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Old Feb 08, 2003, 08:52 PM
Chris Roberts
Guest
n/a Posts
Re: Header Tank - what does it do?

Hi,

I'm a newbie too, so I may not be 100% right here, but I think the idea is
that the smaller header tank is always kept full by the pressurised fuel
system (until you're really low on fuel). This helps because when the
helicopter is upside-down or in any odd orientation, the clunk in the tank
will always be able to pick up fuel.

Hope this helps (and I hope I'm right!!)
- Chris

"Alan Spott" <alanspott@insightbb.com> wrote in message
news:W_h1a.38220$iG3.4944@sccrnsc02...
> Ok, I'm not afraid to ask a newbie question. Could someone briefly

explain
> the purpose of a header tank? Exactly what benefit does it bring?
>
> Thanks
>
>



Old Feb 08, 2003, 11:32 PM
Chuck W
Guest
n/a Posts
Re: Header Tank - what does it do?

"Alan Spott" <alanspott@insightbb.com> wrote in message
news:W_h1a.38220$iG3.4944@sccrnsc02...
> Ok, I'm not afraid to ask a newbie question. Could someone briefly

explain
> the purpose of a header tank? Exactly what benefit does it bring?
>
> Thanks
>
>


This is RC car knowledge, so it may be a bit off, but here goes:

The header tank on a nitro car is there because your feul pressure system
has a natural delay time from when you gun the throttle to when it actually
increases fuel pressure (and flow) to your carburator. If you gun it quick
enough, that can kill the engine, or at least cause a lag and attempt to
die. In an RC heli, this would cause a loss of power to the head,
presumably when you wanted it the most. The header can give you a
momentary supply of fast fuel to the engine during that lag period while
your exhaust system catches up.

-Chuck W


Old Feb 09, 2003, 04:02 AM
Tim van Halteren
Guest
n/a Posts
Re: Header Tank - what does it do?

> This is RC car knowledge, so it may be a bit off, but here goes:
>
> The header tank on a nitro car is there because your feul pressure system
> has a natural delay time from when you gun the throttle to when it

actually
> increases fuel pressure (and flow) to your carburator. If you gun it

quick
> enough, that can kill the engine, or at least cause a lag and attempt to
> die. In an RC heli, this would cause a loss of power to the head,
> presumably when you wanted it the most. The header can give you a
> momentary supply of fast fuel to the engine during that lag period while
> your exhaust system catches up.


I don't see how the header tank would solve the problem you describe while
the pressure in the header tank is the same as the pressure in the main
tank.

Tim


Old Feb 09, 2003, 08:22 AM
Courseyauto
Guest
n/a Posts
Re: Header Tank - what does it do?

I don't see how the header tank would solve the problem you describe while
the pressure in the header tank is the same as the pressure in the main
tank.
>>>


No it's not the same, the pressure in the header tank is constant and the
pressure in the main changes, this why you get a constant needle valve setting
while the engine runs on the header tank. without a header tank the needle
setting will change as the fuel level drops, unless you have a pump and
regulator, or a YS engine.
Old Feb 09, 2003, 10:32 AM
Tim van Halteren
Guest
n/a Posts
Re: Header Tank - what does it do?

> I don't see how the header tank would solve the problem you describe while
> the pressure in the header tank is the same as the pressure in the main
> tank.
> >>>

>
> No it's not the same, the pressure in the header tank is constant and the
> pressure in the main changes, this why you get a constant needle valve

setting
> while the engine runs on the header tank. without a header tank the

needle
> setting will change as the fuel level drops, unless you have a pump and
> regulator, or a YS engine.


Some people still think this is how it works. I don't believe the header
tank keeps the pressure to your carb constant. It isn't possible.
If what you say is true and the pressure in the header tank remains constant
and the pressure in the main tank drops then there would be a growing
difference in pressure between them. This would cause fuel to move from the
higher pressure to the lower pressure thus it would go out of your header
tank and into the main tank. While we can all watch that this isn't the case
you statement can't be correct.

I don't argue the usefulness of header tanks but the one thing that it
doesn't do is to keep the pressure constant.

Tim



Old Feb 09, 2003, 12:22 PM
Martin Round
Guest
n/a Posts
Re: Header Tank - what does it do?

"Alan Spott" <alanspott@insightbb.com> wrote in message
news:W_h1a.38220$iG3.4944@sccrnsc02...
> Ok, I'm not afraid to ask a newbie question. Could someone briefly

explain
> the purpose of a header tank? Exactly what benefit does it bring?
>
> Thanks



Three things:

1. Catches bubbles during aerobatics.
2. Increases fuel capacity.
3. Makes it easier to see when you are low on fuel.

The last one is especially significant on helis where the main tank is
mounted inside the canopy (e.g. X-Cell ST and SE)

There are drawbacks too:

1. Heavier.
2. More plumbing to go wrong.

Martin.


