fuel tank plumbing

My apologies to the group if this has been covered recently.

I bought a Smith Miniplane DSA-1 off eBay recently which has a 10gal aux
fuel tank in the upper wing center section which is not plumbed into the
fuel system yet. I would like some input from the RAH gallery as to how this
could be accomplished; all practical ideas would be most welcome, with
emphasis on simplicity. The fuel system in operation to feed the O-200
presently is a 12gal fuselage tank directly behind the firewall with about a
2gal header tank underneath.

Thanks,
Monty

On Tue, 25 Jan 2005 08:46:25 -0600, "pwm" wrote:

My apologies to the group if this has been covered recently.

I bought a Smith Miniplane DSA-1 off eBay recently which has a 10gal aux
fuel tank in the upper wing center section which is not plumbed into the
fuel system yet. I would like some input from the RAH gallery as to how this
could be accomplished; all practical ideas would be most welcome, with
emphasis on simplicity. The fuel system in operation to feed the O-200
presently is a 12gal fuselage tank directly behind the firewall with about a
2gal header tank underneath.

Thanks,
Monty


I'm not sure why you have a header tank unless it is for inverted
flight. On my Jungster the wing tank feeds into the fuel valve as does
the fuselage tank. I can then select either the wing or fuselage tank,
but not both otherwise the wing tank could overflow the fuselage tank.
I have both upright and inverted vents on the fuselage tank and
inverted tank. On the wing tank I just use a vented cap.

Ed Sullivan

On Tue, 25 Jan 2005 08:13:09 -0800, Ed Sullivan
wrote:

I'm not sure why you have a header tank unless it is for inverted
flight. On my Jungster the wing tank feeds into the fuel valve as does
the fuselage tank. I can then select either the wing or fuselage tank,
but not both otherwise the wing tank could overflow the fuselage tank.
I have both upright and inverted vents on the fuselage tank and
inverted tank. On the wing tank I just use a vented cap.

Ed Sullivan

Really? You can't just plumb the wing tanks into the header tank?
Thought that was done all the time. Is it necessary to vent the
header tank if the wing tanks are properly vented?

Thanks, Corky Scott

"Corky Scott" wrote in message
...
On Tue, 25 Jan 2005 08:13:09 -0800, Ed Sullivan
wrote:

I'm not sure why you have a header tank unless it is for inverted
flight. On my Jungster the wing tank feeds into the fuel valve as does
the fuselage tank. I can then select either the wing or fuselage tank,
but not both otherwise the wing tank could overflow the fuselage tank.
I have both upright and inverted vents on the fuselage tank and
inverted tank. On the wing tank I just use a vented cap.

Ed Sullivan

Really? You can't just plumb the wing tanks into the header tank?
Thought that was done all the time. Is it necessary to vent the
header tank if the wing tanks are properly vented?

Thanks, Corky Scott

Well, maybe, but wing tanks on a Taylorcraft are vented with ram-air tubes
on the caps and so is the header tank. In flight those tubes make positive
pressure on the 6-gallon wing tanks and the 12-gallon header tank.

I've seen a few times, too, that the wing tank gets balky emptying into the
header tank during flight, despite the ram-air tubes.

On Tue, 25 Jan 2005 13:14:41 -0500, " jls"
wrote:

Well, maybe, but wing tanks on a Taylorcraft are vented with ram-air tubes
on the caps and so is the header tank. In flight those tubes make positive
pressure on the 6-gallon wing tanks and the 12-gallon header tank.

I've seen a few times, too, that the wing tank gets balky emptying into the
header tank during flight, despite the ram-air tubes.

Well if the header tank is below the wing tanks, and the header tank
is vented, what's preventing the wing tanks from overfilling the
header tank as Ed Sullivan suggested?

Does the header tank vent have a checkvalve?

I was picturing the header tank being downstream of the wing tanks and
not being vented. In effect, the header tank is simply a distorted
downstream fuel line.

