300 Series
Additional questions
and answers of a more technical nature can be found on
the Tech-Talk page.
Does
the IGC permit flight data transfer from a flight
recorder via floppy diskette, Compact Flash card, or
Pocket PC?
I recently purchased a new laptop computer
but it does not have a 9 pin serial port. How can I
connect my 302 to this computer?
Can the vario response rate can be set
independently for climb and cruise modes?
Why
does the 300 series not use the g-meter to switch from
cruise to climb mode?
I
would like to install the 302 in my two seat glider, is a
repeater option available?
What is the difference between the
Pocket-NAV and the 304?
Can
I use the 303 LCD Display and the 304 Pocket-NAV moving
map display together with the 302?
Does the 302 supply the contact switches
etc. for dive brake and landing gear warning?
I have some questions about the 304 mounting
system.
What
type of audio sound control is there?
Where does the data for the moving map come
from?
Does the 302 have a built-in antenna like
the Model 20?
You
state the Pocket PC or Compact Flash card can be used to
transfer secure flight logs. Does the FAI/IGC/GFAC call
that an approved method?
Given
that the flight recorder is integral with the instrument,
how do I get it calibrated for badge flights etc?
Is the
temperature sensor information used to report back the
temperature of the outside air reduced to sea level
pressure?
Does the IGC permit flight data
transferred from an approved flight recorder via floppy
diskette, Compact Flash card, or Pocket PC to be approved
for FAI badges and Records?
Yes. The IGC position in
this matter can be found on page 10 of the TECHNICAL
SPECIFICATION FOR IGC-APPROVED GNSS FLIGHT RECORDERS, May
2001, including Amendments 1-4
http://www.fai.org/gliding/gnss/tech_spec_gnss.pdf as
follows:
"2.8.
SECURITY-PRINCIPLES. Security procedures and hardware,
firmware and software standards must be used so that no
alteration of data may occur without such alteration
being detectable. The method of ensuring that GNSS FR
flight data is secure is through the generation of a
digital signature (DS) in the FR, which becomes part of
all flight data transferred from the FR. PC's, transfer
software, email, and portable storage media such as
diskettes may be used to transmit data from the FR to the
validating authority (NAC or FAI). Regardless of the
level of physical control used in handling and
transmitting data between the FR and the validating
authority, the DS must enable detection of any alteration
of data throughout the transfer process from the FR and
any time afterwards. ------"
Note: FR is the
abbreviation for Flight Recorder.
Note: The text does not mention Pocket-PC's or Compact
Flash cards by name. However, the words "-- portable
storage media such as --" applies to ANY portable
storage media, including the memory of a PC, a Pocket-PC,
or a Compact Flash card.
I recently purchased a new
laptop computer but it does not have a 9 pin serial port.
How can I connect my 302 to this computer?
For pilots who have laptop
computers with no serial port (Legacy Free) we now have a
solution for you. We have tested a USB to Serial
converter made by IOGEAR. It is model UC232A. It requires
no external power
source so its completely portable. We have tested it with
our DOS based PC software as well as Cambridge Aero
Explorer. You can find out more about this at the IOGEAR
website www.iogear.com.
Can the vario response rate can be set
independently for climb and cruise modes?
Whenever the variometer
reads >0 lift, the vario response speed is set by the
user, and is typically rather fast. This is true in both
Climb mode and Cruise mode.
When the instrument is in
Climb mode and is configured for "Sink Tone
ON", The vario will be fast, even though the vario
is showing sink.
When the instrument is in
Cruise mode, and the vario is indicating sink (the normal
case), both the pointer and the audio response times are
lengthened to about 3 seconds.
Why does the 300 series not use
the g-meter to switch from cruise to climb mode?
The Cambridge g-meter
based cruise/climb switching algorithm requires high
accuracy and stability from the sensor (~ 0.01g long term
stability). We are not sure yet whether we need to
implement temperature compensation of the readings. This
upgrade will happen when we have full confidence in the
sensors.
