If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#111
|
|||
|
|||
Why The Hell... (random rant)
|
#112
|
|||
|
|||
Why The Hell... (random rant)
Mxsmanic wrote:
Ron Natalie writes: No you are confused. Magnetic SOUTH is the exact opposite of magentic north you fool. The fact that the MAGNETIC SOUTH POLE is not exactly opposite the MAGNETIC NORTH POLE is a different issue. I assumed that others would understand this, but I often get into trouble when I assume others will understand things. You expect others to understand things when you blither incorrect concepts. The fact that the poles aren't aligned with the arbitrary "true" datum just means that the variation equations aren't as simple as they might be. They are more than just misaligned: they are not at opposite points in terms of longitude and latitude, either. A line drawn between them does not intersect the center of the Earth. Correct, that was my point. It doesn't change anything. Magnetic south and magnetic north are still opposite directions at any given point on the earth. Really, like what? GPS and inertial reference platforms, VORs, NDBs, you name it. GPS and INS use elaborate internal computation to determine it, yes. Haven't ever seen an INS in anything smaller than a transport category. NDB's chortle..you haven't a clue. VORs not on your life, unless you're sitting on station. You should learn something about navigation and geodessy before you make these bogus statements. Compasses are still damned reliable compared to anything else. Cheap too. The only thing that presumes to do better perhaps is GPS. And it's easier to program that to deal with the magnetic measurements than to try to force everybody else the other way. So how often do you fly using just your magnetic compass alone? Give me a chart and a compass and I'll do just fine VFR. Managed to fly the Navion around just fine that way when I had all the avionics and the gyros pulled out while I was redoing the panl. |
#113
|
|||
|
|||
Why The Hell... (random rant)
Ron Natalie writes:
Correct, that was my point. It doesn't change anything. Magnetic south and magnetic north are still opposite directions at any given point on the earth. They are close to opposite, but not exactly so. Give me a chart and a compass and I'll do just fine VFR. If you have a chart, you're not using your magnetic compass _alone_. And even if you have a chart and a compass, how do you determine where you are? -- Transpose mxsmanic and gmail to reach me by e-mail. |
#114
|
|||
|
|||
Why The Hell... (random rant)
Mxsmanic wrote:
writes: A sensor to find true north in an airplane in flight doesn't exist. GPS finds true north. Nope, GPS finds a 3-d position based on the relative distances between sets of satellites in geosynchronous orbit. It knows no more about true north than magnetic without elaborate conversion between where the satellites are at any given instant and where the earth is. And, just incidentally, you can find true north by looking at the sky. ANS will do that, and people can do it, too. Funny, I'm looking at the sky today and all I see are clouds. My compass still works. The isogonic lines on a chart take care of all the problems of where the actual north/south magnetic poles are. Documenting them doesn't really eliminate them. It gives you the tool, just like your beloved GPS knows how to find the real north pole between the combination of the downloaded data on where the satellites are and a substantial amount of information on the shape of the earth inside it's internal database. Unless the airplane is a glider, you have power. You are clueless aren't you. The engine in just about every airplane out there runs just freaking fine without any electrical power consumed nor delivered to the rest of the aircraft. One third correct: it requires power, but engines provide power. It doesn't have to be set up against anything else to find true north. It doesn't need to be constantly updated; the whole idea is to be fairly autonomous. You are clueless. Your GPS is constantly updated or it won't work. You put the thing in a box for a week or so or power it up in an undisclosed location and it will DO NOTHING for you until it downloads enough information to continue. |
#115
|
|||
|
|||
Why The Hell... (random rant)
Mxsmanic wrote:
Tim writes: Not all planes have GPSes. In fact, most don't. That depends on what category of aircraft you're looking at. Doesn't matter what category you are looking at. We've still got transport aircraft with just steam gauges. Many of the haldheld units fail. How many? I've never seen one fail, although I'm sure it happens occasionally. They don't even have any moving parts. I've had them fail lots of times. All it takes is the battery to go doead. The failure rate for compasses is quite low. So is their accuracy, even when they are functioning perfectly. Accurate enough. Reliable...never really have seen one fail. Not really. It is unreliable. Its signals can be disrupted - rendering them useless. Magnetic bearings are constantly disrupted, everywhere on Earth. Between your ears primarily. You have an engine turning. That's power. And it can fail, just like electrical power. That power only propells the aircraft. There's no guarantee that it provides electricity for avionics. I can tell you that I've been in a number of aircraft where it did not, either by malfunction or DESIGN. Not in the real world. On a computer maybe... Even in the real world. The purpose of INS is to have a way of navigating without any external references; it's a very advanced and accurate implementation of dead reckoning. CHORTLE. Have you any experience with a real INS. A real INS can't find squat without being told where it is starting from. This has to be boostrapped from other navigational devices. It's long term stability isn't any better than a compass. It needs additional input. It's useless for truth north unless you have a chart _and_ you know where you are. Even for magnetic north, it can be substantially off. And just knowing which way is north doesn't help you much, anyway. Your GPS and INS are useless without a chart or their internal electronic equivelent. |
#116
|
|||
|
|||
Why The Hell... (random rant)
Mxsmanic wrote:
Nomen Nescio writes: The category that has wings and goes up in the sky. You mean like a 747-400? It has two GPS receivers, three IRUs, two VORs and two ADFs. One rarely falls back upon the magnetic compass. Once again you decide to generalize the entire realm of aviation by your simplistic study of the simulation of one aircraft. There are a great number of transport category aircraft with neither INS nor GPS. |
#117
|
|||
|
|||
Why The Hell... (random rant)
Mxsmanic wrote:
DR writes: LOL! How do _you_ do that exactly? I don't. I know the direction of true north at my location, and I don't go anywhere else. This is perhaps not only the truth, but the telling story of your problem. You don't go anywhere else. |
#118
|
|||
|
|||
Why The Hell... (random rant)
Mxsmanic wrote:
That's one reason why I often like to fly big aircraft. No you like to fly simulations of big aircraft. Not all real airplanes have electrical systems. True, and some are powered by rubber bands as well, but there's a lower threshold below which I don't bother. Yes, but you come here arguing that any outside your willingness to simulate don't exist. This is makes you look pathetically stupid and is the main reason that most people on this forum are hostile to you. |
#119
|
|||
|
|||
Why The Hell... (random rant)
wrote in message oups.com... On Apr 5, 5:33 pm, RomeoMike wrote: DR wrote: Declination in navigation is actually something else but I'll let you googgle for it. I'm not sure that's really true. In aviation we talk about variation, but when I'm using 7.5' topo maps on the ground, declination is the term used for the difference between magnetic and true north. (See the bottom left of a US DOI Geologic Survey 7.5' topo.) Variation and declination are defined the same If there's a more sophisticated use of the word declination in navigation, I'm willing to be enlightened. OK, it's celestial Nav. Stars are located by declination (angle from the celestial equator) and RA. The geographical use of declination to describe variation is the result of bad education propagating a specilaized technical term into incorrect use IMHO. As I think about it, how could a word derived from "decline" be related to horizontal angle...? Cheers MC Declination also applies to the earth's magnetic field, and can be measured and charted. However, its use generally involves an earth inductor compass. (BTW, Lindberg apparently had one installed on the Spirit of St Louis; but I don't know whether he ever commented on the ease of use in what obviously qualified as a light aircraft.) Peter |
#120
|
|||
|
|||
Why The Hell... (random rant)
Ron Natalie writes:
CHORTLE. Have you any experience with a real INS. A real INS can't find squat without being told where it is starting from. This has to be boostrapped from other navigational devices. It's long term stability isn't any better than a compass. It needs additional input. Not to find true north. It can find true north all on its own. Your GPS and INS are useless without a chart or their internal electronic equivelent. I have a GPS with no chart and it's extremely useful. -- Transpose mxsmanic and gmail to reach me by e-mail. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
RANT! | wise purchaser | Owning | 2 | March 27th 07 10:04 PM |
Random thoughts 2 | Bill Daniels | Soaring | 6 | September 1st 06 05:37 AM |
A Jeppesen rant | Peter R. | Piloting | 4 | January 17th 05 03:54 AM |
Why didn't GWB [insert rant] | Jack | Military Aviation | 1 | July 15th 04 11:30 PM |
Random Hold Generator... | Tina Marie | Instrument Flight Rules | 0 | November 5th 03 04:21 PM |