Posted on 02/08/2023 12:39:34 AM PST by libh8er
Balloon With 3 Hypersonic Missiles Tested by China in 2018
“Think of a bow thruster without water......... “
May want to refresh your physics knowledge.
B-17 Flying Fortress service ceiling: 35,000 ft.
B-24 Liberator service ceiling: 28,000 ft.
B-29 Super Fortress service ceiling: 31,850 ft.
P-51 Mustang service ceiling: 41,900 ft.
FW-190 Wurger service ceiling: 31,960 ft.
BF-109 service ceiling: 39,000 ft.
DC-3/C-47 service ceiling: 23,200 ft.
C-131 Samaritan service ceiling: 24,500 ft.
Lockheed Constellation service ceiling: 24,000 ft.
C-130 Hercules Service ceiling: 33,000 ft
DCH-6 Twin Otter service ceiling: 25,000 ft
DCH-8/Q400 service ceiling: 27,000 ft
Yeah ... some of them can “go as high as 12,500 ft”. And yeah, they can and do cruise above 12,500.
Doctor Fu Manchu now has a secret island base.
Nein un neintzig luftbaloons?
九十九个气球
Jiǔshíjiǔ gè qìqiú
Thorough article.
Boat bow thrusters are under the water. So now refresh my physics......
So what's your point? Mine was that there is no propeller driven device that could propel that balloon......
...at 68,000 feet
I vote for the latter.
First point: your statement about propeller driven aircraft being limited to 12,500 ft is simply incorrect. You have new information ... this is a good day for you: You learned something.
Second point: Propellers can “perform” in much thinner air than you realize. I gave you examples of propeller driven aircraft, in which the propeller must provide energy for both lift and forward motion. This thread is about the possibility that a balloon might use props for maneuvering, a much less demanding task. A prop is just a wing; if there’s enough air for a wing to generate lift, there’s enough air for a prop to generate thrust.
Third point: Neither you nor I know for sure if this balloon was capable of maneuvering, nor how it managed the feat if it was so capable. I saw no evidence in the handful of photos showing any sort of maneuvering device. That said, I think you should reconsider your adamant assertion that using props for maneuvering a high altitude balloon is impossible. Your call.
Keyword
TERCOM
If the thruster had a water supply, it would not matter as long as the outlet was not obstructed.
Force and reaction. A water hose exhibits thrust whether the nozzle is above or below water.
We're talking 68,000 feet, not 42,000.
At 68,000 feet, the air is just not dense enough. The propeller works by displacing the air pulling it behind itself (the action), this movement of air then results in the aircraft being pushed forward from the resulting pressure difference. Without the density of the air, there is nothing to pull against and thus no forward movement.
But you knew that........
......Your call now
Lift is a combination of both air density and air speed which are both required to maintain the weight of the aircraft while in flight. That is why all the planes you listed had their max ceilings along with the fact that their engines were not capable of flying with the diminished oxygen at the higher altitudes..
Take any one of them to the 68,000 feet altitude and their engines would fail due to lack of oxygen...............
You mention propellers capable of flying in thinner air. I've already posted the statistics of the record height of a helicopter, which is specifically designed to hover due to the immense size of their propellers......
We're not talking about boats here, he's trying to make a comparison of an under water thruster used to move a boat and a propeller on the balloon at 68,000 feet using the same philosophy.
My point, which you obviously missed, is that at 68,000 feet, there is not enough air density for the propeller to pull against and thus add thrust, much the same as that bow thruster being out of the water and not having any water to push against......
You missed the point entirely.
I’m not talking about propellers generating lift. It’s a friggin’ BALLOON!!! Lighter than air! The gas bag generates lift. All the propellers need to do is generate some lateral thrust for maneuvering. If, that is, they exist.
As you know perfectly well, wings can generate lift at >85,000 ft. Wings can generate lift, therefore propellers can generate thrust. They’re both airfoils.
As you know perfectly well, electric motors don’t need oxygen to run.
Now ... I’m not saying this chinese contraption had ANYTHING for maneuvering. Just that there is at least one possible way of doing it.
I understand exactly what you are saying but at that altitude of 68,000 feet, the air is not dense enough for a propeller to function. It's like a boat propeller out of water........
Look at this atmospheric chart and compare the air density of 40,000 feet compared to over 60,000 feet. The air density is almost non existent.........
https://www.engineeringtoolbox.com/standard-atmosphere-d_604.html
And then there is inertia. Causing such a large object in the conditions noted make it very very very difficult to react to change
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