Stealth Aircraft?

Do AIR FORCE or military have STEALTH aircraft that can make no sound while moving fast?

Because if so, then when people see UFO travelling really fast - it could be just our military testing aircrafts if they have them can't they? I am sure we do have some aircrafts that make no sound while travelling.

Originally posted by porsche2006
Do AIR FORCE or military have STEALTH aircraft that can make no sound while moving fast?

Because if so, then when people see UFO travelling really fast - it could be just our military testing aircrafts if they have them can't they? I am sure we do have some aircrafts that make no sound while travelling.

If your sure we have an aircraft that makes no sound while travelling then please name me one. From my limited knowledge of aviation I know that the faster the aircraft goes the more noise it makes because of sonic booms. People that have reported hearing the secret Aurora plane claim that its extremely loud, louder than other plane they have heard before. So it seems planes are getting louder, no quiter....

I forgot to add, what does stealth have anything to do with this? Stealth means its more difficult to pick up on radar. Do stealthy aircrafts look more like disk shaped UFOs than regular aicraft to you??

[edit on 18-4-2007 by surf911]

The B-2 is incredibly quiet, but it DOES make noise as it flies, and it's not exactly fast. ALL aircraft that we know of make SOME noise as they fly. And as was stated if they're going supersonic there's a sonic boom which can be picked up on seismic sensors a LONG way off. When I lived in Hawaii we were getting "earthquakes" over the space of months that turned out to be the ANG F-4 Phantoms going supersonic over 100 miles off shore.

Originally posted by surf911


If your sure we have an aircraft that makes no sound while travelling then please name me one. From my limited knowledge of aviation I know that the faster the aircraft goes the more noise it makes because of sonic booms. People that have reported hearing the secret Aurora plane claim that its extremely loud, louder than other plane they have heard before. So it seems planes are getting louder, no quiter....

Don't u think it would be a good move to make supersilent stealthy planes?
When u start thinking about it for a while it aint a bad idea . UAVs are planes to and maybe the whole disc shape is something to keep the sound in. Only an idea though!

silentaircraft.org...

just found this ! Its a Paper on the subject of making an silent plane , funded by MIT/Cambridge .

Originally posted by Spartannic

Originally posted by surf911


If your sure we have an aircraft that makes no sound while travelling then please name me one. From my limited knowledge of aviation I know that the faster the aircraft goes the more noise it makes because of sonic booms. People that have reported hearing the secret Aurora plane claim that its extremely loud, louder than other plane they have heard before. So it seems planes are getting louder, no quiter....

Don't u think it would be a good move to make supersilent stealthy planes?
When u start thinking about it for a while it aint a bad idea . UAVs are planes to and maybe the whole disc shape is something to keep the sound in. Only an idea though!

Im sure the military would love a silent stealth aicraft but we either havent made the breakthrough technologically to do it, the economics dont add up, or its not a priority.

Originally posted by surf911
If your sure we have an aircraft that makes no sound while travelling then please name me one. From my limited knowledge of aviation I know that the faster the aircraft goes the more noise it makes because of sonic booms.

It's because of the engines. The sonic boom is mostly all of the engine sound compressed into a shock wave. If the aircraft had no noisey engines then the sonic boom would be a lot less. A bullet going by your head only makes a small snap and that's due to the sound it makes going through the air.

People that have reported hearing the secret Aurora plane claim that its extremely loud, louder than other plane they have heard before. So it seems planes are getting louder, no quiter....

Supposedly, the Aurora is loud because it uses scramjet engines.

Actually sonic booms are usually TWO booms. One when the nose goes supersonic, and the second when the tail goes supersonic. They're so close together that we only hear one. The size of the boom is proportional to the size of the object going supersonic. A bullet has such a small mass, that it only displaces a small amount of air, so you get a tiny crack.

The reason I was asking was because the B3 (i think thats what it was called) in the movie I was watching, BROKEN ARROW, was silent and couldn't be picked up in Radar so I thought it existed in reality too.

The closest is the B-2. At high altitude it's almost impossible to hear. I've had them fly over me at less than 500 feet, and didn't hear them until they were past me already. I saw them long before I ever heard them.

I don't think that it's the lack of sound that make people ask questions. i think that it's the videos and sightings of objects going one way, then instantly changing the direction or then disappearing instantly.

