"A Guide to Transponders in Sailplanes" - updated!

I find it difficult to believe that adding a battery would cost $1,000. I
would think that this could be included as part of the installation of the
transponder.

Mike Schumann

"Eric Greenwell" wrote in message
...
On Feb 14, 8:59 pm, Mike the Strike wrote:
On Feb 14, 9:42 pm, Mike the Strike wrote:



Also.....consider, a Transponder equipped aircraft is also REQUIRED
to have
the transponder ON and reporting at all times from wheels up to
wheels
down......not just as I have heard many glider pilots saying they
"only use"
the transponder when they are flying at or near areas of high
traffic....
think about this....

A lot of us have thought about this, including people in the FAA, and
decided it's a lot better to have a transponder on in areas that need
it, instead of risking a dead battery (meaning NO radio or
transponder) later in the flight, or discouraging pilots with
marginal
batteries from installing a transponder. I covered this in the the
"Guide". Take a look at that section and see if it promotes flight
safety better than strict adherence to the "always on" rule; also,
take a look at the "Why doesn't the SSA ..." section that addresses
the FAA's official position.

This argument seems rather like deciding to put your seat belt on in a
car just before you have a crash!

Anyway, this rule isn't an option, it is mandatory. If you have a
transponder the regs say it MUST be on while you are flying. No pilot
discretion here.

And don't give me the battery argument. Electricity is the fuel for
your instruments, including your safety ones such as the radio and
transponder. In my book, starting a flight with insufficient battery
power is as irresponsible as flying a power plane cross-country with
insufficient fuel.

It's the pilot's responsibility to make sure that he has everything
needed for a safe flight and to comply with regulations and that
includes power for the instruments.

Mike

I should add that the article is excellent - the battery issue and
turning transponders off is the only point that I disagree with. With
a $2,000+ transponder in a $50,000+ sailplane, it seems ironic that
people are too mean to add another $10 battery.

That's not what stops pilots - it's the $1000 battery that stops them.
Many gliders require and additional battery when a transponder is
installed, and doing this in certified glider can be expensive.
Experimental certificate gliders can usually get by more cheaply.

A dedicated 7 Ah
battery will power a Microair transponder for 12 to 15 hours, in my
experience. This is a no-brainer.

That is the solution I recommend, but see the cost of implementing it
stops some pilots from adding another battery. A 7 AH battery won't
run a vario, radio, gps, AND a full-time transponder for very long.


We have had a collision between an aircraft and a sailplane whose
transponder was turned off "to save the batteries", so this isn't just
a theoretical problem.

And we are all agreed that if that was actually the case, it was a
very foolish decision, because that is a prime area for using a
transponder. But answer this: if that glider had not had a
transponder, would the jet have hit it more gently? He was not
required to have one, after all.





--
Posted via a free Usenet account from http://www.teranews.com

Mike Schumann wrote:
I find it difficult to believe that adding a battery would cost $1,000. I
would think that this could be included as part of the installation of the
transponder.

FWIW, we had a great deal of trouble with battery failures using a Terra
TRT250D transponder (nearly twice the power consumption of a Becker,
which wasn't then available in the US) in our Duo with the standard
installation of two 7ah batteries. We would get about 3 to 4 hours out
of each, failing to switch at the proper time would result in a useless
battery after a few cycles. We wanted to switch to 12ah batteries, but
there is essentially no room in a Duo for anything that size in an
accessible spot, if we still wanted to continue to carry drinking water,
survival kits, and/or jackets (this isn't the only glider with this
problem). So, we had the local shop reshape the molded battery wells in
the floor to accommodate the larger batteries. This involved cutting
out the existing wells, molding new larger ones, glassing them back in,
and painting. When all was said and done, it cost well over $1000, but
it solved the problem...

