Fuel tank foam

[Stuart & Kathryn Fields]

Is there anyone out there using fuel tanks filled with open cell foam? I've
heard that explosions are tamed as well as fuel slosh. I've also heard that
the foam must be replaced periodically. How often is the replacement
necessary? I'm using 100LL Av gas.

--
Stuart & Kathryn Fields, Publishers
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478 ph
(760) 408-9747 publication cell
(760) 608-1299 technical cell
www.experimentalhelo.com
www.vkss.com

[Orval Fairbairn]

In article >,
"Stuart & Kathryn Fields" > wrote:

> Is there anyone out there using fuel tanks filled with open cell foam? I've
> heard that explosions are tamed as well as fuel slosh. I've also heard that
> the foam must be replaced periodically. How often is the replacement
> necessary? I'm using 100LL Av gas.

Most of the foam is polyurethane foam, which decomposes after exposure
to water vapor. It is not an instantaneous process, occurring over
several years, but the decomposition product is a black powder, which
can clog fuel filters, injectors, etc.

It is good for race cars, which have a limited useful life, but may
impose problems in aircraft, which operate for years.

[Ron Natalie]

Stuart & Kathryn Fields wrote:
> Is there anyone out there using fuel tanks filled with open cell foam? I've
> heard that explosions are tamed as well as fuel slosh. I've also heard that
> the foam must be replaced periodically. How often is the replacement
> necessary? I'm using 100LL Av gas.
>
Fuel cells (bladders with foam) are pretty common in the auto racing
industry. They real purpose of it is to avoid the fuel from spraying
out if the tank is ruptured. Other than that I'm not sure what
"explosion" resistance you're going to get. I suppose it might
mitigate some sloshing. I'd make sure that I was getting the
max flow rate for takeoff if I were to use one in an aircraft.

The big drawback is that they drastically decrease the fuel
carried per unit volume.

[JP[_1_]]

"Stuart & Kathryn Fields" > wrote in
...
> Is there anyone out there using fuel tanks filled with open cell foam?
> I've heard that explosions are tamed as well as fuel slosh. I've also
> heard that the foam must be replaced periodically. How often is the
> replacement necessary? I'm using 100LL Av gas.
>
> --
> Stuart & Kathryn Fields, Publishers
> Experimental Helo magazine
> P. O. Box 1585
> Inyokern, CA 93527
> (760) 377-4478 ph
> (760) 408-9747 publication cell
> (760) 608-1299 technical cell
> www.experimentalhelo.com
> www.vkss.com
>
>


Aero Tec Laboratories Inc
http://www.atlinc.com/US/racing.html

http://www.atlinc.com/US/catalogs.html
Some ATL Fuel Cells catalogs.

http://www.atlinc.com/US/faqs_racing.html
Here's some answers concerning the foam replacement etc.

JP

[Morgans[_2_]]

"Ron Natalie" > wrote

I'd make sure that I was getting the
> max flow rate for takeoff if I were to use one in an aircraft.

That should not be a problem, considering the run NASCAR engines with it,
putting out 750+ HP, at constant wide open throttle, for lap after lap, at
some tracks. Our biggest engines putting out around 300 HP would not drawn
nearly as much.

It seems to me that if you were willing to overlook the weight, the extra
volume to carry the same amount of fuel, and the extra $$$, the fact that
they can wear out and plug up your fuel system is a show stopper.
--
Jim in NC

[Stuart & Kathryn Fields]

JP: Thanks for the links. I've learned enough to avoid fuel tank foams.
When the engine suddenly gets quiet in my helicopter, my suds level gets
pretty high.
Thanks again.

