2-Batteries

Jim,

Of what you quoted (below) only the sentence 'Noone
picking up on Dick Johnson's last paragraph??' was
written by me. I was trying to attract attention to
Dick Johnson's hint that he had tested the Sinha deturbulators
- the progress of which I have followed with great
interest on your website.

John Galloway



At 23:02 31 December 2006, wrote:
John,

You use what you have.

Jim Hendrix
(The Johnson deturbulator flight tests were sponsored
by Dallas Glider
Association.)

On Dec 26, 11:01 am, wrote:
John Galloway wrote:
Noone picking up on Dick Johnson's last paragraph??

http://sinhatech.com/SinhaFCSD-Progress-12132006.asp

John GallowayThe results are interesting, but way
do the testing on a Std. Cirrus?
To be taken seriously put them on a modern ship and
test them. I
can't believe Dick did the testing on the Std. Cirrus
and did not at
least put them on his Ventus for some additional comparisons.

Jim,

Of what you quoted (below) only the sentence 'Noone
picking up on Dick Johnson's last paragraph??' was
written by me. I was trying to attract attention to
Dick Johnson's hint that he had tested the Sinha deturbulators
- the progress of which I have followed with great
interest on your website.

John Galloway



At 23:02 31 December 2006, wrote:
John,

You use what you have.

Jim Hendrix
(The Johnson deturbulator flight tests were sponsored
by Dallas Glider
Association.)

On Dec 26, 11:01 am, wrote:
John Galloway wrote:
Noone picking up on Dick Johnson's last paragraph??

http://sinhatech.com/SinhaFCSD-Progress-12132006.asp

John GallowayThe results are interesting, but way
do the testing on a Std. Cirrus?
To be taken seriously put them on a modern ship and
test them. I
can't believe Dick did the testing on the Std. Cirrus
and did not at
least put them on his Ventus for some additional comparisons.

John Galloway wrote:

I was trying to attract attention to
Dick Johnson's hint that he had tested the Sinha deturbulators
- the progress of which I have followed with great
interest on your website.

I have been intrigued by reports here which suggest that Dick Johnson
can take a glider which has been extensively developed and tested by
manufacturers (and, in some cases, Akafliegs or Idaflieg), shift the
turbulators by a couple of inches and report huge performance
increases.

Are his results reproduceable? Have they been independently verified?

Ian

I wish it were so. While most loggers can handle a momentary power
loss, not all can. I spoke at the last convention on this and related
avionics wiring issues. I contacted each manufacturer and as of Feb,
2006, I compiled the information below. I need to add the EW
MicroRecorder. I will be speaking on Saturday at the Memphis
convention if you are interested in more details.

2:00PM 3:00PM John DeRosa
Understanding Soaring Recorders and Computers
Convention Center Ballroom C

3:15PM 4:15PM John DeRosa
Aviation Electrical And Electronic Wiring Basics
Convention Center Ballroom C

- John DeRosa "67R"
======================
Cambridge
During a power Interruption, will IGC file be maintained?: Yes
How long of a power interruption can be survived?: 2 hours with aux
battery, otherwise no response
Start new log file?: 5 mins before starting new log file
Require secondary power source?: CAA-117 auxillary battery
Other information maintained?: Yes
Minimum operational voltage?: 8vdc is guaranteed but 6vdc is possible

Garrecht Volkslogger
During a power Interruption, will IGC file be maintained?: No, new file
How long of a power interruption can be survived?: 0.1 sec
Start new log file?: Yes
Require secondary power source?: Yes
Other information maintained?: Yes
Minimum operational voltage?: 7vdc

LX Navigation
During a power Interruption, will IGC file be maintained?: Yes
How long of a power interruption can be survived?: Approximately 1 min
Start new log file?: 1 min before starting new log file.
Require secondary power source?: No
Other information maintained?: Yes
Minimum operational voltage?: 8vdc

New Techologies
During a power Interruption, will IGC file be maintained?: Yes
How long of a power interruption can be survived?: few seconds
Start new log file?: 5 mins before starting new log file
Require secondary power source?: No
Other information maintained?: Yes
Minimum operational voltage?: 8.9vdc

Borgelt
During a power Interruption, will IGC file be maintained?: Yes
How long of a power interruption can be survived?: hours to weeks
Start new log file?: no response
Require secondary power source?: Internal "super" capacitor
Other information maintained?: Yes
Minimum operational voltage?: 10.0vdc




Eric Greenwell wrote:

I thought all loggers just started again after a momentary power loss,
and continued the same flight file. It sounds like yours isn't behaving
properly, or are some brands a bit touchy?

I use a Cambridge Model 25 GPS. Can either Tim or John supply power
interruption data for this "legacy" model data logger? Thanks!

-John

Tim Newport-Peace wrote:
ContestID67 writes
Cambridge
During a power Interruption, will IGC file be maintained?: Yes
How long of a power interruption can be survived?: 2 hours with aux
battery, otherwise no response
Start new log file?: 5 mins before starting new log file
Require secondary power source?: CAA-117 auxillary battery
Other information maintained?: Yes
Minimum operational voltage?: 8vdc is guaranteed but 6vdc is possible

John, that is specific to the 302. The answers are somewhat different
for the legacy models.