Old Feb 09, 2003, 12:52 PM
Biggie in PA
Guest
n/a Posts
Re: Header Tank - what does it do?

Who said anything about a car?

--
Biggie in PA
sjg1958 at hotmail dot com
"Chuck W" <cwiley101@comcast.spamdeath.net> wrote in message
news:Q3-dnU6TS944StijXTWcqg@comcast.com...
>
> "Alan Spott" <alanspott@insightbb.com> wrote in message
> news:W_h1a.38220$iG3.4944@sccrnsc02...
> > Ok, I'm not afraid to ask a newbie question. Could someone briefly

> explain
> > the purpose of a header tank? Exactly what benefit does it bring?
> >
> > Thanks
> >
> >

>
> This is RC car knowledge, so it may be a bit off, but here goes:
>
> The header tank on a nitro car is there because your feul pressure system
> has a natural delay time from when you gun the throttle to when it

actually
> increases fuel pressure (and flow) to your carburator. If you gun it

quick
> enough, that can kill the engine, or at least cause a lag and attempt to
> die. In an RC heli, this would cause a loss of power to the head,
> presumably when you wanted it the most. The header can give you a
> momentary supply of fast fuel to the engine during that lag period while
> your exhaust system catches up.
>
> -Chuck W
>
>



Old Feb 09, 2003, 12:52 PM
Biggie in PA
Guest
n/a Posts
Re: Header Tank - what does it do?

The header tank should be void of air bubbles. This "buffer tank" keeps the
engine from sucking in air that may occur :
1) if the heli vibrates and the engine foams.
2) when performing 3D maneuvers
--
Biggie in PA
sjg1958 at hotmail dot com
"Alan Spott" <alanspott@insightbb.com> wrote in message
news:W_h1a.38220$iG3.4944@sccrnsc02...
> Ok, I'm not afraid to ask a newbie question. Could someone briefly

explain
> the purpose of a header tank? Exactly what benefit does it bring?
>
> Thanks
>
>



Old Feb 09, 2003, 01:52 PM
Chuck W
Guest
n/a Posts
Re: Header Tank - what does it do?

"Tim van Halteren" <t_dot_van_dot_halteren@inter.nl.net> wrote in message
news:3e461546$0$19800$19deed1b@news.inter.NL.net.. .
> > This is RC car knowledge, so it may be a bit off, but here goes:
> >
> > The header tank on a nitro car is there because your feul pressure

system
> > has a natural delay time from when you gun the throttle to when it

> actually
> > increases fuel pressure (and flow) to your carburator. If you gun it

> quick
> > enough, that can kill the engine, or at least cause a lag and attempt to
> > die. In an RC heli, this would cause a loss of power to the head,
> > presumably when you wanted it the most. The header can give you a
> > momentary supply of fast fuel to the engine during that lag period while
> > your exhaust system catches up.

>
> I don't see how the header tank would solve the problem you describe while
> the pressure in the header tank is the same as the pressure in the main
> tank.
>
> Tim
>
>


My fault. What I'm talking about is a booster tank, or boost bottle. It's
not part of the actual tank. Different animal.

-Chuck W


Old Feb 09, 2003, 07:42 PM
Phil Noel
Guest
n/a Posts
Re: Header Tank - what does it do?

Hi Tim,

You are absolutely correct. The header tank DOES ABSOLUTELY NOTHING to "keep
the pressure constant". As this has been a "wives tail" believed by many
years ago, it finally seems to have been put to bed. I have explained the
physics of this many times here and in other forums, and have conducted
experiments, at many symposiums/seminars over the years, that clearly
illustrate the fact that it does diddly squat to keep the pressure constant,
I will not go into detail again.

I thought that the world has finally accepted the fact that it does nothing
for constant pressure. As decoursey's post illustrates, it seems there are
still a few that believe it does.

As the others have pointed out, it is a "air-bubble" trap in the fuel line,
it gives a bit more fuel capacity, and it can be poitioned in a location to
indicate fuel capacity (as a small reserve tank) in systems where the
maintank is not in plain vue.

Those are its' only benifits.

Phil


"Tim van Halteren" <t_dot_van_dot_halteren@inter.nl.net> wrote in message
news:3e4670b3$0$19805$19deed1b@news.inter.NL.net.. .
> > I don't see how the header tank would solve the problem you describe

while
> > the pressure in the header tank is the same as the pressure in the main
> > tank.
> > >>>

> >
> > No it's not the same, the pressure in the header tank is constant and

the
> > pressure in the main changes, this why you get a constant needle valve

> setting
> > while the engine runs on the header tank. without a header tank the

> needle
> > setting will change as the fuel level drops, unless you have a pump and
> > regulator, or a YS engine.

