Androids don't have to be hacked to download from other sources. I have a HTC Hero running Android 2.1, which I have not bothered to root (no real reason to, so far), yet I can still download from third party sources by clicking Settings | Applications | Unknown Sources. Not a big deal.
My airplane, for example, cost $10,000 and weighs about 450 pounds, empty. It has very little space to add *any* unnecessary equipment, and even if it did, it doesn't have an electrical system; somehow, I doubt that your INS runs on batteries. Requiring a 17 pound, 3U rackmount box that won't work unless I *also* install an electrical system to my airplane (not a trivial task; I've checked) is just stupid.
The smartphone is a lot more practical, but my Hero sucks battery power like mad when I'm using the GPS and navigation software. Also, I don't know how your smartphone works, but mine requires a 3G network to download the maps (which it does in realtime, so you don't typically notice it). A lot of places I fly don't have telephone networks, so that rules out smartphone navigation.
Even 2-seat aircraft usually have a flux compass system but this requires the electrical system to be functional.
Maybe in the new technically advanced airplanes (TAA), but in twenty years of flying -- half of that as an instructor -- I have not yet flown in a single airplane that had a flux gate compass. Certainly none of the old 152/172/182/206/Citabria's I have ever flown had one.
Don't be so black and white. The world is full of shades of grey.
A mag compass has it's advantages, namely simplicity and reliability. It also has it's disadvantages, in that it can be difficult to read in certain flight conditions.
Likewise, the D.G. also has it's advantages and disadvantages. Although not quite as simple or reliable as a mag compass, it is still relatively simple and relatively reliable, and is much easier to read in flight than a magnetic compass.
Electronic navigation systems, like GPS and INS are the least simple and least reliable, but also offer the most flexibility and utility. A wise pilot learns to use all the tools at his disposal, and also learns how to tell when they are lying to him.
A magnetic compass, even a fluxgate, is only useful while flying straight and level for a period of time.
Wrong.
As part of my early instrument flight training, I was taught to understand compass errors and how to correct for them in flight, including leading/lagging the roll-out in a turn due to turning errors and how to average the compass swing when flying in turbulence to get a general idea of the heading I was flying. It was a real PITA, and I'd never *choose* to fly by magnetic compass alone in actual instrument conditions, but in a pinch, it's possible. It just sucks.
The regulations are there for very, very good reasons. As an instrument-certified pilot, I really don't want to be sharing airspace with some yahoo using the GPS on his cellphone to maintain separation from me. I've seen the GPS on my cell phone (HTC Hero running Android 2.1) showing me over a hundred miles away from where I was really at (it has shown me in Prince William Sound, off the coast of Cordova, Alaska when I was in the middle of downtown Anchorage, and it has shown me somewhere near the McNeill bear refuge when I was in my backyard in East Anchorage). You will never* see a GPS in a certified airplane off by that magnitude. I can't answer for parent, but for me, I'd argue against the logic of parent's post. With all due respect, he doesn't understand what he is talking about.
It's fairly simple to bring along a handheld GPS that will give you true, rather than magnetic, heading. However, if you want to fly in instrument conditions (roughly speaking, if you want to fly in the clouds), your smart phone won't cut it. And no matter how sophisticated your electronics, they can always fail. The magnetic compass is by far the most reliable instrument in an airplane's cockpit, so in my twenty years' experience as a pilot, it's just a better idea to stick with magnetic headings, and repaint runway markings every decade or so.
However, you are quite right about inertia, but it's the FAA that slows things down. They require very strict testing to approve equipment to be used in certified airplanes, and for something like navigation equipment, especially navigation equipment used in instrument conditions, they are particularly strict. Having said all that, most new airplanes being sold now are being sold with glass panels, so I might even argue that more and more "hobbyist" airplanes (that's a rather condescending view of general aviation, by the way, but I won't follow that bunny trail for now) are probably equipped to show true headings as well as magnetic headings.
I think you are probably confusing the directional gyro (D.G.) with the magnetic compass. You can set the D.G. within a full 360 degree range of motion, but not the compass, and as you said, setting the D.G. to match the compass is a part of the pre-takeoff checklist.
