Feds Want to Equipe Gliders With Transponders and Radios

In article "Morgans" writes:
"Peter Dohm" wrote

I 'm confident that the installation is the biggest part of it--especially
when you include enough solar panels to power it all reliably.

Why solar cells? A 7 amp hour lead acid gel cell can be had for about 20 bucks,
and would run a solid state transponder for a whole flight.

One doesn't want to run the lead acid battery down past about 1/2 its capacity
to get a reasonable service life from it, so that limits you to 3.5 AH.

Given that they are also probably running some of:

o A com radio.
o An elecronic variometer.
o A gps.
o A flight logger.

and that they are wanting these to run for flights of 5 - 8 hours or more,
it is fairly clear that the 7 AH battery cannot do it.

I would expect they have already trimmed the list of electronic items
in order to get their flight time from the battery, so a transponder would
need another battery, or giving up some of the other equipment.


More thoughts on the basic issue of protecting IFR aircraft from gliders.
How about designating that area as having fairly low speed limits all the
way up to 18,000 feet (where wave windows would take over for separation),
only in this case note that if the aircraft is unable to fly that slowly,
they have to go around the airspace.


Alan

On Apr 29, 5:35*pm, Larry Dighera wrote:
On Tue, 29 Apr 2008 13:15:46 -0700 (PDT), "kirk.stant"
wrote in
:

Larry Dighera obviously hasn't been around a modern
glass glider recently or he would understand that most have electrical
systems and many have transponders.

As a percentage of the entire sailplane fleet, how many would you
estimate are "modern glass gliders?" *

Been to a glider field lately? Or a contest, or fun meet?

At my club, we have 5 older generation, non-glass gliders. The rest
of our fleet, club and private, totals perhaps 12 glass ships - all
with electrical systems (and one with a transponder). So that is a
pretty high percentage.

I would estimate that by flight hour, the majority of glider flying in
the US (and the rest of the world) is done in "modern glass gliders".

So if your idea of a typical American glider is a beat-up 2-33, you
might be surprised. While you will still find a lot of them around,
it's amazing how little they fly (with some obvious exceptions, of
course!).

Kirk

In rec.aviation.soaring Alan wrote:
In article "Morgans" writes:
"Peter Dohm" wrote

I 'm confident that the installation is the biggest part of it--especially
when you include enough solar panels to power it all reliably.

Why solar cells? A 7 amp hour lead acid gel cell can be had for about 20 bucks,
and would run a solid state transponder for a whole flight.

One doesn't want to run the lead acid battery down past about 1/2 its capacity
to get a reasonable service life from it, so that limits you to 3.5 AH.

What kind of unreasonable service life do you get if you use the full
capacity, and at $20 each do you care if you use it up faster? Unless you
can count the number of cycles on your fingers that may be the simplest
and most cost effective way to go, although of course I may be overlooking
something important.

--
Michael Ash
Rogue Amoeba Software

wrote:
On Apr 29, 5:35 pm, Larry Dighera wrote:
On Tue, 29 Apr 2008 13:15:46 -0700 (PDT), "kirk.stant"
wrote in
:

Larry Dighera obviously hasn't been around a modern
glass glider recently or he would understand that most have electrical
systems and many have transponders.
As a percentage of the entire sailplane fleet, how many would you
estimate are "modern glass gliders?"

Been to a glider field lately? Or a contest, or fun meet?

At my club, we have 5 older generation, non-glass gliders. The rest
of our fleet, club and private, totals perhaps 12 glass ships - all
with electrical systems (and one with a transponder). So that is a
pretty high percentage.

I would estimate that by flight hour, the majority of glider flying in
the US (and the rest of the world) is done in "modern glass gliders".

So if your idea of a typical American glider is a beat-up 2-33, you
might be surprised. While you will still find a lot of them around,
it's amazing how little they fly (with some obvious exceptions, of
course!).

Similar in Boulder. 60% of our club fleet is glass (OK it's only three
out of five, but still...) Mile High Gliding is about 50:50, then there
are the 30 or so private ship. I believe there are one or two HPs, the
rest are composite.

Shawn

"Michael Ash" wrote

What kind of unreasonable service life do you get if you use the full
capacity, and at $20 each do you care if you use it up faster? Unless you
can count the number of cycles on your fingers that may be the simplest
and most cost effective way to go, although of course I may be overlooking
something important.

