Mounting plastic tanks on profiles

What's a good way to do this? I've used, in the past, the usual bent wire and rubber bands, nylon cable-ties (on Slow Combat models), eyelets with rubber bands, etc. But none of these look very neat or elegant, and aren't terribly adjustable height wise (though on a plastic tank, I've heard somewhere that instead of tweaking the tank height you can just move the uniflo vent instead).

Is there an advantage to plastic tanks? They've always been a pain to work with for me. I only used them because they were the spec racing tank in FoxBerg.

I've seen them mounted with a wide aluminum strap with a little cut out for the locator bump.

Giffy

If you have a plastic tank with the tank plug in the center of the tank with 3 exit tubes. Ex: one for engine, one for uniflow, and one for filling. You can loosen the plug and rotate it thus moving the tube to the engine up or down as needed.

On mine, I'd just have two vents - the line to the engine, which is used for filling, and one uniflo vent. To fill the tank, I would stand the plane on its inboard wingtip.

Works OK for 1/2-As and Slow Combat.. (the tanks didn't work that great in Slow, but the filling technique worked OK).

I have a four year old profile that's had it's fair share of prangs and biffs. Painted with spray can enamel. I use 10% nitro fuel and the motor is a K&B 40 so it's fairly smooth. The Dubro clunk tank was glued straight to the fuselage side (painted) with silastic. It's shown no signs of moving and I grip the tank (and fuselage) when starting.

Having said that, a mate did something similar at about the same time and had no end of trouble. Mind you, he was going through a period where nothing worked for him.

I did a similar thing with the kid's trainers and had no problems but in that case, the tanks only stayed on for a few weekends - the tiny clunk tanks proved to be a failure so I cut them off and replaced them with tin tanks that were recessed into the fuselage. However, the tanks were well stuck in place so I would have anticipated them lasting as well ... if only they'd worked.

Here is what I do for mounting a plastic tank. Make a plywood piece about 1/4-3/8" larger than the fuel tank heightwise. Make it out of 1/8" plywood. Put 2 slots in this piece about 2" apart and each about 1" long. They will run from top to bottom in the plywood piece. These slots are for adjustment of the tank mounting plate which through these slots you use 2 or 4(prefered) mounting screws (woodscrews). On the top and bottom of the plywood mounting plate glue 2 strips of hard spruce lengthwise and screw your eyelets that hold the rubber bands for holding the tank in these pieces. When your done gluing,coat the mount with clear epoxy (thinned) and then paint and mount on the side of your model. Use the screws for height adjustment of the mount through the slots and mount your tank with rubber bands. Fly and adjust as necessary.

Hi Rob,
I use "almost" the same set up. Let me see if I can describe the difference.
Instead of the hardwood strip for the eyelets, I bend two "c" shaped pieces of 1/16 music wire which are inserted through the plywood plate from the back. The "c" is just wide enough to clear the height of the tank. Once in place, I bend a hook on each end to capture the rubber bands. I think it is just a touch lighter.
Bill

...And before mounting to the plane, weigh the whole thing to compare it with your standard metal wedge---you'll be surprise at the small difference.

Small cup hooks or J-bolts (4) with rubber bands if you arent going to a concours. We put two CF rods in to support shims under the tank for height stability. You can also split CF arrow shafts for this. Light and very rigid.

The twisting of the uniflow tube for height adjustment also works.

The down sides, in my opinion are: Weight close to metal. Lots of joints to leak and fail. Clunk can get trapped/twisted. And finally, for the capacity, they need alot of room fore and aft. The ability with a metal tank to exit the feed and vents along the sides of the tank instead of the end allows alot more mounting freedom on smaller planes.

recent weight analysis on a friends 7 oz PA tank---plastic saved .2oz!

On a 65+ oz plane! THe question with these is also, not if they will ever leak, but when they will leak.

Not a real fan --- but for quick and dirty they're ok.

FWIW

>Not a real fan --- but for quick and dirty they're ok.

I love'em! Maae tem uniflow and use muffler presssure.

When I used Foxes the "burp" went away...

God bless you!

In Christ,

In this case, I'm thinking small, not large. One oz. Sullivan Slant tank, Norvel .061.

Lots of food for thought here. I'll be trying out several things.

Be careful if going for small. The last ones I bought were Dubro for the kid's .15's. The caps are the same size as the big tanks. The clunks are the same size as the big tanks. Sorry, not much room left for tubing. But that's okay, they supplied water hose that won't flex anyway. The tanks were useless and my lads watched over two sessions as I tried to make the rotten things work on their new models. I ripped the tanks off and made a couple of tin tanks. Instant good engine runs. Funny about that.

I've used a number of clunk tanks in r/c and c/l models and the quality, even among the same supplier, is variable. Mind you, I'm fussy. I'd complain about things (like leaks, lousy pipes, lousy tubing) that'd have my r/c buddies (hey, a yankie term from an aussie) scratching their heads. Perhaps we ask too much in control line. Perhaps it's too late at night for me to be making this post. Perhaps I need another red wine.

Note that I'm grumpy about the quality of the tanks, not clunk tanks themselves. I've used them a lot in stunt. I prefer tin but clunk has its place. Strangely, with some tanks (even sullivan and dubro), there's not time saving either - a tin tank doesn't take all that long to make. Even less if Mr Brodak does it for you.