The sonic boom is about the same for all aircraft, it mainly depends on the mass of the aircraft. It occurs at Mach 1.0 exactly. There is no such thing as a "louder sonic boom" if the plane goes faster. Nonsense.
I never said the opposite. A plane skipping over the higher atmosphere at hypersonic speeds would bounce up and down over long periods of time. While bouncing up it is subject to an upwards acceleration, so its passengers feel an increase in "gravity".
I'm using SFCs of 5 to 10, just like what real rocket engines have. The useful load really depends on the size of the aircraft, that's true. I made one that is very small (around twelve feet in length) and can carry one man (250 lbs of payload), for example. As I've pointed in another comment down the page, the economics you're mentioning have some engineering solutions too.
Saving time also means saving fuel
on
The Future of Flight
·
· Score: 4, Informative
Before someone posts about how rockets are fuel-inefficient compared to other engines, I'd like to point out that it mostly depends on the cruise speed of the aircraft.
If the plane completes the flight in ten times less time than a conventional subsonic plane, then its engines are burning fuel for ten times less time as well.
Modern high-bypass turbofan engines have a specific fuel consumption (SFC) rate around 0.5 lb of fuel per lb of thrust per hour. Current liquid fuel rockets' SFC is around 10, and solid / hybrid rockets' SFC is around 5. But the concept of "pound of thrust" evolves with speed: for example, a reciprocating engine with a propeller will give you much more (approximately four times as much) pounds of thrust than the number of HP the engine develops, _at low speeds_. At 375 mph, you get one pound of thrust per HP. And beyond, you get much less. That's why high subsonic planes use turbofans and the slower planes still use propellers.
At supersonic speeds the fuel consumption per distance covered of a turbofan engine can grow as high as 3+, but that of a rocket engine does not grow with speed, so there's a given speed beyond which rockets are more efficient than turbofans.
I think you might have misunderstood it. It uses the liquid hydrogen fuel to cool the engine and the fuselage: when the liquid hydrogen expands into gaseous state, it absorbs considerable amounts of heat, just like the liquid freon in your fridge. This technique was used on the XB-70 Valkyrie, and it could run hours at Mach 3.
LEO orbital speed is around Mach 30. The Hyper Soar is supposed to fly at Mach 10 "only". At altitudes of 200,000 feet gravity is reduced significantly, but no weightlessness if you don't change vertical speed.
Actually, it would mean: - strong acceleration during take-off and climb - low gravity during most of the flight, oscillating between 0.2 to 0.8 g, or maybe an alternation of weightlessness and 1g gravity. I'm sure most tourists would appreciate a free fall experience as a bonus;) - strong deceleration during the whole approach
According to my own virtual tests
on
The Future of Flight
·
· Score: 3, Interesting
I've done a few tests in X-Plane and came to the conclusion that with today's rockets and advanced materials it might be fairly easy to make a suborbital plane that can go from Paris to New-York in under an hour. I've got three different designs that could do it. The one obstacle is leading edge temperature at supersonic and hypersonic speeds, but shockwave shaping and the use of cryogenic fluid (liquid hydrogen ?) like on the 70s' XB-70 Valkyrie can overcome it.
In all the parties involved, there is a minority of warmongers / hatebreeders, that point at each other and try to federate the rest of the community into hatred.
Maybe YOU, Slashdot reader, are part of them, without knowing or aknowledging it.
Right now antimuslim racism is growing strong in various western countries, antisemitism is back in Europe, antiamericanism gets mixed with antiglobalization fears, and antipalestinianism grows in Israel too. Even anti-war sentiments are leading some to hatred.
I forewarn you all that this HATRED will be the cause of WW3. Not one particular community will be responsible, they will all be, altogether.
This is so true. I mean, Bush clearly did something fantastic for the Iraqi, there's no denying it, and for this they should reelect him as President next November 2004.
If there a challenge-response, then the device is not entirely passive, so it must have an energy source ? Then it is possible to exhaust it with a lot of non-legit requests ?
If they did get a back-up online which was then subsequently DDoSed along with the main, then why was the 216.250.128.20 webserver up and responsive during the _whole_ attack ?
Slashdot Mirror
I mean a design that virtually flew. That's what we're talking about, right ?
The sonic boom is about the same for all aircraft, it mainly depends on the mass of the aircraft. It occurs at Mach 1.0 exactly. There is no such thing as a "louder sonic boom" if the plane goes faster. Nonsense.
I never said the opposite. A plane skipping over the higher atmosphere at hypersonic speeds would bounce up and down over long periods of time. While bouncing up it is subject to an upwards acceleration, so its passengers feel an increase in "gravity".
