Slashdot is powered by your submissions, so send in your scoop


Forgot your password?
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×

Comment Re:News for Nazis (Score 1) 1482

Apparently Romney and other Republicans also boycotted Obama's inauguration, apparently for the specific purpose of planning obstruction to anything he was going to do. Still trying to hunt down specifics though, but it hardly seems they are doing anything surprising.

I don't know about Romney, but let's say he boycotted. Rick Perry is the only other Republican I can verify as having boycotted (Obama's 1st inaguration). Neither he nor Romney were sitting members of Congress at the time; I'm not clear on how they could implement the obstruction you mentioned.

Comment Re:Best fucking part (Score 1) 794

As far as I can tell, there are no formal US charges pending against Assange. There aren't likely to be any charges either, because he's done no more than the NY Times did with the Pentagon Papers. Unless, of course, the Justice Department wants to start indicting newspapers for publishing this sort of thing.

Comment Re:Amazon stories (Score 1) 186

They probably figured they would take some vacation... which would reduce this to at least 48 or 49 weeks instead. It looks like they were using 46 weeks as the guideline (as that is what the math works out at).

I considered that, and calculated the same 46 work-week figure you came up with. Have you ever known anyone in the US that started a new job with 6 weeks of vacation? I haven't; it's usually 2 weeks until you've been employed for a few years. I suppose we'll be hearing from someone who started off with unlimited vacation, but that has to be freakishly rare (and definitely not Amazon).

Comment Re:Amazon stories (Score 1) 186

"An additional 23 minutes a day spent in traffic may not sound like much, but when it adds up over a year it becomes 89 hours." (Whoever wrote that must be accustomed to Seattle misery. An additional 23 minutes a day spent in traffic sounds HORRIBLE.)

Whoever wrote that is also sorely lacking in arithmetic skills. 23 minutes a day, 5 days a week, 52 weeks a year comes out to over 99 hours.

Comment Re:No, *physics* killed it (Score 1) 62

There isn't much air at 55kft ether. I don't presume to know the flight envelope for an entire class of yet unbuilt airplanes.

Stratospheric flight at altitudes above 60kft using solar powered fixed wing aircraft was achieved quite a few years ago. You might find this informative. Still, long endurance remains a daunting challenge.

Comment Re:No, *physics* killed it (Score 1) 62

You think a solar powered, long loiter airplane would have the speed to fight the jetsteam? Solar powered planes will have the same problem.

Yes they might work outside the jetstream, but it moves.

A high altitude, long endurance aircraft would fly at nearly twice jetstream altitude, so the jetstream would not pose a problem for station-keeping. There isn't much wind at 55,000 to 65,000 feet. The problem, as I pointed out in an earlier post, is getting the airplane though the weather on ascent or descent. The structural robustness required to achieve that tends to make the airplane too heavy to climb to stratospheric altitudes. There are interesting experiments being done involving very flexible wings and active shape control, but that is definitely not ready for prime time at this point.

Comment Re:No, *physics* killed it (Score 1) 62

Satellites are prohibitively expensive, and are not a great solution for Internet connectivity because of very high latency, as anyone who has ever used Hughes Net can attest. Tethered balloons are a poor solution because they're vulnerable to inclement weather, and if you deploy them in sufficient numbers to provide decent coverage, the tethers become hazards to aircraft.

Untethered airships with station-keeping capability would be much better, if you can load them up with enough batteries to station-keep and run the comms equipment through the night, and carry enough solar cells to recharge the batteries while keeping station and running the comms equipment during the day. Solar-powered fixed-wing aircraft are interesting because they can climb during daylight hours and then trade altitude for power at night.

Long-term (i.e., months at a time) persistent coverage is a tough nut to crack, which is why it hasn't yet been demonstrated. The problem will likely become easier with the development of higher energy-density batteries and solar arrays with higher power/weight capability.

Comment Re:No, *physics* killed it (Score 1) 62

Yes, good old balloons make much more sense if you just need to get up high and stay there.

If by "stay there" you mean, "stay at high altitude", yes. If you mean "stay at a fixed location relative to the Earth's surface", then not so much. Station keeping is difficult and expensive with good old balloons unless they're tethered, and tethering is not practical at stratospheric altitudes.

Comment Re:took a while; (Score 4, Insightful) 62

Actually, building a solar airplane that can stay aloft as long as their business model demands, is a significant challenge. Reliability of servo actuators and electric motors is a major issue. Designing a structure light enough to minimize the power required to climb to very high altitudes, but robust enough to survive winds/gusts during ascent and descent, is a major issue.

Slashdot Top Deals

"Why waste negative entropy on comments, when you could use the same entropy to create bugs instead?" -- Steve Elias