The main problem holding back reusable hypersonic planes is that traditional ramjet engines become very inefficient over mach 2 while hypersonic engines do not work well below mach 4. There is the need to solve the hypersonic speed gap between mach 2 and mach 4. Rotating Detonating Engines can be more efficient up to mach 3 and also enable hypersonic engines to work down to mach 3. This can close the gap and enable efficient hypersonic planes.
Rotating Detonating Engines use supersonic explosions which are more efficient than subsonic deflagration. The detonation goes around the chamber.
The rotating detonating engine can be smaller and lighter which is always better for planes.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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Hi Brian.
Next Big Future seems to take forever to load.
Are you having problems?
Cheers,
Jim Lynch
Are other people experiencing this issue? I did change the caching to prevent caching of searches which was messing up many people going to the front page. Those people would get random front pages.
[ If there’s another picture button for random front pages, that could be interesting for the interested in all subjects throughout longer periods, but with keeping direct access to first news front page, also?
Thanks a lot for all Your input and information work. ]
I’m sometimes just not getting opinions I’ve posted in response to other people’s opinions, or my own. Oh, I’m Sooooooo depressed… (but I think I’ll live…)
Thanks for fixing the front page issue. It was a problem for a long time on both my phone and laptop, but now seems to be fixed. Thanks!
And I’m not having any problems with long load times. So everything seems good.
small correction; ramjets are most efficient in Mach 3-4 range, and are generally better than scramjets up to about Mach 5.
[ What’s a reasonable guess for power requirements on up to Mach 5?
Mach 5 cruising speeds for aircrafts is maybe suitable above ~70000 feet altitude?
Wind tunnel compressor power at NASA ~1950’s for up to Mach 10 range is around the order of 175000kW/175MW. So maybe that’s about the order for power requirements accelerating and keeping a scramjet engine channel (and plane design) at these speeds?
X43 had its record flight to Mach 9.6 in 2004.
An air crafts surface temperature can get around a 1,900°C (~3,500°F) towards a Mach 20, but that told without reference to atmospheric density.
Space Shuttle on return into atmosphere had speeds on up to about Mach 25.
“High temperature reusable surface insulation, HRSI, was primarily designed to withstand transition from areas of extremely low temperature (the void of space, about −270 °C or −454 °F) to the high temperatures of re-entry (caused by interaction, mostly compression at the hypersonic shock, between the gases of the upper atmosphere & the hull of the Space Shuttle, typically around 1,600 °C or 2,910 °F).” ]
What’s old is new again. PDE (Pulse Detonation Engine) has all the rage 20 years ago, loads of progress, until it all went dark.
Curious, PDE were all the rage 20yrs ago, and before that actually. Then it went “dark”. While some may think it “went dark”, because of some conspiracy, what might have happened, may be more basic. Funding dried up, the powers that be who controlled the cash were distracted by “other things”, and well s*** happens. (sorry). If it “went dark” because of western attempts to keep it quiet well that went over like a fart in church. EVERONE heard it…
Currently, according to open-source media, the Chinese are ahead in PDE tech. Yes, the Chinese will steal anything they can from whomever they can. Their very good at it. Not a conspiracy on the part of my government (I’m an American), but the work of a hostile intelligence force.
Lots of IP theft, but not this. One of the tech leads on it was American educated and then hired on our development team. When it was defunded by CONgress ( I believe it was by GOP ), the guy was let go, so he went back to China and developed there.
Yes, there is a great deal of IP theft but even more stupidity on CONgress and CEO parts.
Likely will be a very difficult meeting alternating stress limits. As constantly rotating may have to be for >10 million cycles.
Yes, you make a point about “alternating stress limits” across a combustion mainframe is problematic. Yet, when it comes to PDE,”stress ” is limited most by the faster combustion is, the less stress is likely to affect any one component of any engine. Of course, this means, combustion must be as complete as possible, whatever you burn w/O2 , must destroy its “other fuel” as quickly and completely as possible.