I'm using SFCs of 5 to 10, just like what real rocket engines have. The useful load really depends on the size of the aircraft, that's true. I made one that is very small (around twelve feet in length) and can carry one man (250 lbs of payload), for example. As I've pointed in another comment down the page, the economics you're mentioning have some engineering solutions too.
Before someone posts about how rockets are fuel-inefficient compared to other engines, I'd like to point out that it mostly depends on the cruise speed of the aircraft.
If the plane completes the flight in ten times less time than a conventional subsonic plane, then its engines are burning fuel for ten times less time as well.
Modern high-bypass turbofan engines have a specific fuel consumption (SFC) rate around 0.5 lb of fuel per lb of thrust per hour. Current liquid fuel rockets' SFC is around 10, and solid / hybrid rockets' SFC is around 5. But the concept of "pound of thrust" evolves with speed: for example, a reciprocating engine with a propeller will give you much more (approximately four times as much) pounds of thrust than the number of HP the engine develops, _at low speeds_. At 375 mph, you get one pound of thrust per HP. And beyond, you get much less. That's why high subsonic planes use turbofans and the slower planes still use propellers.
At supersonic speeds the fuel consumption per distance covered of a turbofan engine can grow as high as 3+, but that of a rocket engine does not grow with speed, so there's a given speed beyond which rockets are more efficient than turbofans.
I think your escape velocity figure lacks an additional zero.
I think you might have misunderstood it. It uses the liquid hydrogen fuel to cool the engine and the fuselage: when the liquid hydrogen expands into gaseous state, it absorbs considerable amounts of heat, just like the liquid freon in your fridge. This technique was used on the XB-70 Valkyrie, and it could run hours at Mach 3.
LEO orbital speed is around Mach 30. The Hyper Soar is supposed to fly at Mach 10 "only". At altitudes of 200,000 feet gravity is reduced significantly, but no weightlessness if you don't change vertical speed.
Actually, it would mean: ;)
- strong acceleration during take-off and climb
- low gravity during most of the flight, oscillating between 0.2 to 0.8 g, or maybe an alternation of weightlessness and 1g gravity. I'm sure most tourists would appreciate a free fall experience as a bonus
- strong deceleration during the whole approach
I've done a few tests in X-Plane and came to the conclusion that with today's rockets and advanced materials it might be fairly easy to make a suborbital plane that can go from Paris to New-York in under an hour. I've got three different designs that could do it. The one obstacle is leading edge temperature at supersonic and hypersonic speeds, but shockwave shaping and the use of cryogenic fluid (liquid hydrogen ?) like on the 70s' XB-70 Valkyrie can overcome it.
In all the parties involved, there is a minority of warmongers / hatebreeders, that point at each other and try to federate the rest of the community into hatred.
Maybe YOU, Slashdot reader, are part of them, without knowing or aknowledging it.
Right now antimuslim racism is growing strong in various western countries, antisemitism is back in Europe, antiamericanism gets mixed with antiglobalization fears, and antipalestinianism grows in Israel too. Even anti-war sentiments are leading some to hatred.
I forewarn you all that this HATRED will be the cause of WW3. Not one particular community will be responsible, they will all be, altogether.
This is so true. I mean, Bush clearly did something fantastic for the Iraqi, there's no denying it, and for this they should reelect him as President next November 2004.
Wishful thinking. There's no way the Iraqi are not going to reelect Bush in 2004 now ! He did so much for them !
The people of Iraq should reelect Bush in 2004 ! He did so much for them !
What a great day to be an American
You misspelt "Iraqi", like many people.
It's a shame Iraqi don't get to vote in November 2004 US Presidential Election, hmm ?
If you're Iraqi or Iranese, you have some serious reason to vote for Bush in 2004 !
I don't think Tolkien had much marketing material done before writing his book.
If there a challenge-response, then the device is not entirely passive, so it must have an energy source ? Then it is possible to exhaust it with a lot of non-legit requests ?
You don't read WHAT was on Groklaw, you read what others have to say about what was on Groklaw, actually.
About time Slashdot mirrored Groklaw's articles linked to.
Here is my favorite article of the collection.
So I guess until someone straps a jetpack on their back and power-dives, no human will ever experience it...
Michel fournier is planning to attempt to skydive from 130,000 feet and reach supersonic speeds (1200 to 1600 kmph / 750 to 1000 mph).
Nick Piantanida tried and failed to do that in 1965. And all these are unpowered skydives.
10 cents say Microsoft will soon "revoke" Win95 and 98 EULAs to force everyone to upgrade (preferably to Linux) !
If they did get a back-up online which was then subsequently DDoSed along with the main, then why was the 216.250.128.20 webserver up and responsive during the _whole_ attack ?
When drowning in speculation, apply Ockham's Razor ;)