sir crashallot

ok guys i have a thread on here and am slightly new to 1/2a, iv heard of all different methods as to what people have used as fuel tanks in these little planes, is it possible to convert a 35m film can from a camera to a fuel tank to run a 049 if so what flight time would be achieved as i have masses of them due to my buisness that im setting up.

all ideas or advice welcome

build light

This should give you some info real quick:
http://search.rcuniverse.com/search....film+cannister

Robert

MJD

My Feedback: (1)

Search 1/2A balloon tank. They work great on suction systems and weigh 3.something grams. Better yet I'll find the link and put it here.. one moment please..

MJD

My Feedback: (1)

Here's the bladder tank. I gotta finish shooting a how-to on these, they work frigging great if I do say so myself. [sm=sleeping.gif]

[link=http://www.rcuniverse.com/forum/m_8040704/anchors_8040704/mpage_1/key_/anchor/tm.htm#8040704]1/2A bladder tank[/link]

sir crashallot

that looks a great little design, does it have to have the exaust pressure as the cox iv bought dosnt have an exhaust so geting exhaust pressure will be near impossible

MJD

My Feedback: (1)

The film can bladder tank is meant for pressure systems. I think it would work on suction too, I would have to try. I'm sure the balloon would collapse just fine inside a film can or not. But for suction you can just use a regular free balloon bladder tank - search 1/2A balloon tank on Glow Engines and look for a Visine bottle.

MJD

mylamo

My Feedback: (1)

In the beginning,( of 1/2 A ) The great Jim Walker sold little
toy airplanes so well set up that even a spitzy .045 would work
real nice. The secret was of course a baloon tank.
Ralph

flyinrog

My Feedback: (1)

a film can tank could run an .049 for a half hour!..so dont fill it up..as for back pressure you can use a small brass vent tube out of the firewall and use the propwash to put pressure into the tank,,it works pretty well...Rog
have also used the visine bottle myself with a vent tube...

MJD

My Feedback: (1)

Visine bottles are nice, they hold 14-15cc and are made from LDPE like flex tanks, so they seal easily. Adding a fuel line to the spout is chled's play, then you are left with fitting a vent. I have had the best luck cutting self-sealing holes using slightly undersize Al tubing, sharpened a bit and heated just hot enough to barely cut through in one pass. If your hands shake the hole gets bigger.

My balloon tank rig uses the neck of a Visine bottle as the closure fitting. I think it works real slick.

MJD

gcb

OK, lets see now...

A baloon tank can be stand-alone with nothing else other than a baloon with pickup tubing in it, except perhaps a cavity to contain it such as the canopy on a Jim Walker Firebaby. Since modern balooons break easily, some folks double them to prevent or lessen leakage.

Bladder tanks are used, as someone stated previously, to run on pressure. You need to learn to make, maintain, and use them. Usually they are used in applications such as combat to maintain steady fuel flow in engines with huge intakes that will not normally run on suction. You usually need to clamp them off until you start the engine or fuel will just squirt out and flood your engine. Also, sometimes pressurized fuel tubing will pop off. When it does, fuel will squirt all over you and, when it gets in your eyes, will cause you to instantly do a rain dance while expounding expletives that have nothing to do with rain. Not recommended for a newby.

Which brings us to the 35mm film tank (or pill bottle, etc.). The easiest way to use them is simple suction. You drill holes for the pickup tube and a fill/vent tube. By making the holes slightly smaller than the silicone tubing you are using, you can get a fuel-tight fit. You pull the pickup tube off the engine when filling the tank, and use it as the vent tube with the plane nose down so the pickup end is at the highest point. The normal vent tube is used to fill.
Of course there other ways to plumb the tubes but this is about the simplest. You can run a small bead of silicone around the lid to prevent leakage.

George

Mr Cox

The 35mm film tank are surprisingly tight and simple to make. As suggested by other on this forum the holes can be made by heating an undersized wire, thus getting smooth edges and avoiding possible cracks.

I fill through the pick-up tube and vent through the "vent", but that's just me...

propjobbill

For a cheap fuel tank about .6 oz it should last about 2 = 4 minutes depending on your engine I have found bubble bottles from Dollar Tree. You can get the small bottles they use for weddings at Dollar tree for $1.00 they come in a twelve pack. Using the fuel tube as stated before.

However If you really want cheap get the plastic stem Q-tips strip the cotton off bend the stem like you would brass line and the tank cost about 9 cents with fuel lines. I am away from home now but if you need pictures let me know and I will take pictures of a bubble bottle tank and post them.

MJD

My Feedback: (1)

Or ballpoint pen ink tubes, a la Bic and the like.

Getting tubing to seal tightly on film cans is not hard at all, unless the holes are ratty-edged or too big. With a clean undersize hole and something pushed through it, they just don't leak. And if you wrap the lid on with tape before the outside of the tank gets oily it won't come off without real effort. But it won't work second time.. .

MJD

combatpigg

My Feedback: (3)

I've taken a short hunk of brass tubing chucked into a drill motor, then "lathed" a sharp edge on the inside diameter of the brass tubing with an Xacto blade as the tubing is turned by the drill motor. If the brass tubing is slightly smaller than the fuel line you intend to use, then the holes you punch with it should be guten-tite.

MJD

My Feedback: (1)

Done that sort of thing too. The whole trick is a clean hole smaller than the tube, and the soft PE plastic takes care of the rest in conjunction with whatever tube you use. I eventually settled on heating a short length of Al tube with tapered edge (yeah Al) and pushing it through - not red heat, just hot. With the fast decay of heat in the tube, it cuts through then stops melting just about as it gets through, so the hole stays on size. Kind of a practiced technique. The sharpened drill tube is probably mroe consistent.

MJD

gcb

If the hole ends up a little loose and you are using silicone tubing, you can slip a small piece of metal tubing inside the silicone and have it provide a little expansion from inside, where it goes through the hole.

Lots of ideas being shared here. I never thought of melting a hole, I always drilled.

George