Originally Posted by
Security007
Hello everyone. I would like to bring up some points of interest that deal with the membrane concept of de-icing on the leading edges of wings.
I also at some later point---want to explore with you---the center of balance of the Q400.
After investigating this balloon concept to deice the wings theres doubt in its design and how it will continue to function as it was intended. In short--here is what I have initially concluded (in part).
This inflatable membrane concept has several drawbacks that may cause it not to function as intended.
One factor to consider---Is there moisture in the plumbing system connecting to the membranes? Is the air inside the plumbing 100% free of moisture? Where does the air come from? Is the air drawn in from the atmosphere--like when its raining? Or is the air special---like a can of compressed air used on computers to clean them?
If theres moisture in the plumbing--the lines or membrane can freeze causing a loss of air pressure to the membranes (the membrane will not expand. (Partially explored)
Another thought is this---Inflating and deflating rubber--or whatever material is used-- changes its elastic properties and therefore the original dimensions of the membrane change with usage.
Electric rubber heating pads are far superior to the balloon concept to deice wings--so why use this balloon concept vs. electric heating pads?
Some answers of a general nature.
The air used to inflate deicing boots is usually drawn from the engines (upstream of the combustion chamber). It is therefore air from the atmosphere, and thus will have humidity in it. It's also pressurised and hot as a result of being pressurised, so it's unlikely that the air in the tubes will form ice. In any case, the system has to be demonstrated in icing conditions for aircraft certification, so any weaknesses in the design should come out at that point.
Electric deicing is not superior to boots - it has a number of problems of its own, including the power required to get equivalent performance, and the need to generate that power from somewhere.
The most effective system around today is almost certainly bleed air used to heat the surface. But it requires a lot of energy from the engines, and isn't a viable solution for all types (nor is it required for all aircraft in the same way).