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Frosty Wings: A Problem
Adapted from the Field Journal of Operation Migration Pilot Joe Duff

In 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 aircraft, it 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 one wing than the other, and the aircraft would roll before it crashed.)"

Dealing With Frost
Frost is 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.

  • We tried covering the wings with surplus parachutes but they weren’t waterproof. We just ended up with frosty wings and yards of wet fabric.
  • We have tried removing the wings, putting them flat on the ground and covering them with tarps, but the moisture in the grass just freezes everything together.
  • At 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, the frost forms on the wings and we are back to waiting for warm air.
  • We have tried de-icing with propylene glycol and warm water from a hose.
  • We have tried rubbing and scraping and cursing, but patience, despite the accompanying frustration, seems to be the only cure.

Wing Covers: A New Solution
Wrapping fabric around the 35-foot wingspan of four aircraft is not an easy job, but we finally decided that it is the only solution. While
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!

We 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

  • What is frost?
  • Think 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).

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