Tony Verhulst wrote:

I've always felt (but have no evidence) that positioning a yaw string on
the canopy is not optimal, and that you really want it in clean,
undisturbed, air (yeah, like the 2-33). There could be 2 problems with
the canopy mount. One, it is flush with a compound curve surface and who
knows that the air is doing there. Two, it is in the boundary layer
between the canopy surface and the airflow and who knows that the air is
doing there.

I wonder if any one has experimented with a "normally" mounted yaw
string and one placed on a post several cm higher.

Tony V.
Our club gliders all had or still have the yaw string mounted some centimetres
off the fuselage.
The Blanik L13 has its on a TE probe about 5cm long, the two BergFalkes have
wire standoffs on the nose. In all cases the string in the free stream tends to
flap like a flag, which can be a little irritating. They also easily drape
around the support and inattentive pilots then end up flying with no yaw
indication. We recently moved the string to the canopy on one of the Bergies,
and the result is an improvement.

In my experience the canopy mounted string is a stabler, and in most situations
better, tool. The small area occluded by the attachment is not significant as
long as you do move your head when scanning. Otherwise it can obscure other
aircraft.
--
Bruce Greeff
Std Cirrus #57
I'm no-T at the address above.