flying-bits´nbytes
3rd Dec 2000, 18:08
What are the Differences in the Deicing fluids ? (except the color !)
Mattvitale
4th Dec 2000, 07:27
All 3 different types use glycol as the base fluid. Type I fluid is glycol, usually dilluted with water and heated. It is primarilly used to deice aircraft (ie- remove accretions of snow and ice) Types II and IV are also glycol based, but have had a thickening agent added. They are typically applied undiluted and cold. They are used as anti-icing, applied after the application of type I deicing fluid. The II and IV fluids depress the freezing point of any new precipitation, preventing it from adhearing to the aircraft. The aircraft then is suppossed to depart within the given hold-over time, and the fluid and any accumulated precipitation comes off as the aircraft gains speed, leaving the airfoils clean (at least in theory) by the time the aircraft reaches its Vr. Type IV fluid is the latest edition, and provides longer hold over times then Type II fluids. Both II and IV are pretty sticky, and generally require the use of a higher Vr speed to assure all the fluid is shed (at least in the turbo-prop commuters I fly.) Hope that helps.