Marc

Excellent update on your fine article, thanks Eric!
Have to disagree regarding your points on NiMH batteries, though.
I've now flown now for over 2 years with them (including a dedicated
transponder battery) and I love them. Weight is about 60% of sealed
lead-acid, same for volume. The big advantage I see is in being able
to quick-charge them with 2A in a couple of hours very safely with
cheap automatic chargers available for example from all-battery.com or
ebay. I fly with 2 batteries for instrumentation/radio, each 5AH and
one for the transponder that has 10AH. One of the smaller batteries
is in the tail. Having much less mass in the area behind the
headrest is another plus. Shop around and find that the prices are
affordable and pre-wired 12V packs are offered.
I have not found the higher discharge rate in storage to be a factor.

Herb, J7

Marc Ramsey wrote:
Mike Schumann wrote:
I find it difficult to believe that adding a battery would cost
$1,000. I would think that this could be included as part of the
installation of the transponder.

snip

So, we had the local shop reshape the molded battery wells in
the floor to accommodate the larger batteries. This involved cutting
out the existing wells, molding new larger ones, glassing them back in,
and painting. When all was said and done, it cost well over $1000, but
it solved the problem...

OK, now I know of two instances.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

On Feb 16, 9:42 pm, "Mike Schumann"
wrote:
I find it difficult to believe that adding a battery would cost
$1,000. I
would think that this could be included as part of the installation
of the
transponder.

I hope I didn't scare anyone off, as I've heard of only one instance and
it was a certified glider. But, it is the kind of thing a few pilots
worry about.

Pilots with "newer" gliders will have factory locations for at least two
batteries; "older" gliders generally weren't so well equipped, so there
may be some effort and expense involved in adding another battery.

I suspect a more common problem than insufficient space for adequate
batteries is the battery getting low during the flight. This can happen
because the flight is much longer than usual, the battery(s) weren't
charged completely before takeoff, there was a battery or wiring
failure, or other problem. This is the main situation I tried to address
with the comments about using the transponder in the areas of greatest
risk, and turning it off elsewhere.

The point I was trying to make is that pilots that have just spent
~$2300 for a transponder, encoder, cabling, and antenna, plus looking at
some more for the installation, aren't going to balk at buying a $10 (or
even a $100 battery!) to power it. It's generally a much bigger amount
for the complete installation (at typical technician hourly rates in the
$50-$70 range) that makes the complete package to expensive for some pilots.

My "Guide" offers some ideas for dealing with the power issue, besides
the obvious one of adding another battery.


--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Mike the Strike wrote:
On Feb 15, 10:18 am, "bumper" wrote:
"Eric Greenwell" wrote in message

...



And to reiterate, it's not a "200 watt transmitter". The peak power of
the pulses is 200 watt, but it's only about a 5 watt max transmitter,
as the pulses are short.
I know you are talking about peak power vs average power. However, even
though pulse width is narrow, and thus the average radiation from a 175 or
250 watt transponder might be on the order of 5 watts, I'm not sure the
radiation exposure should be equated to just the low average power.

Consider a single high powered pulse as being one .22 rifle bullet. The
bullet might have on the order of 100 ft pounds of energy and would
obviously do considerable tissue damage. Compare that to several hundred
BB's from a low powered air rifle, the combined energy of which equals the
energy of that one .22 bullet. Same total energy, far less damage. The point
I'm trying to make is that pulsed high energy may well do more tissue damage
than the same total amount of low level energy delivered over a longer time
frame.

I want that transponder antenna installed away from me.

bumper

A colleague who deals with radiation safety said that the argument
that low energy long-duration doses of radiation are equivalent to
high energy short duration doses is like equating jumping off a 3-foot
wall ten times with jumping off a 30-foot wall once.

Please ask your colleague if his analogy applies to microwave radiation.
Where I worked, "radiation safety" generally meant "atomic radiation
safety", including ionizing radiation (a bit like the bullet in bumper's
analogy) and gamma radiation. These tend to interact with tissue much
differently than microwave (radio) radiation.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Herb wrote:
Excellent update on your fine article, thanks Eric!
Have to disagree regarding your points on NiMH batteries, though.
I've now flown now for over 2 years with them (including a dedicated
transponder battery) and I love them. Weight is about 60% of sealed
lead-acid, same for volume. The big advantage I see is in being able
to quick-charge them with 2A in a couple of hours very safely with
cheap automatic chargers available for example from all-battery.com or
ebay. I fly with 2 batteries for instrumentation/radio, each 5AH and
one for the transponder that has 10AH. One of the smaller batteries
is in the tail. Having much less mass in the area behind the
headrest is another plus. Shop around and find that the prices are
affordable and pre-wired 12V packs are offered.

