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DARPA's hypersonic scramjet achieves successful flight

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Re: DARPA's hypersonic scramjet achieves successful flight

#101

Post by avmich »

Gravityloss wrote: post #82
pengaru wrote: post #70

Earlier quoted context omitted.

And the SR-71 is so simple the complexity falls off a cliff at the engine, hence your inclination to only care about that in comparing the two. The space shuttle is like a reusable mobile space station, airlocks and all. Occupants of the SR-71 wore space suits the entire time, there's a lot of minimalism on display in the SR-71 which is a large part of what makes it so glorious.

The SR-71 was very complex. For example it had multiple heat exchangers to get rid of heat, to transfer it to the fuel before it was combusted. The titanium structure was complex to maintain. Welding needed to be done in "bubble" work stations under protective gas.

The arguably most complex technology of Space Shuttle was SSME. Also, arguably the most important part of LEO rocket technology is engine - as soon as engines matured enough, space era started. Yes, there are gyros and superlight tanks, but Lambda-4S still does illustrate the importance. And hypersonic winged flight problems were greatly decreased in the Space Shuttle case by a "brute force" approach with ceramic tiles.

SSME was more or less repeated in results by RD-0120, and rather soon. I'd argue RD-0410 was more complex. SR-71 engine works in two different modes, and even today is not really repeated elsewhere. I think that shows how awesome the SR-71 design was - especially, but not only, for its time.

I'd appreciate a good analysis of design problems and solutions of SR-71 to decide which project was technically more complex.

Re: DARPA's hypersonic scramjet achieves successful flight

#102

Post by _2d30 »

tomcam wrote: post #90
corndoge wrote: post #87

Is it just me or has the Pentagon and the complex largely replaced the word "soldier" with "warfighter"? Feel like I've seen it a lot lately and I'm not sure what the change implies

Good call. Seems unnecessary, like the slow transformation of “emergency room “which used to be known as the ER to “emergency department“.

In fairness, emergency department is more sensible. They generally aren't a single room.

Soldier to warfighter seems unnecessary.

EDIT: It seems possibly using "warfighter" is more accurate as marines and pilots aren't soldiers?

Re: DARPA's hypersonic scramjet achieves successful flight

#103

Post by JumpCrisscross »

corndoge wrote: post #87

Is it just me or has the Pentagon and the complex largely replaced the word "soldier" with "warfighter"? Feel like I've seen it a lot lately and I'm not sure what the change implies

> replaced the word "soldier" with "warfighter"

Technically, only the Army has soldiers. The non-exclusionary term used to be “men and women in uniform,” but that got tired, so I guess we get “warfighters” now.

Re: DARPA's hypersonic scramjet achieves successful flight

#105

Post by nimbius »

jokoon wrote: post #95

I don't understand the purpose of having a missile that fast.

Missile interception technology like aegis relies on other ships detection and coordination with onboard defenses in an aegis fleet network.

Faster missiles mean a solution may be coordinated or countermeasure plotted too slowly to have any effect, or to arm things like CIWS countermeasures.

hypersonics, simply put, can sink US aircraft carriers before their protective fleet can take action, effectively neutralizing US presence in a region.

Re: DARPA's hypersonic scramjet achieves successful flight

#107

Post by ud7d7uegrvvy »

This is an instance where I think the domain (.mil) explains it pretty well. "Warfighter" and "warfighting" have been fairly common vernacular in the literature for awhile in the same way many fields have specialized jargon that may be largely synonymous with more common word choices. If it's unfamiliar it's probably because most people don't read military literature (despite often having strong opinions on military activity).

Re: DARPA's hypersonic scramjet achieves successful flight

#108

Post by JumpCrisscross »

nimbius wrote: post #105
jokoon wrote: post #95

I don't understand the purpose of having a missile that fast.

Missile interception technology like aegis relies on other ships detection and coordination with onboard defenses in an aegis fleet network. Faster missiles mean a solution may be coordinated or countermeasure plotted too slowly to have any effect, or to arm things like CIWS countermeasures. hypersonics, simply put, can sink US aircraft carriers before their protective fleet can take action, effectively neutralizing…

> hypersonics, simply put, can sink US aircraft carriers before their protective fleet can take action

Hypersonic missions are slower than ballistic missiles. Their advantage isn’t speed per se, but in being able to fly under the horizon for longer. They’re also more manoeuvrable, though at those airspeeds you’re somewhat limited in this domain.

Re: DARPA's hypersonic scramjet achieves successful flight

#109

Post by SkyMarshal »

JumpCrisscross wrote: post #103
corndoge wrote: post #87

Is it just me or has the Pentagon and the complex largely replaced the word "soldier" with "warfighter"? Feel like I've seen it a lot lately and I'm not sure what the change implies

> replaced the word "soldier" with "warfighter" Technically, only the Army has soldiers. The non-exclusionary term used to be “men and women in uniform,” but that got tired, so I guess we get “warfighters” now.

Yeah, Marines particularly don’t like being called “soldier”, they’re not soldiers they’re Marines. Probably same for the Navy, Air Force, Coast Guard, CIA operatives, etc. The civilian executive branch probably had a headache over that, and just started using the catchall term warfighter to refer to them all.

Re: DARPA's hypersonic scramjet achieves successful flight

#110

Post by jack_pp »

jhgb wrote: post #78

> The HAWC vehicle operates best in oxygen-rich atmosphere, where speed and maneuverability make it difficult to detect in a timely way. I'm reasonably sure that the infrared trace of a hypersonic vehicle doesn't make it difficult to detect. Likewise existing approaches to radar stealth are hard to reconcile with hypersonic speeds, which doesn't help avoid radar detection either.

Isn't the point of these weapons that even if you can detect them they are too fast to intercept?
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