I saw something in this thread about not liking them because a propellor sends how a huge radar signature making them easy to shoot down by a missile that is radar guided. Well, if that’s true about a prop, what about a rotor?
Think about what a radar sees looking from several miles away. A rotor viewed from the front (or side or rear) is like looking at the lid of a coffee can ON EDGE. But a propeller on a plane viewed from afar is like looking at the lid of the coffee can as if you were staring at it face-on....a much bigger signature on radar.
So a helicopter remains perfectly flat and doesn’t bank or otherwise shift the orientation of its rotor throughout flight?
I didn't say that. Of course it banks and such. But, if you you're looking at a helicopter's rotor from missile distance (a couple to several miles away, let's say) what do you (on average) see? You're seeing the helo's rotor on EDGE and even though it's bigger than a typical plane's propeller it results in a much smaller signature on radar. As the helo yanks and banks during flight a radar may see the helo's signature come and go.
I work as a meteorologist and specialized in Doppler radar during my graduate studies. I have a couple of scientific journal publications on dual-Doppler radar analysis. One thing I can assure you - radar, while technologically well-developed and generally robust, is some persnickety s hit. Atmospheric conditions along with power output and tuning have to be just right in order to "see" exactly what you want to "see" with radar. Anything to reduce an aircraft's signature on radar is paramount to remaining stealthy - and the last thing you want to have is a giant fan turning in front of you 100% of the time that ends up looking like a great big bullseye to a radar. The only way to get THAT signature to come and go like with a helo would be to fly the airplane straight up or straight down - one of those is unattainable for any length of time, the other unsustainable for any length of time. ;-)
