[ARCHIVED THREAD] - Pilots- navigation question (Page 1 of 2)
Posted: 2/12/2012 6:03:20 PM EDT
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I really hope I am not exposing too much ignorance, but I thought about this last week for no reason at all- just curiosity. I remember reading a while back that military artillery had to account for the Coriolis effect when shooting at long distances. When navigating an aircraft flying north to south, for example, over a distance of several hundred miles, does the Coriolis effect have to be allowed for, or do you just fly a compass heading? Jim |
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I really hope I am not exposing too much ignorance, but I thought about this last week for no reason at all- just curiosity. I remember reading a while back that military artillery had to account for the Coriolis effect when shooting at long distances. When navigating an aircraft flying north to south, for example, over a distance of several hundred miles, does the Coriolis effect have to be allowed for, or do you just fly a compass heading? Jim It doesn't matter what course you fly, Center is just going to re-route you anyway. 
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You correct for winds aloft, that never matches the forecast winds aloft.
It used be done using the good ol' E-6B plane killer - it took three hands to operate and still fly the plane at the same time. now days, you plot a bunch of way points on the GPS, and keep the plane on the track...and bitch when your waypoints aren't even close to the direction ATC wants to route you.... airways are for weenies. Quoted:
I really hope I am not exposing too much ignorance, but I thought about this last week for no reason at all- just curiosity. I remember reading a while back that military artillery had to account for the Coriolis effect when shooting at long distances. When navigating an aircraft flying north to south, for example, over a distance of several hundred miles, does the Coriolis effect have to be allowed for, or do you just fly a compass heading? Jim |
| What I meant is if I looked at a map and drew a straight line from the city I am leaving to one 700 miles due south, assuming no wind, and flew a compass course exactly on the bearing on the map, would I hit the destination or would the earth's rotation have me off course to the side? |
| Magnetic variation is also a factor. Check out SkyVector if you want to see what our charts look like. Research magnetic variation as well, but radio navaids and gps negate the issue. |
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Magnetic variation is also a factor. Check out SkyVector if you want to see what our charts look like. Research magnetic variation as well, but radio navaids and gps negate the issue. I am not a pilot, or in training. I am, however, an old nosy SOB, and this was just a question that a random misfiring of brain cells came up with. I just remember reading a while back that artillery had to account for the Coriolis effect when shooting long distances to hit their target. I just wondered if the Earth would rotate out from under an airplane if it flew in a straight line flying from north to south. |
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Quoted: What I meant is if I looked at a map and drew a straight line from the city I am leaving to one 700 miles due south, assuming no wind, and flew a compass course exactly on the bearing on the map, would I hit the destination or would the earth's rotation have me off course to the side? With NO wind, you'd fly right to your destination, remember wind is measured relative to the ground. |
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You'd have to correct for magnetic variation - as you fly into different areas, the compass will be off because of variations in the earth's magnetic field, metallic ores in the earth's crust, and other factors. So you would have to make compass heading corrections.
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What I meant is if I looked at a map and drew a straight line from the city I am leaving to one 700 miles due south, assuming no wind, and flew a compass course exactly on the bearing on the map, would I hit the destination or would the earth's rotation have me off course to the side? With NO wind, you'd fly right to your destination, remember wind is measured relative to the ground. |
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If you aren't using gps or navigation aids your are using a map and compass. Since you are constantly correcting your route using land marks, coriolis its negated. Let's assume no winds, the zombie apocalypse happens, I climb in a plane, climb to 10,000 feet, set the cruise on a compass heading that on a map takes me to Zanadu and take a nap. When the alarm goes off and wakes me up will I be there or be off to the side because the earth rotated my destination out from under me. |
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Beacon to beacon, stab a rudder pedal for course correction. Same as with GPS NAV (but if you have GPS NAV you probably have your AP coupled to it anyways).
Op, please remember that an aircraft is not fired from a fixed point aimed at a target designation. That is why there are such things as pilots to drive the aircraft to the desired location which they actually hope to land at. |
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If you aren't using gps or navigation aids your are using a map and compass. Since you are constantly correcting your route using land marks, coriolis its negated. Let's assume no winds, the zombie apocalypse happens, I climb in a plane, climb to 10,000 feet, set the cruise on a compass heading that on a map takes me to Zanadu and take a nap. When the alarm goes off and wakes me up will I be there or be off to the side because the earth rotated my destination out from under me. No, there are a myriad of other factors that will be much more influential. Also, there are ALWAYS winds. If you take away all of the other factors (engines being one of them), you're really just back to being an artillery shell aren't you? 
