![]() |
| If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|||||||
|
|
Thread Tools | Display Modes |
|
#13
|
|||
|
|||
|
Morgans wrote:
Also, keep in mind that you only need to de-ice the leading edge of the wing (look at how much boots cover). Different princples at work. If you *melted* the first few inches of ice, it would run back and re-freeze, before it got off the wing. Bad thing. VERY bad thing, as in guaranteed crash, after about 1/4" of ice. I couldn't find any definitive references with a quick search, but I'm pretty sure that jets with heated wings, only heat the leading edge, not the entire wing surface. I suspect that the ice melts slowly enough that it evaporates (or sublimates) long before it can run back over the wing. So the area is probably closer to 2' times the wingspan which means 50-80 sq. ft. one a typical light airplane. Nope, see above. Good for crashing, if it did stay hot enough to melt ice. And you don't need to coolant at 180F+ to deice a wing, so you can push the coolant through a lot more area than a radiator and still keep sufficient temperature to melt or prevent ice. You will have to add another pump (more weight) to move that "cooler" water, then. ALL of the water that comes out of the engine is at 180 degrees. Preventing it is easier than melting an accumulation to be sure. This holds with other systems such as TKS as well. Different, once again. Preventing it from forming on the leading edges, and letting it freeze further back does no good. TKS keeps everything that runs back from freezing, because the antifreez has mixed with all of the water running back, to make a mixture that is above freezing. If you melt it at the front of the wing with heat, the water must stay hot enough to run ALL OF THE WAY back, and off of the wing. Jet engines have enough waste heat to do that. IC engines DO NOT. Get that through your head! It is not done, because it CAN NOT be done! Get it? Sorry, I've not seen any data that supports this conclusion. I don't think Jet engines are that much less efficient than piston engines, especially given that amount of heat they directly eject out the tailpipe. For my final argument, why are wing radiators not commonplace? I'd guess cost and complexity would be two big reasons. Yes, but you missed the biggest one. Weight. Weight. Weight. If it were cost and complexity, someone would still do it. They *will not* sacrifice the weight. Yes, I'm sure weight is another reason, although this could be minimized if the coolant channels were formed integrally with the leading edge skins. However, that would then bring back the cost issue. Matt |
| Thread Tools | |
| Display Modes | |
|
|