I suppose you could set the D.G. to true heading, but not every airplane has a D.G. (although a *magnetic* heading indicator is an FAA requirement), so if you started aligning runways and airways with true headings instead of magnetic headings, it could get confusing when you switch airplanes. For example, a couple of years ago, I was flight instructing at a school in Anchorage in airplanes that had D.G.s, but my airplane only had a rudimentary compass. It would have been a pain to try to remember when to correct for deviation and when not to. I can guarantee I would have mixed it up from time to time. It is less confusing, IMHO, to just use magnetic heading and repaint runway designations every ten or twenty years.
I have a friend who says, "Democrats want to be your mommy. Republicans want to be your daddy. Libertarians just wish the government would treat us all like adults." I think he's right, by the way, so I'd agree that "Nanny state" and "Democratic lead (sic) government" are pretty much synonymous. However, Republicans certainly don't get a free pass from me, since IMHO, they are largely closet fascists looking to extend the government-led power grab of the last decade+. Unfortunately, the Dems seem to be following along in that tradition quite nicely, too.
But who are any of us to say that this is not a good thing for the original poster to investigate? Maybe he's idle rich. Just because it isn't a priority for you or for me doesn't mean it shouldn't be a priority for anyone.
You are quite right to say that it is impossible to disprove "make believe notions that only exist in the confines of [one's] skull". That, however, is a great example of a logical fallacy known as "begging the question". Because you believe that there is no such thing as "ghosts" you assume that the only place they exist is in the minds of deluded, gullible individuals. You may very well be right, but without bringing the scientific method to bear on the question, "Are there such things as ghosts?" you and I will never know for sure. That is all that Causality is saying in the GPP.
Think about it this way, if it helps you. Suppose that you and I are living in the days of Louis Pasteur. Louis Pasteur begins raving that there are small creatures of some kind, so tiny that we cannot see them, living in milk produced by cows. Furthermore, he claims that the tiny, invisible creatures are responsible for many of the illnesses that you and I suffer, but by heating the milk before distributing it for human consumption, he can destroy those tiny, invisible creatures that make us sick.
Off the top of my head, I do not recall if microscopes were around in Louis Pasteur's day (I suspect they weren't) and honestly, I am too lazy to look it up to find out right now. So, for the sake of this little thought experiment, let us assume that microscopes had not yet been invented. Given that assumption, how would you expect Louis Pasteur to "prove" that these tiny creatures really exist? By heating milk before serving it, there seems to be a decline in illnesses, but as we all know, "correlation does not imply causation" so that is not proof of their existence.
This is, in fact, exactly what happened, by the way. Look up Ignaz Semmelweis for a really fascinating read. He was scoffed and mocked because he believed that tiny, invisible pathogens caused puerperal fever (which, incidentally paved the way for Pasteur's work). But you know what? Semmelweis was right.
Sorry -- I didn't take the time to see what dcw3 had posted. He was incorrect to say that pilots "...are able to adjust the aircraft compasses for magnetic deviation..." While we can adjust the compass within a rather limited range of error for electromagnetic fields within the airplane (as you suspected), we don't adjust the compass for magnetic deviation. I had to replace the compass in my airplane about three years ago, and IIRC, I could only get about ten, maybe fifteen, degrees of variation with the adjustment screws. In a lot of places, that wouldn't be enough of an adjustment to correct for deviation (I have to subtract about 23 or 24 degrees from the compass heading to get true heading where I live). Making the problem worse, when you adjust north-south errors, it tends to introduce east-west errors in the compass. The trick is to find a point at which both errors are minimized, then, just like with magnetic deviation, you correct for the calibration errors in your flight planning. It's actually sounds a lot more complicated here on/. than it really is to perform:)
No, it shows magnetic north, because deviation isn't constant everywhere on the earth. On a typical 50-70 mile cross country flight in my neck of the woods, deviation changes by about three degrees (I'm rather far north and rather far west, so the change is a bit more extreme than it would be in, say, Arkansas). If you were to adjust your compass to point to true north rather than magnetic north, how would you know if you forgot to adjust it? This would be a trivial problem if I stayed in my local area, but the further I fly, the greater this problem becomes. By leaving the compass set to magnetic north, I have a constant, fixed reference point to base my navigation upon. When I plan a flight, I calculate the deviation into my navigation log, but always base my calculations upon magnetic heading. Then, even if I have a complete electrical systems failure in my airplane, I can still use my watch, my compass, and my (paper) navigation log to navigate. Once I start mucking with my compass in flight, I no longer have a reliable reference point.
