Go. Warming Air + Headwinds (+0
November 13, 2009: Migration Day 29
more about the pilot's helper, the GPS, in today's lesson.
winds are again blowing warmer to Stopover #5. The temp will rise
to a balmy 60 degrees F later today with gusts to 20 mph. Aloft
the SSE winds are ripping along at a powerful 35mph. Warm + windy
= no go.
But today is a good time to appreciate the GPS units
in the ultralight planes. Imagine
if the pilots hadn't had the benefit of the GPS in making their
decision to turn back on Day 27! Joe wrote: "We
slowly climbed to 700 feet and watched as the ground speed dropped
to 17, then 15 miles
The GPS gives you the time-to-destination in hours and minutes.
We took off with 2 hours to go and now, after flying for 30 minutes,
the next stop was 3 hours, 20 minutes away. We only carry enough
fuel for 3 and a half hours so it was obvious we were not going
the velocity of the aircraft through the air, says
pilot Joe Duff. "If you go too slowly the
wing cannot generate enough lift. At the same time,
the air through which you are flying is also moving.
Think of a speed boat going upstream in a river.
It may be cruising at 50 mph though the water,
but if the water is flowing downstream at 20 miles
per hour, the boat is only passing the shore line
at 30 mph. In the air that is called ground
speed, or the actual speed you are passing
over the surface. On our flight two days ago, the
birds were eagerly flying along at 38 miles per
hour air speed, but only making 25 mph ground speed.
What speed was the headwind?
(b-for-bonus) Click here to
study the photo of the GPS unit pilot Chris's ultralight
42 of last fall's migration. The photo gives us
a snapshot of the exact moment it was taken during
the flight. What information did the GPS give Chris
at that moment? Answer the questions to find out.
North is pleased to feature this educational adventure presented in
cooperation with the Whooping
Crane Eastern Partnership (WCEP).