GPS glide ratio calculations

Hi the

I think the Vista and will log altitude, but you have no control over
the timing of the recording unless it is a higher end version - it is
always automatic. The Garmin76 has long tracks and has better timing
control (more expensive though) - The GPS12X does not record altitudes.
Magellans have much worse support for logging tracks. They are always on
and you have almost no control over the track. I don't know about the
Flyer - it may be better. Occasionally the altitudes on GPS can be be
off and sometimes will jump around or plummet to the ground (goes to
zero suddenly because of loss of signal). I think you must keep the
antenna on the GPS clear of obstructions and then everything is fine. I
would say that the Garmin76 would be the best for your purposes.

On software - I have 3DTracer myself. It will calculate glide ratios as
you can select any section of the flight track and then perform
calculations on it. You can also load 3d maps from terrain DEM files.
(The animations are just amazing - but off topic I suppose). It is
cheaper than SeeYou and the animations are better - but less support for
OLC. I also looked at CompeGPS, too - it is geared to hanggliders - But
it had a few crashes on my machine and the 3D part was difficult to move
around in. The hard part in 3DTrace is getting the files properly set up
- the data is on the web you just must find it and calibrate the map
properly. Oh yes it also has a cool flight deck that shows you
everything thats occurring.

The other option is to hook up a PDA to the GPS and this can be your
logger - this has the difficulty that it is and extra cable, an extra
set of batteries and getting the software on the PDA. But it works - I
have the GPS12 with PDA software on an old Palm, with spliced together
cabling. It was around $500 altogether - $200 for GPS, $200 for the PDA,
$100 for the software - and you can use the PDA for its originally
intended use.

Any how my 2 cents


Kirk Stant wrote:
James,

Interesting hobby!

You could use a GPS logger (like a Volkslogger or Colibri), set to
minimum logging interval (1 or 2 seconds). You would have to download
the trace afterwards and use a program to view it. I would recommend
SeeYou, but some other more terrain-oriented programs might have
better terrain resolution (which would be important for you, I
assume).

This setup would require a small battery hooked up to the logger, but
with the short flight duration it shouldn't be too big.

Some of the newer Garmin handhelds also log altitude, they may be a
lot cheaper and just as useful. The key is probably going to be the
software you use to look at the trace.

Let us know how it works out.

Kirk
LS6-b "66"