Can some-one please explain the difference between netto and Super Netto as
used on the Cambridge 302 variometer.
Also what should the 302 be set to?
Thanks
Ross

Yes. This is an area where the 302 is weak and something
I wish Cambridge would rectify.

'Netto' should display the vertical motion of the air
mass (as opposed to the vertical motion of the glider)..so
in still air, it would show zero, even if your glider
is decending at 130 feet per minute. In gently rising
air, it would start to show, say, 0.5 up, in sinking
air, it shows down. This display means you can seek
out rising air and so maximise your glide angle, without
the need to stop and turn. It displays what the airmass
is doing irrespective of the sink rate or speed of
your glider.

'Super Netto' shows the climb rate you could achieve
if you stopped to circle at your best climb rate...in
effect this means it only functions differently from
a t/e vario at higher speeds, when it removes the additional
sink rate caused by you flying at 100kts rather than
50kts.

Netto is a really useful function in countries with
weaker lift (like the UK) and it is a real issue not
having this function in an otherwise excellent vario....come
on Cambridge, implement the *****function properly!

Chris




At 05:54 12 September 2003, Ross Biggar wrote:
>Can some-one please explain the difference between
>netto and Super Netto as
>used on the Cambridge 302 variometer.
>Also what should the 302 be set to?
>Thanks
>Ross
>
>
>
>

Chris,

You can select netto, super-netto or always TE in cruise
mode for the 302 using the 300 Utility or a 303.

John Galloway

At 06:48 12 September 2003, Chris Davison wrote:
>Yes. This is an area where the 302 is weak and something
>I wish Cambridge would rectify.
>
>'Netto' should display the vertical motion of the air
>mass (as opposed to the vertical motion of the glider)..so
>in still air, it would show zero, even if your glider
>is decending at 130 feet per minute. In gently rising
>air, it would start to show, say, 0.5 up, in sinking
>air, it shows down. This display means you can seek
>out rising air and so maximise your glide angle, without
>the need to stop and turn. It displays what the airmass
>is doing irrespective of the sink rate or speed of
>your glider.
>
>'Super Netto' shows the climb rate you could achieve
>if you stopped to circle at your best climb rate...in
>effect this means it only functions differently from
>a t/e vario at higher speeds, when it removes the additional
>sink rate caused by you flying at 100kts rather than
>50kts.
>
>Netto is a really useful function in countries with
>weaker lift (like the UK) and it is a real issue not
>having this function in an otherwise excellent vario....come
>on Cambridge, implement the *****function properly!
>
>Chris
>
>
>
>
>At 05:54 12 September 2003, Ross Biggar wrote:
>>Can some-one please explain the difference between
>>netto and Super Netto as
>>used on the Cambridge 302 variometer.
>>Also what should the 302 be set to?
>>Thanks
>>Ross
>>
>>
>>
>>
>
>
>
>

Chris,

I usually use the super-netto but I have tried the
netto on a couple of flights.

To be honest I find the super-netto a bit confusing
because if I set the 302 time constant to 3 seconds
my 302 and back up Borgelt B40 needles seem to always
closely match each other no matter what speed I fly.
However with the 302 on the bench and the airspeed
inlet pressured to simulate flight the super - netto
seems to be correctly set up.

The netto itself works on the bench and seems to make
sense in flight. And yes, the 1.5 knot up on the ground
(and on the bench) is compatible with the netto being
switched on.

My own gripe about the 302 is the lack of a bugs adjustable
speed to fly in the vario. From past reactions to
this observation noone else seems to think that is
an ommission and are happy to have a bugs adjusted
final glide height calculation on Glide Nav/Winpilot
and then fly cruise speeds based on a different polar;-)
I would prefer to fail to follow accurate data than
to fail to follow inaccurate data.

John Galloway


At 18:12 12 September 2003, Chris Davison wrote:
>John, do you use Netto and does it work? I have just
>had one of those 'I may be an idiot' moments....the
>issue being when I have set the vario to Netto in the
>past, with the glider on the ground, the needle points
>to about 1.5kts up....which I have just realised it
>what it should do...as it is assuming if the glider
>is maintaining altitude it must be in rising air eauivalent
>to the sink rate.....DOH.
>
>Chris
>
>
>At 15:18 12 September 2003, John Galloway wrote:
>>Chris,
>>
>>You can select netto, super-netto or always TE in cruise
>>mode for the 302 using the 300 Utility or a 303.
>>
>>John Galloway
>>
>>At 06:48 12 September 2003, Chris Davison wrote:
>>>Yes. This is an area where the 302 is weak and something
>>>I wish Cambridge would rectify.
>>>
>>>'Netto' should display the vertical motion of the air
>>>mass (as opposed to the vertical motion of the glider)..so
>>>in still air, it would show zero, even if your glider
>>>is decending at 130 feet per minute. In gently rising
>>>air, it would start to show, say, 0.5 up, in sinking
>>>air, it shows down. This display means you can seek
>>>out rising air and so maximise your glide angle, without
>>>the need to stop and turn. It displays what the airmass
>>>is doing irrespective of the sink rate or speed of
>>>your glider.
>>>
>>>'Super Netto' shows the climb rate you could achieve
>>>if you stopped to circle at your best climb rate...in
>>>effect this means it only functions differently from
>>>a t/e vario at higher speeds, when it removes the additional
>>>sink rate caused by you flying at 100kts rather than
>>>50kts.
>>>
>>>Netto is a really useful function in countries with
>>>weaker lift (like the UK) and it is a real issue not
>>>having this function in an otherwise excellent vario....come
>>>on Cambridge, implement the *****function properly!
>>>
>>>Chris
>>>
>>>
>>>
>>>
>>>At 05:54 12 September 2003, Ross Biggar wrote:
>>>>Can some-one please explain the difference between
>>>>netto and Super Netto as
>>>>used on the Cambridge 302 variometer.
>>>>Also what should the 302 be set to?
>>>>Thanks
>>>>Ross
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>
>
>
>

