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Author Topic: Bladder fuel tanks for stunt  (Read 1392 times)

Offline John Skukalek

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Bladder fuel tanks for stunt
« on: March 09, 2023, 06:49:13 AM »
I'm a beginner. Wondering why bladder tanks aren't used in stunt. Or are they?

Offline frank mccune

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Re: Bladder fuel tanks for stunt
« Reply #1 on: March 09, 2023, 09:56:55 AM »
     Hi:

     They have been used in the past.  How well, is debatable! 

      Frank

     

Offline John Skukalek

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Re: Bladder fuel tanks for stunt
« Reply #2 on: March 09, 2023, 10:41:10 AM »
Hi Frank, and thank you for your response.

Offline Dan McEntee

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Re: Bladder fuel tanks for stunt
« Reply #3 on: March 09, 2023, 11:05:43 AM »
  You see some guys use bladder tanks on smaller models to help with the power and the run for flying stunt. I'm sure it has been used and tried by many people, but bladders have their own set of problems to deal with, namely they tend to burst, and that just doesn't fit in with having one in a 20 point finished stunt model!! The one exception is Paul Walker's B-17 four engine stunt model. Look around here on the forum or the internet for videos of it if you haven't seen it. He fed the four OS .15 ( I think ) from one main bladder to help ensure that the engine all quit at approximately the same time. Used a pressure regulator on each engine that I think might have been his own design, to help with getting each engine to run evenly and consistently. Paul built two or three of these I believe and to say they were a resounding success is an understatement. I never read about any issues with the bladder he used, and I imagine he just changed them frequently to avoid the bursting issue. Fore most single and even twin engine stunt models, if any kind of tank pressure is needed, simple muffler pressure is a lot easier to apply and maintain.
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Offline Brett Buck

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Re: Bladder fuel tanks for stunt
« Reply #4 on: March 09, 2023, 12:33:30 PM »
I'm a beginner. Wondering why bladder tanks aren't used in stunt. Or are they?

   Only in special circumstances (like Paul Walker's B-17). Otherwise, since you can use arbitrarily large engines and generally don't need to push the venturi size to the limit, suction works plenty well enough, and is much more reliable. I have 100's to 1000s of flights on a fuel tank without any maintenance. Bladder tanks have finite life and when they fail it is a huge mess.

        Brett

Online GERALD WIMMER

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Re: Bladder fuel tanks for stunt
« Reply #5 on: March 14, 2023, 04:28:03 AM »
Hello Bladders can be really annoying even with out bursting, I always seem to have a line pop off and fuel squirting everywhere especially over my glasses. Muffler pressure seems to solve the pressure issue on our muffled combat wings and stunters when suction will not do . My sons have had good success with inboard tanks on profile stunt and combat models once you get used to them and they are much easier set up then a bladder.

Regards Gerald

Offline doug coursey

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Re: Bladder fuel tanks for stunt
« Reply #6 on: March 14, 2023, 07:08:17 AM »
THERE USE TO BE A TANK MADE WITH A BLADDER IN A PLASTIC TANK..PRESSURE WAS APPLIED THE THE OUTSIDE OF THE BLADDER WHICH KEPT AIR FROM  FOAMING THE FUEL..I THNK THEY WRERE USED IN PYLON RACING
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Offline Brett Buck

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Re: Bladder fuel tanks for stunt
« Reply #7 on: March 14, 2023, 08:45:03 AM »
THERE USE TO BE A TANK MADE WITH A BLADDER IN A PLASTIC TANK..PRESSURE WAS APPLIED THE THE OUTSIDE OF THE BLADDER WHICH KEPT AIR FROM  FOAMING THE FUEL..I THNK THEY WRERE USED IN PYLON RACING

And, there were/are "slack bladder" tanks that have no pressure, just a bag that holds the fuel. They work very well, but, again, not as reliable/durable as hard tanks for stunt purposes. And there is no control over the cutoff, it runs until dead empty whether you want it or not.

     Brett

Offline John Skukalek

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Re: Bladder fuel tanks for stunt
« Reply #8 on: March 14, 2023, 01:58:00 PM »
Thanks for all the information guys. The reason I asked about bladders for stunt is that I am completing construction of a full fuse .15 size model(Musciano Challenger). The tank compartment is small and I am wondering if a bladder tank could be a solution.

Offline Howard Rush

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Re: Bladder fuel tanks for stunt
« Reply #9 on: March 14, 2023, 05:13:08 PM »
It might work, depending on the engine.  It pretty much requires the engine to run screamin’ lean.  Fuel flow is constant.  If you run an engine rich and it slows down, it gets richer and stops. 

Bladder tubing like Phil Cartier’s Yellow Jacket is pretty reliable, but should be in a sealed compartment with a big access hole.  The B-17 used that tubing in a .004”-wall carbon fiber tube with no problem.

Be sure to wear glasses while using a bladder tank.  I’ve seen two guys get serious eye damage from a bladder pissing fuel directly in their faces.
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Offline John Skukalek

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Re: Bladder fuel tanks for stunt
« Reply #10 on: March 14, 2023, 06:35:33 PM »
Holy Cow that's great advice Howard. The engine is an OS Max 15 and I don't want it to fly screaming fast. I wonder if a low pitch prop could put it at a good stunt pace with a bladder? 

Offline Air Ministry .

