News Chinese spy balloons ‘used a U.S. internet provider’ – as well as American hardware

[bit_user]

You forgot that air pressure 20 km up is about 1/15 that at ground level -- just under 1 psi.

No, I didn't. That's irrelevant, because the same drop in pressure has a proportionate impact on propellers' ability to move the craft. Without rocket propulsion, you don't gain any extra mobility from the pressure drop.

And you're ignoring that your theory conflicts with reality. A defense official has stated the balloon "flew figure-eight passes" over several bases.

I didn't actually contradict that. You seem to like arguing, so it doesn't surprise me that you get your hackles up at the slightest hint of disagreement.

I don't know what the actual wind speeds were, at the times & places it was alleged to happen. I accept that they could've been low enough for the alleged maneuvers to have occurred, as far as I know.

However, if we're being even-handed, I would also point out that we don't know precisely what that statement means. A figure-8 in the air could translate into a zigzag on the ground. The statement needs further qualification.

Even if we assume this is some conspiracy by the US government,

Nobody is saying that. It doesn't have to be all one thing or another. Nobody in this thread denied the existence of propellers on the gondola and they obviously do something. That doesn't mean it can counteract a wind current of any arbitrary speed, however.

there are dozens of eyewitness accounts of the balloon lingering over these areas for several hours.

At that height, it can be difficult to perceive motion. It's not like standing on a mountain and watching a car drive down a road in the valley, because that would at least have landmarks on the ground for you to use as reference points.

In order for the balloon to appear to linger, it just has to counteract a meaningful fraction of the wind speed.

A 30mph wind will move a balloon 150 miles in 5 hours time ....

Do you know there was a constant 30 mph wind? Where's your data?

 

[USAFRet]

Given the very little wind at that elevation, why shouldn't the propellers have been able to move the thing around?

The balloon enclosure was just providing the lift/buoyancy. Just like wings on a semi-conventional aircraft. Like the very light and fragile Airbus Zephyr, which has a cruising speed of around 30 knots, and is able to fly a very detailed path at that same altitude range.

Given a little $200 UAV can maneuver or hold station in a 20mph breeze, why would this thing not be able to?

 

[bit_user]

Given the very little wind at that elevation, why shouldn't the propellers have been able to move the thing around?

Okay, let's see some figures of how much thrust you can generate from propellers powered by a solar array of that size. Then, let's see some areodynamic drag calculations for a balloon of that size. That's what it would take to meaningfully move the conversation forward. If nobody knows or cares enough to work that out, then we should just drop it.

The balloon enclosure was just providing the lift/buoyancy.

Have you ever tried to setup a tent, when it's windy? Doesn't matter if the thing isn't generating lift, the wind is still pushing against it. It acts like a giant sail.

Like the very light and fragile Airbus Zephyr, which has a cruising speed of around 30 knots, and is able to fly a very detailed path at that same altitude range.

Given a little $200 UAV can maneuver or hold station in a 20mph breeze, why would this thing not be able to?

That's just a flying wing. You're talking about pushing a 200-foot-tall wall, at that speed. That will require significantly more thrust.

 

[USAFRet]

then we should just drop it.

This. ^^^^^

I'm pretty sure the USAF has a pretty detailed track of what this thing was doing.
But that is classified.

So...I'm out.

 

[COLGeek]

This thread has run its course. Closing now.

Thank you for the dynamic discussion.