Quote from: Rocket Science on 05/09/2018 04:51 pmQuote from: D_Dom on 05/09/2018 04:44 pmNeither does an MBA make a businessman. Props to UK Royal Society for recognizing his contributions with reference to Luigi Galvani, and early 19th century. https://en.oxforddictionaries.com/definition/galvanize"to stimulate by electricity"Galvani was a great Italian scientist, MBAs are a dime a dozen...MBAs used for making the quarterly results appear great are a dime a dozen.MBAs starting businesses that employ tens of thousands (50k-ish at the moment), disrupt established industries, and open new futures are priceless.
Quote from: D_Dom on 05/09/2018 04:44 pmNeither does an MBA make a businessman. Props to UK Royal Society for recognizing his contributions with reference to Luigi Galvani, and early 19th century. https://en.oxforddictionaries.com/definition/galvanize"to stimulate by electricity"Galvani was a great Italian scientist, MBAs are a dime a dozen...
Neither does an MBA make a businessman. Props to UK Royal Society for recognizing his contributions with reference to Luigi Galvani, and early 19th century. https://en.oxforddictionaries.com/definition/galvanize"to stimulate by electricity"
So like Edison without the Elephant electrocution...
If the loop is pumped down to a vacuum how possible is hypersonic ?
Quote from: DistantTemple on 05/09/2018 06:42 pm Although a technologist, and not a pure scientist, as father of the space revolution, his place will eventually be like Newton's <snip>Ummm... really?
Although a technologist, and not a pure scientist, as father of the space revolution, his place will eventually be like Newton's <snip>
Quote from: D_Dom on 05/09/2018 03:58 pmIf the loop is pumped down to a vacuum how possible is hypersonic ?A true vacuum with literally no molecules is impossible. The standard hyperloop only reduces pressure by like a factor of 100, and there are definitely still aerodynamic effects, especially near Mach 1.Hypersonic speeds would need a higher vacuum.
Quote from: Robotbeat on 05/11/2018 03:17 amQuote from: D_Dom on 05/09/2018 03:58 pmIf the loop is pumped down to a vacuum how possible is hypersonic ?A true vacuum with literally no molecules is impossible. The standard hyperloop only reduces pressure by like a factor of 100, and there are definitely still aerodynamic effects, especially near Mach 1.Hypersonic speeds would need a higher vacuum.Does the nose impeller as pictured in the Hyperloop white paper reduced the aerodynamic effects enough to enable near hypersonic speed in a Hyperloop near vacuum tube?
Quote from: Zed_Noir on 05/19/2018 12:10 amQuote from: Robotbeat on 05/11/2018 03:17 amQuote from: D_Dom on 05/09/2018 03:58 pmIf the loop is pumped down to a vacuum how possible is hypersonic ?A true vacuum with literally no molecules is impossible. The standard hyperloop only reduces pressure by like a factor of 100, and there are definitely still aerodynamic effects, especially near Mach 1.Hypersonic speeds would need a higher vacuum.Does the nose impeller as pictured in the Hyperloop white paper reduced the aerodynamic effects enough to enable near hypersonic speed in a Hyperloop near vacuum tube?Hyperloop vehicles are generally shown with a big compressor at the front. But that doesn't actually make sense. The first thing to contact incoming air should be a heat exchanger which would chill the incoming air stream. This greatly reduces the amount of shaft energy that gets converted to heat energy in the compressor, which in turn reduces the size of the battery which supplies that energy and the heat dump which absorbs it.For those of you interested in supersonic or even hypersonic travel in a tube, the folks at Reaction Engines Limited have figured out how to make this heat exchanger work at those speeds. I have grave doubts about the Skylon system as a whole, but this part has seen a lot of development and works.As Elon described it, the pod would dump the compressed air out the back. This is pointless -- any thrust the vehicle achieves costs the next vehicle even more in drag. Having done the hardest part of the compression, you are better off compressing the air further and storing it, to be ejected from the system entirely after the vehicle arrives at its destination. The pods are far better at evacuating air from the tubes than vacuum pumps would be, so much so that the tubes would quickly drop well below the 100 Pa pressure that Elon envisioned. At around 10 Pa pressure the aerodynamics of the pumps change, as the mean free molecular path gets to be an interesting fraction of a turbine blade chord. I suspect compressor efficiency would drop at this point and the vehicles would stop effectively scavenging air from the tube.Actual supersonic speeds might be largely unnecessary if there is significant traffic. The pods heat the air as they pass through, and at low pressures that air becomes effectively more viscous (relative to its momentum). That means the lower pressure air is worse at transferring heat to the tube walls, and is likely to get quite warm. At higher temperatures the speed of sound increases.The real problem with supersonic and certainly with hypersonic speeds is that the turn bend radius becomes very, very large. The standard turn for a commercial aircraft is 0.5 G laterally, which is quite aggressive for a land-based vehicle. At 320 m/s, approximately Mach 1 at room temperature, the bend radius is 21 km, and it increases quadratically with speed. You might argue that you can eliminate bends in the point-to-point system that Musk described, but transportation systems are never point to point, but rather networks. Networks have switch points which require bends. Very large turn radii reduce the density of switch points which increases the travel time once you exit the Hyperloop system and get back onto surface streets. Mach 1 might be approached midway between San Francisco and Los Angeles, but most travel time would be spent at perhaps half that speed. A network designed to get people from San Francisco to Los Angeles in around 30 minutes would be seriously suboptimal for the much larger number of passengers who wish to travel at high speed within those metropolises, or even for those not near the few Hyperloop terminal points possible. 50 minutes is a much more reasonable goal.
Elon Musk’s rocket rideSpaceX is soaring. Tesla is roaring. How the world’s most creative and controversial CEO is transforming one industry after another—and why he’s Fortune’s Businessperson of the Year.BY ANDREW NUSCA AND MICHAL LEV-RAMDecember 2, 2020 11:30 AM GMT
Elon Musk has been elected to the National Academy of Engineering, joining 132 other new members.https://nae.edu/270224.aspx
Musk, Elon Reeve, founder, chief executive officer, and chief engineer, SpaceX, Hawthorne, Calif. For breakthroughs in the design, engineering, manufacturing, and operation of reusable launch vehicles and sustainable transportation and energy systems.
CONGRATULATIONS to our awardees!🏆 Elon Musk the winner of the IAF World Space Award, Stephanie Bednarek received it on his behalf. The IAF World Space Award for Teams was awarded to @NASA, @csa_asc @esa and handed to Pam Melroy during the Opening Ceremony!✨#IAC2023
Thank you on behalf of the people of SpaceX for whom all credit is deserved!