Why do they use magnetic north and not true north?
Because disciplined pilots will line up on the runway, then perform a quick compass check to verify that they are, in fact, on the runway they intended to be using. It's a big deal because there are runways that are not quite parallel with each other, and taxiing into position on the wrong runway can and has caused fatal accidents.
That way they wouldn't have to renumber runways periodically and reprint maps and charts leading to confusion when someone has an out of date chart.
They would have to reprint charts anyway. First, things change, more often than you would expect. Frequencies change, cities grow and die, new towers are erected, airspace is allocated where it was previously uncontrolled (or at least, was a different class of airspace), etc. Consequently, NOAA publishes sectional charts -- the most common chart for low altitude navigation -- every six months to keep things up to date. Airport diagrams, which I suspect are more what you were referring to, change even more often as new runways and taxiways are built, new ramps and terminals are constructed, etc. While pilots do fly with out of date charts, it's a really, really bad idea and runway numbering is the least of the problems you can encounter if your charts are expired.
Most small plane pilots fly close enough to home that they just have to remember their deviation from magnetic north.
Are you sure about that? In my "local area" magnetic deviation varies by about 3-4 degrees, IIRC, but offhand, I couldn't tell you which airports are 23E, 24E, 25E or 26E deviation in my local area. I'd have to look it up. Also, I may be odd, but I've made some rather long trips away from home, including flying the AlCan highway a few times. I certainly couldn't remember the magnetic deviation for every airport I've visited even on a single one of those trips. Asking pilots to "just...remember their deviation from magnetic north" is just asking for trouble, especially if the only reason for doing so is to keep the once-a-decade-or-two task of renumbering an airport from being necessary. That's making a whole lot of work to eliminate a very rare -- but nevertheless mundane -- task.
Larger private plane and commercial pilots already have electronic equipment that can show them true north.
Yes, but the most reliable instrument in the cockpit is the whiskey compass. Even the most jaded glass cockpit jock still should be checking that the compass is more or less aligned with the runway heading before takeoff.
They already use true north in areas where compass readings are unreliable by appending T to the runway number. Why not extend that to all runways?
Because surface winds are reported in magnetic heading? Because there isn't a compelling reason to do so, and retraining everyone to a new, arbitrary standard is more effort than repainting a runway number once every 10-20 years (less often the further south you go, IIRC). Because using a magnetic heading -- which matches your compass headed -- allows pilots to double check things before take-off? I could go on, but you get the idea.
I learned to fly at Elmendorf AFB, in Anchorage, Alaska back in the early '90s. When I first started flying at the Elmendorf Aero Club, the main runway was runway 05. A few years later, it was redesignated runway 06. Merrill Field, a civilian airport just a couple of miles away, also had to change the primary designation from 06 to 07 at about the same time.
The magnetic poles shift with time, eventually by a significant factor. Since runways are designated by magnetic heading (for example, Elmendorf's runway 06 means the runway is pointed roughly to 60 degrees, and Anchorage International Airport's runway 14 is pointed roughly to 140 degrees), every so often airport management has to redesignate the runways to match the approximate magnetic heading with which the runways are aligned. It's no big deal, and has been happening for as long as there have been runways. All of the speculation at the end of TFS about "...shifting poles finally starting to affect air travel..." and "falling birds" is alarmist nonsense.
My only complaint is that it doesn't remember passwords the way AndFTP does (another excellent tool, by the way). I'd like to not have to type in the darned password every time, but oh well, it's a lot better than no ssh.
I don't know that I would want it to remember passwords. What happens if you lose your phone, or if someone steals it? If Connectbot remembers your passwords, you've just given a complete stranger the keys to your kingdom. It's a bit of a PITA to type passwords on my Hero with Connectbot, but less so than changing all of the passwords on every system to which I connect were I to lose the phone somewhere.
