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