simple ballon tank

balogh Thu Jan 09, 2014 1:27 pm

Despite this topic has been addressed a couple times here, I thought I would share with you how I built my simplest, yet, most reliable and versatile balloon tank for my TD051-powered R/C plane.

(Not my invention, a replica of the balloon tank the late and great Roger Freiheit of Micro-Flite sold me once together with the PET throttle of a TeeDee010....)

balloon tank - simple ballon tank Ballon10

balloon tank - simple ballon tank Ballon10

This is a simple party balloon you can snatch from your kids before/after the birthday party Smile

that safely holds about 2 ounces (60 cu cm) nitro fuel, i.e. the tank material does not decay in nitro, and the ballon is large enough not to be pressurized while holding this fuel volume, thus your engine will be supplied with fuel at constant atmospheric pressure from the first till the last drop during the flight. The white plug through which the short fill line and supply line are led is a commercially available tank plug..this one comes from this Sullivan-made, Bernie-sold item: http://coxengines.ca/1oz-fuel-tank-for-cox-engine.html

When assembled, the neck of the balloon tightly fits the white rubber plug and the rolled-up neck-end of the balloon acts like a cuff on the plug, assuring firm, air-tight sealing of the tank. I.e. no additional wire ring etc. is needed for the assembly.

balloon tank - simple ballon tank Balloo10

balloon tank - simple ballon tank Balloo10

I fill the tank through the short fill line with a veterinary-syringe, first removing the air by pulling back the piston of the syringe, then pushing the fluid from the syringe into the tank.

The fuel thus completely fills the tank, with the air evacuated no foaming due to vibration occurs. The tank ensures uninterrupted fuel supply to the engine even in inverted flights.

I gave up on commercially available fuel tanks like those of Sullivan as these have a fixed geometry that sometimes does not fit the tight space available in the fuselage, and require a heavy clunk inside the tank attached to the supply line end to enable inverted flights. (My clunks never worked, vbecause the supply line inside the tank is too short and stiff to yield/bend towards the tank bottom in inverted flights, even if the clunk is attached.)

I hope to have provided a useful tip to at least some of you....

SuperDave Thu Jan 09, 2014 2:43 pm

Good suggestion. I run one very similar with excellent results.

Thanks, Balog.

SDh

roddie Thu Jan 09, 2014 3:41 pm

Ironically.. I just bought some small balloons today for trying out a tank design to fit in a streamlined "Silly-Putty" egg... for 1/2A C/L profile models. I may try a "cork" stopper.. and looked at some real small ones at Lowe's Home Center.

You didn't mention "V" notching the inside end of the fuel pick-up tube.. I think that's important, in case the balloon gets "sucked" against it's opening... which would instantly end all fun. Maybe it's not necessary.. but it certainly wouldn't hurt.

Roddie

andrew Thu Jan 09, 2014 4:26 pm

roddie wrote:
You didn't mention "V" notching the inside end of the fuel pick-up tube.. I think that's important, in case the balloon gets "sucked" against it's opening... which would instantly end all fun. Maybe it's not necessary.. but it certainly wouldn't hurt.

Roddie

Agree -- it's fairly standard procedure when using standard suction. If using the harder ink pen tube, notches along its length is also common practice.

batjac Thu Jan 09, 2014 5:23 pm

balogh wrote:I hope to have provided a useful tip to at least some of you....

WHY didn't you post this this morning?!? I just got home a from a hobby shop run, and I'd've picked up a couple of replacement stoppers while I was there. Now I'll have wait another week before my next run to get them. Neutral

By the way, thanks for sharing and the pics.

The Poor Timing Mark

pkrankow Thu Jan 09, 2014 6:07 pm

Good idea with the stoppers.

I have used a tie with hard tube and it works just fine, but that looks easier in the long run. I found some small silicone rubber bands for making bracelets that work very well as ties.

I have had mixed success with running on non-pressure bladder as if the engine does not draw nicely it doesn't work nicely.

Phil

**RknRusty** Thu Jan 09, 2014 6:32 pm

The most important thing I've found is to keep it contained in a way so that it isn't scrunched up but is restrained from flopping around, especially when you flip over inverted.

