Boom is not attempting a low-sonic-boom design. So, yes, overwater routes only.

I’m not sure I agree with your first point. I thought most sustainable Jet A replacements had comparable energy density. Agree with many of your other points, however. I’d also point out that the routes they’re touting are all over-water. I could see this as a mostly trans-Atlantic, trans-Pacific plane (if it ever…

It’s a lot cheaper than the RS660, which lists at $11,300. The R7 is $8,999. So they’re at distinctly different price points. If you want to spend the dough, go Aprilia (or some literbike, if you’re not specifically looking for the twin experience). If you’re on a bit more of a budget, here’s the R7.

It’s unfortunate that this article makes the R7 look like a replacement for the R6. For one thing, the R7 has a list price of $8,999. It’s not like Yamaha is proposing this as the answer for the R6 departure. That was Yamaha completely exiting a market, not to return (at least immediately). As mentioned elsewhere,…

You might want to read Jonathan McDowell on Twitter. An astrophysicist who is possibly the foremost expert on orbital junk (at least the foremost expert who posts in public). He compliments the Chinese on the things they do right (some perigee lowering techniques they use for some of their spacecraft), but also…

You’re missing the real point here. Skylab was a matter of poor prediction (they meant to get the Space Shuttle launched before Skylab was in danger, but too many delays and unpredicted sunspot activity led to Skylab coming down far earlier than predicted). The S-II stage that launched Skylab was bigger than the Long…

I assume you meant the RD-0120 (the Russian LH2/LOX engine, not the LOX/RP1 RD-120)? Different technology - the Russian engine is staged, the Chinese engine is gas generator - less efficient and simpler.

Actually LOX/LH2 (it’s the core stage, not the LOX/RP1 boosters). A more interesting technology, although probably little we would learn that we don’t already know. Would be interesting to see the state of their technology, though.

Most of these guys were test pilots; a profession that offered even greater opportunity for flaming termination. At least on Apollo, you had teams of hundreds of thousands of people whose only purpose was making sure you got back alive, which usually wasn’t nearly the case for the test pilots (and the statistics bore…

I’m listening to the Marshall Pruett series on John Paul Jr., who we recently lost at too young an age to Huntington’s, and now this. . .

No, that was a small and ultimately aborted attempt to graft some DoD missions onto an ultimately civilian project to get additional funding. The Space Shuttle has a rich and twisted development history that can’t be reduced into a single sentence. It is true, though, that design decisions to meet DoD needs that were…

Thank you for this much needed intervention. I hope he appreciates what a friend you are.

Brazing has been the primary way of making steel bike frames for the entire history of steel bike frames. Mostly lugged, but plenty of fillet brazing.

It looks like it’s trying to sing . . .

Mosler improved its aesthetics greatly with the MT900

Read about ETOPS - TL;DR, the aircraft should be able to fly for a given period of time on one engine, and the aircraft must never be further away from an airport than the distance the airplane can fly in that time. It’s based on the likelihood of a double engine failure, and is based on airplane design, maintenance…

Look up something called “Balanced Field Length.” The tl;dr of it is that an airplane must have enough runway length to take off or stop after losing an engine at any point during the takeoff run.

They’re going for a more “Agile” approach to development than the “Waterfall” project management style traditionally used in aerospace development. Time will show which works better, but each launch costs a tiny fraction of what it does for the more traditional competitors to even put a rocket stage on a test stand…

Naah, just sharpen the leading edge to razor-sharpness. The bridge has gotta lose sometime!

Based on the following links, the individual blades for moderately-sized turbines are within the weight limits of a Sikorsky/Ericson S-64 Skycrane, but I’d imagine that the sensitivity to winds would make it impractical. Also, it gets expensive given the number of flights a full wind farm would require.