I use connectbot on my HTC Hero, but there are a few things that are somewhat annoying about it. First, I haven't got SSH Trusts working with it, which is kind of a big deal, since I'm paranoid enough to require the connecting device have its public key stored in the.ssh/authorized_hosts file on the SSH bastion host on my home network (although it hasn't been a big enough deal that I've spent a lot of time working on it). Second, since the Hero's virtual keyboard isn't a full 101-key keyboard, it's a bit clunky to do things like send an escape or CTRL-C character. It's possible, just a bit of a pain. Finally, every other app on the Hero allows you to press and hold a key on the keyboard to choose numbers or special characters, for example, press and hold the "t" key to type the number "5" or press and hold the "h" key to select an ampersand ("&"). Connectbot, for some obscure reason detects that as two key strokes. So, for example, if I try to type a quote character by pressing and holding the "x" key, connectbot detects an "x" and then a quote. As long as you are aware of the limitations and know how to work around them, connectbot is usable, just a bit clunky. Nevertheless, whenever possible, I prefer to do like someone else mentioned earlier and just tether a laptop to the phone so I can use a "normal" SSH client.
Oops...I caught one error. The arc sine of (11.miles / 4000 miles) is actually 0.02 degrees. We have to subtract that from 90 degrees to get the latitude I wanted, sorry.
If my thumbnail calculations are right -- and I make no pretensions about my abilities, so they very likely are not -- that latitude (on earth) would be at 89.8 degrees.
Work:
The rotational period of the earth is 24 hours, which is about 15 degrees per hour (360 degrees / 24 hours).
That means an average person can walk about 72 miles in a day (assuming non-stop, which we all know won't happen long term, but I ignored that). Therefore the circumference of a circle that a person can walk non-stop in a day is 72 miles, and therefore the circumference of the earth at the latitude where a person walking would match the speed of the sunrise would be 72 miles.
The diameter of a circle with a circumference of 72 miles would be 22.9 miles, and so the radius of such a circle would be approximately 11.5 miles (C=2 x pi x r, so r ~11.5 miles).
Given a plane that intersects the earth such that the circle transcribed upon that plane has a circumference of 72 miles, let y1 be the distance from the center of the earth to center of the circle transcribed upon the plane, and let x1 be the radius of that circle (i.e., 11.5 miles).
If x^2 + y^2 = 4000^2 (the equation for a circle, and r = the radius of the earth, or 4,000 miles), then let x1^2 + y1^2 = 11.5^2 be the circle transcribed upon the plane described in the last sentence. In this case, when y1=0, x1^2 = r1^2, so x1=11.5. From this, you can draw a triangle with the apex at the center of the earth, with the x axis being 11.5 miles, the y axis being the distance from the center of the circle x1^2 + y1^2 = 11.5^2 to the center of the earth and the hypotenuse being the radius of the earth, or 4000 miles. Therefore, the arc sine of (11.5 miles / 4000 miles) is equal to the latitude we are looking for. I think:)
Ditto. I downloaded "Echoes" and "One of these Days" off of Amazon a long time ago, so I was kind of curious what the fuss was about. Maybe Pink Floyd decided that "Meddle" wasn't a popular enough album to argue over, unlike say "Dark Side of the Moon" or "The Wall"?
I rather suspect that one who describes something as "lugubrious" on an Internet forum has no business calling anything else "pretentious". Besides, I rather enjoyed "Shine on you crazy diamond" (as well as the rest of "Wish You Were Here" for that matter).
People are trying to get away from managing device drivers and hardware compatibility bugs.
Maybe I'm just weird, but that's not why my desktop and laptop computers have been getting lonely lately. It's because my mobile device is, you know, mobile.
Because the mutual co-existence of USPS, UPS, DHL, FedEx, et al, ensure that no one company is going to be extremely egregious in their pricing. I.E., there is a free market that tends to seek a fair price for the service provided. With Internet service, that is not always the case.