Your Googling was more productive than mine! Please send links to the
batteries and chargers you use, and part numbers if you can. I'll review
them and rewrite that section as needed.

I have not found the higher discharge rate in storage to be a factor.

And pilots who find it is a factor might be able to counter it with
solar panel on the trailer.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

On Feb 20, 9:35 pm, Eric Greenwell wrote:
Herb wrote:
Excellent update on your fine article, thanks Eric!
Have to disagree regarding your points on NiMH batteries, though.
I've now flown now for over 2 years with them (including a dedicated
transponder battery) and I love them. Weight is about 60% of sealed
lead-acid, same for volume. The big advantage I see is in being able
to quick-charge them with 2A in a couple of hours very safely with
cheap automatic chargers available for example from all-battery.com or
ebay. I fly with 2 batteries for instrumentation/radio, each 5AH and
one for the transponder that has 10AH. One of the smaller batteries
is in the tail. Having much less mass in the area behind the
headrest is another plus. Shop around and find that the prices are
affordable and pre-wired 12V packs are offered.

Your Googling was more productive than mine! Please send links to the
batteries and chargers you use, and part numbers if you can. I'll review
them and rewrite that section as needed.

I have not found the higher discharge rate in storage to be a factor.

And pilots who find it is a factor might be able to counter it with
solar panel on the trailer.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes"http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" atwww.motorglider.org

Eric,
Here is a link for the battery (10Ah):
http://www.all-battery.com/index.asp...OD&ProdID=1344
The charger I use is on the same page.
I just ordered 10 individual NiMh batteries of 10Ah capacity on ebay
but will have to wire the pack up myself. The price was only $60 plus
$10 for shipping:
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN:IT&ih=014

Regards,
Herb

Tim Mara wrote:


...a Transponder equipped aircraft is also REQUIRED to have
the transponder ON and reporting at all times from wheels up to wheels
down....


Yes, we keep bumping against this reg whenever the subject comes up.

What is the rationale behind such a requirement?

Whose interests does it serve to differentiate between uninstalled
transponders and unused transponders?

Is it just another example of bureaucratic passive/aggressive
bitchiness, or is there an actual Safety of Flight context that
thoughtful glider pilots can appreciate?



Jack

On Feb 22, 9:17 am, J a c k wrote:
Tim Mara wrote:
...a Transponder equipped aircraft is also REQUIRED to have
the transponder ON and reporting at all times from wheels up to wheels
down....

Yes, we keep bumping against this reg whenever the subject comes up.

What is the rationale behind such a requirement?

Whose interests does it serve to differentiate between uninstalled
transponders and unused transponders?

Is it just another example of bureaucratic passive/aggressive
bitchiness, or is there an actual Safety of Flight context that
thoughtful glider pilots can appreciate?

Jack

I suspect it is to prevent thinking like "I'll just turn this little
box off and bust whatever FAR I feel like cuz noboby can see me" (even
if ATC can see you as a primary on radar). Seems a perfectly fine
requirement for a powered aircraft and I'd be surprised if gliders
were front and center in any thinking about this requirement. As for
bitchiness, the FAA seems to be showing perfect restraint in not
enforcing the thing you seemed concerned about, and therefore helping
encourage use of transponders in sailplanes. Of course we can keep
whining about this and other requirements and maybe in a long shot end
up with removing a regulation that does not seem to be enforced or
maybe worse end up with more regulations, maybe mandatory Mode-C/ADS-B
for all flight...

For many people flying in high-traffic areas, and that's a lot more
than just around Reno, it is not outrageous to expect them to install
batteries (and/or possibly solar panels at significantly higher cost)
so they can operate transponders thought quite long flights. So there
is no need to turn off those transponders - and in those areas that
*is* a safety of flight issue.

Darryl