elidourado's comments

Hard disagree. Anthropic hired Mike Krieger. He's awesome at product. Give it time.

Literally the next sentence is “It’s possible by some lights that the market will not produce the optimal amount of safety at all relevant margins, and so regulation persists.”

Did you read the whole thing? There's an entire section at the end that talks about what current players are doing wrong, while raising the question of whether even the suggested approach is fundable.

And if not he can just switch from Stripe to Pomelo Pay.

Where is My Flying Car? by J. Storrs Hall.

The flying car is both literal and metaphorical. If you’ve ever wondered why technology has stagnated, this is the book for you. If you doubt technology has stagnated, this book will challenge that view. If you’ve ever wondered why literal flying cars have taken so long to appear, this book is for you.

Fake news. Smaller particles from exhaust are way worse for you than larger particles from tires. Within a category like PM2.5, mass is a terrible metric. A given mass of fuel exhaust will contain orders of magnitude more particles because they are tinier. Smaller particles can penetrate deeper into your lungs and can go into your bloodstream.

Got it, thanks. I think it is your last sentence that is most clarifying for me. I thought the multifocal lenses were a good solution but it sounds like they aren’t as great as I had hoped. Thanks for taking the time to reply.

Thanks, I appreciate it. From my layman’s reading, it seems like RLE is very safe and doesn’t have the same side effects as LASIK. I guess my real question is why shouldn’t it be more widely used for younger or less extreme corrections. It’s likely that I am misunderstanding something and I am wondering if it’s obvious to you as an expert what it is.

Do you have thoughts on LASIK/PRK vs. refractive lens exchange? I’ve been holding out for something “better than LASIK.” Would love your perspective on whether that’s sensible or misinformed.

Business travel broadly is a huge boon to trade and economic growth. http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.212....

I agree that developer conferences may be wasteful, but don't paint non-conference travel with that brush.

Every chance I get, I sing the praises of Finite and Infinite Games by James Carse. It sounds like you could use it. Good luck!

Build us a Mach-2.2 electric engine where the aircraft design closes and we'll use it! We're an airframer, not an engine company. Would love to see some innovation in engines. Maybe a good idea for another YC startup.

NYC-SF is a 2h30m block time (gate-to-gate) if it were allowed. Our sonic boom will be quieter than Concorde's, but because of the policy challenge, we are baselining overwater operations only.

The Concorde entered service in 1976, and program launch was in the Kennedy administration. It would be surprising if technology didn't advance enough to bring huge improvements over that time period.

There are broadly three enabling technologies, plus a couple of economic factors. Technologies:

1. Carbon fiber. With the 787, we finally have a transport-category aircraft with significant amounts of carbon fiber that has gone through full FAA certification, which significantly lowers the barrier to us using it. Carbon fiber does a lot for us. It is lighter and stronger than aluminum, but it is also more thermally stable. Concorde grew about 15 inches in flight as its temperature rose in flight. Our leading edges will reach over 300ºF at Mach 2.2, and our plane will grow less than an inch in flight. That is a significant maintenance cost reducer. Carbon fiber also enables more complex geometries without expensive tooling costs. Our plane won't have a straight line on it. We can take better advantage of area ruling to improve aerodynamics. In contrast, Concorde's fuselage was a cylindrical tube.

2. Engines. There is a (much slower) Moore's law for engine cores; they get better at a rate of around 1 percent a year. Move 50+ years forward from when Concorde's engines were designed and you have a real improvement. Concorde used 4 turbojets (i.e, zero bypass ratio) and we have 3 medium-bypass turbofans. Plus no afterburners are needed. When Concorde used afterburners to punch through the transonic regime, they had a 78% increase in fuel flow for a 17% increase in thrust.

3. Computational fluid dynamics. Concorde is all the more impressive for the fact that it was designed with slide rules and wind tunnels. Wind tunnel tests are expensive, taking six months and costing millions of dollars. We can do virtual wind tunnel tests in software in about 30 minutes. We still use tunnels to closely test harder aspects of the design (e.g., low-speed handling qualities), but we have much more rapid design iteration than Concorde could have hoped for.

On the economics, we are right-sizing the aircraft. Concorde had 100 seats, but it usually flew with a very low load factor (half-empty). Our design has 55 seats, which is similar to the premium cabin on today's widebody subsonic airliner. What this means is that any route that can sustain widebody subsonic service today will basically work supersonically. We expect much higher load factors, which are helped by business class fares and a lower number of seats to fill relative to Concorde.

This leads to economies of scale. Whereas Concorde really only was profitable between New York and London, Boom flights make economic sense on hundreds of global routes. Which means we'll sell more planes and drive maintenance costs down further. Only 14 Concorde units ever saw commercial service. Ultimately, when Concorde shut down, it was because Airbus stopped making spare parts. In contrast, one public report by the Boyd Group estimated supersonic demand at 1300 planes. With almost two orders of magnitude of planes in service, we'll achieve much better scale on maintenance.

Hope this answers your question about the magic.

Disclosure: I'm at Boom, which is building a Mach-2.2 airliner. https://boomsupersonic.com/

I think it all depends on how much cost savings for how much speed. In today's dollars, a round-trip ticket on Concorde from New York to London was $20,000, or 4x today's business class price. For that, you got a tiny seat in a cramped cabin.

What we're targeting at Boom is an improvement over business class. We're making it profitable for airlines to operate the plane at today's business class fares. We're getting you there in half the time. And instead of a cramped two-and-two cabin arrangement, it's a one-and-one configuration (every seat is a window AND an aisle). The seats are similar to today's domestic first class seats, only designed for productivity.

So the choice a business traveler could soon face is: Would you like to get from New York to London in 7 hours in a lay-flat bed, or in 3h15m in a comfortable, productive environment? Price is the same either way. We think most people will pick the supersonic flight.

It should be noted also that the premium cabin market today is much larger than it was a few decades ago.

And finally, premium-cabin economics are only the first step. We think there's a roadmap to making supersonic flight cheaper than subsonic flight is today. It will take a few decades, but that is absolutely the path that Boom is on.

See Boom (YC 2016) http://boom.aero/

Keep in mind that authors don't always write the headlines and subheadlines.

Yes, the Concorde actually flew with afterburners, which are notoriously fuel-inefficient. Modern engines can do Mach 2.2 without afterburners.

What about selective noscript on amp pages? Should be doable with an extension. Pages will render and no tracking.

There's a new Twitter video service on the way. I'm sure they'll capture a lot of the disgruntled YouTube creators.

https://video.twitter.com