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-   -   Sullivan flex tank experience? (https://www.rcuniverse.com/forum/glow-engines-114/11283843-sullivan-flex-tank-experience.html)

ululi1970 11-01-2012 06:50 PM
Sullivan flex tank experience?
 
I am considering a sullivan flex tank for a 1/2A warbird. The space between the firewall and the next former is less than 3'. I can fit a 2oz tank, but I'd like to have a little extra fuel. The sullivan slant flex tank 4oz is advertised
to be deformable and can be reshaped with a heat gun. Any experience/suggestion? I am planning to pu a .15 engine and would like to fly ~ 6 min with some fuel to spare...
Thank you

blw 11-01-2012 07:19 PM
RE: Sullivan flex tank experience?
 
I've had problems with larger flex tanks. Poor fit on the stoppers and holes for brass tubing. They leaked.

MJD 11-02-2012 06:19 AM
RE: Sullivan flex tank experience?
 
Hayes has a nice little 3oz tank. What I like about Hayes tanks for small models is that the stopper assembly doesn't weigh as much as the engine..

Hayes 3oz specifications (copied from a retailer's website so no guarantees on accuracy):

Capacity: 88 cc (3 Oz.)
Height: 47 mm (1.85")
Width: 38 mm (1.50")
Length: 76 mm (3.00")
Weight: 18 grams (.75 Oz.)

I like 3oz for sport .15's and 4oz for .15's with a bigger appetite for fuel, 2oz is okay on sport engines when you're stuck for space but I prefer that size for .09-.10.

j.duncker 11-02-2012 06:29 AM
RE: Sullivan flex tank experience?
 
I have used the Sullivan flex tank in larger sizes where I had unusual tank vaults and they worked OK.

ululi1970 11-04-2012 05:28 AM
RE: Sullivan flex tank experience?
 

ORIGINAL: MJD

Hayes has a nice little 3oz tank. What I like about Hayes tanks for small models is that the stopper assembly doesn't weigh as much as the engine..

Hayes 3oz specifications (copied from a retailer's website so no guarantees on accuracy):

Capacity: 88 cc (3 Oz.)
Height: 47 mm (1.85'')
Width: 38 mm (1.50'')
Length: 76 mm (3.00'')
Weight: 18 grams (.75 Oz.)

I like 3oz for sport .15's and 4oz for .15's with a bigger appetite for fuel, 2oz is okay on sport engines when you're stuck for space but I prefer that size for .09-.10.
That unfortunately is too long. The space between the firewall and the next former is only 2.75''. I wonder if adding a 1 oz tank of top of a 2 oz tank is feasible. Any downside?

1QwkSport2.5r 11-04-2012 05:37 AM
RE: Sullivan flex tank experience?
 

ORIGINAL: ululi1970


ORIGINAL: MJD

Hayes has a nice little 3oz tank. What I like about Hayes tanks for small models is that the stopper assembly doesn't weigh as much as the engine..

Hayes 3oz specifications (copied from a retailer's website so no guarantees on accuracy):

Capacity: 88 cc (3 Oz.)
Height: 47 mm (1.85'')
Width: 38 mm (1.50'')
Length: 76 mm (3.00'')
Weight: 18 grams (.75 Oz.)

I like 3oz for sport .15's and 4oz for .15's with a bigger appetite for fuel, 2oz is okay on sport engines when you're stuck for space but I prefer that size for .09-.10.
That unfortunately is too long. The space between the firewall and the next former is only 2.75''. I wonder if adding a 1 oz tank of top of a 2 oz tank is feasible. Any downside?

It will work, provided you have enough muffler pressure to force fuel from the lower tank to the upper tank. I suppose you could feed off the bottom tank and pressurize the upper tank but you might lose some pressure doing it that way since you would essentially have two vessels you're pressurizing instead of one.

Those tiny tanks are cheap enough, it might be worth trying just for the heck of it. It should work, but how well depends on your specific application.

w8ye 11-04-2012 09:03 AM
RE: Sullivan flex tank experience?
 
The Sullivan white stoppers don't hold up more than a season for the rubber gets too soft and leaks. Flex tanks themselves held up OK for me using Dubro stoppers.

If a Flex tank is allowed to rub back and forth against something hard like hardwood, it will rub a hole through the tank eventually, But it might take a couple hundred flights to do it?

I say all this but the truth is, you should re-do your tank every year or so anyway with a new stopper and metal lines as well as clunk line. Be sure to check the tank for abrasion.

Even the metal lines through the stopper can wear out though you don't think of them moving. The metal will fatigue and crack inside the stopper and cause air bubbles.

ululi1970 11-06-2012 03:24 AM
RE: Sullivan flex tank experience?
 

ORIGINAL: w8ye

The Sullivan white stoppers don't hold up more than a season for the rubber gets too soft and leaks. Flex tanks themselves held up OK for me using Dubro stoppers.

If a Flex tank is allowed to rub back and forth against something hard like hardwood, it will rub a hole through the tank eventually, But it might take a couple hundred flights to do it?

I say all this but the truth is, you should re-do your tank every year or so anyway with a new stopper and metal lines as well as clunk line. Be sure to check the tank for abrasion.

Even the metal lines through the stopper can wear out though you don't think of them moving. The metal will fatigue and crack inside the stopper and cause air bubbles.
At this point, I will try to use two Hayes tank stacked...


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