Tell me about the Green Lady, /K/

Absolutely nothing. Tell me more. No, I won't google it.

>>31655642
>Borane-Burning
Colour me dubious

>>31655642
>>>/o/
>>>/sci/

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>>31655642
I wasn't the only that thought of this when I saw this thread.

>>31655642
The thing in the picture? That's a render for a supersonic airliner that's quiet enough to fly overland. I haven't heard claims of superspeed t just mach and some change without pissing everybody off. Also just renders\ models, no plane yet, but concept is 40 or 50 seats I think.

>>31655996
Okay just had to googlify it. 80 seats, Mach 1.7, not hypersonic, not that interesting
http://www.lockheedmartin.com/us/news/features/2014/getting-up-to-speed.html

>>31655996
OP here, I used it as a filler image, but supposedly most of Lockheed's recent press work about quiet supersonic airliners is a white-world reflection of the work that they did on the Lady.

Basically, they cracked the quiet supersonic code with that XB-70 looking demonstrator that was spotted at Groom from Tikaboo in the 90s, and the Lady further builds on those ideas.

>>31656028
Yeah, the civilian interpretations of it fly at Mach 1.5-2 to save on fuel and make heat management. From what I've heard, the Lady flys much higher and faster than that. My conjecture is that if it exists, then the lady probably does Mach 4-5, but does it at ~100-120,000 feet altitude, where the friction heating of those speeds is no more than Mach 3.5 was for the Blackbird at 90,000 feet.

The borane fuel additives would then likely be needed to keep the turbo-ramjets from flaming out in such thin air.

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>everything in this thread
I don't even know where to start.

Quiet supersonic flight is a tricky problem that they only very recently started to figure out. Effectively, the sonic boom is a function of the pressure differences you get from the shocks the aircraft creates as it moves through the air. Steeper deflections (lower sweep of a surface with respect to the airflow) cause a lower wave angle, meaning that waves from across the plane will usually converge into a single more powerful (and thus louder) one.

So to make a boom quiet, what you need to do is reduce the pressure differences that the shocks create. That means
>higher sweep of surfaces (see NACA 1135)
>shocks spread across aircraft (meaning longer surfaces)
>higher flight (because pressure changes over shocks are a fraction of the ambient pressure)
>slower flight (because wave angle and pressure change increases with Mach number)

There's also things like just generally trying to avoid creating shocks on the underside of an aircraft, meaning either very careful shaping of the underside or just slapping engine nacelles on the top of the aircraft.

The current class of quiet supersonics that's being looked at now is even slower than the Concorde - about Mach 1.6 to 1.8. Any faster and it really stops being practical - favorable shaping gets more important, but that shaping starts to conflict with the kind of layout you need for high supersonic flight.

>cont

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>>31658515
>cont

Any kind of Mach 4+ vehicle is going to by no means be quiet, even at very high altitudes. The design elements necessary for quiet booms at that speed would make a Mach 4 vehicle impractical. And no, you can't just fly higher, because beyond about 80,000ft conventional jets stop working and it takes a Scramjet to really get any air-breathing propulsion

>friction heating
It's compression heating, and the added altitude wouldn't be enough to make it any easier (or even as "easy" as the SR-71). For reference: https://www.grc.nasa.gov/www/BGH/stagtmp.html

The temperature at the leading edges of the aircraft will get close to (but fortunately not all the way up to) the stagnation temperature for that particular Mach number and altitude. As you can see, the stagnation temperature for Mach 4 is significantly higher at every altitude than Mach 3.

And that's not even getting into the control problems they'd have at altitudes beyond about 90,000ft. The NF-104 used rockets to get to those altitudes and it required a reaction control system to provide any control around its peak.