"Eric Greenwell" wrote in message
...
snip

Some of the sensors actually sensed at right angles to the sensor beam
to measure crosswinds, and maybe one of these could be also be pointed
straight down into the same airmass the vertical speed unit was looking
at.


I think it might work - though at a hefty price I bet.

Yes, all the units I came across seemed to be high end or developmental,
and rather large to stick into a glider. A careful search might have
better luck.

The sensor I posted a link to was small enough to be mounted on a rifle as a
sight.
http://www.navysbir.brtrc.com/succes...navsea_p3.html

That would seem to be a feasible size, weight and ruggedness for a glider
I've sent an email with some questions I had, but haven't yet received an
answer.

Some of the applications they mention on that website -- Automotive,
Collision Avoidance,
Cruise Control, Parking Aid, would require the cost to be fairly reasonable
(though the volume would be a lot more than sailplanes would ever give
them.)

A mitigating factor for cost is gliders already have a pretty good
forward airmass speed sensor - the ASI - so perhaps only a downward
aimed laser sensor good for measuring 100 to 500 feet per minute at 2%
accuracy would be satisfactory.

If the laser and optics can be made to "see" through the canopy, pointing it
upward might make for an easier install. I've seen compasses mounted on top
of the panel.
OTOH, with it pointing downwards, it might give a good input to a gear
warning device. If it can detect small particles, I'll bet it can detect a
solid surface -- and that the signals are way different.



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Eric Greenwell
Washington State
USA