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Androids don't have to be hacked to download from other sources. I have a HTC Hero running Android 2.1, which I have not bothered to root (no real reason to, so far), yet I can still download from third party sources by clicking Settings | Applications | Unknown Sources. Not a big deal.
My airplane, for example, cost $10,000 and weighs about 450 pounds, empty. It has very little space to add *any* unnecessary equipment, and even if it did, it doesn't have an electrical system; somehow, I doubt that your INS runs on batteries. Requiring a 17 pound, 3U rackmount box that won't work unless I *also* install an electrical system to my airplane (not a trivial task; I've checked) is just stupid.
The smartphone is a lot more practical, but my Hero sucks battery power like mad when I'm using the GPS and navigation software. Also, I don't know how your smartphone works, but mine requires a 3G network to download the maps (which it does in realtime, so you don't typically notice it). A lot of places I fly don't have telephone networks, so that rules out smartphone navigation.
Magnetic compass, ftw.
Even 2-seat aircraft usually have a flux compass system but this requires the electrical system to be functional.
Maybe in the new technically advanced airplanes (TAA), but in twenty years of flying -- half of that as an instructor -- I have not yet flown in a single airplane that had a flux gate compass. Certainly none of the old 152/172/182/206/Citabria's I have ever flown had one.
Don't be so black and white. The world is full of shades of grey.
A mag compass has it's advantages, namely simplicity and reliability. It also has it's disadvantages, in that it can be difficult to read in certain flight conditions.
Likewise, the D.G. also has it's advantages and disadvantages. Although not quite as simple or reliable as a mag compass, it is still relatively simple and relatively reliable, and is much easier to read in flight than a magnetic compass.
Electronic navigation systems, like GPS and INS are the least simple and least reliable, but also offer the most flexibility and utility. A wise pilot learns to use all the tools at his disposal, and also learns how to tell when they are lying to him.
A magnetic compass, even a fluxgate, is only useful while flying straight and level for a period of time.
Wrong.
As part of my early instrument flight training, I was taught to understand compass errors and how to correct for them in flight, including leading/lagging the roll-out in a turn due to turning errors and how to average the compass swing when flying in turbulence to get a general idea of the heading I was flying. It was a real PITA, and I'd never *choose* to fly by magnetic compass alone in actual instrument conditions, but in a pinch, it's possible. It just sucks.
The regulations are there for very, very good reasons. As an instrument-certified pilot, I really don't want to be sharing airspace with some yahoo using the GPS on his cellphone to maintain separation from me. I've seen the GPS on my cell phone (HTC Hero running Android 2.1) showing me over a hundred miles away from where I was really at (it has shown me in Prince William Sound, off the coast of Cordova, Alaska when I was in the middle of downtown Anchorage, and it has shown me somewhere near the McNeill bear refuge when I was in my backyard in East Anchorage). You will never* see a GPS in a certified airplane off by that magnitude. I can't answer for parent, but for me, I'd argue against the logic of parent's post. With all due respect, he doesn't understand what he is talking about.
It's fairly simple to bring along a handheld GPS that will give you true, rather than magnetic, heading. However, if you want to fly in instrument conditions (roughly speaking, if you want to fly in the clouds), your smart phone won't cut it. And no matter how sophisticated your electronics, they can always fail. The magnetic compass is by far the most reliable instrument in an airplane's cockpit, so in my twenty years' experience as a pilot, it's just a better idea to stick with magnetic headings, and repaint runway markings every decade or so.
However, you are quite right about inertia, but it's the FAA that slows things down. They require very strict testing to approve equipment to be used in certified airplanes, and for something like navigation equipment, especially navigation equipment used in instrument conditions, they are particularly strict. Having said all that, most new airplanes being sold now are being sold with glass panels, so I might even argue that more and more "hobbyist" airplanes (that's a rather condescending view of general aviation, by the way, but I won't follow that bunny trail for now) are probably equipped to show true headings as well as magnetic headings.
I think you are probably confusing the directional gyro (D.G.) with the magnetic compass. You can set the D.G. within a full 360 degree range of motion, but not the compass, and as you said, setting the D.G. to match the compass is a part of the pre-takeoff checklist.
