On Sun, 24 Apr 2016 10:33:05 -0400, Frank Krygowski
wrote:

In another thread, John proposed: "The NEW bicycle helmet
incorporating the speed sensitive flag pole (at no additional cost).
The faster you go the more the flag pole bends. At a sedate 7 MPH the
pole will be vertical and as speed increase the air resistance causes
the pole to incline further and further from the vertical."

Which reminded me of a cereal box toy one of my friends had when I was a
teenager. It pretended to be a bike speedometer operated by the
(relative) wind. As I recall, it was a pivoting airfoil. The faster
the bike moved relative to the air, the more torque the airfoil exerted,
cranking it clockwise against a scale purporting to read speed in miles
per hour.

I recall it being dismally inaccurate. And of course, it measured air
speed, not ground speed. It might read 15 miles an hour while standing
still.

BUT:

I'm a bit surprised that sophisticated bike cyclometers don't have an
airspeed function. While I've never gotten even an altimeter model, I
know you can get them with speed, distance, time, cadence, altimeter,
percent grade, feet climbed, heart rate, etc. etc.

Seems to me airspeed would be as interesting to gripe about as percent
grade, no?

Certainly and a simple propeller mounted on the helmet could be used
to calculate "apparent" wind speed. Sail boats use this system. If
this figure were to be compared with the actual speed of the bike a
"wind factor" could be determined.

I suspect that the propeller on the beanie is probably a major factor
in the system's failure to become popular :-)

--

Cheers,

John B.