Matronics Email Lists Forum Index Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
 
 Get Email Distribution Too!Get Email Distribution Too!    FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

AW: Automatic header tank filling

 
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> AeroElectric-List
View previous topic :: View next topic  
Author Message
air.peter(at)googlemail.c
Guest





PostPosted: Wed May 31, 2017 4:29 am    Post subject: AW: Automatic header tank filling Reply with quote

Thanks Bob for the answer.

I agree with you that adding complexity/automatism adds possible failures to the ac. And yes, I am aware that it may fail and thinking about backups like my – already independent - low level warning light.

In addition I already installed an aviation approved switch with which I can select manually between automatic and manual filling.

Also there is a drain (standard for Lancair header tanks) in case you overfill – it just goes overboard.

Would you mind sharing the schematic you already invented ?

Thanks in advance,

Peter
LNC360 MK II
D-EPSO

Von: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] Im Auftrag von Robert L. Nuckolls, III
Gesendet: Dienstag, 30. Mai 2017 20:04
An: aeroelectric-list(at)matronics.com
Betreff: Re: Automatic header tank filling

Hi,

I am flying a Lancair 360 with wing tanks and the standard header tank. Rather thinking every 20 to 30 minutes to fill up the header tank again I would like to have an automatism filling the tank.

I've done a couple of similar systems. Last
one was for the Piaggio P-180.

I have a capacitive fuel gauge (output 0 to 5 V) and an independent emergency reminder looking up at the annunciator panel (at) about 5 gallons.

The analog output makes the 'control' easy to do.
The dragon to slay is failure mitigation.
Any time you add a automatic feature to the
airplane, it's wise to assume that it will
fail at some point.

What are the ways it can fail? How will you
become aware of the failure? Is the failure
pre-flight detectable? What are plans A, B, etc.
for dealing with the failure(s)?

You have a low level warning light . . . this should
be totally independent of any other function.
Suppose the transfer sticks ON and overfills the
tank. What happens if the tank is over filled;
what happens to excess fuel? Is there a practical
way to add a high level warning?

Rather re-inventing the wheel – is there a circuit diagram out there I can use for such a fuel filling mimic ?

You can watch the dc voltage from the
fuel gage with a comparator that will,
for example, turn the transfer ON at
3 volts or below and OFF at 4 volts or
above . . . or what ever hysteresis values
seem most practical.

The existing low level warning backs up
a failure to transfer, some kind of high
level warning should back of a failure to
stop transferring.


Bob . . .


- The Matronics AeroElectric-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List
Back to top
nuckolls.bob(at)aeroelect
Guest





PostPosted: Fri Jun 02, 2017 6:02 pm    Post subject: AW: Automatic header tank filling Reply with quote

Quote:

Also there is a drain (standard for Lancair header tanks) in case you overfill – it just goes overboard.

Would you mind sharing the schematic you already invented ?

Thanks in advance,

Peter

Actually, the systems I've already developed are not applicable
to your task . . . but it's not difficult to sketch out
a suitable alternative.

I've got a deck project in Wichita that is soaking
up some prime-time energies . . . but I'll get
it posted Sunday.


Bob . . .


- The Matronics AeroElectric-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List
Back to top
nuckolls.bob(at)aeroelect
Guest





PostPosted: Sun Jun 04, 2017 5:23 am    Post subject: AW: Automatic header tank filling Reply with quote

At 09:01 PM 6/2/2017, you wrote:
Quote:
Quote:

Also there is a drain (standard for Lancair header tanks) in case you overfill – it just goes overboard.

Would you mind sharing the schematic you already invented ?

Thanks in advance,

Peter


Here's a couple of approaches to a fuel
transfer controller applicable to your
project.

http://tinyurl.com/yc4754vw

The first page shows ship's wiring for
power, switch, relay, pump and over-fill
warning light.

The second page illustrates a micro-controller
based control module. Input signal voltage
from the fuel gate is watched. The pump and
warning light are activated based on numbers
stored in the uC memory at the time software
is loaded to the controller. This is the
lowest parts count approach and very compact.
All the electronics would fit into the backshell
of a 15-pin d-sub connector.

The third page illustrates an analog comparator
approach to the same task. Potentiometers allow
you to 'tune' the switch points for pump operation
and illumination of the warning light.

In both cases, the warning light can be left
out if deemed unnecessary. Page 3 lends itself
to a DIY approach. If fuel gage voltages are
known, the uC approach would also work as a DIY
project. We can supply the uC with the target
voltages in situ. Those values are easily altered
as experience dictates. Just order up another chip
with revised calibration. The 'bad' chip isn't even
worth returning . . . they're about 80 cents.




Bob . . .


- The Matronics AeroElectric-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List
Back to top
yellowduckduo(at)gmail.co
Guest





PostPosted: Sun Jun 04, 2017 8:19 am    Post subject: AW: Automatic header tank filling Reply with quote

That surprises me. Even in my high wing aircraft the header tank vents
back to a main tank in the wing
Ken

On 04/06/2017 9:21 AM, Robert L. Nuckolls, III wrote:
Quote:
At 09:01 PM 6/2/2017, you wrote:
>>
>> Also there is a drain (standard for Lancair header tanks) in case
>> you overfill – it just goes overboard.
>>
>> Would you mind sharing the schematic you already invented ?
>>
>> Thanks in advance,
>>
>> Peter
>

Here's a couple of approaches to a fuel
transfer controller applicable to your
project.

http://tinyurl.com/yc4754vw <http://tinyurl.com/yc4754vw>

The first page shows ship's wiring for
power, switch, relay, pump and over-fill
warning light.

The second page illustrates a micro-controller
based control module. Input signal voltage
from the fuel gate is watched. The pump and
warning light are activated based on numbers
stored in the uC memory at the time software
is loaded to the controller. This is the
lowest parts count approach and very compact.
All the electronics would fit into the backshell
of a 15-pin d-sub connector.

The third page illustrates an analog comparator
approach to the same task. Potentiometers allow
you to 'tune' the switch points for pump operation
and illumination of the warning light.

In both cases, the warning light can be left
out if deemed unnecessary. Page 3 lends itself
to a DIY approach. If fuel gage voltages are
known, the uC approach would also work as a DIY
project. We can supply the uC with the target
voltages in situ. Those values are easily altered
as experience dictates. Just order up another chip
with revised calibration. The 'bad' chip isn't even
worth returning . . . they're about 80 cents.

Bob . . .



- The Matronics AeroElectric-List Email Forum -
 

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List
Back to top
Display posts from previous:   
Post new topic   Reply to topic    Matronics Email Lists Forum Index -> AeroElectric-List All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group