On Fri, 12 Sep 2003 17:48:03 +1200, "Ross Biggar" >
wrote:

>Can some-one please explain the difference between netto and Super Netto as
>used on the Cambridge 302 variometer.
>Also what should the 302 be set to?
>Thanks
>Ross
>
>

Please see the article on our website under articles called "basic
glider instruments"
That will explain all.

Mike Borgelt

Borgelt Instruments
www.borgeltinstruments.com

On 12 Sep 2003 20:26:36 GMT, John Galloway
> wrote:


>
>My own gripe about the 302 is the lack of a bugs adjustable
>speed to fly in the vario. From past reactions to
>this observation noone else seems to think that is
>an ommission and are happy to have a bugs adjusted
>final glide height calculation on Glide Nav/Winpilot
>and then fly cruise speeds based on a different polar;-)
> I would prefer to fail to follow accurate data than
>to fail to follow inaccurate data.
>
>John Galloway
The B50 does this properly and has done since its inception in 1995.

Mike Borgelt

Borgelt Instruments

What I got from Cambridge is that both of you are partially
correct. Yes, you can transfer a bugs setting to the
302 and you can also read it back out. However, I
was told by Cambridge that the instrument does not
'currently' use the bugs setting to degrade the polar
information that the 302 contains. That was about
a year ago though so perhaps that has changed with
one of the later firmware versions. Later!-MarkAt 03:06 13 September 2003, Eric Greenwell wrote:>In article , says...>> My own gripe about the 302 is the lack of a bugs adjustable>> speed to fly in the vario. From past reactions to>> this observation noone else seems to think that is>> an ommission and are happy to have a bugs adjusted>> final glide height calculation on Glide Nav/Winpilot>> and then fly cruise speeds based on a different polar;-)>>Are you sure of this? The vario has a page for setting
>bugs, so I >assume it is used for the speed fly. Since the vario
>doesn't have a >final glide calculation, and the bug setting in Glide
>Nav is >transferred to the vario if you set it there, I can't
>think of any >other reason for having that page. >>-- >!Replace DECIMAL.POINT in my e-mail address with just
>a . to reply >directly>>Eric Greenwell>Richland, WA (USA)>

> > My own gripe about the 302 is the lack of a bugs adjustable
> > speed to fly in the vario. From past reactions to
> > this observation noone else seems to think that is
> > an ommission and are happy to have a bugs adjusted
> > final glide height calculation on Glide Nav/Winpilot
> > and then fly cruise speeds based on a different polar;-)
>
> Are you sure of this? The vario has a page for setting bugs, so I
> assume it is used for the speed fly.


I can't seem to find this bug setting on the "302 Operator's Card" on the
Cambridge website. Am I looking in the wrong place?


Since the vario doesn't have a
> final glide calculation, and the bug setting in Glide Nav is
> transferred to the vario if you set it there, I can't think of any
> other reason for having that page.
>
> --
> !Replace DECIMAL.POINT in my e-mail address with just a . to reply
> directly
>
> Eric Greenwell
> Richland, WA (USA)

In article <HQw8b.1629$v%5.827@fed1read02>,
says...
>
>
> I can't seem to find this bug setting on the "302 Operator's Card" on the
> Cambridge website. Am I looking in the wrong place?

Nope. I got confused - it's the ballast setting that's on the vario,
not the bug setting.

--
!Replace DECIMAL.POINT in my e-mail address with just a . to reply
directly

Eric Greenwell
Richland, WA (USA)

That's my point - you can configure winpilot/GlideNav
for a bugs adjusted final glide height calculation
on your PDA but there is no capability for the 302
to accept a bugs adjusted polar from either the PDA
or a 303. This is confirmed by CAI who, when I queried
this, said there was no need for a bugs page on the
302 or the 303 because the 302 couldn't use it.

It seems such a simple capability to add to the 302
- just add another bugs page to the vario, like the
ballast one, and calculate the adjusted polar for the
STF. To me it is extraordinary that something all
other speed directors do (including the L/S-Nav) cannot
be done on a 302.