On Jan 1, 5:28 pm, "ContestID67" wrote:
Garrecht Volkslogger
During a power Interruption, will IGC file be maintained?: No, new file
How long of a power interruption can be survived?: 0.1 sec
Start new log file?: Yes
Require secondary power source?: Yes
Other information maintained?: Yes
Minimum operational voltage?: 7vdc

I have heard stories that the Volkslogger will also create a new
declaration on power up. That is, it sets the timestamp of the
declaration that is currently stored to be the time of power on. Any
idea this happens? Though, since one is already splicing together two
logs, the declaration of the previous log should be good enough.

The CAI 302, on the other hand, will not update the declaration (with
the timestamp of when it was made) until it starts a new log. This is
after about 5 minutes of "inactivity". I sent a concern to CAI a while
ago about this, as there could be a situation where a pilot will decide
to make a new declaration during a quick relight. If no OO is
available to do a paper declaration, then only the electronic one can
be used - and it's possible it won't take. (Consider a self-launcher
at an unattended airport).

....No matter how had one thinks during the design, the application will
always be different...
-Tom

T o d d P a t t i s t wrote in
:

Marc Ramsey wrote:

The 302 has an internal capacitor across the power supply lines, the
Volkslogger does not. Volkslogger owners can solve this problem by
adding an external capacitor, as is suggested in the manual...

IIRC, the Volkslogger recommended capacitor size was 22,000
microfarads. That's a fairly large cap (physically and
electrically), and it holds the VL on for only a second or
so. It's enough to switch batteries, but don't delay. It
also can cause problems on initial power-on when it first
charges up if your fuse is not large enough. The inrush
current is pretty high.

The inrush current issue can probably be solved by a circuit thus:


-------batteries---------------------------------logger---
| -ve and +ve | |
| switches | |
| and fuse ------------- |
| | | |
| ---- _ |
| /\ | | |
| Diode / \ | | Resistor |
| ---- |_| R |
| | | |
| ------------- |
| | |
| Capacitor --- +ve |
| 22mF --- -ve |
| | |
----------------------------------------------------------


When the switch is first closed the voltage across the capacitor
is zero and the diode is reverse biassed. Hence there is negligible
current through the diode and current flow into the capacitor
is limited to a peak of V/R amps.

After the capacitor is fully charged and the switch is opened,
current will flow through the forward biassed diode into the
logger with a voltage drop of ~0.6V (silicon diode) or ~0.3V
(schottkydiode).

Choose a diode with:
- reverse voltage greater than the battery voltage
- forward current greater than the peak logger current

Choose the resistor to limit the inrush peak current flow.

Tom Gardner wrote:
Choose a diode....

It's hard to read your schematic but it looks as though there is
nothing stopping the capacitor trying to power everything connected to
the same bus. Don't you need another blocking diode so the cap only
feeds the logger?

Andy

Andy wrote:
Tom Gardner wrote:
Choose a diode....

It's hard to read your schematic

Sorry about the ASCII schematic; it looks less bad when used with a
fixed-width font.

but it looks as though there is
nothing stopping the capacitor trying to power everything connected to
the same bus.

That's correct. The schematic is sufficient only to show how how to
limit the inrush current.

Don't you need another blocking diode so the cap only
feeds the logger?

If that's the case then another (forward biased) diode would be
required between the battery +ve and the rest of the circuit in my
schematic.

test
"Ian" wrote in message
news
On Tue, 26 Dec 2006 01:39:44 +0000, Steve Paavola wrote:

Gary Emerson wrote:

wrote:
Better yet is to use diodes so that both batteries will always be "on"
in parallel and you're always pulling from the best battery with no
fiddling required from the pilot. Relatively low voltage drop diodes
are available with 18 Amp forward capacity.

If both batteries are on-line all the time, how do you know when one is
getting weak and needs to be replaced? Or do you replace both batteries
when voltage is marginal at the end of a flight?

I used two small diodes to provide a "fail safe" supply to the
Volkslogger, but the radio, vario, transponder etc get theirs via a 2 way
toggle switch.

Then when one battery dies in flight, I will notice and switch to the next
one manually. But in the meantime the logger always draws current from the
highest voltage battery and hence no interruption to the trace.

The diodes are equivalents of IN 5817 "Shottky rectifying diodes". They
are cheap and tiny. At the low currents drawn by the logger, the forward
voltage drop is very small (less than 0.2V). No cooling is required. I
soldered them directly in line with the wires from the fuse holder to the
toggle switch, without a circuit board.

I test the voltage on each battery during my pre-flight by setting the
Volkslogger on its battery voltage function and disconnecting the
batteries one at a time. (If the electric vario had a battery voltage
function, I could switch it between the batteries and measure their
voltage in flight.)

The weak link in this setup is the toggle switch which has to be sized to
handle a significant DC current.

(The u/c warning buzzer is now also running off a 2 diode "fail safe"
supply - but there is another story behind that ...).


Regards


Ian