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DARPA's hypersonic scramjet achieves successful flight

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Re: DARPA's hypersonic scramjet achieves successful flight

#201

Post by dotancohen »

sudosysgen wrote: post #79
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.

Plasma stealth is an existing approach to radar stealth that is made easier by hypersonic speeds. Infrared targeting of multiple hypersonic missiles is easier said than done. The missile you're hitting them with is going to be heating up the air around the camera probably at the same temps as the missile it's intercepting, and a base station wouldn't have enough resolution to guide a missile accurately from 100+km aw…

  > Plasma stealth is an existing approach to radar
  > stealth that is made easier by hypersonic speeds.
Does a vehicle traveling at such speeds that it compresses the air into a plasma have much aerodynamic control? I am aware that the space shuttle orbiters would roll during the plasma stage to control their rate of decent (less lift vector in the "up" direction) but could a missile maneuver to a target? Assuming that the sensors-through-plasma issue were resolved (which is another issue that I do not believe can be easily resolved).

Re: DARPA's hypersonic scramjet achieves successful flight

#202

Post by canadianfella »

sandworm101 wrote: post #196

>> released from an aircraft seconds before its Northrop Grumman scramjet (supersonic combustion ramjet) engine kicked on. No. The scramjet would only work at supersonic speeds. The missile was boosted to speed/altitude by another conventional rocket before lighting the scramjet. >> The HAWC vehicle operates best in oxygen-rich atmosphere As opposed to a oxygen-poor atmosphere? Mars? Venus? And "best" suggests that t…

Oxygen concentrations vary by altitude. You seem unnecessarily combative.

Re: DARPA's hypersonic scramjet achieves successful flight

#203

Post by canadianfella »

nurgasemetey wrote: post #198
JumpCrisscross wrote: post #121

Earlier quoted context omitted.

As a former aerospace engineer, I’m sceptical of the strategic value of hypersonics. Tactical? Sure. They’d have a better chance of taking out SAMs, light radar, et cetera . But the talk about these being carrier killers is, based on everything we’ve seen, off the mark. (Spending the cost of one hypersonic on a swarming attack would probably do more damage.)

I think taking out SAMs is huge thing. Or I am wrong?

Did you read the rest of the comment?

Re: DARPA's hypersonic scramjet achieves successful flight

#204

Post by redis_mlc »

JumpCrisscross wrote: post #121
jhgb wrote: post #118

Earlier quoted context omitted.

But maneuvering at high velocities won't be that easy. As far as I understand it, your lift/drag ratio decreases appreciably with increasing Mach numbers. So either you'd have to limit your maneuvering, or you'd have to have a propulsion unit with ridiculous amounts of thrust - at a situation when any amount of useful thrust is hard to obtain, since we still don't know really well how to do propulsion in this regime.

As a former aerospace engineer, I’m sceptical of the strategic value of hypersonics. Tactical? Sure. They’d have a better chance of taking out SAMs, light radar, et cetera . But the talk about these being carrier killers is, based on everything we’ve seen, off the mark. (Spending the cost of one hypersonic on a swarming attack would probably do more damage.)

As a student of war, anything you target at the enemy just might work, especially with the element of surprise.

The best example is the Exocet(s) that hit the Stark in the Falklands War:

- the Stark had a temporary commander from a sub. He was unable to organize the fire-fighting (damage control) effort, which is the biggest threat to a ship.

The US Navy prides itself on training every member of the crew on damage control, especially after the 1967 Forrestal fire:

https://en.wikipedia.org/wiki/1967_USS_Forrestal_fire

- the Stark had electronics problems, with the radar system interfering with radio transmissions/reception. You could argue that the ship was blind, even non-operational.

- one of the Exocets did not detonate, but destroyed a ship - the kinetic energy and remaining rocket fuel was enough.

- the air-launched Exocets used improvised rails, since the French embargoed parts.

