On May 17, 6:30*pm, "Peter Dohm" wrote:
"Wayne Paul" wrote in message

...

"Peter Dohm" wrote in message

.. .

The idea of the string, or the string on each side, is not that that it is
a
true angle; but, if the canopy sides are at a promising height and also an
adiquate distance from the wing, that the positions can be marked as
calibration points for the particular angles of interest--such as best L/D
and minimum sink.

I understand the process. *I currently have a yaw string on my glider. *The
other canopy strings might be somewhat effective; however, I'm spoiled. *I
flew 13 years in the US Navy with "real" AOA systems. *I am not looking for
a crude substitute. *I'm looking for the real thing.

Waynehttp://www.soaridaho.com/

I can certainly understand that, and there is no question about which is
"better".

Also, the issue of whether the string(s) can be easily, accurately and
safely read in flight is open to question--and certainly must be resolved
under conditions other than ridge lift. *IIRC, you were amoung the
participants, a number of months ago, in a human factors discussion
regarding the effects of head movement while circling and the relationship
of that to an otherwise unexplained glider crash into a mountain side. *The
issue is not one that I would take lightly, and anything that requires a
head movement up or down while also turning the head to either side should
probably be avoided; but a cheap and dirty solution could conceivably work
if peripheral vision, or an eyes only glance, is truly sufficient.

OTOH, a true AOA system that can be calibrated over the full reasonable
range of angles is far from trivial--and probably well beyond my design
capabilities.

Peter



Having used "pitch strings" on several gliders, I can assure there are
no 'human factors' issues whatsoever. The "pitch strings" are in easy
view and not any more distracting than a yaw string which they
complement. It would be equally absurd to claim that an airspeed
indicator is 'distracting'.

In fact, the indications are so intuitive that all pilots who have
used them feel they had a much better understanding of what the glider
and the atmosphere was doing. Think of them together as a "3D yaw
string"

They actually help with thermalling reacting 3 seconds or so ahead of
a vario indication. The strings flick upward as you enter a thermal.
One pilot told me that the strings "got him home" by improving his
'dolphin flying' technique.

Let me add that if a pilot DOES find them distracting, he would fail
that part of the Practical Test Standards dealing with pilot
distractions.

AOA indicators are 100% a good thing. There are no downsides to
having one. There is nothing "open to question". While there are
many crashes that are arguably due to the pilot NOT having AOA
information, there are probably NONE where having that knowledge was a
contributing factor.