quote:

Originally posted by jbcummings:

quote:

Originally posted by billnchristy:
I think half a mile is only a close call in nuclear warfare.

I think I saw in the video a ~390 MPH speed for the jet. That's about .055 second reaction time should something go amiss. Not to mention the turbulence in the wake of that thing. I'm surprised it didn't flip the balloon over.

It really depends.

We routinely fly less than 1/4 mile from each other. At least momentarily. 1000 foot vertical separation is not uncommon, and I have flown directly over someone so closely that my radar altimeter pinged off their fuselage. 1000 feet horizontally is also very close, and against the regs, but not deadly. The only time reaction time becomes an issue is when you are going to occupy the same space, and that's why we have eyeballs, controllers and collision avoidance equipment.

I'm not sure how big the payload of that balloon was, but I don't think hitting it would have been catastrophic even if they took it right on the windshield (as long as it wasn't too big).

Needless to say though, there wouldn't be any reaction time. Just "What's that?" followed by a *WHACK!* if it was a direct hit.

But if the balloon wasn't there, would it have made a sound?

quote:

Originally posted by qxsoup:
If n A320 is going .90 mach then something is wrong.

They normally cruise at .80 at most. My 747-400F normally flies at .84 and high speed cruise can be as high as .88. Whale for the win!
David Lee- Those Polar/DHL 747's are the ones that my company operates, We also operate most of the Amazon and DHL jets that you see out there as well.

They are beautiful aircraft and I truely enjoy seeing them. Also, sigmonkey was a Phantom fixer upper at war time. If he tuned up a air bus, it would do .9 at cruise.

quote:

Originally posted by slosig:

quote:

Originally posted by David Lee:
I love watching the big birds coming in and out of CVG. Favorites are the Polars and DHL. They aren't going fast and those Polars look like they just hang there in the sky. I think one of the other large birds is Allegis. Now we are seeing many Amazon flights. I've viewed 1 beautiful South West bird.

I've been wrong before, but I always thought those '47s were going as fast as anything else, if not faster, in the arrival area and that they only looked slow because they are so big.

Probably correct about their speed. They just are huge.

How does a C 17 compare for engines and power? I would jump at the chance to ride on one of those.

quote:

Originally posted by Otto Pilot:

quote:

Originally posted by jbcummings:

quote:

Originally posted by billnchristy:
I think half a mile is only a close call in nuclear warfare.

I think I saw in the video a ~390 MPH speed for the jet. That's about .055 second reaction time should something go amiss. Not to mention the turbulence in the wake of that thing. I'm surprised it didn't flip the balloon over.

It really depends.

We routinely fly less than 1/4 mile from each other. At least momentarily. 1000 foot vertical separation is not uncommon, and I have flown directly over someone so closely that my radar altimeter pinged off their fuselage. 1000 feet horizontally is also very close, and against the regs, but not deadly. The only time reaction time becomes an issue is when you are going to occupy the same space, and that's why we have eyeballs, controllers and collision avoidance equipment.

I'm not sure how big the payload of that balloon was, but I don't think hitting it would have been catastrophic even if they took it right on the windshield (as long as it wasn't too big).

Needless to say though, there wouldn't be any reaction time. Just "What's that?" followed by a *WHACK!* if it was a direct hit.

So would you know a weather balloon is there, and to avoid it, or is it just sheer luck that a plane and a weather balloon have never met in midair?

So what happens in the unlikely event the plan suck the balloon in engine?

quote:

Originally posted by Georgeair:
So what happens in the unlikely event the plan suck the balloon in engine?

The plane would be making an emergency landing on one engine most likely. They train for it so it isn't as dire as it sounds.

quote:

Originally posted by Georgeair:
So what happens in the unlikely event the plan suck the balloon in engine?

At least one ham radio club I know of in the DFW area launches balloons south of DFW. I'm not sure what altitude they reach but certainly high enough to potentially be a hazard to general aviation, and likely commercial aviation. I always wondered why the FAA allows it.

quote:

Originally posted by ubelongoutside:
...
So would you know a weather balloon is there, and to avoid it, or is it just sheer luck that a plane and a weather balloon have never met in midair?