Originally posted by Zaphod58
The closest is the B-2. At high altitude it's almost impossible to hear. I've had them fly over me at less than 500 feet, and didn't hear them until they were past me already. I saw them long before I ever heard them.

Any aircraft going supersonic will have that effect. It's basically ahead of it's own sound. If a supersonic aircraft is approaching you won't hear it until it passes.

No, it doesnt have to be supersonic, although the faster it is the greater the difference in its actual distance and where it was when you heard the noise it generated.

It isnt like something that is going M.99 is going be exactly where it sounds and something M1.01 will be something different.

Originally posted by firepilot
No, it doesnt have to be supersonic, although the faster it is the greater the difference in its actual distance and where it was when you heard the noise it generated.

It isnt like something that is going M.99 is going be exactly where it sounds and something M1.01 will be something different.

Yes, that is correct and doppler shifting will be in effect.

[edit on 19-4-2007 by 10538]

Originally posted by Zaphod58
A bullet has such a small mass, that it only displaces a small amount of air, so you get a tiny crack.

Haha! I would love for you to shoot a 30-06 or other high powered rifle a few times with no hearing protection. You might rephrase the word "tiny". You will have no hearing for 5+ days.

But in comparing to a sonic boom yes it is tiny.

Originally posted by Stockburn

Originally posted by Zaphod58
A bullet has such a small mass, that it only displaces a small amount of air, so you get a tiny crack.

Haha! I would love for you to shoot a 30-06 or other high powered rifle a few times with no hearing protection. You might rephrase the word "tiny". You will have no hearing for 5+ days.

But in comparing to a sonic boom yes it is tiny.

You are misunderstanding what he said. If you shoot a 30-06 over his head from a distance. He will hear the small snap of the sonic boom as the bullet passes by. He will later hear the blast of the gun when the sound of it reaches him. This is all part of army infantry training. It's how a sniper is located.

Originally posted by 10538
Any aircraft going supersonic will have that effect. It's basically ahead of it's own sound. If a supersonic aircraft is approaching you won't hear it until it passes.

Except the B-2 ISN'T going supersonic. And it has the same effect at LOW altitude as well due to engine quieting technologies used. As I said in an earlier post, I've had B-2s go over me at less than 500 feet and didn't hear them until they were past me, and they were moving at MAYBE 400 knots.

Originally posted by Stockburn
Haha! I would love for you to shoot a 30-06 or other high powered rifle a few times with no hearing protection. You might rephrase the word "tiny". You will have no hearing for 5+ days.

But in comparing to a sonic boom yes it is tiny.

From the RIFLE yes, from the BULLET, no. The shape and mass of a bullet mean that it only displaces a very small amount of air, and causes a very small sonic boom. You're comparing the initial sound of the bullet firing, which IS a big noise, to the tiny crack that a bullet leaves as it travels through the air. If you didn't hear the rifle firing, you'd only hear a small snap as the bullet went by you, because it doesn't displace much air. And airplane on the other hand, displaces a huge amount of air. The shockwave of them going supersonic makes a much bigger boom than the shockwave from a very small bullet.

Originally posted by Zaphod58

Originally posted by Stockburn
Haha! I would love for you to shoot a 30-06 or other high powered rifle a few times with no hearing protection. You might rephrase the word "tiny". You will have no hearing for 5+ days.

But in comparing to a sonic boom yes it is tiny.

From the RIFLE yes, from the BULLET, no. The shape and mass of a bullet mean that it only displaces a very small amount of air, and causes a very small sonic boom. You're comparing the initial sound of the bullet firing, which IS a big noise, to the tiny crack that a bullet leaves as it travels through the air. If you didn't hear the rifle firing, you'd only hear a small snap as the bullet went by you, because it doesn't displace much air. And airplane on the other hand, displaces a huge amount of air. The shockwave of them going supersonic makes a much bigger boom than the shockwave from a very small bullet.

Very true. If you have ever been shot at (from 300 yards+), you hear the crack (super sonic) from the bullet first, then you hear bang (sub sonic) of the rifle itself. The crack believe it or not is fairly loud, louder than the rifle bang at the 300 yard distance. Least in my experience.

Hmm, I wonder if the expanding gasses in the rifle barrel produce a sonic boom when exiting the barrel, creating two sonic booms when firing a bullet from a rifle My guess would be yes.

From what I recall, yes it does. The bullet is supersonic almost from the time it leaves the barrel if I remember right.