New Cox Fuel Tank?

NEW222 Wed Apr 06, 2016 7:42 pm

While away in the US for holidays, the host hotel did not know it, but I believe that they supplied me with a couple of possible fuel tanks. Lightweight and holds approximately .87 ounces of fuel. Only thing is can this be plumbed for control line flying practically? If I used some sort of a clunk, would it work? Any help or opinions would be greatly appreciated.

roddie Thu Apr 07, 2016 10:26 am

I would try using it as a balloon-tank housing. Not sure about the cap though.. Is it metal? You'd need to drill a "clean" hole in the center to create a "compression-fit" for your silicone fuel-tubing. A thin metal cap might be too sharp and result in slicing through the tubing in a short time.

Here's something I came up with a few months ago.. using small bottles with "plastic" caps. The photos pretty much show how it would go together. A small round party balloon (4-6" diameter) is inserted into the bottle and it's neck stretched over the top where the cap screws-on.

New Cox Fuel Tank? Water_10

The tubing has a few notches cut on the inside end to ensure fuel-flow as the balloon collapses when emptying.

New Cox Fuel Tank? Water_11

A little petroleum-jelly helps to seal when installing the cap with it's tubing in place.

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Filling is done using a bulb or syringe.. and first; sucking all the air out prior to filling. This is NOT a pressurized design.. and still relies on the suction available from the engine's venturi. There is no vent needed.. because the balloon collapses as fuel is consumed. There is no "clunk" needed with this design.

pkrankow Thu Apr 07, 2016 10:39 am

Another choice is to do that using the balloon rubber banded directly to the punched hose where it is stiffened by the connector. The cap gets thrown away. The threads can be left or cut away. The whole thing could be buried in the wing too.

Make or get a rubber/silicone plug and make a tiny clunk tank in another choice.

Phil

NEW222 Thu Apr 07, 2016 11:06 am

@roddie - yes, the cap is metal. I was thinking along the lines of JB Weld on the joint and using a brass tube to go through. I know that you had mentioned before that you got your 1/8" copper tubing at an auto parts store. While on holidays in Fargo, I went to 3 auto parts stores asking them if they had any, and looked around myself, but came up empty handed. I was bummed again. Anyways, thank you for the pictures as they will be a good help. Lastly, as it is a metal cap, it does have a thin 'cardboard' seal in the top. Would it be best to leave it to seal it, or remove it? This is only if I use the whole tank for the build.

pkrankow Thu Apr 07, 2016 11:18 am

The auto parts store carry oil pressure tube for certain gauges. Typically this is a useful size for us, in soft copper.

Phil

NEW222 Thu Apr 07, 2016 11:49 am

Thank you. I will try calling around.

balogh Thu Apr 07, 2016 12:06 pm

I think the sylicon stoppers used in stock plastic fuel tanks will also do it...it is already punched for the fuel and filler lines and will probably fit tight in the neck of the shampoo plastic bottle (the neck dia of the stopper is 16mm) that is provided as guest amenities in hotels.

balogh Thu Apr 07, 2016 12:09 pm

And I use emptied/spent plastic tubing from ballpoint pens. Strong enough, has an internal dia sufficient to cater for the 049 appetite, and resist nitro fuel, and will not kill the sylicon fuel tube inside/outside the tank.

getback Thu Apr 07, 2016 12:19 pm

New you may try Hobby Lobby HERE they have the tubing in seizes and usually 3 pack for a few bucks , getback , I like the ink pen tube Huh...

NEW222 Thu Apr 07, 2016 1:15 pm

@ getback - Oh, I am familiar with the Hobby Lobby chain there. I was there three times I believe. Picked up some brass tubing last time, some tinplate, and on this trip, a K&S Tubing bender set and Epoxy. Very Happy

Although I did not buy the 1/8" tubing, but rather the 3/32, as this is what I had used previously.

**RknRusty** Fri Apr 08, 2016 5:23 am

New, I'd combine some of the above ideas and cork it(rubber plug), and I think it would make a wonderful clunk tank.
Rusty

NEW222 Sat Apr 09, 2016 12:46 am

Hi there. So, I decided to try to make a small clunk tank of this shampoo bottle. So, I went ahead and drilled a small hole in the metal lid. I then cut and JB welded it in place after roughing up the surface of the brass tubing before gluing in place. So, now with the question as this is all new to me. Do I need a second tube installed, or is the one just good enough? If I do need the second line, does it just go in and then bent upwards? Sorry for the stupid questions, but I would like to nail this on the first try. If this does work as planned, would this also work on a control line plane also, keep in mind this is for 1/2a. Thank you.

getback Sat Apr 09, 2016 9:20 am

Hi man , yes two tubes one for fuel and one for vent if pressurized three , cut the vent inside the tank pipe so it can at an angle or a good notch, see pic.... don't cap it off though if not running pressure

Eric

roddie Sat Apr 09, 2016 9:27 am

NEW222 wrote:Hi there. So, I decided to try to make a small clunk tank of this shampoo bottle. So, I went ahead and drilled a small hole in the metal lid. I then cut and JB welded it in place after roughing up the surface of the brass tubing before gluing in place. So, now with the question as this is all new to me. Do I need a second tube installed, or is the one just good enough? If I do need the second line, does it just go in and then bent upwards? Sorry for the stupid questions, but I would like to nail this on the first try. If this does work as planned, would this also work on a control line plane also, keep in mind this is for 1/2a. Thank you.