I have found that using 60% or perhaps 70% does not seem to limit their life
noticeably. What does kill them is to charge them too fast, or most
importantly, leaving them sitting around in a discharged state. Doing that one
time could be the end of them.

The better question than asking how much more quickly a higher discharge kills
them for the price, is to ask why not buy an extra one, or two.

Larger gell cells are also available, but I'm not sure where the economics of
buying more small ones versus buying a single larger one come into play.
--
Jim in NC

In article Michael Ash writes:
In rec.aviation.soaring Alan wrote:

One doesn't want to run the lead acid battery down past about 1/2 its capacity
to get a reasonable service life from it, so that limits you to 3.5 AH.

What kind of unreasonable service life do you get if you use the full
capacity, and at $20 each do you care if you use it up faster? Unless you
can count the number of cycles on your fingers that may be the simplest
and most cost effective way to go, although of course I may be overlooking
something important.

It depends on the details of the battery. Lead acid batteries come in a
lot of sub-types, with varying ability to handle deeper discharges. The
better ones cost more.

Other factors include the output voltage under load at discharge -- a
lead acid battery is rated to 10.2 to 10.5 volts for a "12 volt" battery
at discharge. Unfortunately, most 12 volt radios and devices are designed
for a charging electrical system, with a voltage of about 14 volts. When
the battery is down to 75% of the expected voltage for the radio, not all
of them work. I have had aircraft radios that would not transmit below
about 11.5 volts, at which point the battery would be still above 50% charged.

Lead acid batteries are normally rated for capacity at a 20 hour rate of
discharge. A 7 AH battery would deliver 7000 / 20 = 350 mA for 20 hours.
Faster discharge rates result in less capacity being available (look up
Peukerts exponent for more details). Discharging faster than that, reduces
the amp-hour capacity of the battery.

Lead acid batteries have less capacity when cold. One guide suggests that
for every 10 degrees centigrade below room temperature, you should add 10%
to the battery capacity needed. High altitude flight tends to get up into
cold places.


Alan

At my club, we have 5 older generation, non-glass gliders. The rest
of our fleet, club and private, totals perhaps 12 glass ships - all
with electrical systems (and one with a transponder).


IMHO, in FAA speak, an aircraft having only battery power does not have
an electrical system.

FAR 91.215:

(3) Notwithstanding paragraph (b)(2) of this section, any aircraft which
was not originally certificated with an *engine-driven* electrical
system or which has not subsequently been certified with such a system
installed, balloon or glider may conduct operations in the airspace
within 30 nautical miles of an airport listed in appendix D, section 1
of this part provided such operations are conducted—.......

Tony V.

Michael Ash wrote:
In rec.aviation.soaring Alan wrote:
In article "Morgans" writes:
"Peter Dohm" wrote

I 'm confident that the installation is the biggest part of it--especially
when you include enough solar panels to power it all reliably.
Why solar cells? A 7 amp hour lead acid gel cell can be had for about 20 bucks,
and would run a solid state transponder for a whole flight.
One doesn't want to run the lead acid battery down past about 1/2 its capacity
to get a reasonable service life from it, so that limits you to 3.5 AH.

What kind of unreasonable service life do you get if you use the full
capacity, and at $20 each do you care if you use it up faster? Unless you
can count the number of cycles on your fingers that may be the simplest
and most cost effective way to go, although of course I may be overlooking
something important.

According to the Powersonic Technical Manual, you can get about 200
cycles using 100% discharges, and about 500 cycles using 50% discharges,
before the battery is down to 60% of it's capacity. If you need 80% of
the battery capacity, the cycle numbers are about 150 and 400,
respectively. 150 cycles is 3 years or more for most pilots - not bad
for $20.

--
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

"Larry Dighera" wrote in message
...

I agree. But rescinding the glider exemption from FARs requiring
transponder use won't address that issue with powered aircraft that
lack an electrical system either. It looks like the FAA's response to
this NTSB recommendation is destined to be a compromise at best.
Hopefully it won't result in all gliders and aircraft without
electrical systems being grounded until they have transponders
installed and signed off.


So just remove the exemption at and above 10,000 MSL.

"WingFlaps" wrote in message
...

How slow does a target need to be to be undisplayed -typically? I
would have thought that even a glider is fast (45 knots) compared to
usual clutter.


There are two windmill farms about twenty miles northeast of Green Bay that
break through the Moving Target Indicator. The windmills are stationary, of
course, but the moving rotors are detected.