Thanks, Corky Scott

"Corky Scott" wrote in message
...
On Tue, 25 Jan 2005 13:14:41 -0500, " jls"
wrote:

Well, maybe, but wing tanks on a Taylorcraft are vented with ram-air
tubes
on the caps and so is the header tank. In flight those tubes make
positive
pressure on the 6-gallon wing tanks and the 12-gallon header tank.

I've seen a few times, too, that the wing tank gets balky emptying into
the
header tank during flight, despite the ram-air tubes.

Well if the header tank is below the wing tanks, and the header tank
is vented, what's preventing the wing tanks from overfilling the
header tank as Ed Sullivan suggested?

I never saw Ed's post, but I can tell you from my own experience that if you
haven't run at least six gallons out of the header tank before you open the
valve on a wing tank, you're going to get overflowing gas sprayed from the
vent tube all over the windshield.

Does the header tank vent have a checkvalve?

No. I've never heard of one. Taylorcrafts are made to fly, not to be
overly complicated.

I was picturing the header tank being downstream of the wing tanks and
not being vented. In effect, the header tank is simply a distorted
downstream fuel line.

That very well may work, Corky, but I think I'd want the header tank vented.

Thanks, Corky Scott


Thanks to you too.

This thread reminds me of the two guys flying a Taylorcraft cross-country
from East to West Tennessee. They stopped near Knoxville to refuel and had
the lineboy fill the wing tanks. As they flew along enjoying themselves,
counting cows in the green pastures below, the wire gauge dropped and they
decided to refill the header by dumping the contents of a wing tank. The
trusty copilot opened a valve and no gas. He opened another valve and no
gas. They began to look for a landing strip to put down, but the engine
quit they landed and nosed over in a muddy cow pasture. The lineboy had
screwed the lids on the wing tanks with the ram air tubes backwards. Low
pressure caused all the gas to be sucked out and emptied the tanks.

Corky Scott wrote:

On Tue, 25 Jan 2005 13:14:41 -0500, " jls"
wrote:

Well, maybe, but wing tanks on a Taylorcraft are vented with ram-air tubes
on the caps and so is the header tank. In flight those tubes make positive
pressure on the 6-gallon wing tanks and the 12-gallon header tank.

I've seen a few times, too, that the wing tank gets balky emptying into the
header tank during flight, despite the ram-air tubes.

Well if the header tank is below the wing tanks, and the header tank
is vented, what's preventing the wing tanks from overfilling the
header tank as Ed Sullivan suggested?

Does the header tank vent have a checkvalve?

I was picturing the header tank being downstream of the wing tanks and
not being vented. In effect, the header tank is simply a distorted
downstream fuel line.

Thanks, Corky Scott


The header tank could have a vent the sme height as the wing tanks,

it would fill completely, bleed to the open air,

I would perhaps vent the header tank to the wing tank/s, not open air,
at any level
--


Mark Smith
Tri-State Kite Sales
1121 N Locust St
Mt Vernon, IN 47620
1-812-838-6351

http://www.trikite.com

On the Champ, wing tanks drain directly into fuselage tank. There's a
valve for each wing tank. If you open that valve before the fuselage
tank has drained sufficiently, gas will spray out the filler cap vent
onto the windshield.

Corky Scott wrote:
On Tue, 25 Jan 2005 13:14:41 -0500, " jls"
wrote:


Well, maybe, but wing tanks on a Taylorcraft are vented with ram-air tubes
on the caps and so is the header tank. In flight those tubes make positive
pressure on the 6-gallon wing tanks and the 12-gallon header tank.

I've seen a few times, too, that the wing tank gets balky emptying into the
header tank during flight, despite the ram-air tubes.


Well if the header tank is below the wing tanks, and the header tank
is vented, what's preventing the wing tanks from overfilling the
header tank as Ed Sullivan suggested?

Does the header tank vent have a checkvalve?

I was picturing the header tank being downstream of the wing tanks and
not being vented. In effect, the header tank is simply a distorted
downstream fuel line.

