The F-117 doesn’t have a vertical tail; it has a V-tail arrangement.
I see no reason that sound waves wouldn’t reflect similarly to radio waves. Especially since the waves are apparently similar in wavelength.
Are dead bats found around non-stealth aircraft?
There’s something intuitively fishy about this story. Is it physically possible for stealth technology to hide an object that has such a large apparent size to the observer trying to detect it? Could you make a “stealth mountain” that airplanes would crash into because they can’t see it on radar?
Edit: Or perhaps a better analogy would be a “stealth island” that submarines plow right into. This sounds like Romulan cloaking technology.
Presumably, the pilot of the airplane would (physically) see Stealth Mountain, and thus avoid it.
Stealth technology doesn’t make things disappear. It makes them appear smaller. Thus, an F-22 looks like a bird to radar (or even an insect). It won’t be totally invisible.
That’s more or less what I’m thinking, but taking it a step further, imagine the radar antenna is about ten feet away from the F-22. It wouldn’t look like a bird then, would it it?
The F-117 has a radar absorbing paint applied to it’s surface which contains tiny spheres coated with ferrite. Here, wiki explains it better than me
I wonder if that could screw up a bat’s sound waves somehow.
No one has brought it up, but I meant to say they don’t exactly park them in tents.
I don’t think the paint will have any effect on the bats sonar. The only reason that could be any plausibility to this, is because they are both waveforms. They might reflect similarly. Sonar will not induce anything in magnetic materials.
The problem I have with this story is that the planes do reflect radar and sound waves, they just don’t send them back the original source. This is easy to do when the source is many miles away. I don’t believe this will work at a distance of a foot or two, which is the distance the bat would be. Even if we assume that the sound waves reflect perfectly off the faceted surfaces, and there is no sound “scattering”, there will always be a point on a flat panel that is perpendicular to the sound source. This point would definitely be visible to the bat.
Of course. I was being lazy. When you talk about such things every day, you actually get less pedantic. I’ve certainly been a part of technical discussions that made mention of the 117’s “vertical tail”, wherein none of the participants batted an eye.
In fact, I think we should ask whether bats actually use their echolocation to avoid large obstacles, or just to find prey. Maybe they use the echolocation for hunting and depend on vision to avoid hitting things.
Edit: In other words, would a bat tend to crash into any large black object in a dark hangar? This could actually be tested by parking a black car in a bat-infested shed, though I personally wouldn’t want to kill a bunch of bats.
I figured. I pointed it out because I think it might be relevant vis-a-vis how easy it is for a bat to detect it in horizontal flight.
But the plane don’t have to be totally invisible to bats echolocation. All you need is one of several dozens polygons that F-117 is made from not to deflect sound waves back to the bat from certain angle. “Ooh, it looks like opening to fly through” - thinks the bat - Splat. While radar echo of whole plane is non-zero, it’s certainly possible to make one or several parts of plane to have no echo at all - looking from certain angle. Hence my anechoic chamber analogy.
IMO a very good question. Maybe a bat expert can see this and answer?
Personally, I don’t find a couple of scattered anecdotes to be credible evidence, regardless of whatever Super Secret 11 Herbs and Spices go into a stealth plane (and this isn’t MIB-level stuff either; the planes have been around for some time. I’ve even got a piece of wing material at home from a stealth aircraft, given to me by a professor years ago).
Well, maybe that would explain how bats would ‘see’ a stealth plane, but still run headlong into it. “Mmmm, yummy bug! Time for some dinn–” SMACK!
Stop all this insanity! The planes are NOT invisible to bats as a function of their stealth technology. The polygons, the paint etc are designed to deter detection by RF microwave frequencies not small mammals using ultrasound. Stealth composites and paints are not sound absorbing in the least.
The only possible scenario of bats not “seeing” them is if they are painted dark/black in a dark hanger and the bats literally run into them because they can’t see them visually. As bats can use echolocation to get around fine in near pitch black caves this scenario seems highly implausible.
Apparently, underwater seamounts are pretty stealthy:
Let’s paint some cave walls with the same coating as on the planes and see what happens.
Someone should submit this to Mythbusters.
An interesting idea, although it would not eliminate all the variables. The bats might be able to navigate their home cave better because it is more familiar to them than an aircraft hangar they bumble into.
I agree with the distance thing.
But it might actually make things WORSE for the bat.
There is a nice flat panel or edge the bat is getting a good echo location from.
He adjusts his directional vector so he WONT hit that panel. The problem is, there is another panel he is NOW headed towards that is one, not reflecting towards him, and two, perhaps its signal is being overwhelmed by that panel that IS reflecting well.