Quick 'n' easy balloon tank (Full Version)

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MJD -> Quick 'n' easy balloon tank (5/8/2008 7:44:58 PM)

The talk about balloon tanks in the “airplane recommendation” thread by maaaarius inspired me to shuffle downstairs and finish something I meant to do ages ago. Gee, it must have taken me 20 minutes to make it, and most of that was taking pictures.

Here is an idea I had for quick and easy balloon tank construction. You need:

- an empty Visine bottle
- a suitable balloon
- a chunk of 1/8” OD tubing (or whatever you choose to use)
- assorted tools you ought to have lying around

Pic1

Visine bottle, balloon, spout (it’s a two piece affair), screw-on cap. Call all your allergy-plagued and/or stoner friends and ask them to save Visine bottles for you.

Pic2

Close-up of the spout and cap. On the spout at left, I have already sliced off the part that push fits into the bottle – it is not needed. I have not yet sliced off the top part of the screw-on cap, it worked well with a singe edge blade. Careful of your fingers.

Pic3

Shows the spout weighing in at 0.87 grams. It has not been drilled out for the fuel outlet tubing yet. I am sure that removed the 0.07 gram part at least.

Pic4

A blurry shot of the screw-on cap at 0.95 grams. The part that projects above the threaded part must be sliced off.

Pic5

Shows a “suitable balloon” weighing in at a whopping 1.35 grams.

Pic6

Shows the two part spout. It has been drilled out to make a push fit for a short section of 1/8” OD tubing – in this case I used some polyurethane tubing I have on hand. It seals beautifully in a push fit hole like this, but so will metallic tubing. Because soft plastics tend to drill undersize, I ended up using a 9/64” drill bit to make a hole that was a nice fit for the 1/8” OD tube. Experiment with what you have beforehand so you don’t screw up too many Visine bottles.

Pic7

Shows the spout components in finished form.

Pic8

Shows the assembled tank. Here’s the cool part – carefully slice the roll-up rim from the balloon’s neck, then slide it over the spout assembly until the neck is just past the threads. Wet the outside of the balloon – your tongue works well, mine did – then carefully screw the cap on to pin the balloon in the threads as you can see here. Works like a charm. Because the spout is a twopart snap together affair, I decided not to tempt fate by using it alone. The tip part snaps pretty aggressively into the other bit, but that would require tying or rubber banding off the tank. I think that using the cap makes the whole affair much simpler, and in addition it is dead nuts simple to change balloons in the field.

As you can see, the completed tank weighs 2.80 grams. That is about 1/10 the weight of a Sullivan one ounce tank, so I figured any weight reduction beyond that was superfluous, but feel free to experiment.

Pic 9

Ta da! The tank is full of water but slack, and with this balloon holds 22 grams of water, aka 22 ml of fuel.

Howzat? Now to mold a lightweight tank compartment cover for the Blink..

Mike D.

attached (hopefully): Pic1 - Pic9

(edit) p.s. if space was an issue you could obviously shorten the balloon neck a bit, and lose just a little capacity. You'll figure it out.



maaaarius -> RE: Quick 'n' easy balloon tank (5/8/2008 9:13:02 PM)

Hurray, someone took pictures! Thanks a lot :)
Will it actually be able to pick up fuel even when the plane makes a loop? Why not make the tube long enough to go all the way into the balloon?

Thanks again!



Jim Thomerson -> RE: Quick 'n' easy balloon tank (5/8/2008 10:31:03 PM)

When you fill a balloon tank, you get all the air out, so the pickup is in fuel all the time.



MJD -> RE: Quick 'n' easy balloon tank (5/8/2008 10:55:44 PM)

quote:

ORIGINAL: Jim Thomerson

When you fill a balloon tank, you get all the air out, so the pickup is in fuel all the time.


Yep. The way you do that easily and reliably, maaaarius (is that the right number of "a's"?), is to get yourself a large syringe, 30ml - 60ml or so. You want one that has at least double your intended fuel capacity. Rig the syringe however you wish to, so that it has a fuel tubing nipple on the end of a section of filler line made from flexible tubing long enough to draw fuel from your can. Depress the plunger all the way, then draw in as much fuel as you want to be in the tank plus a few ml more, e.g. 5ml extra. Now, disconnect the fuel line from the engine and connect this to the filler line on the syringe. You must now hold the syringe vertically, filler line down, and pull the plunger back farther - it will now suck out any air from within the tank. This air will bubble up through the fuel in the syringe. and collect at the top of the column. When you have drawn out all the air, depress the plunger to discharge the fuel, which is now at the bottom of the syringe with the air on top, into the bladder. BUT, be careful you do not inject any air into the bladder after the fuel - this is where the extra 5ml of fuel comes in. Discharge the amount wanted in the tank, and stop when only the 5ml of fuel is remaining. Done! Connect the fuel line to the engine again, and take care to keep the nose up a bit from now on as fuel will easily gravity siphon into the engine.