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Beacon to beacon, stab a rudder pedal for course correction. Same as with GPS NAV (but if you have GPS NAV you probably have your AP coupled to it anyways). Op, please remember that an aircraft is not fired from a fixed point aimed at a target designation. That is why there are such things as pilots to drive the aircraft to the desired location which they actually hope to land at. This was meant more as mental masturbation than a factual inquiry. |
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If you aren't using gps or navigation aids your are using a map and compass. Since you are constantly correcting your route using land marks, coriolis its negated. Let's assume no winds, the zombie apocalypse happens, I climb in a plane, climb to 10,000 feet, set the cruise on a compass heading that on a map takes me to Zanadu and take a nap. When the alarm goes off and wakes me up will I be there or be off to the side because the earth rotated my destination out from under me. No, there are a myriad of other factors that will be much more influential. Also, there are ALWAYS winds. If you take away all of the other factors (engines being one of them), you're really just back to being an artillery shell aren't you? Screw it. I'll drive. 
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If you aren't using gps or navigation aids your are using a map and compass. Since you are constantly correcting your route using land marks, coriolis its negated. Let's assume no winds, the zombie apocalypse happens, I climb in a plane, climb to 10,000 feet, set the cruise on a compass heading that on a map takes me to Zanadu and take a nap. When the alarm goes off and wakes me up will I be there or be off to the side because the earth rotated my destination out from under Without really researching it, not taking winds into account and you are using a compass heading; my thought would be that coriolis still may not really be a factor since you are navigating using a magnetic heading. |
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Quoted: Center is going to re-route you anyway... Trust me, coriolis effect is waaay down on your list of shit to think about. My favorite is when you finally figure out what route the controllers like to give on a often repeated trip so you file it that way, then you finally get your read back and it takes them 2 minutes to read you some fucked up non logical misdirected route to get to the closest VOR that is only 3 miles from your departure airport. |
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Back in Nav School @ Randolph, the mantra was, "Mag course, kill the drift." It'll always get you there (or at least on a parallel course to there. ) We were never told to be concerned with the Coriolis effect (it was never even brought up), so I doubt it's a significant player.
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Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though I am not sure you do...he is talking about flying a compass heading. Doing that would not be anything like a bullet, unless a bullet has a compass. Now, of the plane was just flying, without using a compass that would constantly correct for coriolis effect, your statement may be true.
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Quoted: Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though Only if you started like a projectile on a course like dead reckoning, the magnetic heading you fly when you follow a course moves with the earth. If you fly from point A to point B in a straight line on a ( constantly corrected ) magnetic heading you have flown just what you drew on a chart. The movement ( or non movement in relation to the ground ) of the magnetic field that you are following has taken care of the Coriolis effect for ya. There are other issues with the curvature of the earth when you are dealing with longer distances. |
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Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though Nope. I got the question as well, just didn't know the answer at first. Sounds like a bunch of politicians in here. It took you to simply say yes J |
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Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though I am not sure you do...he is talking about flying a compass heading. Doing that would not be anything like a bullet, unless a bullet has a compass. Now, of the plane was just flying, without using a compass that would constantly correct for coriolis effect, your statement may be true.Read the op again. He's taking a bearing and flying it. No corrections |
| In theory yes, practice no. Coriolis effects wind and weather much more than an aircraft flying through the air. For example, an airplane flying from north to south would miss its destination slightly in a no wind situation due to Coriolis effect, even on a long flight. Now add strong crosswinds on that fight due to coriolis effect and you miss your destination by hundreds of miles. We have a "wind correction angle" that used on each segment of a flight. However, magnetic variation, compass correction, and other factors are more critical to navigation than coriolis effect. |
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Yeah, VOR's aren't going anywhere until the ADS-B system is fully integrated.
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VOR is dead. Fixed it for ya...
