Sunday, March 21, 2021

Bending 3/8" fuel tubing for the selector - 8.5 hours

 I am ready to start bending fuel tubing for the fuel selector. The plan is to install an Aerolab filter/gascolator between the fuel selector and the fuel pump. I want to install the filter/gascolator for a few reasons. It is debatable whether the gascolator is still a Canadian requirement (it was in the past, but recent information points it may no longer be required). I want to install one to avoid any issues down the road with Transport Canada wanting one. From a functionality standpoint, I think its wise to install one at the low point just in case there is water ever present in the fuel system. Its placement under the plane not in the engine compartment is a big plus. The fact that it is so easy to access and service from outside the plane is a huge bonus. 

Tom from TS flightlines provided me a sample pic of the type of tube he manufactures for this type of installation on a post I made on Vans Airforce. It will be my guide.

As I have never bent aluminum tubing before....I went to work. I bent a ton of different variations. Learning how to bend the tubes, what shapes I can do with my tools, etc etc. I used 25' of tubing in the end.




I ended up making my J tube. With the tools I have I am basically committed with a particular set of dimensions and minimum radius. The result is a very nice looking J tube, but ultimately the tube is too tall. It doesn't go back far enough to the spar web, but I am not too worried about that. The height is a big problem. 


It becomes very apparent that the NPT thread on the bottom of the selector means that with all the required fittings, valuable space is eaten away resulting in an extremely short amount of space to work with. I tried fabricating a simple 90deg bend to see if that will work. It does work, but it pushes the gascolator and the fuel pump quite forward. The fuel pump doghouse will need to be quite big to cover it all.



I tried everything I could think of to fit the gascolator further back to the spar. I even bent a unique shape tube to get the proper height and offset the gascolator to the side. Its a really desirable option since the fuel connection on my pump is offset to the side. But ultimately this will not work as with the bend radius I can do with my tools pushes the gascolator too far to the side and I would have to cut out the floor stiffener....not an option.


I will keep at trying to figure something out.