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Re: Bladder fuel tanks for stunt
« Reply #11 on: March 14, 2023, 06:40:54 PM »
This thing won the world champs . MVVS 5.6 Stunt , on a 4 inch pitch prop . and a BLADDER TANK . ( a fountain pen bladder ? )



Is a Stunt Version of a Speed Motor . Or is that engine .



http://sceptreflight.com/Model%20Engine%20Tests/MVVS%205.6.html

Theres the CLAMP THE FUEL LINE , Prime . Flick , & release the fuel at the right instant , or youre doomed . Proceedure .

Offline Air Ministry .

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Re: Bladder fuel tanks for stunt
« Reply #12 on: March 14, 2023, 06:43:29 PM »
Holy Cow that's great advice Howard. The engine is an OS Max 15 and I don't want it to fly screaming fast. I wonder if a low pitch prop could put it at a good stunt pace with a bladder?

ARGGH !



Somehow He may not have got it quite right . f we're talking about AIRFOILS . There .

 >:( %^@ VD~ S?P

Might wanna trya 3 in pitch prop . Were olde Grey FAI Power 7 or 8 x 3's , wotwere good . Before the F'Glass props . COX even - the Make !
A 1960's prop , was the ' in ' prop .



Wot goes UP , must come down . Tho this is a Fallacey . My Brothers FAI A1 Glider , is still up there , we believe ! .  ;D
« Last Edit: March 19, 2023, 07:23:04 PM by Air Ministry . »

Offline Steve Helmick

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Re: Bladder fuel tanks for stunt
« Reply #13 on: March 18, 2023, 07:27:53 PM »
Holy Cow that's great advice Howard. The engine is an OS Max 15 and I don't want it to fly screaming fast. I wonder if a low pitch prop could put it at a good stunt pace with a bladder?

Keeping in mind that you probably wouldn't be doing competition or the full stunt pattern (Beginner, maybe), a 1.5 oz tank should be adequate for your Max .15 to sport fly and do the basic tricks safely. I wouldn't suggest anything but a tin tank. You might have to solder up a homemade tank, but do check RSM and Brodak's websites.  y1 Steve
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Offline George Fruhling

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Re: Bladder fuel tanks for stunt
« Reply #14 on: March 18, 2023, 08:13:14 PM »
I build a couple of VooDoo combat planes fuel by a bladder tank. Placed a small aluminum pudding can in the wing with a fuel proofed 1/16' balsa lid. A burst bladder did not damage the plane. Maybe a bladder inside a clunk tank.

Offline Paul Smith

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Re: Bladder fuel tanks for stunt
« Reply #15 on: March 19, 2023, 05:34:43 PM »
Back in the early 1960's, pen bladders were actually the ink sacks used in fountain pens.  We used to buy them at an office supply in Detroit.  The owner didn't know why young kids would want to buy a dozen pen bladders.  After while he didn't want sell to us because his supply was limited and he needed the bladders for his customers who owned high end fountain pens.

These bladders were good because they didn't have the high pressure of tubing bladders or the round ball shape of pacifiers.

The advent of the ink cartridge was the death of the pen bladder.
Paul Smith

Offline Air Ministry .

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Re: Bladder fuel tanks for stunt
« Reply #16 on: March 19, 2023, 07:15:25 PM »
Looks like theyre still around , thanks to the Vintage Fountain Pen Movement . !    S?P



Of  Course . You have to call them " sacs " these days . Or thereyll be trouble .

https://www.indy-pen-dance.com/Fountain-Pen-Sacs.html

just put " fountain pen bladder " in woogle soich .

COX props . 7 x 3 1/2 . dunno if they didum inna 8 x 3 or 4 .  were thin & efficent , for the G-15's & Rossi's .





Looks like they were only 7 x 3 1/2 . were running low 20.000 rpm's . Dunno if a 8'd be wotcher need .




Offline Ken Culbertson

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Re: Bladder fuel tanks for stunt
« Reply #17 on: March 19, 2023, 07:23:10 PM »
Looks like theyre still around , thanks to the Vintage Fountain Pen Movement . !    S?P



Of  Course . You have to call them " sacs " these days . Or thereyll be trouble .

https://www.indy-pen-dance.com/Fountain-Pen-Sacs.html

just put " fountain pen bladder " in woogle soich .

COX props . 7 x 3 1/2 . dunno if they didum inna 8 x 3 or 4 .  were thin & efficent , for the G-15's & Rossi's .






Those sure beat the surgical tube in the cigar tube or the baby pacifier in the whiffle ball.  LL~

Ken
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If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Air Ministry .

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Re: Bladder fuel tanks for stunt
« Reply #18 on: March 19, 2023, 07:35:58 PM »
Oh  Dear ;



it ran a 250 x 100 PROP , anyway .

ACTUALLY ; I think it did run a bladder , for the first year or two . So There .  H^^

Giveitago Cobber .

« Last Edit: March 20, 2023, 06:32:42 PM by Air Ministry . »

Offline George Fruhling

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Re: Bladder fuel tanks for stunt
« Reply #19 on: March 19, 2023, 10:14:35 PM »
How about a baby pacifier nipple?

Offline Richard Fleming

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Re: Bladder fuel tanks for stunt
« Reply #20 on: March 21, 2023, 05:18:02 PM »
Back in the eighties I built some slow combat planes with a Fox .36 Mark5. Made a balsa and thin plywood container. A medium size balloon was used as the tank and it ran off suction. Ran pretty good.
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Offline Richard Fleming

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Re: Bladder fuel tanks for stunt
« Reply #21 on: March 22, 2023, 06:07:54 PM »
I also remembered we installed a Fox 35 stunt. Set slightly rich on the ground and ran very well on the balloon tank.
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