I suppose you could set the D.G. to true heading, but not every airplane has a D.G. (although a *magnetic* heading indicator is an FAA requirement), so if you started aligning runways and airways with true headings instead of magnetic headings, it could get confusing when you switch airplanes. For example, a couple of years ago, I was flight instructing at a school in Anchorage in airplanes that had D.G.s, but my airplane only had a rudimentary compass. It would have been a pain to try to remember when to correct for deviation and when not to. I can guarantee I would have mixed it up from time to time. It is less confusing, IMHO, to just use magnetic heading and repaint runway designations every ten or twenty years.
I have a friend who says, "Democrats want to be your mommy. Republicans want to be your daddy. Libertarians just wish the government would treat us all like adults." I think he's right, by the way, so I'd agree that "Nanny state" and "Democratic lead (sic) government" are pretty much synonymous. However, Republicans certainly don't get a free pass from me, since IMHO, they are largely closet fascists looking to extend the government-led power grab of the last decade+. Unfortunately, the Dems seem to be following along in that tradition quite nicely, too.
But who are any of us to say that this is not a good thing for the original poster to investigate? Maybe he's idle rich. Just because it isn't a priority for you or for me doesn't mean it shouldn't be a priority for anyone.
You are quite right to say that it is impossible to disprove "make believe notions that only exist in the confines of [one's] skull". That, however, is a great example of a logical fallacy known as "begging the question". Because you believe that there is no such thing as "ghosts" you assume that the only place they exist is in the minds of deluded, gullible individuals. You may very well be right, but without bringing the scientific method to bear on the question, "Are there such things as ghosts?" you and I will never know for sure. That is all that Causality is saying in the GPP.
Think about it this way, if it helps you. Suppose that you and I are living in the days of Louis Pasteur. Louis Pasteur begins raving that there are small creatures of some kind, so tiny that we cannot see them, living in milk produced by cows. Furthermore, he claims that the tiny, invisible creatures are responsible for many of the illnesses that you and I suffer, but by heating the milk before distributing it for human consumption, he can destroy those tiny, invisible creatures that make us sick.
Off the top of my head, I do not recall if microscopes were around in Louis Pasteur's day (I suspect they weren't) and honestly, I am too lazy to look it up to find out right now. So, for the sake of this little thought experiment, let us assume that microscopes had not yet been invented. Given that assumption, how would you expect Louis Pasteur to "prove" that these tiny creatures really exist? By heating milk before serving it, there seems to be a decline in illnesses, but as we all know, "correlation does not imply causation" so that is not proof of their existence.
This is, in fact, exactly what happened, by the way. Look up Ignaz Semmelweis for a really fascinating read. He was scoffed and mocked because he believed that tiny, invisible pathogens caused puerperal fever (which, incidentally paved the way for Pasteur's work). But you know what? Semmelweis was right.
Sorry -- I didn't take the time to see what dcw3 had posted. He was incorrect to say that pilots "...are able to adjust the aircraft compasses for magnetic deviation..." While we can adjust the compass within a rather limited range of error for electromagnetic fields within the airplane (as you suspected), we don't adjust the compass for magnetic deviation. I had to replace the compass in my airplane about three years ago, and IIRC, I could only get about ten, maybe fifteen, degrees of variation with the adjustment screws. In a lot of places, that wouldn't be enough of an adjustment to correct for deviation (I have to subtract about 23 or 24 degrees from the compass heading to get true heading where I live). Making the problem worse, when you adjust north-south errors, it tends to introduce east-west errors in the compass. The trick is to find a point at which both errors are minimized, then, just like with magnetic deviation, you correct for the calibration errors in your flight planning. It's actually sounds a lot more complicated here on /. than it really is to perform :)
No, it shows magnetic north, because deviation isn't constant everywhere on the earth. On a typical 50-70 mile cross country flight in my neck of the woods, deviation changes by about three degrees (I'm rather far north and rather far west, so the change is a bit more extreme than it would be in, say, Arkansas). If you were to adjust your compass to point to true north rather than magnetic north, how would you know if you forgot to adjust it? This would be a trivial problem if I stayed in my local area, but the further I fly, the greater this problem becomes. By leaving the compass set to magnetic north, I have a constant, fixed reference point to base my navigation upon. When I plan a flight, I calculate the deviation into my navigation log, but always base my calculations upon magnetic heading. Then, even if I have a complete electrical systems failure in my airplane, I can still use my watch, my compass, and my (paper) navigation log to navigate. Once I start mucking with my compass in flight, I no longer have a reliable reference point.
