On Jan 13, 11:03*am, wrote:
On Jan 13, 8:36*am, Darryl Ramm wrote:





On Jan 13, 8:23*am, "kirk.stant" wrote:

Is anyone working on or studying using WAAS GPS data to make a stand-
alone vario? *How would TE be implemented in such a device? Ground
speed change during a pullup? *TAS based on circling winds?

Do the current PDA software programs (mSeeYou, Winpilot, etc.) when
used in GPS-only mode provide accurate vario data when hooked up to a
WAAS GPS?

Just curious - seems a 5 hz WAAS GPS could be the basis for a really
nice vario that wouldn't need any pitot-static imputs. *I use mSeeYou
and a Themi, non-WAAS, and the "vario" data seems close, but I use it
more for trend and average than instantaneous data.

Winter can't end soon enough!

Kirk
66

Yes but how does it tell the difference between an increase in wind
and a pull up? How will it handle STF calculations in a strong
headwind/wave where it may be really confused what is going on?

Darryl

Darryl's right (again).

I don't think there's really a satisfactory way to take wind out of
the equation. You could try to do it with track and drift trends, but
that's not very precise given how much the wind can vary with
altitude, position and over time.

9B- Hide quoted text -

- Show quoted text -

Cmon, let's think out of the box!

An INS/IMU can measure winds without air data. How accurate (read
"expensive") would an inertial sensor need to be to provide useful
wind data (or just TAS vs GS)?

Or bite the bullet and T into the pitot/static system and provide the
data to the GPS vario - no worse than a TE connection for a
conventional vario.

Question is whether it would be cheaper and/or better than current
mechanical or electronic TE varios? Better or worse at altitude,
faster/slower response, etc?

I'm thinking: One little box with an LCD display. TE vario, audio,
horizontal lift distribution in the current thermal in real time (for
centering), current average, past averages/acheived climbs (trend for
MC settings), logger, GPS output for other devices. Run off ship
power and have a backup rechargeable battery.

Stick in a 68mm hole, hook up pitot/static and power, off you go.
Replaces your backup mechanical or electric, gives you a real backup
when your TE probe falls off! Do it for less than $500 (yeah, right,
I know...) and you stick it in every glider out there (think of all
the crap instruments in club/commercial gliders in the US).

And please don't say "Cambridge 302" - TE probes are soooo 20th
century!

Kirk
66