ET3

I dont know about 'hyperloop' but ET3 (tm) tubes (if placed underground) require less than 1/15th as much earth removal than a train tunnel or freeway tunnel. Our patented (US 5,950,543 and others) ET3 system optimizes tube size to strike a balance between low cost and high utility (as cars do), we use a freeway network design philosophy (not like a train track) see www.et3.com and www.et3.net to learn more.

To mince words, Musk used the word "tunnels" (and not "tubes"), perhaps intentionally?? Tunnels are know for leaking water (and air), while tubes (or pipelines) are implied to not leak.

At any rate, the subject of Evacuated Tube Transport Technologies (ET3) tm was disclosed in US patent 5,595,543 in 1999. For the record, Coanda's system was pneumatic (and took alot of power to move the air). Search for "evacuated tube transport" on youtube for an overview. I have not noted any claims for 'hyperloop', that are not exceeded by ET3 (tm). see www.et3.com and www.et3.net

The drag of ships moving at less than hull speed (non planing) is a function of: skin friction (shearing of the boundary layer), wave making, and Reynolds number (related to the length of the ship, and the viscosity of the fluid).

One interesting article says that one of the mega container ships pollutes more than 50 million cars see:

http://www.guardian.co.uk/environment/2009/apr/09/shipping-p...

The claim is that just 15 of the worlds biggest ships pollute more than all cars in the world combined.

The principal of "choked flow" limits flow velocity in a constant section tube to Mach one unless the pressure drop is much higher than 1 atm. The drag force at choked flow would be about 20 tons. Tests show drag in a tunnel with high blockage ratios can be more than an order of magnitude greater than the same shape moving in open air.

Pressuring a system (depending on the pressure) would be more stress and risk than a vacuum. Depending on materials used (concrete for instance - that prefers to be loaded in compression), the vacuum can actually IMPROVE stability and safety. As far as a pressurized "loop" as you describe, it would greatly INCREASE DRAG compared to a vehicle in the open air. What you describe is a 'Pneumatic Tube Transport' (PTT) system (as used in bank drive-up windows). PTT does not scale up well due to the enormous drag of air on the ENTIRE inside surface of the tube. Large PTT systems take a lot of power regardless of use. The energy per vehicle would be greater (but could be reduced a little by using hydrogen or helium that has less drag than air (mostly nitrogen)); however small molecules leak much more than large ones, and the expensive working fluid would have to be replaced.

Google "Evacuated Tube Transport" (ETT) or "Evacuated Tube Transport Technologies" (ET3) (trade marks of ET3 Global Alliance, and et3.com Inc.) on google and youtube -- watch the videos to learn of more advantages. Read the first US patent (5,595,543) to learn exactly how all of what Musk claims (and much more) can be accomplished. NOTE: ET3 (tm) is the product of over 200 experts, companies, and institutions in 18 countries. We hope musk joins our efforts to implement ET3. ET3 is optimized to accommodate BOTH cargo and passengers in car sized vehicles. Initial (local) routes will be at 300-400mph, and ET3 will accomplish over 50 times more transportation (ton-miles and passenger-miles) per KWh than the most efficient electric car or train. ET3 cost is less than a tenth as much as HSR (high speed rail), mostly due to much less vehicle mass It takes 1/30th as much concrete and steel to support 1200lb car sized capsules (400lb vehicles that haul the same 800lb payload as a typical automobile) than to support 100 ton locomotives on elevated structure. ET3 has over 10 times more capacity than HSR at 350mph design speed, and 0ver 100 times more at 4000mph. Refs: search “ doi: 10.3969/j.issn.2095-087X.2011.01.007 “ for a peer reviewed paper published in Journal of Modern Transportation; US patent 5,595,543 (many additional patents in the ET3 portfolio)

You are correct that reasonable people do not fear what is safe. Phobia rules the minds of the irrational. Many refuse to fly in a commercial jet in spite of the fact it is 1/15th the risk of driving in a car the same distance. 1/3 of Americans have never been in an aircraft of any kind, and another 1/3 fly less than 1 time per year. Americans fly more than most other nations, yet air travel in the us is only 7% of passenger miles. Others have phobia about being in a small enclosed space like a car, and even more people have unfounded fears of being in large vehicles like trains, planes and buses with hundreds of strangers, however the unreasoned fears do not prevent the success of our transportation modes (even relatively risky modes like bikes).

Google "Evacuated Tube Transport" (ETT) or "Evacuated Tube Transport Technologies" (ET3) (trade marks of ET3 Global Alliance, and et3.com Inc.) on google and youtube -- watch the videos to learn of more advantages. Read the first US patent (5,595,543) to learn exactly how all of what Musk claims (and much more) can be accomplished. NOTE: ET3 (tm) is the product of over 200 experts, companies, and institutions in 18 countries. We hope musk joins our efforts to implement ET3. ET3 is optimized to accommodate BOTH cargo and passengers in car sized vehicles. Initial (local) routes will be at 300-400mph, and ET3 will accomplish over 50 times more transportation (ton-miles and passenger-miles) per KWh than the most efficient electric car or train.