Hi Steve
I've used the Dubro sintered bronze clunk filter (middle link above) since the early 90's. Your fears about the engine starving out, with fuel still in the tank, just have not happened to me in all that time. My tanks are empty of any fuel at the end of a flight. I also use the same style of filter in my fuel jug pickup line. I like the idea of prefiltering the fuel before it is put in the tank, just because I'm a little obsessed with having clean fuel. It seems to help keep the engines running as they should.
Most of the tanks I use are RC plastic tanks converted for CL use and run with a fixed, non-moving, not connected to the clunk, uniflow venting arrangement. I have had the best success with that style of venting.
There's another benefit that comes from this arrangement. I make 2 small bends in the uniflow line. The first one will go inside the tank to position the end about the middle of the sidewall. The second one will be made after the tank is assembled. Experience has taught me that this bend does not need to be more than about 30-45 degrees, it's only there to help you move it, up or down.
Moving it up or down, effectively changes the relative height of the tank, without having to physically move it.
I believe that when the uniflow vent end, inside the tank, and the clunk pick-up are connected, your relative apparent tank heights could change every time the clunk moves up or down. Perhaps this may be part of the reason some people have a bad taste in their mouths when trying to use a plastic uniflow tank.
There are several other advantages inherent to using plastic tanks.
RC plastic tanks are usually less expensive and more readily available.
No soldering is involved, with the problems of bad joints, and residue inside the tank. Having to desolder to see, or correct problems inside.
Depending on the brand and type, some are easy to see inside. In any case, they are easily opened up should the need arise.
You can simply swap out the annealed, brass tubing for copper tubing to avoid the brass tubing cracking, or splitting from reaction to our fuels. This can be accomplished as you assemble the tank the first time.
Easy tank height adjustment as detailed above.
One of the possible cons could be trying to use a style of plastic tank that may not work for your setup. Unless you have no need to adjust your tank height, I suggest you not use the slant front style for stunt. It is difficult to impossible to properly raise or lower your apparent tank height with that style of tank. I prefer the rectangular style with the tubes coming straight out the front. Other styles can work as well, as long as the stopper has the tubing, outside the tank, aligned parallel to the top and bottom.
I apologize for the thread drift and the length of my reply. In a way, it does have relevance to the subject matter. The sintered bronze-style clunk pickup has been shown to have helped some with minimizing bubbles in the fuel line. Split or cracked brass tubing in the metal tank will, at the least cause bubbling. There have been more than a few posts relating to this on the forum.
If desired, I can dig out the CAD drawing I did that shows how I set my tanks up and repost it. It was Allen Brickhaus, who passed several years ago, who showed me how to set up a plastic RC tank for stunt work. I made a few modifications to make it easier to use and since then, with 1 or 2 exceptions, that's all I use.
John Miller