Rusty

balogh Fri Jan 10, 2014 3:51 am

roddie wrote:Ironically.. I just bought some small balloons today for trying out a tank design to fit in a streamlined "Silly-Putty" egg... for 1/2A C/L profile models. I may try a "cork" stopper.. and looked at some real small ones at Lowe's Home Center.

You didn't mention "V" notching the inside end of the fuel pick-up tube.. I think that's important, in case the balloon gets "sucked" against it's opening... which would instantly end all fun. Maybe it's not necessary.. but it certainly wouldn't hurt.

Roddie

Roddie,
it sure is V-notched (the poor close-up photo does not reveal it) not only at the tube-end, but intermittently, along the pick-up line to make sure the thirsty Small Cox Logo

beasT(eeDee) of burden can gulp the last hide-out drop of liquor from the balloon tank, that will collapse by the end of the run

**RknRusty** Fri Jan 10, 2014 4:02 am

balogh Fri Jan 10, 2014 4:05 am

RknRusty wrote:

Yes, Rusty, I must admit yours is way more professional than what I made...Unfortunately I only have our kitchen platform on which I build my RC planes under the permit of my RC (=Rarely Complaining) wife....

roddie Fri Jan 10, 2014 9:01 am

Here's something to try.. (I haven't yet) The "capsule" is a single-stem flower watering-tube that you can get from any florist. It has a silcone-rubber cap with a hole in the center for the stem, which attaches firmly on the tube. I had a bag of the wooden "spools" already.. so that's what I used. (the spool is 1/2" dia. at the flares... so a 1/2" dowel would also work, if drilled-out for a brass/copper tube and grooved around the center for a rubber band)

I cut the balloon to length (the balloon's "neck" was too tight a fit on the spool, to fit into the capsule.. and the balloon was too long anyway) This particular approach is limited to approx. 1/3 oz. capacity... but one could certainly obtain larger plastic test-tubes.. and use lightweight "cork" stoppers to make a larger capacity tank if desired. I doubt that there'd ever be trouble with the balloon kinking.. even with the most violent of maneuvers during flight.

Note: a few "V" notches should be sliced into the pick-up tubing's wall (not shown) to prevent loss of suction as the balloon shrinks around it as fuel is consumed.

Roddie

balloon tank - simple ballon tank Balloo10

balogh Fri Jan 10, 2014 9:12 am

roddie wrote:Here's something to try.. (I haven't yet) The "capsule" is a single-stem flower watering-tube that you can get from any florist. It has a silcone-rubber cap with a hole in the center for the stem, which attaches firmly on the tube. I had a bag of the wooden "spools" already.. so that's what I used. (the spool is 1/2" dia. at the flares... so a 1/2" dowel would also work, if drilled-out for a brass/copper tube and grooved around the center for a rubber band)

I cut the balloon to length (the balloon's "neck" was too tight a fit on the spool, to fit into the capsule.. and the balloon was too long anyway) This particular approach is limited to approx. 1/3 oz. capacity... but one could certainly obtain larger plastic test-tubes.. and use lightweight "cork" stoppers to make a larger capacity tank if desired. I doubt that there'd ever be trouble with the balloon kinking.. even with the most violent of maneuvers during flight.

Note: a few "V" notches should be sliced into the pick-up tubing's wall (not shown) to prevent loss of suction as the balloon shrinks around it as fuel is consumed.

Roddie

Yes, it seems to be a very neat one, and the 1/3 oz capacity is certainly sufficient for C/L applications..If you look at my latest posting at my Tee Dee 051 flight video topic, I posted a picture about how the balloon tank accommodates itself in the tank compartment of the plane...needles to say that this is rather untidy and spontaneous...but despite this spontaneous positioning and loose fit especially when the tank shrinks after the majority of the fuel has been spent, the loops and wing-overs I do with the Toucan never kink the balloon such that it would hamper the fuel supply....you and Rusty may be absolutely right in making it a rule to have the tank positioned as stable as possible...my experience so far shows the balloon tank, if confined in a fuselage compartment a bit larger than the tank, works reliably...

**RknRusty** Fri Jan 10, 2014 10:28 am

For a bigger tubular balloon I bored a hole in the round end of an aluminum Macanudo cigar tube and it was a decent container. I cut it short and left the rear open ended. I made an amateurish video of it running my Medallion.

