How We Might Have Scramjets Sooner than Expected 674
loralai writes "Recent breakthroughs in scramjet engines could mean two-hour flights from New York to Tokyo. This technology, decades in the making, could redefine our understanding of air travel and military encounters. 'To put things in context, the world's fastest jet, the Air Force's SR-71 Blackbird spy plane, set a speed record of Mach 3.3 in 1990 when it flew from Los Angeles to Washington, D.C., in just over an hour. That's about the limit for jet engines; the fastest fighter planes barely crack Mach 1.6. Scramjets, on the other hand, can theoretically fly as fast as Mach 15--nearly 10,000 mph.'"
10000mph! (Score:1, Interesting)
2 seconds of research reveals... (Score:5, Interesting)
F-22 top speed at altitude: Mach 2.42 (officially...it's reported it can exceed Mach 4)
F-18 top speed at altitude: Mach 1.8+
I actually couldn't find a modern jet fighter that COULDN'T exceed 1.6 (at least within my aforementioned 2 seconds of research)
Of course, that doesn't diminish the insanity of Mach-15, but still.
Oh yeah, if you turn, your heart will forcibly exit your body via your anus before exploding. Have fun.
Re:SR-71 Blackbird (Score:5, Interesting)
Re:SR-71 Blackbird (Score:4, Interesting)
I've heard stories that imply that the true top speed of SR-71 is somewhere closer to M5 or M8 - as tested "unofficially" by the military sector.
Most likely such speeds are attainable but not sustainable (fuel runs out, plane breaks in mid-air,
Maybe they used some experimental (or nonstandard) fuel -- then again, it may be a bunch of bullshit.
Cost? (Score:3, Interesting)
Re:SR-71 Blackbird (Score:5, Interesting)
I wager this technology has been near perfected sometime ago, but as with all things, it was probably kept back to be used in case of sagging sales due to rights abuses at airports (Atlas has Shrugged, and it is visible in that people are avoiding airports now because of the downright abusive behaviors of the TSA and federal shock troops there to protect us from incompetent unshaven twits with box cutters and toothpaste.
Seriously, this will be the carrot on a stick to dissuade people from using other less regulated means of transportation. Obviously L.O.S.T. was ratified recently in Congress to restrict private sea travel... now only warships and those with "permission papers" will be "allowed" to travel, and who knows what else is coming. Free travel is becoming far less so.
Changing the scope of local again (Score:3, Interesting)
Trains changed it to 400-600 miles a day...
Cars made it routine to drive 100 miles a day...
Planes made it routine to fly 3000 miles for a vacation...
I really can't wait until it's routine to nip out to Luna for a weekend.
2 hours, eh? (Score:3, Interesting)
Scramjets are only a small piece of the puzzle (Score:3, Interesting)
Re:SR-71 Blackbird (Score:5, Interesting)
If not then maybe they want the scramjet because its quiet(er) then the ramjets of old? I know tons about the SR-71, but I haven't really researched much on scramjets beyond the mythological Aurora(fabled successor to SR-71). Does a scramjet produce a less significant sonic boom then a ramjet?
yet another ridiculous projection (Score:3, Interesting)
Usually they are based on some person's preliminary doctoral research. This time it was based on that perennial nerd baby boomer childhood favorite with a cool name, scramjets.
Ho hum.
Re:SR-71 Blackbird (Score:2, Interesting)
Re:2 seconds of research reveals... (Score:3, Interesting)
There are many hazards in high speed flying, but having the plane explode around you from simply turning at high speed is not one of them. There will be restrictions but turning a plane at high speeds is not some mysterious capability we have yet to sort out.
I know this because I've done it.
How do they get to minimal operating speed? (Score:4, Interesting)
I wonder if Scramjets would increase or decrease condensation trails, which are known to have a dimming and cooling effect on everything below them. Decreasing would mean more sunlight hitting the ground, but also more heat, which would only heat up the Earth at ground level that much more. If it increases, it means more cooling, but also more dimming.
Interesting times.
Re:Amazingly . . . (Score:3, Interesting)
Running out of oil a myth ... (Score:3, Interesting)
We are not going to run out of oil. The price of oil will increase and make alternatives feasible. As this occurs the demand for oil will decrease. The rate of consumption will also peak, it just lags production. The question is really when the transition to alternatives will occur and how much pain do we have to feel to get the process started. In short, as we use less oil to go to work and the supermarket, to get food from the farms to the supermarket,
Re:SR-71 Blackbird (Score:3, Interesting)
Growing up I heard that line every time I pointed out that the books all say Mach 3.
