Minumum Sink Rate/Best L/D at 17,000 feet ?

Kemp wrote:
A related and very critical point that I've not seen mentioned or
written anywhere about higher altitude soaring (17K and above) is that
it is much easier to exceed Vne because of human factors combined with
thinner air.
1) Less noise: Because the air is thinner, there is less air flow
noise in the cockpit. Many pilots use air flow noise as a secondary
way to monitor airspeed.

My perception is the noise is greater, but maybe what I'm reacting to is
noise that's a higher frequency than the same IAS at a lower altitude.
Or, maybe what I'm responding to is more vent noise at higher altitudes,
not the glider airframe noise. I'll have to pay attention the next time
I fly!

--
Eric Greenwell - Washington State, USA
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On Jan 1, 2:18 pm, Eric Greenwell wrote:
Kemp wrote:
A related and very critical point that I've not seen mentioned or
written anywhere about higher altitude soaring (17K and above) is that
it is much easier to exceed Vne because of human factors combined with
thinner air.
1) Less noise: Because the air is thinner, there is less air flow
noise in the cockpit. Many pilots use air flow noise as a secondary
way to monitor airspeed.

My perception is the noise is greater, but maybe what I'm reacting to is
noise that's a higher frequency than the same IAS at a lower altitude.
Or, maybe what I'm responding to is more vent noise at higher altitudes,
not the glider airframe noise. I'll have to pay attention the next time
I fly!

--
Eric Greenwell - Washington State, USA

I notice a significant reduction in noise when climbing or
descending... but when my ears pop, the noise is restored to its
previous level. ):

Seriously, a gliders sound is different in character and seems quieter
in laminar wave which I have always assumed was due to increased
laminar flow in the very smooth wave. I have also noticed that my
voice assumes a "helium breathing" character when I use the radio at
higher altitudes.

As for sound as an airspeed cue, the glider I fly is quiet enough the
ASI is needed for accurate speed control.

Bill Daniels
Wintering in San Diego, CA

Bill Daniels wrote: As for sound as an airspeed cue, the glider I fly is
quiet enough the ASI is needed for accurate speed control.



The air noise seems mainly a matter of a good canopy seal. Is there a good
sealing material that anyone has found? I've tried commercial foam strip,
but it's rather too thick, and smears to a gummy mess after a while.

On Jan 1, 4:00 pm, Andrew Wood wrote:
Bill Daniels wrote: As for sound as an airspeed cue, the glider I fly is

quiet enough the ASI is needed for accurate speed control.

The air noise seems mainly a matter of a good canopy seal. Is there a good
sealing material that anyone has found? I've tried commercial foam strip,
but it's rather too thick, and smears to a gummy mess after a while.

My canopy seems to seal well without a gasket. However, I've seen an
external seal that looks like a smaller version of a aileron gap seal
and was told it's available from hardware stores.