So you never know if a powerful missile will be intercepted in time or not, which is magnified with nuclear warheads.

Oya, and the Falklands was the best ad ever for Aerospatiale!

Ironically, the US Sidewinder missile won the second Taiwan Straits War. The CCP stopped the air battle after the Taiwanese AF downed multiple jets with the Sidewinder, the first time it was used in battle. (Note the USSR always talked down the CCP when they were on the losing end, rather than allowing them to escalate further.)

The Sidewinder was and is one of the most lethal weapons ever invented, true "fire and forget."

Re: DARPA's hypersonic scramjet achieves successful flight

#205

Post by CTDOCodebases »

rsj_hn wrote: post #135
burkaman wrote: post #111

Earlier quoted context omitted.

I assume someone thought it sounds cooler and will help them recruit. It's an awful term, although maybe it will make it slightly harder for people to claim that the US military is a force for good because "our warfighters are global peacekeepers". Really highlights the absurdity.

It is politicians that keep insisting the job of the army is to get Afghanis to read and adopt liberal values. Peacekeeping is not popular in the army, for good reason. They are there to fight wars, not deliver social programs, build nations, or referee conflicts. If using language like "warfighter" can get the politicians to lay off on using the army for things other than fighting wars, then the clumsiness of the ph…

I think it is for recruitment. For me the word soldier makes me think of someone who is unempowered. Just another pawn on the table, getting their balls busted by their senior officer for not shining their boots enough.

Warfighter makes me think of someone who is empowered. A warrior willingly testing themselves in the harshest conditions imaginable. Fighting against adversity. Not submitting to it.

Your post reminded me of all the videos I watched on this subject. The ridiculousness of it all. A group of marines in Afghanistan who in the process of trying to deliver security to a village end up outside of it on a vantage point, ordering artillery shelling of the same village they are tasked with protecting because tabliban started firing mortars at them from within the village walls.[0]

[0] https://youtu.be/ZvZj3u1Eenw?t=2684

Re: DARPA's hypersonic scramjet achieves successful flight

#206

Post by tada131 »

qaq wrote: post #59
tada131 wrote: post #54

Earlier quoted context omitted.

> Ukraine gave up 3d largest Nuclear arsenal on the promise that other nuclear powers mainly US would provide security > mainly US You missing historical order here. Ukraine gave up their arsenal long before they decided to drop Russia as an ally and play with Europe/USA (latter happens after "Maidan"). So at given time point (when Ukraine signs memorandum) they done it with _only_ Russia' protection in mind (as ther…

Please enlighten me on the order :) being a Ukrainian born in 70th

Citing nti.org:

> By 1996, Ukraine transferred all Soviet-era strategic warheads to Russia.

> Ukraine received extensive assistance to dismantle ICBMs, ICBM silos, heavy bombers, and cruise missiles from the __U.S.__ funded Cooperative Threat Reduction Program

Citing wiki: > Euromaidan was a wave of demonstrations and civil unrest in Ukraine, which began on the night of __21 November 2013__ with public protests in Maidan Nezalezhnosti (Independence Square) in Kyiv

Easy, uh?

Re: DARPA's hypersonic scramjet achieves successful flight

#207

Post by qaq »

tada131 wrote: post #206
qaq wrote: post #59

Earlier quoted context omitted.

Please enlighten me on the order :) being a Ukrainian born in 70th

Citing nti.org: > By 1996, Ukraine transferred all Soviet-era strategic warheads to Russia. > Ukraine received extensive assistance to dismantle ICBMs, ICBM silos, heavy bombers, and cruise missiles from the __U.S.__ funded Cooperative Threat Reduction Program Citing wiki: > Euromaidan was a wave of demonstrations and civil unrest in Ukraine, which began on the night of __21 November 2013__ with public protests in Ma…

well even by your convoluted logic you would have to go back to Orange revolution in 2004. But none of what you site has anything to do with Russia being considered a mil ally. by Ukrainan gov. Russia was considered the biggest threat to Ukraine independence starting with Ukraine's first president.

