CASA register search and pick glider option. Lots of oldies I know of though
who did not comply with 9/11 fallout panic and have fallen off the register.
From: Ron Sanders
Sent: Thursday, February 28, 2013 3:50 PM
To: Discussion of issues relating to Soaring in Australia.
Subject: [Aus-soaring] glider register
can anyonwe tell me how to find the totl australian glider register?
ron
On 27 February 2013 20:55, tom claffey <[email protected]> wrote:
Aircon? - I want one! :)
------------------------------------------------------------------------------
From: Mike Borgelt <[email protected]>;
To: Discussion of issues relating to Soaring in Australia.
<[email protected]>;
Subject: Re: [Aus-soaring] LiFePo4 ~ Why not move to 24 volt systems?
Sent: Thu, Feb 28, 2013 12:44:04 AM
You usually move to higher voltage to transmit greater power at the
same or lower current which reduces wiring weight. I suspect in light aircraft
the power requirement for the electrics is driven by systems other than the
avionics i.e electrically driven hydraulic pumps or simply electrically driven
flaps, landing gear retract etc.
There is consideration of going to 42 volts for cars for this reason.
B50s work down to 10 volts, B300/B500/600/800 a little less. B400 and
B700 down to 4 volts.(internal boost regulator cuts in). A 12 v nominal SLA
battery is about to die at 11V terminal voltage when discharged at typical
glider rates. If you are losing more than 0.2 volts or so between the battery
and the instrument you need to fix the wiring, fuses switches etc.
There doesn't seem to be any overwhelming reason to go to 24 volts in
gliders. I'll bet most "24 or 28 volt" avionics has a switch mode regulator to
get 14 volts before going to the rest of the gadget or simply to the 5 volts or
so required by the logic circuits.
If we go to electric flaps and aircon like the Duckhawk this may
change. I think it has something like a 54 A-H battery.
Mike
At 08:13 AM 28/02/2013, you wrote:
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_0056_01CE1593.E2557430"
Content-Language: en-us
My contribution to the battery aspect of this thread is to question
why we are so infatuated by 12 volts? [I once wrote Standards, and Standards
often impede innovation]
I also agree that the electrical systems must be designed and
implemented taking into consideration volts, amps, temperature high and low,
wiring, insulation, noxious gases, fusing, short circuit and thermal runaway, G
load, weight and many other factors
At Oshkosh 2006 the Blue Mountains Avionics presentation said for
light aircraft the move to 24 volt systems was a no brainer, just so logical.
Most instrumentation and radio’s require 10 volts and a 12 volt system decays
to 10 volt reasonably fast. Microair’s need probably 10.5 before the
transmitter goes garbled, Cambridge falls over at about 8 volts. Mike could
perhaps comment on the minimums for Borgelt instruments. PDA’s and XCSoar have
a USB 5 volt input so may work longer on a 12 volt system? Some avionics are
designed for 35 volt DC maximum input [but XCOM and Microair apparently have 16
~ 17 volt maximum input specification]
But starting with 24 volts gets much more out of the battery before
avionics fail. Even moving to say 16 volt to keep within radio specification
could lead to increased useful battery life.
Cranking amps for starter motors is at the high drain end of the
drain spectrum but arguably is early in a batteries discharge cycle in the
glider application.
So why not have 16 ~ 24 volt systems in gliders?
Alan Wilson
[ARMIT Comm Eng]
Canberra
From: [email protected] [
mailto:[email protected]] On Behalf Of
[email protected]
Sent: Wednesday, 27 February, 2013 8:58 PM
To: Discussion of issues relating to Soaring in Australia.
Subject: Re: [Aus-soaring] LiFePo4
Nice one Arie.
You do bring a bit of costing perspective into the argument here.
The YouTube footage is interesting (horrific?), but I suspect
basically irrelevant.
I think that any glider pilot who knows anything about the problem,
does not want to experience an inflight cockpit fire UNDER ANY CIRCUMSTANCES. I
know of one example, where the pilot was VERY happy to have survived the
experience - without having to bail out. He reported that fire - as in burning
- was NOT the problem. He reported that the amount of fumes and smoke generated
in an incredibly short time from the ignition of the plastic wire covering due
to shorting of the electrical system was in fact the primary problem. For this
unfortunate pilot, there were really two problems: first he had to be able to
breathe, and secondly he had to be able to see what you are doing - basically
impossible in a cockpit filled with smoke!
Re your statement "willing to replace a couple of batteries each year
...." Probably a slip of the pen: As Bernard has pointed out a high quality SLA
gel cell type battery MAY last up to 9 or 10 years, but this is hardly likely
to be the norm. Five - seven years seems to be much more realistic estimate. As
far as I can tell, the life of the LiFePo4 batteries is not claimed to be any
better than this latter figure.
At this point in time, LiFePo4 batteries are MUCH more expensive.
However I expect that in a few years time the price will have fallen, and many
glider pilots will be using these "new fangled" devices,.