Generally, IIRC, there is a "Notices To Airmen" or NOTAM put out about balloon launches. To my knowledge, they do not carry the equipment required to give us an instrument warning of their position. I have never seen such or heard a warning of such. So, we may know they are in the area, but it's a big sky.

From what I have just read, the latex type balloon will expand to about 35 feet at 60,000 feet, so it will probably be 20-30ish at 30,000. The real trick is that when you are on a collision course with something, it doesn't move in your windscreen. It keeps the same relative position which makes it so tough to see. Our human eyes are evolved to detect movement. It will stay very small until it blossoms in size. Usually by then, it's too late to maneuver unless you are traveling slowly.

In all honesty, I would be MORE surprised if I heard of a plane hitting a balloon since balloons follow the wind and not the "roads" in the sky. Airplanes see each other because we follow common routes. Balloons just go where they want.

quote:

Originally posted by David Lee:
How does a C 17 compare for engines and power? I would jump at the chance to ride on one of those.

Good power, solid engines, different design philosophy.

Pretty slow as far as most commercial jets go. I've passed them pretty handily before. They cruise in the low .7s of Mach. Most of the planes I fly are in the high .7s or .8s

Thank you Otto. I wondered about the C 17. Its a hansome piece of equipment.

quote:

Originally posted by Otto Pilot:

quote:

Originally posted by ubelongoutside:
...
So would you know a weather balloon is there, and to avoid it, or is it just sheer luck that a plane and a weather balloon have never met in midair?

Generally, IIRC, there is a "Notices To Airmen" or NOTAM put out about balloon launches. To my knowledge, they do not carry the equipment required to give us an instrument warning of their position. I have never seen such or heard a warning of such. So, we may know they are in the area, but it's a big sky.

From what I have just read, the latex type balloon will expand to about 35 feet at 60,000 feet, so it will probably be 20-30ish at 30,000. The real trick is that when you are on a collision course with something, it doesn't move in your windscreen. It keeps the same relative position which makes it so tough to see. Our human eyes are evolved to detect movement. It will stay very small until it blossoms in size. Usually by then, it's too late to maneuver unless you are traveling slowly.

In all honesty, I would be MORE surprised if I heard of a plane hitting a balloon since balloons follow the wind and not the "roads" in the sky. Airplanes see each other because we follow common routes. Balloons just go where they want.

Caption on the video said their balloon contained a radar reflector. Would that give some kind of notification or visibility?

quote:

Originally posted by STS:
...
Caption on the video said their balloon contained a radar reflector. Would that give some kind of notification or visibility?

Possibly. There is a problem in assumptions though. Our radar specifically looks for and is tasked to warn about weather. We occasionally might get a skin paint off another plane, but it's rare.

Generally, I have my radar/navigation display set to a 40 mile range on up. So, a reflection that simulates even an airplane is going to be minuscule on my display. Also, weather radar are known for creating transient blips on the display that have nothing to do with the reality of the outside world. They are just artifacts of the electronics and imperfections in the radome. All of this means that if I see a tiny blip on my radar that is indicating nothing more than a green intensity (being the lowest level of energy return), I am going to ignore it.

The ATC traffic radars may get a return, but without a transponder*, it will just be a primary return with no information attached and therefore almost, but not quite useless.


*Radar and transponders are like a giant game of Marco Polo. The radar sends out a radio pulse that is the equivalent of yelling "Marco!". All the transponders in the area will then respond with their unique 4 digit code and then also various information about altitude, airspeed, rate of climb/descent, etc. The equivalent of the "Polo!" yell. This information is overlaid on the radar as well as the flight number, if the plane is in contact with ATC. Planes not in ATC contact, but in the radar environment will be squawking a generic code, but still passing on the altitude/airspeed type info.

I recently took some video of a takeoff from Abu Dhabi in a 787. I thought the engines sounded very quiet, all things considered.

Also, note the really long takeoff roll. It was a full flight and I guess with a 14 hour flight it must have been close to full of fuel.



Link to original video: https://www.youtube.com/watch?v=3keri3M0akg

JP