Re:SR-71 Blackbird (Score:3, Interesting)
It was very impressive to watch that aircraft disappear from sight in mere seconds.
Re:SR-71 Blackbird (Score:3, Interesting)
Also, no doubt time will be saved for long flights, but turning a 2hr hop into a 10 min hop really wouldn't be that useful. You still have to slow down on both sides (which should take considerably longer with a faster plane) wait in turn for a position to take off and land, and have all the normal flight overhead of getting there early and getting your luggage and stuff. That is what did the Concord in, it just simply wasn't worth halfing your flight time which translates into about a 20% savings for short flights, at a price several times that of a normal plane.
Assuming it could be made affordable, it could cause problems too. If there was less time involved in flying the amount of travel being done (especially for business) could drastically increase. Our airports can barely handle the load they currently have, so if the airplane was available in large numbers, it could still be years before the infrastructure would be available to support it.
Bugs ARE a problem at 100K ft (Score:3, Interesting)
Re:SR-71 Blackbird (Score:3, Interesting)
Re:SR-71 Blackbird (Score:1, Interesting)
Re:SR-71 Blackbird (Score:3, Interesting)
Actually, you want fanatics to be your warriors. Let's call it for what it is, and say, you want people in your military that have the ability to make a game out of hunting other people. This is particularly true in the Air Force, where the whole culture is about a solo hunter out there, going out and bagging his or her prey - either other enemy aircraft, or ground targets.
Quite often, this will attract those who might also tend to be religious fanatics.
Re:SR-71 Blackbird (Score:5, Interesting)
Re:SR-71 Blackbird (Score:3, Interesting)
Re:SR-71 Blackbird (Score:4, Interesting)
Re:Sonic Boom - Bust (Score:3, Interesting)
After all, if you look at normal transport aircraft [Boeing & Airbus] they have got progressively larger and larger with more powerful but also more fuel efficient engines.
. That is what has brought the cost of air travel so low. As time passes and Concorde recedes more into the distance, I think it will be seen more and more as a missed opportunity.
Re:Sonic Boom - Bust (Score:4, Interesting)
Maybe, but not in Oklahoma City in 1964 [wikipedia.org].
Re:Max speed of little value ... (Score:3, Interesting)
Air-launched cruise missiles (which use turbine engines) must be launched at subsonic speed, or the turbine won't start.
I can't say definitively, but I'm pretty sure that all bombs (whether free-fall, precision, guided, or retarded version of either) must be released at subsonic speeds if you want anything resembling accuracy.
The Hound Dog missile, an early form of cruise missile carried by B-52s, had its own turbine, and there are anecdotal stories of B-52 pilots using the Hound Dogs for supplemental thrust during heavy takeoffs - but I find that hard to believe. The B-52, of course, was high-subsonic in any flight regime. Cross the sound barrier in a dive, and the wings had a nasty habit of coming off.
Re:SR-71 Blackbird (Score:5, Interesting)
One of the problems they had was dissimilar metals in the airstream, mostly for sensors and plugs -- they had different rates of thermal expansion than the skin. Things that leaked and didn't fit on the ground were designed to fit together quite well at rated speed.
Heat was definitely a problem. There was at least one reported case where a pilot inadvertently got his helmet welded to the canopy in flight. And while sitting in the spa at the Jokewood in Mountain View a few years back I heard a story of a KC135Q refueling officer having to wait while the SR71 made slow S-turns to keep from stalling, while the skin of the aircraft changed from strawberry red to black. Too hot to refuel until he did.
"Turn your ECM off please, I can't see you". "ECM is off. You will acquire visual prior to radar".
Dang what an aircraft. Remember we had this before LBJ outed it in front of Congress. And word had it that one pilot said if they ever needed to break the record again, all they needed was to move the throttle up another notch.
Re:SR-71 Blackbird (Score:3, Interesting)
There's a lot to overcome to get to that point. That said, if it's within reach, and if it can be done without major sacrifices when it comes to fuel economy, then it's certainly worthy of the time and effort. Unfortunately you're spot on when it comes to the capacity of airports, and that would be one area that would need drastic improvements if this became commercially viable.
Disclaimer: I've been drinking, and my numbers could very well be wrong. What I came up with was
Fighter pilots more like Vulcans (Score:5, Interesting)
All of them are calm like a brick, not even a flinch when told they had cancer.
"OK Doc, what do I do next?"
