Prem rishi Posted November 10, 2016 #1 Share Posted November 10, 2016 Is it possible that a quad copter propeller can produce thrust if it is at an altitude of 200 km above earth's surface? Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted November 10, 2016 #2 Share Posted November 10, 2016 5 minutes ago, Prem rishi said: Is it possible that a quad copter propeller can produce thrust if it is at an altitude of 200 km above earth's surface? Not a chance. Outer space begins at 100 km. Link to comment Share on other sites More sharing options...
Prem rishi Posted November 13, 2016 Author #3 Share Posted November 13, 2016 But the air density at 200 km altitude is about 1.75E-10 Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted November 13, 2016 #4 Share Posted November 13, 2016 5 hours ago, Prem rishi said: But the air density at 200 km altitude is about 1.75E-10 1.75E-10 what? Numbers without units are meaningless. I repeat at 100km the atmosphere is so sparse that outer space is considered to have been reached. You are basically asking if a quad-copter can operate in space. It really should need some one else to tell you that no it can't. 10 seconds on google would have told you that the world record altitude reached by ANY rotorcraft is 12,440 metres. Are you seriously asking if a quad-copter can operate16 times higher than this? 1 Link to comment Share on other sites More sharing options...
bmk1245 Posted November 14, 2016 #5 Share Posted November 14, 2016 20 hours ago, Prem rishi said: But the air density at 200 km altitude is about 1.75E-10 Waspie already answered, so I'll bring just few numbers: if you want to have the same thrust (same rotor thrust coefficient) at altitude of 200 km (with density 1.75⋅10-10 kg/m3) as on sea level (1.17 kg/m3, and given that you have rotor with radius 0.1 m, and motor delivering 6000 RPM), you would need to have motor capable to deliver ~500 million (!) RPM (rotor tip velocity ~5000000 m/s). 1 Link to comment Share on other sites More sharing options...
Prem rishi Posted November 16, 2016 Author #6 Share Posted November 16, 2016 @Waspie_Dwarf i think you feel annoyed with my question,sorry for that Link to comment Share on other sites More sharing options...
Prem rishi Posted November 16, 2016 Author #7 Share Posted November 16, 2016 Let's have some conversation The number 1.75x10^-10 kg/m^3 represents the air density. Which means, a minimum mass of air is present per unit area at an altutude of 200 km.Is it possible to collect and compress the air and provide the minimal amount of thrust? Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted November 16, 2016 #8 Share Posted November 16, 2016 (edited) 1 hour ago, Prem rishi said: @Waspie_Dwarf i think you feel annoyed with my question,sorry for that I wasn't annoyed with the question. I am annoyed that when two people have given you clear answers to your question, myself and bmk1245, you start arguing. What is the point of asking a question if you are not prepared to listen? 46 minutes ago, Prem rishi said: Is it possible to collect and compress the air and provide the minimal amount of thrust? NO! Read bmk1245's answer. Once again you are trying to argue that it is possible to operate a quad-copter in outer space. You shouldn't need to ask, the answer is painfully obvious. Edited November 16, 2016 by Waspie_Dwarf Link to comment Share on other sites More sharing options...
skookum Posted December 3, 2016 #9 Share Posted December 3, 2016 On 16/11/2016 at 7:44 PM, Prem rishi said: Let's have some conversation The number 1.75x10^-10 kg/m^3 represents the air density. Which means, a minimum mass of air is present per unit area at an altutude of 200 km.Is it possible to collect and compress the air and provide the minimal amount of thrust? If you collect compressed air you could use that for thrust and ditch the blades. Link to comment Share on other sites More sharing options...
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