It takes much more time to explain it than to do it. It is extremely simple when you understand what you are trying to accomplish - no air in the system - and how. Make darn sure you are not creating any pressure in the bladder! Know the relaxed capacity of the bladder beforehand. This is a key point of their use - you must fill them only to capacity or you will have some misery either due to bladder pressure or damage to the bladder itself.

This BTW is how you fill Jett and Tettra bubbleless tanks as typically used in pylon racers, and by those that have seen the light with respect to bladder tanks and their miraculous properties. Oddly, many people never try them, yet they are so simple, and so amazingly effective at eliminating fuel system troubles. They are, IMHO, well worth the money and more so in terms of peace of mind, and I have decided I will from this point forward use only bladder tanks of some sort in all my glow aircraft, no matter the aircraft type and purpose.

Hope this is of some help.

MJD

(EDIT) p.s. the fuel will swell the rubber plunger in the syringe, so I keep them empty at all times when not using them, and usually get along okay. If you remove the plunger and let it dry out it will reduce in size again, eventually. A filler I own made by Jett, uses a metal plunger with o-ring seals that are compatible with fuel, so it doesn't have this problem.



Mr. Mugen -> RE: Quick 'n' easy balloon tank (5/9/2008 5:30:40 PM)

Very nice! Thanks for taking the time to show us. I need to make one for a small boat project I have on the back burner.



gabe200 -> RE: Quick 'n' easy balloon tank (5/10/2008 12:02:28 AM)

so how long can you run an .049 on this bladder tank



MJD -> RE: Quick 'n' easy balloon tank (5/10/2008 3:14:58 AM)


quote:

ORIGINAL: gabe200

so how long can you run an .049 on this bladder tank


That depends on the size of the balloon of course, and there is some variety available there. The one in the picture held 23cc of water with the longish neck, and about 21cc when I cut the neck shorter. It looked more sensible once trimmed, and fits with room to spare in a Blink's tank compartment. For those not running pressure of course.. [:)]

Duration? A Black Widow runs 3-4 minutes on it's 8cc tank according to posts I've read here. From my recollection that sounds right, I think 3:30-3:40 was what I used to see on a 6-3 MAS, but it has been ages since I ever timed a run so I could be OTL. So this bladder would, I guess, run a Black Widow for 8-10 minutes, which is more than enough for me. A Tee Dee a bit less due to higher power output I presume, a Sure Start may run longer depending on it's level of anemia.

MJD



maaaarius -> RE: Quick 'n' easy balloon tank (5/11/2008 8:24:09 PM)

Thanks a lot for the detailed explanation. I had to read it like three times before I fully understood it :p Seems like I will try to get some balloons and something similar to that small Visine bottle. Hopefully I can find a usable bottle/tip. Tried my engine today and to my surprise it actually worked. The fuel I have is rather old and one of my cans have brownish fuel in it... not sure if it works. What kind of fuel should I buy? My options are:

Blue Thunder 20% nitro, car
Cool Power HP 30% nitro, heli - High Performance
Power MV 15% nitro 18% oil, heli
Sidewinder 25% nitro 10% oil, car - pro race blend

Not sure if any of those can be used with a cox engine. The higher the nitro the faster? Should it have oil in it?

@MDJ: Yes, that is the correct number of a's, but you can feel free to use any number you like, although I do prefer one simple a :)



Jim Thomerson -> RE: Quick 'n' easy balloon tank (5/11/2008 9:14:07 PM)

Designman had an article a couple of months back in Flying Models where he showed how to make a two layer balloon tank. Muffler pressure went into the outer balloon and fuel (of course) into the inner balloon. Looked pretty neat.



MJD -> RE: Quick 'n' easy balloon tank (5/12/2008 3:01:32 AM)


quote:

ORIGINAL: Jim Thomerson

Designman had an article a couple of months back in Flying Models where he showed how to make a two layer balloon tank. Muffler pressure went into the outer balloon and fuel (of course) into the inner balloon. Looked pretty neat.


