"Matt Whiting" wrote
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.
Pure volumes of fuel burned, is the all important factor. What does a
modern airliner burn per hour. Doug, or other jet qualified dude? 50
galons per hour for a regional turbo prop? 100 or more for a smaller
turbofan? Compared to 20 or 25 for a piston. Not even in the ballpark.
Not enough energy avaliable.
That many gallons being burned is a lot of energy available, and a
percentage can be used for anti ice. It is no free lunch, and the jets burn
more fuel when the anti ice is on. I don't know how much, but it is a large
enough factor to have to be calculated, AFAIK. Bleed air is used, and that
is capable of a tremendous volume, at a high temperature. An airplane
piston engine might be able to make that much heat and volume from
comperssed air, if it ran a rotary comperssor, and didn't have to mess with
a propellor. It would not fly very good without a prop! g
You also mentioned the water running back, only being heated from the front
with jets. OK, but they can heat it hot enough to evaporate some of it,
and get the rest hot enough that it does not refreeze before running off.
The piston engines could not put enough heat out, like the turofans. Even
the turboprops have to use boots.
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
If it would work, someone would have done it, with the cost not being an
object. The weight issue is too much to overcome, along with the
complexity. Still, the whole thing comes back around to the fact that it
demands more energy than is available.
Give it up. I know you won't; you just want to tilt at windmills. That's
OK, if that is your thing. It is not mine.
I'm done here. Good luck.
--
Jim in NC
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