Why do they use magnetic north and not true north?
Because disciplined pilots will line up on the runway, then perform a quick compass check to verify that they are, in fact, on the runway they intended to be using. It's a big deal because there are runways that are not quite parallel with each other, and taxiing into position on the wrong runway can and has caused fatal accidents.
That way they wouldn't have to renumber runways periodically and reprint maps and charts leading to confusion when someone has an out of date chart.
They would have to reprint charts anyway. First, things change, more often than you would expect. Frequencies change, cities grow and die, new towers are erected, airspace is allocated where it was previously uncontrolled (or at least, was a different class of airspace), etc. Consequently, NOAA publishes sectional charts -- the most common chart for low altitude navigation -- every six months to keep things up to date. Airport diagrams, which I suspect are more what you were referring to, change even more often as new runways and taxiways are built, new ramps and terminals are constructed, etc. While pilots do fly with out of date charts, it's a really, really bad idea and runway numbering is the least of the problems you can encounter if your charts are expired.
Most small plane pilots fly close enough to home that they just have to remember their deviation from magnetic north.
Are you sure about that? In my "local area" magnetic deviation varies by about 3-4 degrees, IIRC, but offhand, I couldn't tell you which airports are 23E, 24E, 25E or 26E deviation in my local area. I'd have to look it up. Also, I may be odd, but I've made some rather long trips away from home, including flying the AlCan highway a few times. I certainly couldn't remember the magnetic deviation for every airport I've visited even on a single one of those trips. Asking pilots to "just...remember their deviation from magnetic north" is just asking for trouble, especially if the only reason for doing so is to keep the once-a-decade-or-two task of renumbering an airport from being necessary. That's making a whole lot of work to eliminate a very rare -- but nevertheless mundane -- task.
Larger private plane and commercial pilots already have electronic equipment that can show them true north.
Yes, but the most reliable instrument in the cockpit is the whiskey compass. Even the most jaded glass cockpit jock still should be checking that the compass is more or less aligned with the runway heading before takeoff.
They already use true north in areas where compass readings are unreliable by appending T to the runway number. Why not extend that to all runways?
Because surface winds are reported in magnetic heading? Because there isn't a compelling reason to do so, and retraining everyone to a new, arbitrary standard is more effort than repainting a runway number once every 10-20 years (less often the further south you go, IIRC). Because using a magnetic heading -- which matches your compass headed -- allows pilots to double check things before take-off? I could go on, but you get the idea.
I learned to fly at Elmendorf AFB, in Anchorage, Alaska back in the early '90s. When I first started flying at the Elmendorf Aero Club, the main runway was runway 05. A few years later, it was redesignated runway 06. Merrill Field, a civilian airport just a couple of miles away, also had to change the primary designation from 06 to 07 at about the same time.
The magnetic poles shift with time, eventually by a significant factor. Since runways are designated by magnetic heading (for example, Elmendorf's runway 06 means the runway is pointed roughly to 60 degrees, and Anchorage International Airport's runway 14 is pointed roughly to 140 degrees), every so often airport management has to redesignate the runways to match the approximate magnetic heading with which the runways are aligned. It's no big deal, and has been happening for as long as there have been runways. All of the speculation at the end of TFS about "...shifting poles finally starting to affect air travel..." and "falling birds" is alarmist nonsense.
Absolutely. How can you find your way around the city hosting ${FavoriteITConference}, if you don't have a map application on your phone?
My only complaint is that it doesn't remember passwords the way AndFTP does (another excellent tool, by the way). I'd like to not have to type in the darned password every time, but oh well, it's a lot better than no ssh.
I don't know that I would want it to remember passwords. What happens if you lose your phone, or if someone steals it? If Connectbot remembers your passwords, you've just given a complete stranger the keys to your kingdom. It's a bit of a PITA to type passwords on my Hero with Connectbot, but less so than changing all of the passwords on every system to which I connect were I to lose the phone somewhere.