--
Stuart & Kathryn Fields, Publishers
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478 ph
(760) 408-9747 publication cell
(760) 608-1299 technical cell
www.experimentalhelo.com
www.vkss.com


"JP" > wrote in message
...
>
> "Stuart & Kathryn Fields" > wrote in
> ...
>> Is there anyone out there using fuel tanks filled with open cell foam?
>> I've heard that explosions are tamed as well as fuel slosh. I've also
>> heard that the foam must be replaced periodically. How often is the
>> replacement necessary? I'm using 100LL Av gas.
>>
>> --
>> Stuart & Kathryn Fields, Publishers
>> Experimental Helo magazine
>> P. O. Box 1585
>> Inyokern, CA 93527
>> (760) 377-4478 ph
>> (760) 408-9747 publication cell
>> (760) 608-1299 technical cell
>> www.experimentalhelo.com
>> www.vkss.com
>>
>>
>
>
> Aero Tec Laboratories Inc
> http://www.atlinc.com/US/racing.html
>
> http://www.atlinc.com/US/catalogs.html
> Some ATL Fuel Cells catalogs.
>
> http://www.atlinc.com/US/faqs_racing.html
> Here's some answers concerning the foam replacement etc.
>
> JP
>

[Stuart & Kathryn Fields]

Richard: I agree the deterioration of the foam is a show stopper for me.
thanks

--
Stuart & Kathryn Fields, Publishers
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478 ph
(760) 408-9747 publication cell
(760) 608-1299 technical cell
www.experimentalhelo.com
www.vkss.com


"Richard Riley" > wrote in message
...
> On Mon, 25 Jun 2007 07:35:36 -0400, Ron Natalie >
> wrote:
>
>>Stuart & Kathryn Fields wrote:
>>> Is there anyone out there using fuel tanks filled with open cell foam?
>>> I've
>>> heard that explosions are tamed as well as fuel slosh. I've also heard
>>> that
>>> the foam must be replaced periodically. How often is the replacement
>>> necessary? I'm using 100LL Av gas.
>>>
>>Fuel cells (bladders with foam) are pretty common in the auto racing
>>industry. They real purpose of it is to avoid the fuel from spraying
>>out if the tank is ruptured. Other than that I'm not sure what
>>"explosion" resistance you're going to get. I suppose it might
>>mitigate some sloshing. I'd make sure that I was getting the
>>max flow rate for takeoff if I were to use one in an aircraft.
>>
>>The big drawback is that they drastically decrease the fuel
>>carried per unit volume.
>
> I looked at the foam a few years ago. Google Reticulated Polyurethane
> Foam Fuel Explosion and you'll find a few technical papers.
>
> You take about a 3% hit on fuel volume, and you increase empty weight
> by about the same. It does break down over time - the racing bladders
> are only rated for 5 years. The breakdown occurs MUCH more rapidly in
> the presence of an oxygenating fuel like ethanol.
>
> I decided against it, I can't open up my tanks every few years to
> replace it.

[Maxwell]

"Stuart & Kathryn Fields" > wrote in message
...
> Is there anyone out there using fuel tanks filled with open cell foam?
> I've heard that explosions are tamed as well as fuel slosh. I've also
> heard that the foam must be replaced periodically. How often is the
> replacement necessary? I'm using 100LL Av gas.
>

Perhaps a few metal baffels would be a better choice.

[Stuart & Kathryn Fields]

I have a couple of baffles already, but having 28 gal 100LL just behind my
head makes my nerves twitch just a bit. Having the foam is supposed to make
explosive conflagration less likely in case of a prang.

Thanks

--
Stuart & Kathryn Fields, Publishers
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478 ph
(760) 408-9747 publication cell
(760) 608-1299 technical cell
www.experimentalhelo.com
www.vkss.com


"Maxwell" > wrote in message
...
>
> "Stuart & Kathryn Fields" > wrote in message
> ...
>> Is there anyone out there using fuel tanks filled with open cell foam?
>> I've heard that explosions are tamed as well as fuel slosh. I've also
>> heard that the foam must be replaced periodically. How often is the
>> replacement necessary? I'm using 100LL Av gas.
>>
>
> Perhaps a few metal baffels would be a better choice.
>

[Maxwell]

I wonder how the safety of the foam would compare to a bladder? It would
certainly complicate the slosh issue, but might provide greater safety in
case of an incident.

>I have a couple of baffles already, but having 28 gal 100LL just behind my
>head makes my nerves twitch just a bit. Having the foam is supposed to
>make explosive conflagration less likely in case of a prang.
>

[Drew Dalgleish]

Try searching for explosafe foam but do you think that a crash sever
enough to cause your fuel tank to explode would be survivable anyways.
Also fuel from a cracked tank can still catch fire with or without the
foan.