Thanks, Corky Scott


--
John Kimmel


Naturally, these humorous remarks are all entirely my own opinion, based
solely
on rumor, supposition, innuendo and damned lies, and should be
interpreted in a
spirit of fun. My memory is faulty, also.

" jls" wrote in message
...

"Corky Scott" wrote in message
...
On Tue, 25 Jan 2005 08:13:09 -0800, Ed Sullivan
wrote:

I'm not sure why you have a header tank unless it is for inverted
flight. On my Jungster the wing tank feeds into the fuel valve as does
the fuselage tank. I can then select either the wing or fuselage tank,
but not both otherwise the wing tank could overflow the fuselage tank.
I have both upright and inverted vents on the fuselage tank and
inverted tank. On the wing tank I just use a vented cap.

Ed Sullivan

Really? You can't just plumb the wing tanks into the header tank?
Thought that was done all the time. Is it necessary to vent the
header tank if the wing tanks are properly vented?

Thanks, Corky Scott

Well, maybe, but wing tanks on a Taylorcraft are vented with ram-air tubes
on the caps and so is the header tank. In flight those tubes make
positive
pressure on the 6-gallon wing tanks and the 12-gallon header tank.

I've seen a few times, too, that the wing tank gets balky emptying into
the
header tank during flight, despite the ram-air tubes.


Let me elaborate on this rather uncomplicated fuel vent system on the
Taylorcraft. The 12-gallon header tank is fixed to 4130 fuselage tubes and
sits behind the firewall and in front of the panel. Its vent --which is
merely an acute angle cut facing forward in a vertical tube rising from the
filler cap on the boot cowl just forward of the windscreen -- is also the
hole through which the fuel gauge wire moves up and down according to the
quantity of fuel in the header tank.

Obviously the positive pressure supplied by this vent tube is slightly less
than the pressure provided by either of the ram-air tubes on the wing tank
caps. Otherwise, wing tank flow into the header tank might not occur. And
I've seen that happen with Taylorcrafts other than mine.

Some people install glorified ram air tubes on their wing tank caps. They
braze onto the caps longer tubes pointed into the slipstream and bellmouth
them. The apparent fix gives them a better pressure differential to push
wing tank fuel down into the already pressurized fuselage tank. Of course,
with the valves on the wing tanks closed, the fuselage tank must have some
way of its own to maintain positive pressure to feed gasoline through the
gascolator and into the carburetor bowl, especially in a climb where
sometimes gravity alone is not enough.

C. G. Taylor, also the designer of the Cub, must have been thinking about
those steep climbs in a Taylorcraft when he designed the ram-air tubes on
the wing tanks because they are bent more than 90 degrees downward so they
face directly into the slipstream during a steep climb.

On the subject of a small header tank in addition to a fuselage tank, that
sure does sound a little like Rube Goldberg to me. It must a device to cure
a history of fuel starvation, something I have never heard of in a simple
system like the Taylorcraft's. OTOH,maybe there's a good reason for it.

I have flown a Taylorcraft since the eighties and never had it give trouble
feeding from the wing tank to the fuselage tank, with one or two exceptions.
And never ever had a fuel starvation problem. Here are the exceptions:
You know those socks you put over a 172's pitot tube to keep bugs out while
you're sitting on the ramp? Well, those bugs, angry at the socks on 172's,
will seek out and set up housekeeping in your ram-air tubes. So you just
take a length of .016 safety wire and punch the little *******s out. When
you get one in your 172's pitot because like me you were too slack to put on
the sock, the cure is not so easy.

On Wed, 26 Jan 2005 09:38:14 -0500, " jls"
wrote:

C. G. Taylor, also the designer of the Cub, must have been thinking about
those steep climbs in a Taylorcraft when he designed the ram-air tubes on
the wing tanks because they are bent more than 90 degrees downward so they
face directly into the slipstream during a steep climb.

There is another possible reason for angling the ram tubes slightly
downward: it prevents rain drops from entering the vent system while
in flight, and sitting on the ground.

Corky Scott