One of my senior partners who was a flight surgeon told me that that's what all the fighter pilots are like - almost unemotional, even when being shot down. All that stuff on TV, with the pilots screaming "WE'VE BEEN SHOT!!!! MAYDAY MAYDAY!!!" is not at all what these guys are like.
Yes, I guess the guy could calmly express that he wanted all the gays/commies/people who don't sweep their sidewalk killed, but I don't think that that type of thinking usually lends itself to calmly expressing those thoughts - they usually come at you like a shotgun.
This thing will land in Tokyo? (Score:3, Interesting)
Of course, there's a trade-off here. In order to go real fast you have to get real high, and to do that you have to go real fast (or follow a ballistic trajectory, which would require you to drink your Chateau Lafitte through a straw). So perhaps there is an economically feasible envelope up at around Mach 5 and 100,000+ feet - Concorde pretty much demonstrated there was not one at Mach 2 and 60,000 feet and presumably this one will be even more capital intensive.
What it does for global warming is another question - you might have to only fly them during the day.
Re:SR-71 Blackbird (Score:5, Interesting)
When an object like the black bird travels at supersonic speeds, an oblique shock [wikipedia.org] is formed starting at the tip of the plane. The angle that the shock wave forms is proportional to the mach number, and they are related in a relatively simple equation. The faster you go, the tighter the shock.
It is wise to keep the wingtips inside of the shock, lest they be ripped off. It is logical to assume that the designers would put the wingtips as close to the shock as possible to maximize the wing's area. Therefore, by drawing a triangle from the tip of the plane to the tip of the wings, and measuring the angle, you should have a pretty good first order approximation of the maximum speed of the blackbird. I don't recall the number off the top of my head, but if someone wants to figure it out, the math is pretty simple.
Re:SR-71 Blackbird (Score:2, Interesting)
Re:SR-71 Blackbird (Score:3, Interesting)
The last commercial Concorde flight was on 23 October 2003 (source). Therefore it was flying more than two years AFTER 9/1
Concorde was taken out of service after the crash in France due to a strip of metal on the runway blowing out a tire, the shards of which tire hit the fuselage and punctured the fuel tank, which started a fire, resulting in the horrific crash we've all seen. The components involved (fuel tank lining, tires, etc.) were redesigned and tested, and the initial public flight of the restored service took place on 9/11 (same day as the WTC attack) with a planeload of Concorde executives and employees; the flight went (as planned) halfway across the Atlantic and returned. The following day, as you all know, all comercial flights in the US were grounded. When commercial flights were finally restored weeks, the initial flight to New York was greated by no less an eminence than (Don Juan) Guliani himself, who exhorted the passengers to do one thing while in NYC -- spend a lot of money.
Reasons for its eventual demise were economic, relating mostly to inefficiencies in the aging technology and marketing model itself (small number of passengers, high expense per passenger, etc.). The airlines had already begun to switch to a strategy of marketing luxury charters (as opposed to depending upon regular commuter traffic) but even this model could not defeat the built in inefficiencies.
It is easily arguable that the huge economic downturn in the airline industry post-9/11 was a contributing factor to this, but what hobbled supersonic commercial flight to begin with (what made the Concorde a losing economic model, and the Boeing SST a no-go) was the worldwide Luddite reaction to the supersonic boom controversy, which limited the avenue for commercial SST traffic to the route between NY and London/Paris exclusively.
Re:SR-71 Blackbird (Score:3, Interesting)
This can also be somewhat confirmed by the pilot reports that noted a reduction in fuel burn when they accelerated past Mach 3.2 to evade missiles.
Now as far as the airframe, that depends on if you want the bow shock to remain clear of the entire airframe, or if you allow it to touch the outer edge of the mouth of the engine inlet. The 3-views I found seem to indicate somewhere just over Mach 4 with 5 a possibility if you let the bow shock reach the edge of the engine inlet.
I haven't had to make this calculation in about 8 years and I don't have a protractor handy, so I could be off a bit.
Re:SR-71 Blackbird (Score:1, Interesting)
(I served in the minuscule Finnish Air Force when we had 20 MiGs and 40 Saab Drakens before Hornets. The regular staff mechanics, very knowledged and well trained, told me that in test flights in Russia they had modified the cone to travel even further forward and had thus achieved Mach 2.4 consistently without any other modifications; and in one occasion even 2.7 but at that point the intake had popped half its rivets out and the aircraft had been lost. In Finland MiG 21bis was specified at Mach 2.05 to allow all pilots in the prestigious if unofficial international "Mach 2 club".)