LOL! I was going to try that sometime as the next step in balloontanking. Seems it's always been done before by someone [:)]



MJD -> RE: Quick 'n' easy balloon tank (5/12/2008 3:08:26 AM)


quote:

ORIGINAL: maaaarius

Blue Thunder 20% nitro, car
Cool Power HP 30% nitro, heli - High Performance
Power MV 15% nitro 18% oil, heli
Sidewinder 25% nitro 10% oil, car - pro race blend

Not sure if any of those can be used with a cox engine. The higher the nitro the faster? Should it have oil in it?



One thing that is pretty important with Coxes is to have a reasonable percentage of castor oil in the fuel. It's been ceovered here a few times, but basically a good Cox 1/2A fuel:

- contains a minimum of 15% nitromethane. They start to run smoothly at 15% and run great on anything from 25-35% in general. Forget what's high for a .40 or .60 - an .049 likes 25% nitro like a .46 likes 10%.
- contains a minimum of 20% total oil content of which 50% at least should be castor.

That said, if all you can find is some 15% syn/cas blend with 18% oil, it will run on that and not too badly. Overall, the service life will likely be shorter, but it won't fall apart before your eyes.

SIG Champion is good fuel is you can find some.



gabe200 -> RE: Quick 'n' easy balloon tank (5/13/2008 3:52:25 AM)

i use sig 1/2a fuel with added castor oil



maaaarius -> RE: Quick 'n' easy balloon tank (5/13/2008 1:27:39 PM)

I'm trying to find suitable fuel in Norway, but it's not easy. Is it ok to buy a 25% nitro fuel and add 20% oil? Does it have to be castor oil? I'll still try to hunt for more proper fuel, but it's possible that I will have to "make" my own.



MJD -> RE: Quick 'n' easy balloon tank (5/13/2008 2:10:31 PM)


quote:

ORIGINAL: maaaarius

I'm trying to find suitable fuel in Norway, but it's not easy. Is it ok to buy a 25% nitro fuel and add 20% oil? Does it have to be castor oil? I'll still try to hunt for more proper fuel, but it's possible that I will have to "made" my own.


If you have 25% fuel available, find out what the oil content is, and the type of oil - synthetic, castor, or synthetic/castor blend, or at least the brand and type. You won't need to add 20% oil, there is already oil in there, but you may need to add some castor oil to bring the total oil and castor oil amounts up to suitable levels.



Andrew -> RE: Quick 'n' easy balloon tank (5/13/2008 2:35:00 PM)

maaaarius

I use Sidewinder Pro car fuel and mix it to get the blend that I like. I contacted Cool Power about their oil content - it's a 50/50 mix of synthetic/castor. I use 16 oz. of Sidewinder 30/10, 12 oz. of Sidewinder 20/10 and 4 oz. of Klotz BeNol (racing castor) to make up a quart. Any quality degummed castor will work. Castor oil is extracted by pressing and by chemical treatment. The oil we use is pressed.

The resulting mix is 22.5% nitro and 21.25% total oil of which 16.88% is castor - that works out to be right at a 20/80 synthetic/castor mix.

If you have access to Sidewinder Pro 25/10, then 28 oz. of fuel plus 4 oz. of castor will give 21.88% nitro and 21.25% total oil of which 16.88% will be castor. I always mix mine to yield a quart of fuel. I use reclaimed 32 oz. peroxide bottles for fuel - nice size to carry to the field and the dark brown blocks sunlight.

Others in the group may have better suggestions or blends.

Edit: Still dropping hyphens; I'll see if the edit puts them back in.



MJD -> RE: Quick 'n' easy balloon tank (5/13/2008 5:08:57 PM)


quote:

ORIGINAL: MJD


quote:

ORIGINAL: maaaarius

I'm trying to find suitable fuel in Norway, but it's not easy. Is it ok to buy a 25% nitro fuel and add 20% oil? Does it have to be castor oil? I'll still try to hunt for more proper fuel, but it's possible that I will have to "made" my own.


If you have 25% fuel available, find out what the oil content is, and the type of oil - synthetic, castor, or synthetic/castor blend, or at least the brand and type. You won't need to add 20% oil, there is already oil in there, but you may need to add some castor oil to bring the total oil and castor oil amounts up to suitable levels.


The castor oil is important for long life of the ball and socket joint where the connecting rod mates to the piston. In addition, it also protects against those lean runs that sometimes happen when the needle is tweaked just a bit too much before flight, as Coxes in general do lean out a fair bit towards the end of the tank.

Any nitro content from 20-35% is fine, don't worry about exactly this or that. Total oil anywhere from 20-24% is a good range, although like I said, 18% syn/cas will do since you might be lucky just to find that in Norway - I specifically mention 18% because it is a common total oil percentage in sport fuels intended for 1cc-15cc engines. The 16% oil and lower car fuels are quite hard on .049s.

