HKP90 Posted February 4, 2023 VT Supporter Share Posted February 4, 2023 2 minutes ago, LondonLax said: This was the take I got from the defence analysist in a BBC article https://www.bbc.com/news/world-64514120 I mean I guess that they can then, but I don't see how they would heat that much gas with a solar powered heater. Look how much heat hot air balloons have to dump into the envelope to ascend. Link to comment Share on other sites More sharing options...
chrisp65 Posted February 4, 2023 Share Posted February 4, 2023 1960: USSR announces it has developed a new ground to air missile capable of shooting down a U2 spy plane at high altitude. To prove it, they say they have indeed shot down a U2 that was taking photos over Russia. The U.S. announces that in fact the Russians have shot down a piece of NASA weather hardware. The USSR then produces the USAF pilot, they had forgotten to say had managed to eject and parachute out of the U2. As a gesture of goodwill, they have also developed the roll of film they have recovered. 2 Link to comment Share on other sites More sharing options...
blandy Posted February 4, 2023 Moderator Share Posted February 4, 2023 15 minutes ago, HKP90 said: I mean I guess that they can then, but I don't see how they would heat that much gas with a solar powered heater. Look how much heat hot air balloons have to dump into the envelope to ascend. None of us are aware of the technical specifications of the balloon system, but it absolutely is possible to raise or lower altitude via a number of different methods. Link to comment Share on other sites More sharing options...
blandy Posted February 4, 2023 Moderator Share Posted February 4, 2023 I don't want to be patronising, but if you decrease the mass you ascend, if you decrease the upward force (e.g. by releasing helium, say, from the balloon you will descend - two valves plus control circuitry...) Link to comment Share on other sites More sharing options...
HKP90 Posted February 4, 2023 VT Supporter Share Posted February 4, 2023 7 minutes ago, blandy said: I don't want to be patronising, but if you decrease the mass you ascend, if you decrease the upward force (e.g. by releasing helium, say, from the balloon you will descend - two valves plus control circuitry...) But as far as I understand, you can't recover mass once it's released (ie ballast) and the mass of helium is the same compressed in a tank as held in a balloon. They seem to have done it somehow, but control over 2000+ miles of flight without heating the gas (changing density) or having another means of propultion must be very difficult. When the Japanese did this in WWII it was so inaccurate they barely hit the right continent. Link to comment Share on other sites More sharing options...
sne Posted February 4, 2023 Share Posted February 4, 2023 Actual flight radar before the balloon was shot down 1 Link to comment Share on other sites More sharing options...
sne Posted February 4, 2023 Share Posted February 4, 2023 Link to comment Share on other sites More sharing options...
HKP90 Posted February 4, 2023 VT Supporter Share Posted February 4, 2023 I would imagine there are frogmen recovering the debris as we speak to have a closer look. Link to comment Share on other sites More sharing options...
brommy Posted February 4, 2023 Share Posted February 4, 2023 2 minutes ago, HKP90 said: I would imagine there are frogmen recovering the debris as we speak to have a closer look. The U.S. will want to get there before the French do. 4 Link to comment Share on other sites More sharing options...
fruitvilla Posted February 4, 2023 Share Posted February 4, 2023 27 minutes ago, HKP90 said: and the mass of helium is the same compressed in a tank as held in a balloon. While true (for our intense porpoises) it is the displacement that counts. 1 Link to comment Share on other sites More sharing options...
Popular Post sne Posted February 4, 2023 Popular Post Share Posted February 4, 2023 13 minutes ago, fruitvilla said: While true (for our intense porpoises) it is the displacement that counts. 2 4 Link to comment Share on other sites More sharing options...
fruitvilla Posted February 4, 2023 Share Posted February 4, 2023 @sne OK I gave you a like for the effort. 1 Link to comment Share on other sites More sharing options...
sidcow Posted February 4, 2023 VT Supporter Share Posted February 4, 2023 I feel quite deflated. 2 Link to comment Share on other sites More sharing options...
JoshVilla Posted February 5, 2023 Share Posted February 5, 2023 Link to comment Share on other sites More sharing options...
blandy Posted February 5, 2023 Moderator Share Posted February 5, 2023 13 hours ago, HKP90 said: But as far as I understand, you can't recover mass once it's released (ie ballast) and the mass of helium is the same compressed in a tank as held in a balloon. They seem to have done it somehow, but control over 2000+ miles of flight without heating the gas (changing density) or having another means of propultion must be very difficult. When the Japanese did this in WWII it was so inaccurate they barely hit the right continent. The gas in a tank is compressed and has high density. Gas released from the tank into the balloon has low density. A full gas tank and an empty balloon will lie on the ground, all heavy n’that. Inflate the balloon with gas from the tank and all that lighter than air helium, or hydrogen, in the balloon exerts an upward force and…up, up and away. Link to comment Share on other sites More sharing options...
OutByEaster? Posted February 5, 2023 Moderator Share Posted February 5, 2023 Out of interest, do we know how they shot it down? Link to comment Share on other sites More sharing options...
HKP90 Posted February 5, 2023 VT Supporter Share Posted February 5, 2023 17 minutes ago, OutByEaster? said: Out of interest, do we know how they shot it down? F22 Link to comment Share on other sites More sharing options...
sidcow Posted February 5, 2023 VT Supporter Share Posted February 5, 2023 25 minutes ago, OutByEaster? said: Out of interest, do we know how they shot it down? They used a projectile 1 Link to comment Share on other sites More sharing options...
Chindie Posted February 5, 2023 VT Supporter Share Posted February 5, 2023 32 minutes ago, OutByEaster? said: Out of interest, do we know how they shot it down? Missile from an F22, over the ocean. 1 Link to comment Share on other sites More sharing options...
OutByEaster? Posted February 5, 2023 Moderator Share Posted February 5, 2023 If nothing else, imagine how excited that pilot would have been. He'll be in a bar somewhere right now, telling a tale that gets bigger with each repetition. Link to comment Share on other sites More sharing options...
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