Frosty Wings: A Problem
Adapted from the Field Journal of Operation
Migration Pilot Joe Duff
preparation for the cold mornings on migration the pilots sewed
wing covers so they wouldn't have to scrape frost off the wings.
With 30 yards of material and 60 feet of Velcro needed for each
wasn't an easy job! Why is frost a problem the pilots want to
solve? Read on as Joe Duff explains.
|Pilot Joe Duff explains: "Ice
on wings is a problem because it forms a rough surface that the air
can't stick to. A layer of air called the boundary layer forms
along the top of the wing and allows the wing to create lift.
The ice disturbs this boundary layer and the lift is destroyed; then
the aircraft can't fly. (Most often the ice forms thicker on
wing than the other, and the aircraft would roll before it crashed.)"
Dealing With Frost
a recurring problem that we face all the way to Florida. Frost most
often develops just before sunrise and continues
to build until
the air starts to warm up. (When the temperature and dew point are the
same number, a thick blanket of fog is produced; when that number
is below the freezing point, it also creates frost.) Frost delays
our take off until the sun comes up and heats the upper surface
of the wings enough to melt it away. The "golden hour" of calm air in
the morning is short lived, and it is frustrating to waste most of
it scraping frost off the wings.
tried covering the wings with surplus parachutes but they weren’t
waterproof. We just ended up with frosty wings and yards of wet
have tried removing the wings, putting them flat on the ground and
covering them with tarps, but the moisture in the grass
some locations we are able to remove the wings and store them
inside overnight. But then it takes time to carry them out and get the aircraft
ready to fly. Sometimes, even in that short space of time,
forms on the wings and we are back to waiting for warm air.
have tried de-icing with propylene glycol and warm water from
have tried rubbing and scraping and cursing, but patience, despite
accompanying frustration, seems to be the only cure.
Covers: A New Solution
around the 35-foot wingspan of four aircraft is not
an easy job, but we finally decided that it is the only solution.
faced with frost a few years ago at the Morgan County, Indiana stop,
our host directed us to a tent and awning manufacturer
where we bought 40
yards of nylon,
50 yards of Velcro, and
a cheap sewing machine. In our stopover host's
hangar we dropped one of the wings to lay out a pattern and began
to cut — with plenty of help from him!
want to cover the wings, both top and bottom sides, while they
are still on the aircraft. This way we can prepare to fly, and
even start the engine before separating the Velcro and slipping
the covers off the ends of the wings. Then we simply jump in,
belt up, and take off before the frost has a chance to form.
At least that's the theory.
Try This: Journal or Discussion
of a time when you had to invent a solution to a problem. How did
you solve your problem in a way you hadn't tried before? What did
you discover from the results?
Journey North is pleased to feature this educational
adventure made possible by the Whooping
Crane Eastern Partnership (WCEP).