So as an example if you find some 20-30% nitro car fuel with 16% oil (syn/cas), you could add 6% castor oil by volume to give you about 22% oil total, and you would have a decent 1/2A fuel.

There are some specific "1/2A fuel" brands, also Sig Champion fuel is a good choice in any suitable nitro percentage, and can be run without additional oil.

MJD



gabe200 -> RE: Quick 'n' easy balloon tank (5/13/2008 7:59:33 PM)

nothing like the smell of castor oil i love it i use castor oil in my weed waker runs real smooth and smells great



maaaarius -> RE: Quick 'n' easy balloon tank (5/14/2008 3:18:18 PM)

Seems like I have to go for Sidewinder 25/10, and add castor oil to it. Now the problem seems to be to find castor oil :)
I wish more people listed what kind of oil they were selling instead of just saying "oil". I'll go and check my hobby store first of all, if I can't find any oil there, would it be ok to try out a motorcycle store? Bet I won't find Klotz BeNol, but maybe they have other suitable oils.



Andrew -> RE: Quick 'n' easy balloon tank (5/14/2008 4:19:11 PM)

You might also try your local pharmacy. Bakers AA castor oil is the same castor that SIG Manufacturing sells. The pharmacist may be able to provide an equivalent product. The AA grade is known as "first pressing" and has been refined for human consumption.



MJD -> RE: Quick 'n' easy balloon tank (5/14/2008 11:56:10 PM)


quote:

ORIGINAL: maaaarius

Seems like I have to go for Sidewinder 25/10, and add castor oil to it. Now the problem seems to be to find castor oil :)
I wish more people listed what kind of oil they were selling instead of just saying "oil". I'll go and check my hobby store first of all, if I can't find any oil there, would it be ok to try out a motorcycle store? Bet I won't find Klotz BeNol, but maybe they have other suitable oils.


Go-karts and 2-stroke motocrossers are both frequent users of castor oil, so a motorcycle or kart shop may be able to help you. Just tell 'em you need castor oil, period, in case they try to convince you go with the latest hot synthetic, for example Blue Marble. You know more than they do for this application.

MJD



maaaarius -> RE: Quick 'n' easy balloon tank (5/16/2008 1:13:42 AM)

Visited the local motorcycle store today.

Me: "Do you have castor oil?"
Store owner: "Yes, we do"
Me: "Castor, not Castrol"
Store owner: "Ah, we only have Castrol"

I went to the local pharmacy, they had never heard of castor oil, but they found ricin(us) oil, which is the same thing according to the internet. Maybe it has another name in Norway. The price was shocking. 3.38oz (100ml) for $19. Since I needed half a litre that oil would cost me $95 :) Checked around the internet in a few Norwegian stores and found something costing 1/10th, so sooner or later I'll get my castor oil and fuel. Hope I can get the engine to run ;)



MJD -> RE: Quick 'n' easy balloon tank (5/16/2008 2:30:34 AM)


quote:

ORIGINAL: maaaarius

Visited the local motorcycle store today.

Me: "Do you have castor oil?"
Store owner: "Yes, we do"
Me: "Castor, not Castrol"
Store owner: "Ah, we only have Castrol"

I went to the local pharmacy, they had never heard of castor oil, but they found ricin(us) oil, which is the same thing according to the internet. Maybe it has another name in Norway. The price was shocking. 3.38oz (100ml) for $19. Since I needed half a litre that oil would cost me $95 :) Checked around the internet in a few Norwegian stores and found something costing 1/10th, so sooner or later I'll get my castor oil and fuel. Hope I can get the engine to run ;)


Klotz's web site says they have a distributor in Norway. Perhaps that distributor can hook you up with a retailer who can get it for you?

"Klotz has distributors all over the world. Listed below are some of the countries where there is a Klotz distributor. For information on contacting a specific distributor, please email sales@klotzlube.com
.
.
Netherlands
New Zealand
Norway
Portugal
Puerto Rico
.
."

Might be worth a try.

MJD



maaaarius -> RE: Quick 'n' easy balloon tank (5/22/2008 7:27:34 PM)

Thanks for the tip, but after visiting around 4-5 RC shops I found one that could order decent priced oil for me.



MJD -> RE: Quick 'n' easy balloon tank (5/23/2008 1:58:25 PM)


quote:

ORIGINAL: maaaarius

Thanks for the tip, but after visiting around 4-5 RC shops I found one that could order decent priced oil for me.


Good, now you are in business.



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