I use connectbot on my HTC Hero, but there are a few things that are somewhat annoying about it. First, I haven't got SSH Trusts working with it, which is kind of a big deal, since I'm paranoid enough to require the connecting device have its public key stored in the .ssh/authorized_hosts file on the SSH bastion host on my home network (although it hasn't been a big enough deal that I've spent a lot of time working on it). Second, since the Hero's virtual keyboard isn't a full 101-key keyboard, it's a bit clunky to do things like send an escape or CTRL-C character. It's possible, just a bit of a pain. Finally, every other app on the Hero allows you to press and hold a key on the keyboard to choose numbers or special characters, for example, press and hold the "t" key to type the number "5" or press and hold the "h" key to select an ampersand ("&"). Connectbot, for some obscure reason detects that as two key strokes. So, for example, if I try to type a quote character by pressing and holding the "x" key, connectbot detects an "x" and then a quote. As long as you are aware of the limitations and know how to work around them, connectbot is usable, just a bit clunky. Nevertheless, whenever possible, I prefer to do like someone else mentioned earlier and just tether a laptop to the phone so I can use a "normal" SSH client.
Oops...I caught one error. The arc sine of (11.miles / 4000 miles) is actually 0.02 degrees. We have to subtract that from 90 degrees to get the latitude I wanted, sorry.
If my thumbnail calculations are right -- and I make no pretensions about my abilities, so they very likely are not -- that latitude (on earth) would be at 89.8 degrees.
:)
Work:
The rotational period of the earth is 24 hours, which is about 15 degrees per hour (360 degrees / 24 hours).
An average person can walk about 3 miles per hour
That means an average person can walk about 72 miles in a day (assuming non-stop, which we all know won't happen long term, but I ignored that). Therefore the circumference of a circle that a person can walk non-stop in a day is 72 miles, and therefore the circumference of the earth at the latitude where a person walking would match the speed of the sunrise would be 72 miles.
The diameter of a circle with a circumference of 72 miles would be 22.9 miles, and so the radius of such a circle would be approximately 11.5 miles (C=2 x pi x r, so r ~11.5 miles).
Given a plane that intersects the earth such that the circle transcribed upon that plane has a circumference of 72 miles, let y1 be the distance from the center of the earth to center of the circle transcribed upon the plane, and let x1 be the radius of that circle (i.e., 11.5 miles).
If x^2 + y^2 = 4000^2 (the equation for a circle, and r = the radius of the earth, or 4,000 miles), then let x1^2 + y1^2 = 11.5^2 be the circle transcribed upon the plane described in the last sentence. In this case, when y1=0, x1^2 = r1^2, so x1=11.5. From this, you can draw a triangle with the apex at the center of the earth, with the x axis being 11.5 miles, the y axis being the distance from the center of the circle x1^2 + y1^2 = 11.5^2 to the center of the earth and the hypotenuse being the radius of the earth, or 4000 miles. Therefore, the arc sine of (11.5 miles / 4000 miles) is equal to the latitude we are looking for. I think
I own "The Final Cut", but still don't listen to it.
Ditto. I downloaded "Echoes" and "One of these Days" off of Amazon a long time ago, so I was kind of curious what the fuss was about. Maybe Pink Floyd decided that "Meddle" wasn't a popular enough album to argue over, unlike say "Dark Side of the Moon" or "The Wall"?
I rather suspect that one who describes something as "lugubrious" on an Internet forum has no business calling anything else "pretentious". Besides, I rather enjoyed "Shine on you crazy diamond" (as well as the rest of "Wish You Were Here" for that matter).
People are trying to get away from managing device drivers and hardware compatibility bugs.
Maybe I'm just weird, but that's not why my desktop and laptop computers have been getting lonely lately. It's because my mobile device is, you know, mobile.
Because the mutual co-existence of USPS, UPS, DHL, FedEx, et al, ensure that no one company is going to be extremely egregious in their pricing. I.E., there is a free market that tends to seek a fair price for the service provided. With Internet service, that is not always the case.