After several attempts to discuss this with CAI I did
get a reply that the subject would be put to the developers
for consideration. This was before the most recent
reorganisation.
Perhaps some other owners might like to take this up
if they feel the same as I do.

Maybe you don't get bugs or rain in US but we sure
as hell do here in Scotland:-)

John Galloway

At 05:36 13 September 2003, Eric Greenwell wrote:
>
>Nope. I got confused - it's the ballast setting that's
>on the vario,
>not the bug setting.
>
>--
>!Replace DECIMAL.POINT in my e-mail address with just
>a . to reply
>directly
>
>Eric Greenwell
>Richland, WA (USA)
>

"John Galloway" > wrote...
> That's my point - you can configure winpilot/GlideNav
> for a bugs adjusted final glide height calculation
> on your PDA but there is no capability for the 302
> to accept a bugs adjusted polar from either the PDA
> or a 303. This is confirmed by CAI who, when I queried
> this, said there was no need for a bugs page on the
> 302 or the 303 because the 302 couldn't use it.

The 302 accepts, but ignores, the bug setting. The 302 data protocol includes a
command to send a new polar, if the authors of the PDA wanted to, they could
send an updated polar each time the bug setting changes. Apparently, some don't
want to...

Marc

Marc,

That is a very interesting and, to me, surprising piece
of information. Here is what Peter Rogers sent me
on Feb 10th in answer to a query about using a 302/303
combination which I had found had no setting for bugs
at all:

'Hello John -
As you know the 303 does not currently have a 'Bugs'
screen. The reason
for this is the 302 does not utilize any 'Bug' information
in determining
final glide. We may at some point implement it but
it has not been a high
priority. Since it's not used we didn't see a point
of making a screen for
it since it would give our customers a false impression
that we were using
the value in our calculations when in fact we were
not.

Pete'

Which software does send a new bugs adjusted polar
to the 302? Will it make the PDA software, the 303
final glide altitudes, and the 302 speed to fly all
use the same polar?
I know that GlideNav and PocketNav do not because if
I fly in buggy conditions and put a bug factor in GlideNav
the GN final glide altitudes and the 303 final glide
altitudes diverge subsantially so the bugs setting
on GN is only being used there and not sent to the
302/303. The ballast setting is sent.

Thanks,

John Galloway





At 09:48 13 September 2003, Marc Ramsey wrote:
>
>'John Galloway' wrote...
>> That's my point - you can configure winpilot/GlideNav
>> for a bugs adjusted final glide height calculation
>> on your PDA but there is no capability for the 302
>> to accept a bugs adjusted polar from either the PDA
>> or a 303. This is confirmed by CAI who, when I queried
>> this, said there was no need for a bugs page on the
>> 302 or the 303 because the 302 couldn't use it.
>
>The 302 accepts, but ignores, the bug setting. The
>302 data protocol includes a
>command to send a new polar, if the authors of the
>PDA wanted to, they could
>send an updated polar each time the bug setting changes.
> Apparently, some don't
>want to...
>
>Marc
>
>
>

"John Galloway" > wrote...
> Which software does send a new bugs adjusted polar
> to the 302? Will it make the PDA software, the 303
> final glide altitudes, and the 302 speed to fly all
> use the same polar?

My homebuilt software changes the polar in the 302 when the bug setting is
changed. This affects the 302 STF indications, but would not, to my knowledge,
change anything in the 303 (I don't have one). The 303 listens for changes in
ballast, MacCready, etc., from the 302, but there probably isn't any way for it
to know that the polar has changed. The only way to get bug support in the 303
is to lobby Cambridge to change the firmware.

Marc

Marc,

Thanks, I understand now. That would be a step in
the right direction and I think that a new pre-calculated
polar sent to the 302 will probably be used by the
303.

However that is not quite the same as the 302 having
the ability to calculate a new polar for itself from
a bugs setting entered on e.g. a hypothetical new bugs
factor screen which is what I think would be far more
generally useful (essential) in that it could be used
no matter what software is used in the PDA or even
with no PDA for 302/303 users.

In the case of ballast settings, I think that GN11
sends a setting to the 302 (which then calculates the
ballast adjusted polar internally) rather than sending
a newly calculated polar, so the 302 should be able
to do the same for bugs settings sent from the PDA
- IMHO.

Another note to CAI I think.


John Galloway


At 18:42 13 September 2003, Marc Ramsey wrote:
>'John Galloway' wrote...
>> Which software does send a new bugs adjusted polar
>> to the 302? Will it make the PDA software, the 303
>> final glide altitudes, and the 302 speed to fly all
>> use the same polar?
>
>My homebuilt software changes the polar in the 302
>when the bug setting is
>changed. This affects the 302 STF indications, but
>would not, to my knowledge,
>change anything in the 303 (I don't have one). The
>303 listens for changes in
>ballast, MacCready, etc., from the 302, but there probably
>isn't any way for it
>to know that the polar has changed. The only way to
>get bug support in the 303
>is to lobby Cambridge to change the firmware.
>
>Marc
>
>
>