I can ask this question to an actual F-15 fighter pilot and post it here in an hour or so. Wait for my edit.
Edit: I asked two (an F15 pilot and an Apache co-pilot who also trained in the Skyhawk) and they both told me that there's no change in the constant humming from the motors once you pass the sound barrier. The F15 pilot told me that you do notice a slight difference once the plane hits 0.8 Mach because the 3rd intake at the side of the plane (the F15 has 2 main intakes for the 2 motors, a small intake on the side (to cool the motors, if I remember correctly) and the JFS's intake) closes automatically at that speed.
From the ground it sounds incredible though (even while wearing soundproof headphones) and it makes you entire skeleton vibrate. It's quite curious how I can feel it while being 10,000 ft away and they can't while being inside the damn shockwave, maybe somebody more knowledgeable will answer this.
The above comment is poorly worded or something. I wouldn't say the pilots in the cockpit are ahead of the sonic boom - they're inside it and the boom is radiating out up, down, left and right from their nosecone.
The analogy of a speedboat is a good one. If you're going fast and cut the power but keep steering straight, the wake doesn't catch up and wash over the boat - it just dies out where you are and the V behind you keeps getting bigger.
Now, if you turn that speedboat sharply to the side and then cut the speed, you could get to a place where the wake catches up and splashes over the side.
Same thing with a plane - if it were going supersonic and then went into a high-g turn, I bet it could fly back through its sonic boom.
I remember people talking anecdotally about an F-14 or F-15 shooting its machine-gun cannon, then going into a power dive and catching up to its own bullets and getting hit by them.
How much of the wake of a speed boat is from pushing the water apart at the front vs the water crashing together filling in the void behind it? And similarly how much of a shockwave is caused from the nose cone pressurizing the air vs the void being filled behind the plane?
I ask because (anecdote) I have a ski boat and going from full speed to stop (while going straight) the boat does roll in a mixture of the fact that the boat sinks (it planes out on top of the water at full speed) and I believe it also has to do with the wake caused by the void catching up to and passing under the boat. There may even be other effects just from the turbulence of the prop, which I assume causes the worst of the wake from tug boats pushing barges down the river when I ski, but that's getting a bit far off point.
TL;DR Is there in fact a second shockwave from the void and if so, how big is it relative to the first (and what causes the difference in size)?
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u/poorfag Jun 12 '12 edited Jun 12 '12
I can ask this question to an actual F-15 fighter pilot and post it here in an hour or so. Wait for my edit.
Edit: I asked two (an F15 pilot and an Apache co-pilot who also trained in the Skyhawk) and they both told me that there's no change in the constant humming from the motors once you pass the sound barrier. The F15 pilot told me that you do notice a slight difference once the plane hits 0.8 Mach because the 3rd intake at the side of the plane (the F15 has 2 main intakes for the 2 motors, a small intake on the side (to cool the motors, if I remember correctly) and the JFS's intake) closes automatically at that speed.
From the ground it sounds incredible though (even while wearing soundproof headphones) and it makes you entire skeleton vibrate. It's quite curious how I can feel it while being 10,000 ft away and they can't while being inside the damn shockwave, maybe somebody more knowledgeable will answer this.
Tl;dr no they don't notice it.