I suspect that I will need to replace my current glider batteries in
the near future. I do not have a max AUW of the non-loading bearing parts
problem - one valid argument for lighter batteries - and my power consumption
figures - high power consumption requirements are another valid argument for
using LoFePo4 - are relatively modest, so I have no intention of using LifePo4
batteries for the replacement.
What this whole discussion has crystallised for me is the
requirement, regardless of the type of battery selected, is to always use a
high quality battery manufactured by a reputable factory who stands behind
their product. [I have in the past tried "cheap" batteries, and regretted it.]
Regards,
Gary
----- Original Message -----
From: Arie van Spronssen
To: Discussion of issues relating to Soaring in Australia.
Sent: Wednesday, February 27, 2013 6:56 PM
Subject: Re: [Aus-soaring] LiFePo4
Hi,
When people start talking of glider batteries I laugh at their
logic. We have a toy that cost anywhere between 2 - 10k and upwards to keep in
the air each year (not including getting to and from the airfield and actually
getting it in the air) and they are not willing to replace a couple of
batteries each year for well under a $100.
These fancy batteries may be ok but in the vast majority of gliders
the simple still works best and is cheap and safe.
Yes I do play with these fancy batteries in my radio control toys
but with great care and they are always stored in a lipo safe bag. You only
have to watch this video to agree http://www.youtube.com/watch?v=mw8jb1KmAG8
yes I know the newer ones are better but these are only small and look at how
they go up and even the newer ones can still have problems.
regards,
Arie
On 27/02/2013 12:52 PM, Future Aviation wrote:
Hello all
It just occurred to me that I have omitted to thank John
Parncutt
for his research and his willingness to share the findings with
us.
Of course, in this context Mike Borgelt's professional advice
must
also be mentioned. Both contributions are extremely useful to
many
of my gliding friends including myself. Many thanks to both of
you!
Believe it or not, the last set of SLA batteries powering the
engine
circuit in my ASH 25 lasted for 10 years. At the time I opted
for the
most expensive SLA batteries I could get my hands on and now it
appears
that the old saying holds indeed true. You only get what you
........
Kind regards to
all.
Bernard Eckey
-----Original
Message-----
From:
[email protected]
[
mailto:[email protected]] On Behalf Of
Mike
Borgelt
Sent: Wednesday, 27 February 2013 11:22
AM
To: Discussion of issues relating to Soaring in
Australia.
Subject: Re: [Aus-soaring]
LiFePo4
As I said yesterday, do proper engineering on your battery
installation.
If you don't have real numbers for temperature limits, discharge
curves at
various rates, charging characteristics etc etc you aren't
doing
engineering, you're just
guessing.
A battery designed to start a racing motorbike and then be
recharged by the
alternator and floated at that voltage likely has quite
different
characteristics, design and longevity from one designed for
charging and
deep discharging over several hours then recharging. You can
also just stop
and get off the bike when the battery catches
fire.
Li batteries all need individual cell monitoring during charge
and use or at
least when charging after mostly
charged.
The problem with Ni MH batteries is the number of cells (10 for
a nominal 12
V system). You will have at least one weaker cell which will
deep discharge
more than the others and will be undercharged or more likely the
other cells
will overcharge resulting in reduced battery life. Individual
cell
monitoring would help but with 10 cells vs 4 for Li it is a
pain.
3 years isn't bad for a NiMH battery
pack.
Some people have a problem with max weight of non lifting parts
and a few
kilos saved may make the difference between flying in or
outside the
weight
and balance envelope. For these LiFEPO4 may be worthwhile but
use the
correct
cells.
The cylindrical Tenergy cells sold by these people have
engineering data and
are Underwriter Labs tested. The tests are published there too.
Start
here:
http://www.all-battery.com/lifepo4battery.aspx
I've dealt with them and they did what they said they
would.
Also these people may be of interest: The batteries seem to be
the same as
the Tenergy cells but with a different colour outer sleeve.
They have battery monitoring/cutoff circuitry available also.
You must use a
low voltage cutoff at
least.
http://lithbattoz.com.au
The old sealed lead acid batteries are OK. They are heavier
although in many
installations that may not matter. The capacity is usually
quoted at the 20
hour rate. In modern gliders 1 amp continuous is not an unusual
load so
that's the 7 hour rate. Likely it is a 5 A-H battery at this
rate. Give it a
couple of dozen charge cycles and it is a 3 or 4 A-H battery and
you begin
to have problems. Note also the number of cycles you get is non
linear with
depth of discharge. Small % discharge you'll get lots of cycles.
Large %
discharge many, many fewer
cycles.
Size the battery to handle the longest flights and then use two
batteries.
Use one routinely, keep the other charged then when the first
battery dies
due to low capacity you have a known good battery.
Put that one in the first position then put a new one in
the standby
position. You should always have a good battery available
then.
If using some new type either learn enough to do an engineering
analysis or
find someone willing to do one for you. Otherwise these things
may get
needlessly banned or we have fires in gliders. It would be
embarrassing to
explain to your insurance compny why you had to bail out of your
burning
glider.
Mike
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