>
> Some people still think this is how it works. I don't believe the header
> tank keeps the pressure to your carb constant. It isn't possible.
> If what you say is true and the pressure in the header tank remains

constant
> and the pressure in the main tank drops then there would be a growing
> difference in pressure between them. This would cause fuel to move from

the
> higher pressure to the lower pressure thus it would go out of your header
> tank and into the main tank. While we can all watch that this isn't the

case
> you statement can't be correct.
>
> I don't argue the usefulness of header tanks but the one thing that it
> doesn't do is to keep the pressure constant.
>
> Tim
>
>
>



Old Feb 09, 2003, 09:52 PM
x-guy
Guest
n/a Posts
Re: Header Tank - what does it do?

Yes you are 100% correct


"Chris Roberts" <chris@bms-systems-ltd.co.uk> glsD
:b24bgn$53i$1@news6.svr.pol.co.uk...
> Hi,
>
> I'm a newbie too, so I may not be 100% right here, but I think the idea is
> that the smaller header tank is always kept full by the pressurised fuel
> system (until you're really low on fuel). This helps because when the
> helicopter is upside-down or in any odd orientation, the clunk in the tank
> will always be able to pick up fuel.
>
> Hope this helps (and I hope I'm right!!)
> - Chris
>
> "Alan Spott" <alanspott@insightbb.com> wrote in message
> news:W_h1a.38220$iG3.4944@sccrnsc02...
> > Ok, I'm not afraid to ask a newbie question. Could someone briefly

> explain
> > the purpose of a header tank? Exactly what benefit does it bring?
> >
> > Thanks
> >
> >

>
>



Old Feb 10, 2003, 08:02 AM
David Lodge
Guest
n/a Posts
Re: Header Tank - what does it do?

A header tank is just like a length of v large bore tubing. It does
two things:
- acts as a bubble trap so you get pure fuel going to the engine
- gives you a couple more minutes run time at the end.

It doesn't affect the fuel pressure to the engine, untill the main
tank is empty, then the header tank becomes the main tank.

David.

"Alan Spott" <alanspott@insightbb.com> wrote in message news:<W_h1a.38220$iG3.4944@sccrnsc02>...
> Ok, I'm not afraid to ask a newbie question. Could someone briefly explain
> the purpose of a header tank? Exactly what benefit does it bring?
>
> Thanks

Old Feb 10, 2003, 10:02 AM
Philip Martin
Guest
n/a Posts
Re: Header Tank - what does it do?

"David Lodge" <david@cherrybank.co.uk> wrote in message
news:6e6cfcb.0302100450.49304007@posting.google.co m...
> A header tank is just like a length of v large bore tubing. It does
> two things:
> - acts as a bubble trap so you get pure fuel going to the engine
> - gives you a couple more minutes run time at the end.
>
> It doesn't affect the fuel pressure to the engine, untill the main
> tank is empty, then the header tank becomes the main tank.
>

Hmmm, let me chuck yon spanner in the works then!

Conventionally the fuel tank seems to be mounted below the level of the
engine / carb. Thus when in normal flight the only pressure on the carb is
that of the exhaust take off pushing the fuel through to the carb (unless of
course we are talking Perry pump or YS engine). However when the heli goes
into inverted flight you have the above pressure plus the weight of the fuel
in the tank = more fuel flow to the carb.

Now if a header tank is fitted with its outlet on centre line with the carb,
the pressure on the carb will be slightly increased (because of the head of
fuel), no matter which way up the heli is.

?;o)

Phil Martin.



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.449 / Virus Database: 251 - Release Date: 27/01/2003


Old Feb 10, 2003, 12:52 PM
Courseyauto
Guest
n/a Posts
Re: Header Tank - what does it do?

<<
A header tank is just like a length of v large bore tubing. It does
two things:
- acts as a bubble trap so you get pure fuel going to the engine
- gives you a couple more minutes run time at the end.
>>


Wouldn't it be more correct to call it a fuel trap, as the idea is to keep it
full of fuel.
I also get a more consistant run with my header tank set up than i did
without it,for what ever reason. DOUG
Old Feb 10, 2003, 01:42 PM
Dan G.
Guest
n/a Posts
Re: Header Tank - what does it do?

"Courseyauto" <courseyauto@aol.com> wrote in message
news:20030210123934.07728.00000485@mb-mg.aol.com...
> <<
> A header tank is just like a length of v large bore tubing. It does
> two things:
> - acts as a bubble trap so you get pure fuel going to the engine
> - gives you a couple more minutes run time at the end.
> >>

>
> Wouldn't it be more correct to call it a fuel trap, as the idea is to

keep it
> full of fuel.
> I also get a more consistant run with my header tank set up than i did
> without it,for what ever reason. DOUG


Maybe since no more tiny air bubbles get to your engine near low tank?


 


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