It probably works better in rough western conditions. As you said, "pitch
strings" are very sub-optimum AOA indicators. I don't use them because
it's such a hassle closing the canopy without trapping the strings between
the canopy frame and fuselage.

I think it's likely that the SafeFlight vane-type AOA indicator works fine
as long as you are fairly good at keeping the yaw string centered.
SafeFlight has been around selling these things to airplane owners for a
long time. It's nice to see them offering a product for gliders.

Bill Daniels


"jcarlyle" wrote in message
...
I've got pitch strings on both sides of the canopy of my ASW-19, Bill,
but I've not seen this behavior. I'll make an effort to look carefully
the next time thermals appear in Pennsylvania! As was said earlier in
the thread, though, strings on the canopy are greatly affected by yaw.
They might help indicate lift, but they won't really be useful AOA
indicators. And if AOA instruments average out rough air fluctuations,
they won't be too useful as incipient lift indicators. Tough problem!

-John

Bill Daniels wrote:
Many pilots who have tried the "pitch strings" report that they give
advance
warning when entering an area of lift. When you enter the edge of a
thermal, the strings show a sharp increase in AOA several seconds before
the
vario shows lift. This improves the efficiency of "dolphin flying" by
providing an earlier signal of when to start a zoom. One pilot on a
marginal final glide told me, "Without them, I wouldn't have made it
home."
An ASI gives the same signal but it's weaker and harder to interpret.

Most AOA sensors have some damping to smooth the signal in rough air.