ThenAsNow

12 ms·

61.
by ThenAsNow 7y ago
> Didn't IBM have OS/2 Warp for PowerPC CHRP systems coming out that later turned into vaporware? It was developed, and pre-release versions were available to developers, but the whole "Workplace OS" initiative and OS
62.
by ThenAsNow 7y ago
Agree with most of your points. There are some valid observations that he then smoothly extrapolates to invalid conclusions. There has been considerable progress in fuel cell vehicles, for example. The Honda Clarity fuel cell version has
63.
by ThenAsNow 7y ago
It would be great if Julia were to take a page from the Rust playbook and have some focused initiatives around making the language more accessible to its potential audience. I've been impressed with how introspective and constructivel
64.
by ThenAsNow 7y ago
Cost control or cost-benefit trades are certainly a critical aspect of engineering but saying "Engineering is about cost cutting" is way overstating the case. There absolutely is a difference between a short-term cost-driven engi
65.
by ThenAsNow 7y ago
> It would be absurd to ask a Aeronautical Engineer to do something like derive the Navier-Stokes Equation on a whiteboard A thorough interview in physical engineering disciplines will often expect you to demonstrate/validate somet
66.
by ThenAsNow 7y ago
I just wrote my first bit of Julia this weekend. I'm impressed - it's clearly been designed for technical/numeric computing with modern language features baked-in. The type system and macros are some significantly distingui
67.
by ThenAsNow 7y ago
The word "Digital" could be eliminated from the headline without loss of accuracy.
68.
by ThenAsNow 7y ago
Since the SR-71 is a perennial HN favorite: https://news.ycombinator.com/item?id=13567554 I think the StackExchange answer linked below covers interesting aspects of supersonic inlet behavior, but doesn't do a great jo
69.
by ThenAsNow 7y ago
Replying for the sake of ensuring accuracy, not for the sake of argumentation. Got busy, wasn't able to get back to this any sooner. We agree on #3 actually. Disagree with the "nozzle extension" terminology on #2, for reaso
70.
by ThenAsNow 7y ago
> I didn't talk about the whole nozzle. The first line of my post: > "A rocket engine nozzle produces thrust only for the part where the pressure is greater than atmospheric pressure" > Then you went on to talk how I
71.
by ThenAsNow 7y ago
If you look at the quasi-1D form of the thrust equation, you'll note the two terms I mentioned. Yes, you can integrate the surface pressure times the surface normals to get the pressure contribution to thrust, which will be negative i
72.
by ThenAsNow 7y ago
At least as insidious to diagnose and overcome, if not more so, was the transient behavior of the engine components outside of even the turbopumps ( e.g. , valves, preburners, thrust chamber) and the high sensitivity to all the time-depende
73.
by ThenAsNow 7y ago
Agree that picking the launch point and azimuth could address these issues. Of course, you'd have to be clear of ground-level weather enough for the Strato stack to take off, and the upper level winds associated with the trajectory wo
74.
by ThenAsNow 7y ago
The SBIR process is based on solicitations. Each solicitation is associated with its own instigators, and there are also a multitude of USGov entities that participate in the program. It's entirely possible for what you experienced t
75.
by ThenAsNow 7y ago
A liquid rocket vehicle would have to be designed to be carried and launched from a carrier vehicle like Strato has, but that's eminently doable. You design in the load paths suitable for carriage and also for engine-on ascent loads.
76.
by ThenAsNow 7y ago
> However, two rockets both cost the same to build and one needs less fuel to orbit that directly translates into more payload to orbit. It’s a question of mass not money. The way you state this is insufficiently constrained as to make t
77.
by ThenAsNow 7y ago
You said: > A rocket engine nozzle produces thrust only for the part where the pressure is greater than atmospheric pressure. This is trivial at best and wrong at worst. When you say "the pressure", what do you mean? If chamb
78.
by ThenAsNow 7y ago
> That being said, I think the math changes somewhat for smaller launchers. Do you have any analysis you can point to to substantiate this? I suspect any such analysis is heavily predicated on assumptions, such as whether or not the sma
79.
by ThenAsNow 7y ago
> the whole stratolaunch plan is predicated on developing a new air-launched rocket, and we just don't know what the specs on that will be Neither will Stratolaunch, any time soon: https://spacenews.com/stratolaunch-
80.
by ThenAsNow 7y ago
> A rocket engine nozzle produces thrust only for the part where the pressure is greater than atmospheric pressure. A rocket engine produces thrust when its chamber pressure exceeds ambient pressure, which is trivially true for any roc
81.
by ThenAsNow 7y ago
I've a detailed comment that addresses several of the points you're making at https://news.ycombinator.com/item?id=19660163 Is it true, strictly speaking, that you may use less propellant in the expendable stage d
82.
by ThenAsNow 7y ago
The real answer, which is somewhat saddening given the immense amount of effort put into Stratolaunch, is that air-launch, when all is accounted for, has negligible benefits from a performance perspective when you are deploying expendable s
83.
by ThenAsNow 8y ago
Definitely not in everything they build that flies, nor do all of their current subsystem vendors. Very sadly, one of the comments from the 2014 thread cited above is right - C is in heavy use with such usage growing.
84.
by ThenAsNow 8y ago
> Thank you for the extensive response. With that context, I would say "full control" should amount to the ability of a pilot to overrule systems that may send an aircraft nosediving due to faulty sensors. Thanks for reading it
85.
by ThenAsNow 8y ago
What does "full and absolute control" mean in the context of a fly-by-wire aircraft? AA587 is blamed on a pilot's inputs driving a structural capability exceedance in the vertical stabilizer. For reasons such as these, all
86.
by ThenAsNow 8y ago
> The thought of flying on a commercial airliner with no inherent stability, akin to a fighter jet, is horrifying to me. What hysteria. Relaxed static stability, or some degree of longitudinal static instability (not the same as "
87.
by ThenAsNow 8y ago
A distortion-induced flameout is pretty unlikely - though something like a compressor stall is not out of the realm of possibility. These can result in brief discharges of flame out of the front of compressor against the direction of fligh
88.
by ThenAsNow 8y ago
> Today's environment is an abnormality in history (e.g. individuals wanting to be herbivores) created by the excess of food and technological advances we have. How this is not true of our artificial cities, dwellings, and infrastru
89.
by ThenAsNow 8y ago
> It’s probably “we now have two idle supersonic jets”. It's likely not. This kind of thing takes a lot of planning and coordination.
90.
by ThenAsNow 8y ago
> Could've gone with a simpler/cheaper wankel or microturbine optimized for high RPM, but I guess it's quicker to slap on an engine you already have. In these size classes, it's pretty hard to beat Otto or Miller cycl

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