Rusty

roddie Fri Jan 10, 2014 10:39 am

RknRusty wrote:For a bigger tubular balloon I bored a hole in the round end of an aluminum Macanudo cigar tube and it was a decent container. I cut it short and left the rear open ended. I made an amateurish video of it running my Medallion.

Rusty

A "Robert Burns" from the humidor please... Cool

I love amateurish videos.. I just posted one! You're turn!

**RknRusty** Fri Jan 10, 2014 10:56 am

Okay. Keep in mind I was brand new to rotary valve engines. Fit90 gave me a Medallion and a Tee Dee. If you think I look like a monkey f'ing a football with the Medallion, you should see me with the Tee Dee.
And I know... I called the cylinder a piston. Twice.

https://www.youtube.com/watch?v=VMPlgF81fgc

roddie Fri Jan 10, 2014 1:29 pm

RknRusty wrote:Okay. Keep in mind I was brand new to rotary valve engines. Fit90 gave me a Medallion and a Tee Dee. If you think I look like a monkey f'ing a football with the Medallion, you should see me with the Tee Dee.
And I know... I called the cylinder a piston. Twice.

https://www.youtube.com/watch?v=VMPlgF81fgc

I enjoyed that immensely!! Have you ever flown that shortened Stuntman with a reedie?

The reedie-ready rowdy Roddie

**RknRusty** Fri Jan 10, 2014 3:06 pm

roddie wrote:
RknRusty wrote:Okay. Keep in mind I was brand new to rotary valve engines. Fit90 gave me a Medallion and a Tee Dee. If you think I look like a monkey f'ing a football with the Medallion, you should see me with the Tee Dee.
And I know... I called the cylinder a piston. Twice.

https://www.youtube.com/watch?v=VMPlgF81fgc

I enjoyed that immensely!! Have you ever flown that shortened Stuntman with a reedie?

The reedie-ready rowdy Roddie

Yeah, it lived most of its life with Black Widow variants. The July prior to posting that video, we had a big day flying over at the church yard with my sister's family. After many flights, I let my nieces try to fly it. Neither made more than half a lap and after that it was really slagged. After repairs and more epoxy and paint, the BW would no longer fly it, other than lumbering around flat and level.

I tried a Killer Bee, which was better but couldn't get any tank configuration to work. I tried cutting out the wing to imbed a wedge, but the nacelle made it too far outboard and it wouldn't draw. My balloons... well, hadn't perfected that yet. Then Fit90 sent me a care package including a Tee Dee and a Medallion. I continued trying to get the Tee Dee to draw but didn't know they only liked perfectly setup suction. I had never used external tanks on non-product planes, so I was frustrated. Fit90 and others at RCGroups were trying to talk me into the mysterious "skill demanding" pressure bladders, but I shied away. Then Fit sent me a bunch of bladder supplies, an NV, 6' of tubing, fittings, and I never looked back.

I did hilariously over complicate it at first, but the result was still amazing. The Stuntman lived again until I just flat wore it out learning to do loops. I was a major retard. I think because at this point, in my life I had never met another control liner. RCGroups and guys like Fit90 were a major boost for my knowledge. Though I've been piddling with C/L since the '60s, I never got serious about pushing my abilities until I was getting gray.
And my hair got gray too. lol!

A short history of the Stuntman 23 AKA Green Death

Here are me and my nieces flying the Stuntman with a Black Widow.
https://www.youtube.com/watch?v=nF6Ge8f_FWw

And the end of Green Death as we Knew it:
https://www.youtube.com/watch?v=HU0KLVSJJvQ

balloon tank - simple ballon tank GreenDeath3

balloon tank - simple ballon tank GreenDeath3

balloon tank - simple ballon tank GreenDeath2

balloon tank - simple ballon tank MyFleet

balloon tank - simple ballon tank SAM_0654-1

balloon tank - simple ballon tank Tankfinished1sm

And then I discovered pressurized fuel feed.

Rusty

roddie Tue Oct 03, 2017 6:34 pm

Thread Linked by Peter Gregory... Smile

Rusty.. I don't remember those vids.. but they're priceless! You were flying that Stuntman like a stolen Volkswagon! Your nieces flights hurt a bit............ Laughing

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