Re: FM signal demodulating
Your new schematic might amplify 'something' at very low frequencies if driven from a low impedance. I wouldn't expect any appreciable volume at the loudspeaker and it wouldn't efficiently amplify anything at frequencies higher than a few KHz. I'm not sure why you call it "airecraft receiver", it stands no chance whatsoever of receiving an aircraft signal unless you are maybe sitting on it's wing!
Brian.
Please don't say this one is carp
Where are you getting these circuits from? They all seem to be variations on a theme but, as we don't know what you are trying to create, it is hard to tell if the variations are getting you any closer to your goal.
Are you try to:
1) build an FM demodulator (as the title says)
2) build an FM radio receiver (which most of your questions imply to me)
3) build an AM radio receiver (which is what you need for an aircraft receiver)
4) build something else entirely
Susan
All of them, I am trying to learn more.
Well.... so far none of them will do what you want!
Basic blocks of a radio receiver are:
1. something to select the frequency you want to listen to. (your circuits have never had this)
2. a demodulator (AM or FM - yours has a wrongly connected AM demodulator)
3. an audio amplifier (only the one post #22 has one and it isn't wired correctly)
For the simplest air band receiver you probably want to research "super-regenerative" receivers. They are far from best but they are simple to build.
Brian.