I would like to install the 302
in my two seat glider, is a repeater option available?
We are working on a
repeater option for the 302. It will be a slave to the
302, meaning it will display data only. Our target
release date is this Summer.
What is the difference between
the Pocket-NAV and the 304?
The difference between the
Pocket-NAV and the 304 is determined by the GPS data
recorder it is connected to. Since the GPS-NAV holds only
250 waypoints, the 304 (connected to the 302) will work
better in some situations for pilots who want more than
250 waypoints at a time. The Pocket-NAV can handle more
than 250, but it requires more knowledge of the (GPS-NAV)
system.
Additionally, enhancements
have been added to the 304 so that MacCready settings are
coordinated between the 304 and 301.
The Pocket-PC will be able
to communicate better with the 302 than it can with the
GPS-NAV and L-NAV, which were not designed with this in
mind. As we release upgrades, there will be improvements
to the 304 that can't be implemented on the Pocket-NAV.
Can I use the 303 LCD Display
and the 304 Pocket-NAV moving map display together with
the 302?
Yes. The 303 LCD display
will provide alphanumeric navigation data, and the 304
will display the moving map features found in the
Pocket-NAV. You cannot connect two 304s into the system.
Does the 302 supply the contact
switches etc. for dive brake and landing gear warning?
This L-NAV feature is
endorsed by pilots who have take the time to install the
required micro switches. The 301 has the same logic and
wires for dive brake and gear warnings. Because different
gliders have very different switch mounting requirements,
we do not supply the micro switches themselves.
How secure is the 304 mount
cradle? Will the pocket-PC NEVER bump out?
A spring-ball detent
retains the Compaq 1500 in the mounting cradle. We have
tested this in the shop to more than 10 g's with
excellent results. If you remove two thin washers, the
fit tightens up so the Pocket-PC can barely be pulled out
of the clamp bracket.
I guess I have short
arms and will have a tough time reaching the panel. How
far out does the mount move the pocket-PC from the
attachment point?
The range is from
1.4" (36 mm) to 3.2" (82 mm) from the
instrument panel.
It looks like the
pocket-PC must be mounted to the panel. Is there a way to
mounted it at the side of the cockpit?
Because there is such a
variety of full instrument panels in gliders, we designed
the mount to be as versatile as possible. The system
includes a "filler panel" for a 2.25" (57
mm) instrument panel opening. However, the articulated
ball-mount can be attached to any 1" square surface.
The rest is up to the ingenuity of the individual owner.
What
type of audio sound control is there? Lift, sink,
deadband? What type of audio sound is used?
The 301 audio is naturally
evolved from the L-NAV audio. Because the sound is
generated directly by the processor, we have been able to
make subtle improvements over the earlier design.
"Future products within the
300 series will include a Cambridge designed panel mount
graphic display". Are you are going to get rid of
the pocket PC?
Consumer product life
cycles are too short for our application. Until the
advent of the Pocket-PC, our policy has been to support
Cambridge products for 10 years after the date of last
manufacture. We cannot do this for the Compaq 1500. Also,
Pocket-PC's have PDA features that have no perceived
value in a gliding application.
Concerning the future
Cambridge graphic display -- "This product will use
the same high resolution LCD screen as the model
304". What do you mean?
At the present state of
LCD technology, the Compaq 1500 series monochrome LCD
screen has the best performance for our application. The
new Cambridge display, the 305, will use a 320 x 240
pixel monochrome DSTN screen with 0.24 mm dot pitch as in
the Compaq 1500 series.
The 305 graphic display
will be smaller than the Compaq 1500, and will be
supplied with the same articulated mount. This means it
can be mounted directly on the front of the panel. Like
the Compaq 1500, the 305 graphic display will have a
Compact Flash slot, so this precludes mounting it behind
the instrument panel.
