3 ms·

Good question, I am not sure. I suspect that power figure is derived from thrust ("The three-stage Saturn V had a peak thrust of at least 7,650,000 pounds-forc

by jlgreco 13y ago

Good question, I am not sure. I suspect that power figure is derived from thrust ("The three-stage Saturn V had a peak thrust of at least 7,650,000 pounds-force (34.02 MN)") and velocity. This (annoyingly "furloughed") page on nasa.gov has an article written by Wernher von Braun that says: >"A large stand was built to static-test the huge stage under the full 7,500,000-pound-thrust of its five F-1 engines. These engines generated no less than 180 million horsepower. As about I percent of that energy was converted into noise, neighborhood windows could be expected to break and plaster rain from ceilings if the wind was blowing from the wrong direction or the clouds were hanging low. A careful meteorological monitoring program had to be instituted to permit test runs only under favorable weather conditions." http://web.archive.org/web/20130216021235/http://history.msfc.nasa.gov/saturn_apollo/giant.html http://web.archive.org/web/20130216021235/http://history.msf... 180 million horsepower is 134.2 GW, so the 190 GW figure is at least in the same general neighborhood.

lostlogin 13y ago
You know its big when a rounding error or suchlike can make a 60 million horsepower difference.
Arjuna 13y ago
Nice estimation. I also don't fully understand how they arrived at 190 GW. For the purposes of a "back of the envelope" calculation to account for the entire capability of the Saturn V: Based on the 180,000,000 HP figure, we can (naively) estimate: Stage 1: 180,000,000 HP (7,500,000 pounds of thrust from 5 F-1 engines) Stage 2: 27,870,000 HP (1,161,250 pounds of thrust from 5 J-2 engines) Stage 3: 5,574,000 HP (232,250 pounds of thrust from 1 J-2 engine) That's a total (non-simultaneous) output of 213,444,000 HP... the equivalent of 159.17 GW (!) That's simply massive. https://en.wikipedia.org/wiki/Rocketdyne_J-2 https://en.wikipedia.org/wiki/Rocketdyne_J-2
omegant 13y ago
Are you counting the turbopumps needed to fire the engines?
- jlgreco 13y ago
  Don't think so, but I don't know if it is appropriate to add those values on either. It should probably be possible to generalize the output of the engines without knowing much about their internal workings, and calculate a power figure just knowing how much they are lifting and how fast. This stuff is really straddling the line of physics that I remember and physics that I forgot/never learned, so... heavy dose of salt, etc.

by jlgreco 13y ago

lostlogin 13y ago

You know its big when a rounding error or suchlike can make a 60 million horsepower difference.

Arjuna 13y ago

Nice estimation. I also don't fully understand how they arrived at 190 GW. For the purposes of a "back of the envelope" calculation to account for the entire capability of the Saturn V: Based on the 180,000,000 HP figure, we can (naively) estimate: Stage 1: 180,000,000 HP (7,500,000 pounds of thrust from 5 F-1 engines) Stage 2: 27,870,000 HP (1,161,250 pounds of thrust from 5 J-2 engines) Stage 3: 5,574,000 HP (232,250 pounds of thrust from 1 J-2 engine) That's a total (non-simultaneous) output of 213,444,000 HP... the equivalent of 159.17 GW (!) That's simply massive. https://en.wikipedia.org/wiki/Rocketdyne_J-2 https://en.wikipedia.org/wiki/Rocketdyne_J-2

omegant 13y ago

Are you counting the turbopumps needed to fire the engines?

jlgreco 13y ago
Don't think so, but I don't know if it is appropriate to add those values on either. It should probably be possible to generalize the output of the engines without knowing much about their internal workings, and calculate a power figure just knowing how much they are lifting and how fast. This stuff is really straddling the line of physics that I remember and physics that I forgot/never learned, so... heavy dose of salt, etc.