sysiek

My Feedback: (176)

Hi to all ,I was working on my old gripen jet fuel tanks and after short inspection and looking on the usually no loop connection ,,this prevent the fuel line from looping back ,,and usually take 4 connection tube Tygon tube Tygon and the fuel pickup ,I did just two connections brass tube Tygon and fuel pickup with using aluminum thin and light tube for the straight part and this works much better I think no tide wires and risk of disconnect just look the pictures show all the first are the old waye .and the new waye much easier faster better 😃

invertmast

My Feedback: (23)

I normally just silver solder a brass tube to a heavy brass clunk. The only concern i have with your aluminum tube over the outside of the tygon is the probability of it eventually cutting into the tube. Flared tubing ends would be better IMO for your method,but it definitely appears easier than the other ways.

rcjets_63

My Feedback: (4)

That is an interesting idea Sebastian, a couple of thoughts though:

This really looks like a disaster. There are multiple brass tubes held to the Tygon with zip ties giving multiple possible leak sites. The vent line tubing has many little crimps where it has been bent and these will restrict air/fuel flow. If there are two saddle tanks, the odds of getting these restrictions the same is near nil, and one tank will empty faster than the other.


This isn't much better. Any debris that accumulates at the filter as the tank is filled through the clunk line will be released all at once as the fuel flows out of the tank. Any debris lodged in the filter provides a permanent restriction. There are no safety wires on the connections (particularly the smooth aluminum tubing) giving the opportunities for leaks. The vent line is much longer than it has to be.


There are several large crimps in the vent line. Get yourself a Dubro 5/32" tubing bender (Cat no 786) or K&S Engineering 1/16" to 3/16" (Stock number 321) spring tubing benders. Also, using a Tygon ring rather than safety wire might cause a problem over time especially at the connection between the Tygon and the brass tube in the stopper. There are burrs on the aluminum tubing (use a file to round the ends) that will wear the Tygon. Is there anything to prevent the aluminum tube from slipping down the Tygon?

I suggest that you solder short length of brass tubing over the end of the brass through the stopper. This will better hold the Tygon in place an prevent it from falling off.

Regards,

Jim

sysiek

My Feedback: (176)

The tube it's tite fit with flanged and sanded edges I think this will work for long time with out problems .

Helijet

DO NOT USE THAT FILTER. Many years ago it was supplied by some turbine manufacturers and we found out very quickly that small micro bubbles accumulate in the screens and once large enough release and caused flameouts. The plastic also loosens over time over the end fittings.

Dean W.

sysiek

My Feedback: (176)

No filter on the new connections ,just Tygon and clunk thru aluminum pipe .

raron455

My Feedback: (38)

I like it a whole lot better than cutting and scabbing in brass tubing, and it should do the job just as well, only less chance of leaks,, Great Idea, Im going to set mine up like this, but I will be safety wiring my connections, I always do that on EVERY fuel connection.

sysiek

My Feedback: (176)

I'm not doing safety wires no more sance I did haved problem with over time the wire cut in to Tygon tube I was doing the Tygon overlap for years in my rc boats and never haved problem with with much harsh conditions ,I'm only using the wire on 4mm tubing right on the fuel pump nipples .

lightningmcnulty

My Feedback: (11)

Looks good, you could use some fuel safe silicone at the ends of the aliminum to make sure there is no risk of cutting through the tygon but your the one who can see everything and determine if its required.

I would use safety wire also, if your having a problem with it cutting through then your not using it correctly, the tygon retaining rings you have made a fine but tygon doesn't remain in the same state forever, having said that since your servicing your tanks now and again it might not be a problem

sysiek

My Feedback: (176)

I have very easy access to make sure that the things work out will inspect after some flights .

junkjet

My Feedback: (55)

I don't think they understand that the aluminum tube is over a length of tygon so no need for safety wire. The aluminum is a sleeve.

sysiek

My Feedback: (176)

I think the idea is to loop the safety wire on the clung and the brass tube

Randy M.

My Feedback: (38)

these will go in my big F18. Using 100oz dubro for the main tank and two 35oz for saddles. The clunks are drilled out and the brass the brass tube is soldered in place. barbs on all brass and safety wired. Works great on long tanks.

sysiek

My Feedback: (176)

The look grate to with the solid connection think I will change it's the clunks to Sullivan the more pointy little heavier and have bigger opening .

joeflyer

My Feedback: (48)

I've done it several different ways. My preferred method is to solder a length of tube to the clunk, like Randy does.

Instead of an aluminum tube sleeve I've used a plastic straw from McDonalds. It's lighter, cheaper, and won't cut into the clunk line. Also I prefer to use Viton tubing inside the tank since it will last indefinitely exposed to fuel.

Helijet

Gentlemen

I have being building an flying turbines for almost 20 years now and have played with all sorts of ideas and installations. A word of advice if I may...
Please think twice about using nylon or plastic based products inside fuel tanks. The issue is not jetA or diesel but the turbine oil that will de plasticize or harden materials causing them to become brittle, crack or crumble. This can happen in as little as 3 - 4 months - in other words a flying season.

Dean W.