On Tue, 26 Jun 2007 11:06:02 -0700, "Stuart & Kathryn Fields"
> wrote:

>I have a couple of baffles already, but having 28 gal 100LL just behind my
>head makes my nerves twitch just a bit. Having the foam is supposed to make
>explosive conflagration less likely in case of a prang.
>
>Thanks
>
>--
>Stuart & Kathryn Fields, Publishers
>Experimental Helo magazine
>P. O. Box 1585
>Inyokern, CA 93527
>(760) 377-4478 ph
>(760) 408-9747 publication cell
>(760) 608-1299 technical cell
>www.experimentalhelo.com
>www.vkss.com


>"Maxwell" > wrote in message
...
>>
>> "Stuart & Kathryn Fields" > wrote in message
>> ...
>>> Is there anyone out there using fuel tanks filled with open cell foam?
>>> I've heard that explosions are tamed as well as fuel slosh. I've also
>>> heard that the foam must be replaced periodically. How often is the
>>> replacement necessary? I'm using 100LL Av gas.
>>>
>>
>> Perhaps a few metal baffels would be a better choice.
>>
>
>

[Ron Natalie]

Morgans wrote:
> "Ron Natalie" > wrote
>
> I'd make sure that I was getting the
>> max flow rate for takeoff if I were to use one in an aircraft.
>
> That should not be a problem, considering the run NASCAR engines with it,
> putting out 750+ HP, at constant wide open throttle, for lap after lap, at
> some tracks. Our biggest engines putting out around 300 HP would not drawn
> nearly as much.
>
It IS a problem. It's a problem for NASCAR, they just engineer around
it. As I said, make sure you are designing your fuel cell for the
max flow rate (typically takeoff) and not for the cruise power
settings.

[Morgans[_2_]]

"Ron Natalie" > wrote

> It IS a problem. It's a problem for NASCAR, they just engineer around it.
> As I said, make sure you are designing your fuel cell for the
> max flow rate (typically takeoff) and not for the cruise power
> settings.

What do you mean by they "engineer around it?"

The fuel cell, in the end, needs to supply the required fuel flow to make
the HP, right?

I am interested in what you have heard. I never heard about fuel cell flow
being a problem.
--
Jim in NC

[TeamFCAR]

Morgans wrote:
> "Ron Natalie" > wrote
>
>
>>It IS a problem. It's a problem for NASCAR, they just engineer around it.
>>As I said, make sure you are designing your fuel cell for the
>>max flow rate (typically takeoff) and not for the cruise power
>>settings.
>
>
> What do you mean by they "engineer around it?"
>
> The fuel cell, in the end, needs to supply the required fuel flow to make
> the HP, right?
>
> I am interested in what you have heard. I never heard about fuel cell flow
> being a problem.

For those not familiar with fuel tank foam and the typical racing
application. I have run a number of SCCA race cars over the years from
Formula Fords to Trans Am, and they all must have a Fuel Cell that is an
~0.06" thick Aluminum Box to protect the Bladder and filled with foam.

The foam is a very open structure where each interconnected "bubble" is
approximately 0.10" in diameter and thus is mostly air. Another poster
mentioned 3% which sounds about right for the density. It is not so
closed as to restrict the flow of fuel in the tank but in case of a
breach in the bladder it will reduce the spray.

In order to get the necessary fuel flow it is only necessary to get the
correct pick up and size of fuel line, really no different than a
"normal" aircraft. Back in the day, circa 1987, the 700+ Hp Trans Am
cars got 4 miles to the gallon on Dash 6 Aeroquip line so unless you
have an extremely high strung motor to feed the fuel cell should be able
to handle the flow.


Mike Butler
Crew Chief
Team Traditional Slate Racing
#10 Formula Atlantic

and student pilot...

[wrenchspinner]

As an alternative to foams you could look into Explosafe which is an
aluminum product. They were at OSH years ago.

http://www.explosafe.ch/