At 23:45 16 July 2008, Martin Gregorie wrote:
On Wed, 16 Jul 2008 14:35:28 -0700, Ian wrote:

On 16 Jul, 20:37, Bruce wrote:

So why install mechanical varios in a new high tech glide? Convince
me.

In my ASW-20 I have a 302 and a Winter mechanical vario and I think if
your a serious XC pilot it is important to have a good TE compensated
mechanical vario on board and heres why:

Ely Nevada July 2006: I was 145 miles north on a big day[ way the hell out
in the middle of nowhere BTW ] and slowly my 302 starts acting strange and
slowly, over about 15 minutes my ASI goes to zero. Well the pitot pressure
drives the 302 and let me tell you, without it, the 302 is completely
unusable. I was having a big flight and did not want to turn off the
302, because I would lose the logger. So I took a piece of chewing gum
and a piece of paper turned down the volume to zero and covered the
instrument face. I flew 6 more hours and turned in a 1000+ km OLC claim.
the next day I pulled my pitot line and blew a bug out of the front of it,
problem solved. What a bug is doing coring a thermal at 17,000' I'll
never know, maybe he was a hang glider pilot in his past life.

Labor Day weekend 2004 Salida Colorado.
Flying with the Boulder Club, I get in my ship and [ It was gonna be cold]
with my big boots on, catch and break off the power switch...hmmmm,bummer,
If I get out of the launch line, [ this was going to be another big day ]
I would lose my flying buddies and the chance to max out the day.
So I took off with a Garmin 12 logger and only my Winter Mechanical vario
and did 400 miles.

It takes a few minutes to get used to flying with the mechanical, silent
vario in your scan [ with the 302 I almost Never look at it, I fly 99% by
the tones] but after a bit, the peace and quiet is NICE, for a change.
These were a couple of experiences I had where having a simple, but high
quality T.E. compensated Mechanical vario in the panel saved the day!

Nick Kennedy
XS & TF
How well do electric ones react to nearby lightning bolts? Apart from
that, isn't it an awful lot easier to fit a mechanical vario than it
is to fit a complete second electrical system?

Depends on which type you pick for your backup vario.

I have a single electric system fitted. I use an SDI C4 as my main
vario and a Borgelt B.40 as backup. Normally the electrical system
drives
both varios, but the B.40 has its factory-supplied backup system. A 9v
PP3
strapped to it and it has a three position power switch (Ext-Off-Int) to
select its power source. As the B.40 is said to run for about 24 hours
on
a PP3, its as likely to get me home as a mechanical unit. I swap the PP3
annually.

The B.40 was no harder to install than a mechanical backup, eliminates
capacity vs pressure sensor problems and is safer in backup mode than a
mechanical because it is an audio vario.


--
martin@ | Martin Gregorie
gregorie. |
org | Zappa fan & glider pilot