Where does data for the moving
map come from? What is the update cost? Schedule? Is
there a legal issue about flying with an out-of-date
database? How does the pilot update the database? Not
that I plan to go flying internationally soon at any
time, but can I load in data for other countries?
There are 4 sources of
Special Use Airspace (SUA) data for the 304 Pocket-NAV
moving map.
a. For Western Europe and
Scandinavia, we have licensed a custom-designed SUA
database. This database is used by "Speed", the
software used to score German competitions. This database
is updated annually and is available at no cost on the
Cambridge web page.
b. For UK, Tim
Newport-Peace has kindly allowed us to use his SUA
database at no charge. Tim's database is used for scoring
in UK contests.
c. On his web site, John
Leibacher maintains SUA databases as well as Navpoint
databases for soaring sites around the world. These
databases are supplied "as is" by gliding
enthusiasts. Are they legal?? This depends on the
definition of “Legal”. If the same
database is used for flight evaluation, it is
“legal” in practice.
d. Complete instructions
for creating your own moving map database are in the
Pocket-PC User's Guide. You can download this from our
web site. Using these tools, you can describe pretty much
any shape or feature you want to see on the screen.
Does the 302 have a built-in
antenna like the Model 20?
A.
The 302 requires an ”active” GPS antenna
with built-in pre-amplifier, and a type SMC coaxial
connector. The antenna is typically mounted under the
fiberglass instrument panel cover. It is not
necessary to cut any holes in the cover as GPS signals
pass easily through the thin fiberglass. Cambridge sells
the required antenna for $90.
You state the
Pocket PC or Compact Flash card can be used to transfer
secure flight logs. They key is the word secure. Does the
FAI/IGC/GFAC call that an approved method?
We have been informally
assured by the Chairman of GFAC that our use of the
Pocket PC and Compact Flash cards will be approved.
Given
that the flight recorder is integral with the instrument,
how do I get it calibrated for badge flights etc? Pull
the whole thing out and be without a flight computer?
The
IGC-mandated barograph certification period for Secure
Flight Recorders is 2 years. You have two choices: 1.
Have the instrument certified every two years during the
"off" season. 2. Have the instrument certified
within 7 days (2 weeks?) of a badge or record flight. I
also note that SSA-sanctioned contests tend to be pretty
relaxed about barograph certification. 302 flight logs
contain GPS altitude, and IGC approved flight recorders
are mandated to store 30 seconds of pre-takeoff barograph
altitude, so it is actually easy to compensate for
significant barograph zero offset by comparing
pre-takeoff GPS and pressure altitudes.
Note that the 302
barograph pressure sensor is separate from the absolute
pressure sensor used by the 302 variometer. This is
because the barograph pressure sensor must not be
accessible to the pilot. It cannot, therefore, have
a tubing connection to the outside world. Altitude
displayed on the 302 comes from the internal barograph
pressure sensor, not the variometer sensor.
Is the temperature sensor information
used to report back the temperature of the outside air
reduced to sea level pressure?
The primary use of Outside
Air Temperature is to determine True Air Speed (TAS).
This is used, in turn, for accurate wind measurement (GPS
Groundspeed - TAS). Potential Temperature, dT/dA,
extrapolated to sea level pressure, is thought to predict
lift at altitude. The Peschges VP-3 and VP-6 reported
this data. It is easy to compute this index from data
gathered in the 302. We have no plans to display
Potential Temperature. We are, however, open to customer
input.
The 302 Outside Air
Temperature probe is a Dallas Semiconductor
"one-wire" device. Dallas Semi. also makes a
"one-wire" relative humidity sensor. Moist air
is more buoyant than dry air at a given temperature. We
think we will learn more about what one might call the
"useful lapse rate" from measurements of
altitude, temperature AND relative humidity. The
"one-wire" low-speed external bus in the 302 is
designed for future expansion to these measurements.
However, we have no plans to do this in the near future.
|
CAMBRIDGE
Aero Instruments
