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Comment Re:Noisy isn't it. (Score 1) 123

Also I'm not sure what those cages around the fan blades are suppose to acheive since the cage gap is huge, anything could be sucked in there, needs to be a cage more like a desktop fan.

I presume the cages are sized to keep body parts out.

Unfortunately the laws of physics seriously don't like your suggestion of tighter cages. At low air speeds and with abundant power available you can use tight cages no problem. But when you're at high air velocities to get substantial thrust and where power efficiency is crucial, any obstruction in the air stream is a serious issue. Aerodynamic drag is proportional to velocity squared. When you multiply air speed by ten, the drag caused by each cage wire is multiplied by a hundred. This means thrust loss, as well as draining the batteries trying to compensate for lost thrust. Adding batteries to compensate for the extra power drain increases your weight. Increased weight means you need to compensate with that much more thrust, which in turn means more weight and more power drain. It is a problem that compounds upon itself. You need the cage wires to be as thin and sparse as as you can get away with, short of inviting serious accidental injury.


Comment Re:Not bicycle powered? (Score 1) 123

I had the same reaction, that strapping a bicycle to it seemed totally irrelevant. But I guess you can bike down to the river, fly across, and continue biking. And if you don't mind burning some of your flight time you can use the batteries to power the bike. That gives you a combination of long ground range with the ability to fly over terrain or traffic at will. Cute. Too bad you're stuck with those big bulky fans all around it in cycle mode. If those could fold down compactly it would actually be a pretty practical combo to place on an electric bike. Well, of course that's setting aside the suicide-machine factor.

Final analysis: Darwin would approve.


Comment Re:Noisy isn't it. (Score 4, Informative) 123

350 pound flight capacity minus 187 pound vehicle weight seems to indicate a 163 pound (74 kilo) passenger limit. Not great, but that's certainly not "anorexic child-size styrofoam dummy" either. I'm an adult male, I could get there if I cut out the peanutbuttercups and switched to diet soda.

Oh well, I guess that means I'm never going to be able to ride it. Diet soda is vile.
How about they work on inventing that? Soda that tastes like sugar-water without being sugar-water? Chuckle.


Comment Re:In other news (Score 2) 442

Best part is you'd have no trouble finding a lawyer to help you sue someone who used the above phrase.

You're right, you wouldn't have trouble finding a lawyer. And that's one of my biggest problems with a lot of lawyers: many of them have no sense of morality or justice. I'm not just talking about lawyers who represent defendants of violent crimes because I realize that they deserve a fair trial. I am referring to all of the lawyers that would argue either side of a case depending on which side offered them more money. These people are not driven by an inner sense of justice and making the world a better place, but simply following their own motivations of greed and rationalizing away any negative effects their greedy actions are causing society.

In almost every dispute, both parties think they're right, and both may even have good and reasonable reasons for believing they're right. So, yeah, a lawyer could argue either side of that, because there may be good reasons on both sides. It may be a question of what the law really is (see the recent Myriad v. AMP patent case as to whether isolated genes are patentable), or may be a dispute over the facts (if a contract term means "A", then party A is correct; if it means "B", then party B is correct; and they both have legitimate reasons why it should be read the way they want), or other such reasonable disagreements. So, since a lawyer could argue either position, suddenly they're immoral or greedy in your eyes?

If every decision was so clear cut between good and evil, or just and unjust, then we wouldn't need lawyers in the first place.

Comment Re:Contradictory Explanations (Score 1) 266

Well, that explains it - the little characters on the y-axis labels are 'h', not 'k', so I think you are reading it as three orders of magnitude too large

Doh! I know exactly what happened. That part was small and blurry, and in my initial scan over the graph, before I sorted out what the graph wa showing, it looked like "kp". A corner of my brain thought WTF is "kp", and I kept scanning elsewhere for information. I saw the speeds across the bottom and the thrusts on the left and I recognized the shape of the graph, then saw the HP vs MPH title at the top. I realized the different color lines had to be different engine inputs and I glanced back at that top-right box to confirm it.... that it was listing different HP engine inputs.... and that "k" from "kp" was still lingering in my brain. chuckle. So the blurry "h" was read twice, once as "k" and once as "h". The 250khp to 500khp power figures did strike me as unreasonably large, but I wasn't going to doubt the graph and my attention was absorbed on other issues. Sso without further consideration I just mentally filed it away as presumptively plausible values for a top end (?military?) engine.

the airflow through the propeller is slowed down... in this view the rotor is acting as a turbine, though a very unusual one in which the power is delivered through its thrust bearing, not by torquing the shaft.

Ohhhh noooooo! You didn't...... cry cry cry. LoL.
I follow your reasoning, and it is a kinda cool point, but oh jezus I wish you didn't make that analogy. The prop is NOT spinning as a turbine, and I know that you know that it's not spinning as a turbine, but someone is going to read what you wrote and think that one or both of us said it's a turbine. Newbies already have a hard time wrapping their heads around the idea that the prop is a fan. Any whiff of describing it as a turbine feeds badly into the exact "contradictory explanations" that set off alarm bells for you.

[the math/science] It's still at high-school level

I wish. You and I went to significantly above average highschools. The majority of U.S. highschool graduates only have one year of science, and it's generally something very generic like "Earth science" or something. It's only in the last few years that most highschools have moved to a two year science requirement, and even then, what percentage are going to include force-energy physics? I think the most common is a year of Bio, and even there most schools avoid or actively deny Evolution in that class :/

with regard to the exam question explanation. It says, correctly, that their formula implies that a totally inefficient device (alpha = 0) would travel at the wind speed.

What happened there is an entirely arbitrary and semi-self-contradictory cornercase crawling out of the simplifying assumptions. They started with a model of an ideal (frictionless) cart, and then to model a "real" cart they lumped together all losses... including rolling friction.... into one term alpha. They then set alpha to total energy loss... and they were still modeling that alpha on an ideal frictionless cart. They also silently and arbitrarily assumed wind drag *wasn't* zero, despite the opposite parallel assumption of zero rolling resistance. chuckle.


Comment Re:DCS network should be totally isolated (Score 1) 284

In related news, an oil refinery did not explode today. Police and rescue workers report recovering zero dead bodies thus far from the fully intact structure. It is feared that the final death toll may rise as high as zero. We have no reporters live on the scene, so stay tuned for more breaking coverage as it doesn't happen.


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