Re: DARPA's hypersonic scramjet achieves successful flight

#208

Post by tada131 »

qaq wrote: post #207
tada131 wrote: post #206

Earlier quoted context omitted.

Citing nti.org: > By 1996, Ukraine transferred all Soviet-era strategic warheads to Russia. > Ukraine received extensive assistance to dismantle ICBMs, ICBM silos, heavy bombers, and cruise missiles from the __U.S.__ funded Cooperative Threat Reduction Program Citing wiki: > Euromaidan was a wave of demonstrations and civil unrest in Ukraine, which began on the night of __21 November 2013__ with public protests in Ma…

well even by your convoluted logic you would have to go back to Orange revolution in 2004. But none of what you site has anything to do with Russia being considered a mil ally. by Ukrainan gov. Russia was considered the biggest threat to Ukraine independence starting with Ukraine's first president.

> convoluted logic

The only convoluted thing here is your own history as you see it.

> Russia was considered the biggest threat to Ukraine independence starting with Kyivan Rus'

Until Yushchenko there was no such president. Relations never were stable, though.

Look at A.I. Kuzmuk paper "Ukraine military doctrine evolution" if curious. VDU-1993 and VDU-2004 never considered Russia as a threat. VDU-2004 states there is no direct military threat against Ukraine, just possibility of being involved into bigger conflict. Kuchma even cancelled statement about NATO integration in VDU-2004, by making it more smooth.

Re: DARPA's hypersonic scramjet achieves successful flight

#209

Post by qaq »

tada131 wrote: post #208
qaq wrote: post #207

Earlier quoted context omitted.

well even by your convoluted logic you would have to go back to Orange revolution in 2004. But none of what you site has anything to do with Russia being considered a mil ally. by Ukrainan gov. Russia was considered the biggest threat to Ukraine independence starting with Ukraine's first president.

> convoluted logic The only convoluted thing here is your own history as you see it. > Russia was considered the biggest threat to Ukraine independence starting with Kyivan Rus' Until Yushchenko there was no such president. Relations never were stable, though. Look at A.I. Kuzmuk paper "Ukraine military doctrine evolution" if curious. VDU-1993 and VDU-2004 never considered Russia as a threat. VDU-2004 states there is…

I highly doubt Kuzmuk ever read that book to begin with :) He certainly never wrote it :). To argue an empire is not a threat to the country that gained independence from it in very recent time is very toll order and Kravchuk always aknowleged Russia as a threat to Ukrainian independence as did Kuchma.

Re: DARPA's hypersonic scramjet achieves successful flight

#210

Post by sudosysgen »

JumpCrisscross wrote: post #189
sudosysgen wrote: post #185

Earlier quoted context omitted.

These maneuvers are in the terminal phase. Knowing the reaction speed and the moment at which LOS is achieved as well as estimating the speed of the missile and it's acceleration one can calculate a relatively short period under which interception is possible. Outside of that there is basically no risk and thus no need for any maneuvers. As for flight envelope we know from the X-15 that not that much is required to p…

> maneuvers are in the terminal phase One, this leaves the missile, which is screaming through the atmosphere, vulnerable in a way ballistics are not. (And visible in a way cruise missiles aren’t, either.) Two, if you have a carrier strike group in the middle of the ocean, this strongly restricts how much manoeuvring can be done. The target knows where you’re ultimately headed—if you tactfully manoeuvre into a blank…

By the time that you're close enough to the strike group that you have a serious risk of seriously missing, it's already too late for the faster interceptors to be effective.

As far as only so much maneuvering you can do before being too slow for the engine, yes that's probably an issue for the HAWC, but scramjet missiles have been demonstrated to achieve Mach 9 in atmospheric flight which allows a lot of energy to bled out before you drop out below Mach 4.

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