normally you would put the vent out the bottom of the plane opposite the direction of the tank vent. Or does the fact that air is constantly flowing into the tank prevent that from happening?
Good Idea for installing tight tubing on those pesky fittings. I tried to get that 4mm stuff that jetcat gives you to fit on those solinoid valves. I had to put lubrication on the fittings, and then heat the tubing to put it on. Only works sometimes.

Dan

I never have noticed any streaking or signs of fuel coming out the vent.. Think about this- when the vent trys to become a drain, then there is no vent to let it, hehe... If you notice in the pic, I have a loop in the vent tube for that reason (which may work better if it looped to the bottom of fuse, then went to top), but I would also assume that the flow of air into the vent also helps keep fuel from exiting vent when inverted.. Many guys do put the vents out the bottom, but I chose the top for several reasons ,similar to kevin #1- keeps belly slick and less possible damage in case of a belly landing , #2- not as much chance of fuel spills from residual fuel during transport, #3- less fuel on your hands, especially when removing taxi tank line just before take off, and #4- easy access is probably the biggest reason, not having to bend my wore out body over or kneel as much to attach or remove the taxi tank line... One interesting thing about a lot of r/c plane kits is lack of precise instructions on how to set up the equipment,. partly due to the many variables of engines types, tanks sizes, landing gear, etc and the placements of them.. This being my 1st turbine jet, I did a huge amount of research on it before building. There were many possible ways of doing everything to be done.. I took what I had seen others do and used the ideas that I liked best. Some things were my ideas, but not many..

Kewwwl.

You're right. There is no other way to let air into the tanks, so theretically liquid can't escape through the only line that has air entering it while the engine is running. I didn't pay much attention in fluid dynamics class.

Dan

I've assembled my tank (coke bottle) but am a bit worried about the 'softness' of the Tygon. I'm scared it will tie itself up in knots.

I've tried the stiff tube supplied with the UAT but it is a bit too stiff.

I'm thinking of using the stiff 4mm tube. This seems ideal but won't fit on the barb on the orbit clunk. I'm considering using 4mm tube and pushing it into a short length of tygon (it's a tight fit) and gluing with cyano. The tygon can then be pushed onto the clunk.

Is this ok or is there a better way of doing it?

siclick33,

I would think that the Kerosine would pretty much dissolve the CA! If you are worried about the Tygon curling up, then just use a short piece of Tygon on the tube that passes through the stopper to connect to a long piece of brass tubing followed by another short piece of Tygon that connects to the clunk (Whew!!) You should secure ALL these connections either with Ty-wraps or safety wire though. I have stuffed on size Festo tubing into a latrger size and bound it tightly with safety wire and had good results as well.

Tailwinds,

John

i agree with john. i wish i had taken a pic of tht before assembling my tank, but you have to have a length of some type of hard line/tube going about 2/3 into back of tank, then a shorter tygon to clunk, to keep the clunk near the rear, or it will end up stuck in the front of tank sooner or later. then down comes birdie, due to a flame out, way before your time limit on flt. (or so i've been told)

B&B also makes some neat fittings that can be of use for overflow, etc... The barbs are 5.2mm which should have no problem accepting the 4 or 6mm tubing