How does fuel (safely) get from the tank to the engine?

[Oliver Arend]

It would seem logical to just draw gas from the lowest point of the
tank into a fuel line leading to the engine. But contrary to a car, an
airplane can experience negative gs, and especially in aerobatics, for
prolonged periods of time. So a pump connected to the lowest point of
the tank would only draw fumes at some point. How is this problem
solved?

Thanks (again) for enlightening me,
Oliver

[Bob Kuykendall]

On Nov 25, 9:23*am, Oliver Arend > wrote:
> an airplane can experience negative gs...

During which times the engines of most airplanes just sputter.
Aerobatic airplanes usually have at least one tank with the fuel
pickup on a flexible hose that follows the fuel. That's usually called
a "flop tube."

Thanks, Bob K.

[Maxwell[_2_]]

"Bob Kuykendall" > wrote in message
...
On Nov 25, 9:23 am, Oliver Arend > wrote:
> an airplane can experience negative gs...

>During which times the engines of most airplanes just sputter.
>Aerobatic airplanes usually have at least one tank with the fuel
>pickup on a flexible hose that follows the fuel. That's usually called
>a "flop tube."

>Thanks, Bob K.

Do any of the experimental aircraft designs use just a simple hose with a
weight that follows the fuel. It's very successful in modeling. You just
stick a weighted fitting on the end of the hose called a "clunk".

[Bob Kuykendall]

On Nov 25, 2:53*pm, "Maxwell" <#$$9#@%%%.^^^> wrote:

> Do any of the experimental aircraft designs use just a simple hose with a
> weight that follows the fuel...

Yes. It's called a "flop tube."

Thanks, Bob K.

[Ed]

On Tue, 25 Nov 2008 15:11:12 -0800 (PST), Bob Kuykendall
> wrote:

>On Nov 25, 2:53*pm, "Maxwell" <#$$9#@%%%.^^^> wrote:
>
>> Do any of the experimental aircraft designs use just a simple hose with a
>> weight that follows the fuel...
>
>Yes. It's called a "flop tube."
>
>Thanks, Bob K.

They are getting a little pricey lately, around $55 at Aircraft Spruce

[Maxwell[_2_]]

>"Bob Kuykendall" > wrote in message
...
>On Nov 25, 2:53 pm, "Maxwell" <#$$9#@%%%.^^^> wrote:

>> Do any of the experimental aircraft designs use just a simple hose with a
>> weight that follows the fuel...

>Yes. It's called a "flop tube."

>Thanks, Bob K.

Duh? I misread your post.

Although you described it as a hose, when you called it a flop "tube", I
pictured a mechanical tube or arm.

[[email protected]]

On Tue, 25 Nov 2008 20:24:38 -0600, "Maxwell" <#$$9#@%%%.^^^> wrote:

>
>>"Bob Kuykendall" > wrote in message
...
>>On Nov 25, 2:53 pm, "Maxwell" <#$$9#@%%%.^^^> wrote:
>
>>> Do any of the experimental aircraft designs use just a simple hose with a
>>> weight that follows the fuel...
>
>>Yes. It's called a "flop tube."
>
>>Thanks, Bob K.
>
>Duh? I misread your post.
>
>Although you described it as a hose, when you called it a flop "tube", I
>pictured a mechanical tube or arm.
>
>
>
>
In aircraft use, generally it IS a tube, not a hose.

[[email protected]]

On Nov 25, 8:22 pm, wrote:
> On Tue, 25 Nov 2008 20:24:38 -0600, "Maxwell" <#$$9#@%%%.^^^> wrote:
>
> >>"Bob Kuykendall" > wrote in message
> >>news:e86e607e-2544-4029-814c->4d581e42e__BEGIN_MASK_n#9g02mG7!__...__END_MASK_i? ...
> >>On Nov 25, 2:53 pm, "Maxwell" <#$$9#@%%%.^^^> wrote:
>
> >>> Do any of the experimental aircraft designs use just a simple hose with a
> >>> weight that follows the fuel...
>
> >>Yes. It's called a "flop tube."
>
> >>Thanks, Bob K.
>
> >Duh? I misread your post.
>
> >Although you described it as a hose, when you called it a flop "tube", I
> >pictured a mechanical tube or arm.
>
> In aircraft use, generally it IS a tube, not a hose.

One also needs to perform similar magic with the oil system if
inversion longer than a few seconds is contemplated.

Actually, its surprising how long the engine will keep running after
forgetting to switch to the acro tank. I've made halfway into an
acro routine before being surprised by the sudden silence. ;-)

K l e i n