Quote from: 93143 on 11/14/2009 02:48 pmI'm pretty sure you're wrong. The engines weren't the limiting factor on the SR-71. Around Mach 3.6 - 3.7, the airframe would start to fail; that's why it never went faster than that.The SR-71 is limited by both engine and structural temperature to about Mach 3.6. If it was just temp, it could dash to engine speed limit.And next time I design a missile, I will remember I can just use a ramjet as long as I am moving. This will save a lot on the large solid to get the engine up to start speed.If not a shockwave to compress the air in a ramjet, what does the compression?Danny Deger
I'm pretty sure you're wrong. The engines weren't the limiting factor on the SR-71. Around Mach 3.6 - 3.7, the airframe would start to fail; that's why it never went faster than that.
So why nasa cancelled the RTA study http://gltrs.grc.nasa.gov/reports/2005/TM-2005-213803.pdf (it also should be used for darpa's falcon project and funded under air force's Histed program). and instead darpa chose to use the vulcan configuration ( cvc/pde embodied with existing turbofan such as the p&w f119 ), pluse i have never seen a turbofan that could get you to mach 4 speeds even the blackbird engine the J58 could 'only' get you to mach 3.2 and that with a ramjet bypass system, currect me if i am wrong .
For many years their raison d'etre was not to colonize space,
Quote from: 93143 on 11/14/2009 02:48 pmI'm pretty sure you're wrong. The engines weren't the limiting factor on the SR-71. Around Mach 3.6 - 3.7, the airframe would start to fail; that's why it never went faster than that.Yes that was my understanding as well, from pilots who flew them. By mach 3.5 the engines were pretty much on pure ramjet mode and could continue to accelerate if you didn't throttle them down.
Quote from: mlorrey on 11/15/2009 12:11 amFor many years their raison d'etre was not to colonize space,Since when is that NASA's charter?
Thats the question the Augustine Commission is asking: is it or is it not the mission of NASA to lead in the goal of colonizing the moon, mars, and other locations in space? If it is not the goal, then the Augustine Commission finds no reason for NASA to pursue the Ares program.
Quote from: mlorrey on 11/15/2009 01:41 amThats the question the Augustine Commission is asking: is it or is it not the mission of NASA to lead in the goal of colonizing the moon, mars, and other locations in space? If it is not the goal, then the Augustine Commission finds no reason for NASA to pursue the Ares program.No. Exploration and colonization are two different things
The holy grail is you catch an early morning flight, have your meeting, and get home at a decent hour.That requires a short stay at the airport,
Quote from: kevin-rf on 11/12/2009 07:32 pmThe holy grail is you catch an early morning flight, have your meeting, and get home at a decent hour.That requires a short stay at the airport,Stop right there. You can improve the flight times to silly hours, but if you have to be at airport 2 hours before, and it takes 1 hour to get out, adding an hour both to get there and back, minutes you will shave off the actual flight time will be irrelevant.
On wait time at airports. It would go much faster if they just gave everyone a knife and had us board. And I pitty the fool that tries to light their shoes next time. There is no way anyone is going to take control of another plane. People don't like to be Kamikazed into buildings on a beautiful fall day.Serious though. There is a good point that there is a point of diminishing returns on decreasing airline travel time due to all the time spent on the ground.
Quote from: William Barton on 11/12/2009 12:35 pmThere's little need for commercial travelers to get anywhere on Earth any faster than they already can.Maybe there's little "need", but there's plenty of "want" to get there faster. India from the West coast takes something like 30 hours. Lot of people would pay more to get there a lot faster.
There's little need for commercial travelers to get anywhere on Earth any faster than they already can.
Concorde was profitable for the for the airline (british airways) for most of it's life but was unprofitable for the company that made it. Mainly due to the 70s spike in oil costs drying up orders and the US restriction on supersonic overflights. I used to live under the flight path and the booms never bothered me, in fact I barely heard them.Shame really.
Quote from: khallow on 11/12/2009 07:01 pmQuote from: William Barton on 11/12/2009 12:35 pmThere's little need for commercial travelers to get anywhere on Earth any faster than they already can.Maybe there's little "need", but there's plenty of "want" to get there faster. India from the West coast takes something like 30 hours. Lot of people would pay more to get there a lot faster.You're talking about the difference between a commercial fleet airliner (which is what Concorde was supposed to be) and a private charter. I don't know what the prospects are for the Aerion Supersonic Business Jet coming to market and succeeding, but obviously somebody thinks there's enough "want" to sell them. Maybe we'll see.
Quote from: William Barton on 11/15/2009 04:28 pmQuote from: khallow on 11/12/2009 07:01 pmQuote from: William Barton on 11/12/2009 12:35 pmThere's little need for commercial travelers to get anywhere on Earth any faster than they already can.Maybe there's little "need", but there's plenty of "want" to get there faster. India from the West coast takes something like 30 hours. Lot of people would pay more to get there a lot faster.You're talking about the difference between a commercial fleet airliner (which is what Concorde was supposed to be) and a private charter. I don't know what the prospects are for the Aerion Supersonic Business Jet coming to market and succeeding, but obviously somebody thinks there's enough "want" to sell them. Maybe we'll see. There are at any given time, depending on the economy between 800-1200 billionaires in the world these days. Such folks would use a ballistic/hypersonic vehicle on a regular basis.There are approximately 320,000 multimillionaires in the world in 2009. All of these are potential passengers at least once, along with family members. The top 20% are in the hundreds of millions of dollars range that makes flights several times a year economically smart if they are working rich.
Quote from: mlorrey on 11/15/2009 04:37 pmThere are at any given time, depending on the economy between 800-1200 billionaires in the world these days. Such folks would use a ballistic/hypersonic vehicle on a regular basis.There are approximately 320,000 multimillionaires in the world in 2009. All of these are potential passengers at least once, along with family members. The top 20% are in the hundreds of millions of dollars range that makes flights several times a year economically smart if they are working rich.It's the same reasoning that leads some to predict sales of "space yachts." The question is, how often do these people really need to travel on business? If I were that rich, would I risk my neck on a ballistic transport, or would I send 50 flunkies economy class? What kind of business does Bill Gates do that requires his personal presense? (Of course, I am someone who doesn't enjoy travel at all. If it weren't for rdp, I'd be in a different line of work.)
There are at any given time, depending on the economy between 800-1200 billionaires in the world these days. Such folks would use a ballistic/hypersonic vehicle on a regular basis.There are approximately 320,000 multimillionaires in the world in 2009. All of these are potential passengers at least once, along with family members. The top 20% are in the hundreds of millions of dollars range that makes flights several times a year economically smart if they are working rich.