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@yogthos the tl;dr is that you basically have super high energy air coming in at Mach 5. You then have to take all that energy away to get your fuel to burn in it, which barely gets you past break even. They create massive amounts of drag too and in order to function need to stay in the part of the atmosphere that’s thick enough to breathe, thus prolonging the drag and problematic heat generation.
Given the point of a scramjet is to get you into a suborbital trajectory for a rapid glide to your destination, the fact that they have inherently terrible thrust performance and only work when you’re in the bit of the atmosphere you desperately don’t want to be in, they’re uniquely terrible at it.
Turborockets solve these problems. Get up to Mach 5 on air, close the intakes, run on liquid oxygen, and CLIMB.
They’re lighter, more efficient, and faster than hypersonic air breathers. You wanna go that fast, use a rocket, and get away from the nasty draggy burny stuff. As enticing as the idea of “free oxidiser” is, it’s a sucker bet.
Again, go ahead and explain what the paper about this specific jet gets wrong. Also, nobody is asking your to be anybody's butler. You made a claim, so now it's up to you to substantiate it.
I find it absolutely hilarious how arm chair aeronautics engineers such as yourself just assume that people building this stuff aren't aware of obvious arguments that even a layman such as yourself understands. Like it took your galaxy brain to figure this out, but the people actually making the jet aren't aware of this.
@yogthos I did.
Scramjets are fundamentally fighting Newton’s 3rd law. Slow air down by Mach 5 only to speed if back up to Mach 5 again. You’re burning tonnes of fuel to accomplish almost nothing.
If they have a practical scramjet vehicle (they don’t), then they should feel free to show the world, rather than posting vacuous bullshit on the Internet.
Nowhere in the paper does it say that this is a scramjet. Meanwhile, obvious solution for a hypersonic vehicle would be to go to upper atmosphere at a lower speed, and then achieve speeds over Mach 5 where there is low atmospheric density. You really think that you're smarter than literally everybody working on this project, and it's absolutely hilarious.
Maybe take your own advice and stop posting vacuous bullshit on the internet pretending that you're an expert on things you have little understanding of.
@yogthos “The paper”.
This isn’t a paper. It’s a blog post.
It’s no more a “paper” that is subject to any kind of scientific debate than some rando who said they made cold fusion in their microwave.
“Jumbo jet prototype”. Bless.
The "paper" that OP is referring to is the one they posted a few levels up. It links to a researchgate paper that I believe is associated with the article. Just from a quick look at the paper, which is only 3 pages, they are talking about the design the aircraft uses to mitigate the negative effects that occur at hypersonic speeds. They refer to the Waverider design and modified it by including a High-Pressure Capturing Wing to improve lift. Waveriders are designed to conform to the shockwaves the vehicle produces at hypersonic speeds to reduce the drag from those shockwaves. When designing high speed aircraft you have to design around the shockwaves it will produce. This enhancement seems to improve the lift the vehicle creates at those speeds.
Also you aren't getting everything right in your arguments. Earlier you stated that scramjets are fighting Newton's 3rd law which states, "For every action, there is an equal and opposite reaction". You do understand that all air-breathing engines slows the air down before it gets to the engine. This is usually done during a compression cycle to increase the pressure and density of the air. Turbojet and Turbofan engines do this using compression fans, Ramjets uses a normal shockwave, and scramjets uses a series of oblique shockwaves called a "shock train". The difference between a scramjet and the other engines is the airflow is subsonic in Turbojet, Turbofan, Ramjet, etc while the air enters the engine at supersonic speeds for scramjets. That's why its called a SCRamjet, Supersonic Combustion Ramjet. But like OP said the paper doesn't mention what type of engine was used, only that it was a hypersonic vehicle so it could be a rocket.
How do I understand this? I actually have a degree in aerospace engineering, I've worked on scramjets (X-51) for the USAF, and I designed engines for GE Aviation. Your arguments are all wrong.
Nothing more adorable than internet randos acting like they're bonafied rocket scientists. Bless.