In addition to Eric's advice.. (we both were typing) Smile

Yes you'll need a vent because the bottle is rigid/airtight and won't collapse when fuel is used.. the way a balloon would. A second tube open to the outside and pointing "up" is all you really need to get started. Later.. if you want to try some inverted flying.. you'll lose some fuel out through the "inverted" vent though. This happens with Babe Bees when stunting, which is why the "Golden Bee" was designed with the larger 8cc tank having extra room for dual top/bottom vents.

Try using the smallest tubing that you can find to start with. You can always enlarge the vent-hole later if it's too small.

Any photos of your clunk set-up?

NEW222 Sat Apr 09, 2016 2:56 pm

I would love to get pics, but my camera just died, and is now on charge. I will get pictures up as soon as it is charged.

NEW222 Sat Apr 09, 2016 4:56 pm

Till the current time this was taken, minutes ago, this is where I am at with my first tank trial. As per request, here is a picture. Any help is appreciated. Also thanks for the above diagram. It is looking like I need a tube above at roughly 90 degrees for a fill vent line as I am going to do a two-line system. This particular tank will be for my airboat, and I MAY test it on a control line plane. As for the plane, I am only at level flight with the odd slight wingover, but not directly overhead.

NEW222 Sat Apr 09, 2016 4:59 pm

Tubing is 3/32" o.d. brass tubing with a wheel collar on the end of 1/2a fuel line. The kink was so that when the lid is in place snugly I will mark it and install it so the tip is at the lower bottom corner. If I try it on a control line plane, I will orient the fuel line/pick-up tube so that the pick-up bend is at the outer edge of the tank. And assuming it is a two-line tank, I should plug the 'vent' while in use according to the picture?

getback Sat Apr 09, 2016 5:14 pm

Go back to the pic and remove the pressure line from your mind , you are looking good no need to worry about the placement of the pick up tube that's what the moveing clunk is for ,,, just be sure the vent is at the TOP and cut a wedge in it so it can vent .... DONT CAP THE VENT ON 2 LINE FUEL TANK lol Eric

NEW222 Sat Apr 09, 2016 5:19 pm

Thank you. I will get to installing the other vent line in a little bit then. Thanks again.

1/2A Nut Sun Apr 10, 2016 1:46 am

http://www.ebay.com/itm/272116026613?_trksid=p2060353.m2749.l2649&var=570924919389&ssPageName=STRK%3AMEBIDX%3AIT

I bought a life time of micro tanks for cheap per the link

Small one in the pic is 3cc then 5 then 10 they don't have the 3cc one in stock but seen them on ebay.

I use a 10cc in the NANO and 15 in the Lil Speedy. cheap 5.95 for 15 of them.
Can use cork for the stopper and aluminum tube to keep the weight down.

NEW222 Sun Apr 10, 2016 1:52 am

1/2A Nut wrote:http://www.ebay.com/itm/272116026613?_trksid=p2060353.m2749.l2649&var=570924919389&ssPageName=STRK%3AMEBIDX%3AIT

I bought a life time of micro tanks for cheap per the link

Small one in the pic is 3cc then 5 then 10 they don't have the 3cc one in stock but seen them on ebay.

I use a 10cc in the NANO and 15 in the Lil Speedy. cheap 5.95 for 15 of them.
Can use cork for the stopper and aluminum tube to keep the weight down.

I've got some of those too. I actually forgot about them. I get them kind of regularly. If you know someone that 'vapes', ask them for their used bottles. Main capacities I find are 10, 15, and 30 ml. There are however 5 ml 'juices' as well, but not as popular. Or even if you have a 'vape' shop nearby, some make their own juices on site and would have the bottles in stock as well.

1/2A Nut Thu Apr 14, 2016 1:42 am

Here you go did up a 5cc for the TD .010 will give 4.5 to 5 mins of run time same tank size that's
in the 42k rpm NANO. I seal the inside cork wall with thick CA to insure no loose bits float into the
tank and the fuel line does not come loose inside the tank. Press fit into place with a final seal on the
outside to insure no leaks and help support the cork. Life time of tanks for under 15 bucks shipped.

I have done a handful of these now this way and no issues even after smacking / crashing the plane.
Use IV drip line type tube for the inside curve line, heat up a bit and shape the curve once cool it hardens and
holds it curve for life. Fuel flow and 2.2g weight is excellent! This lil duration tank is one and done in 15 min.
Small Cox Logo

NEW222 Thu Apr 14, 2016 2:46 am

Nice.

NEW222 Thu Apr 14, 2016 2:53 am

So stupid me. Just after seeing your post I thought I never saw my update. Then I realize that I deleted the pictures thinking they were something else. So, I re-downloaded them, and now here they are. A bit heavier than yours though (mine is approximately 8.5 grams vs your 2.2 grams), but am hoping it will work. Testing will be done in the next short while.

NEW222 Thu Apr 14, 2016 2:56 am

3/32 brass tubing in the cap and pick-up. Wheel collar as a clunk/weight, and pick-up is curved to get the last drop, hopefully. Tubing is off the LHS 1/2a tubing roll.

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