Slashdot Mirror
HyShot Scramjet Test Declared a Success
An anonymous reader writes: "ABC news is reporting
that analysis of the flight data from the recent
HyShot scramjet test (covered by Slashdot
previously) suggests that the test was successful and that the engine achieved combustion in flight after reaching Mach 7.6. The University of Queensland is also reporting the news."
BBC story
There's a ton of photos at http://photos.cc.uq.edu.au/HYSHOT/ and also at http://www.mech.uq.edu.au/hyper/hyshot/HyShot_phot os.html. The former link has some friggin huge jpegs.
There is also a page about the HyShot program itself at http://www.mech.uq.edu.au/hyper/hyshot/
Depends on what you think is better. The Gillete Mach3 system will take 3 swipes at your hair. This Scramjet system seems to attempt to take a record 7.6 swipes at your hair. Not sure how they do the .6 of a blade though... but from the commercials, the 3rd blade seems to essentially get as close to the skin as possible. So then the 4th blade must then (in a logical progression) take of the top layer of skin. The 5th blade then takes out the middle layer of skin. The 6th blade takes out the lower layer of skin. This is a highly good design as if you shave really fast, by the time it hits the 6th blade you should have shaved off all your nerves so it shouldn't even hurt anymore.
.6 of a blade that is left... maybe its some new encryption scheme for their razor so no one can exactly copy their design, as who would want to make .6 of a blade? Perhaps it means its only 60% as sharp as the rest of the blade and used to buff your bone?
Which leaves the 7th blade to shave off some bone, to polish it maybe. Now that
Well then, this has to be the closest shave you'll get, and with your skin gone, you should have no growth after, as the bulbs should have been rooted with that skin by then.
Mach 7.6 is right around 2,260 m/s (7,414 ft/s) or about 5,055 mph. It would still take you 5 hours to circumnavigate the globe. Plus you have to consider acceleration time - the rocket doesn't have to worry about killing people.
Realistically, we probably won't hit Mach 7 in commercial flights for some time, and there will probably be "low-speed" versions for shorter distances. As the article notes (emphasis mine):
--
Warning! Error reporting system failu
That what was all this school was for... to teach us how to solve our own problems. -- janeowit
Untrue. Sound travels slower because the air is colder, not thinner. The speed of sound in the Earth's atmosphere is proportional to the square root of the temperature, nothing else. http://www.allstar.fiu.edu/aero/mach.htm
Here's an atmosphere simulator where you can pick an altitude and see the speed of sound. As it says, "the speed of sound depends on the temperature and the gas," not on pressure.
The 2nd article points out that the engine is for use with space payloads, you dont have to carry your oxidizer while in the atmosphere, reducing vehicle weight and increasing payload.
Now, getting to Mach 7.6 to light one of these off may take a railgun, something that rules out living payloads, but good for launching cheap infrastructure into LEO.
Starman97@Gmail.com (bring it on spammers)
Almost everything. Normal jet engines have lots of moving parts - turbines, compressors, etc. Ramjets and scramjets don't have any moving parts. They also require very high velocities to work properly, whereas a turbojet/turbofan is quite happy running all day long without moving.
G-force is created by acceleration, not speed. Otherwise the speed of Earth's orbit around the sun would crush us all.
Nonetheless, I'd rather be in Sydney in 2 hours with a bloody nose and bruised ribs than endure a 20 hour flight with a bunch of Englishmen...
there will probably be "low-speed" versions for shorter distances
Probably not. To understand why requires some knowledge of how a scramjet differs from a normal turbofan engine. There are no spinning parts in a scramjet or ramjet engine. The (sc)ram engine requires a strong standing shock to me maintained in the intake. This standing shock replaces the compressor section of a normal turbo fan. There is a minimum speed which will produce a sufficiently strong, stable shock that will allow this to work.
The SC part is for supersonic combustion which makes that standing shock also replace the combustor portion of the turbo fan. Chemical reactions and transonic fluid dynamics can interact in very complicated ways. This can make this supersonic combustion unstable. The best way to stabilize it is to go faster and increase the strength of the shock.
So, to sum up, operating scramjets at lower speeds is more difficult, so if anything, we will probably see them operating at the highest possible speeds that the airframe and aerodynamics will allow.
Very fast ramjet cruise missiles were under development in the 1950's, but they fell out of favor because ICBMs are even faster and just about impossible to shoot down. However, they did look way cooler than today's boring ICBMs.
As I read the comments, it seems that some people don't get the implications. In a normal jet engine the flow has to be slowed to less than Mach 1 for compustion to occur. Faster, and it goes out. This limits the range of velocity that can be attained. So, there is a range of velocity that can only be attained with rockets. With a working Scramjet it becomes possible to fly most of the way to orbit. From an energy consideration, once you are in low earth orbit you are half way to anywhere in the solar system and can use low acceleration, high efficency engines to get anywhere.
Scramjets are the realistic key to space exploration.
Eschew Obfuscation