I wish, we still use ndb's Posted Via AR15.Com Mobile ADF is the shiT ! Follow the Cone, follow the tone ! A - N |
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Quoted: Quoted: Yeah, VOR's aren't going anywhere until the ADS-B system is fully integrated.Quoted: Quoted: VOR is dead. Fixed it for ya... I wish, we still use ndb's Posted Via AR15.Com Mobile I heard that promise on NextGen/ADS-B in CTI school(Green River June 2011) but after getting to talk controllers at Seattle ARTCC about how well ERAM-ERIDS(tour/job shadow day)was working, i have my doubts on the current timetables. Radio navigation will be around for a while. 10 years at least. |
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Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though I am not sure you do...he is talking about flying a compass heading. Doing that would not be anything like a bullet, unless a bullet has a compass. Now, of the plane was just flying, without using a compass that would constantly correct for coriolis effect, your statement may be true.Read the op again. He's taking a bearing and flying it. No corrections I know, thats my point. If you are flying a bearing, using a compass, you are negating coriolis effect. Simply flying a magnectic heading would have you constantly "correcting" your course to fly the bearing. You aren't being launched out like a bullet or arty round. |
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Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though I am not sure you do...he is talking about flying a compass heading. Doing that would not be anything like a bullet, unless a bullet has a compass. Now, of the plane was just flying, without using a compass that would constantly correct for coriolis effect, your statement may be true.Read the op again. He's taking a bearing and flying it. No corrections I know, thats my point. If you are flying a bearing, using a compass, you are negating coriolis effect. Simply flying a magnectic heading would have you constantly "correcting" your course to fly the bearing. You aren't being launched out like a bullet or arty round. Sure you are. Right off that conveyer belt. |
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Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though I am not sure you do...he is talking about flying a compass heading. Doing that would not be anything like a bullet, unless a bullet has a compass. Now, of the plane was just flying, without using a compass that would constantly correct for coriolis effect, your statement may be true.Read the op again. He's taking a bearing and flying it. No corrections I know, thats my point. If you are flying a bearing, using a compass, you are negating coriolis effect. Simply flying a magnectic heading would have you constantly "correcting" your course to fly the bearing. You aren't being launched out like a bullet or arty round. I am not a pilot and admit my concept is pretty dumb. What I meant was not following a compass bearing. I meant if I took off, pointed the airplane in a direction, made no corrections and had no winds so I flew in a perfectly line. |
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I really hope I am not exposing too much ignorance, but I thought about this last week for no reason at all- just curiosity. I remember reading a while back that military artillery had to account for the Coriolis effect when shooting at long distances. When navigating an aircraft flying north to south, for example, over a distance of several hundred miles, does the Coriolis effect have to be allowed for, or do you just fly a compass heading? Jim It doesn't matter what course you fly, Center is just going to re-route you anyway. This!
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Lulz. I must be the only one who is understanding what op is asking. Yes. Same effect as bullets. I don't think you'd notice too large of an effect though I am not sure you do...he is talking about flying a compass heading. Doing that would not be anything like a bullet, unless a bullet has a compass. Now, of the plane was just flying, without using a compass that would constantly correct for coriolis effect, your statement may be true.Read the op again. He's taking a bearing and flying it. No corrections I know, thats my point. If you are flying a bearing, using a compass, you are negating coriolis effect. Simply flying a magnectic heading would have you constantly "correcting" your course to fly the bearing. You aren't being launched out like a bullet or arty round. I am not a pilot and admit my concept is pretty dumb. What I meant was not following a compass bearing. I meant if I took off, pointed the airplane in a direction, made no corrections and had no winds so I flew in a perfectly line. OK - In real life the error you are talking about is so minuscule that it is never even thought about or even compensated for in navigation data bases. The real life variables of navigation are so large compared to what you are talking about that it's never talked about. So I'll just say this - given your stimuli (no wind, no isogonic variation, etc,) then yeah - you'll get there, or close... |
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Quoted: I just finished CTI at Middle Ga. in December. Quoted: Quoted: Yeah, VOR's aren't going anywhere until the ADS-B system is fully integrated.Quoted: Quoted: VOR is dead. Fixed it for ya... I wish, we still use ndb's Posted Via AR15.Com Mobile I heard that promise on NextGen/ADS-B in CTI school(Green River June 2011) but after getting to talk controllers at Seattle ARTCC about how well ERAM-ERIDS(tour/job shadow day)was working, i have my doubts on the current timetables. Radio navigation will be around for a while. 10 years at least. Did you get picked up yet? March will be my first panel.
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Quoted: No. It's doubtful it'll happen before i "expire"Quoted: I just finished CTI at Middle Ga. in December. Quoted: Quoted: Yeah, VOR's aren't going anywhere until the ADS-B system is fully integrated.Quoted: Quoted: VOR is dead. Fixed it for ya... I wish, we still use ndb's Posted Via AR15.Com Mobile I heard that promise on NextGen/ADS-B in CTI school(Green River June 2011) but after getting to talk controllers at Seattle ARTCC about how well ERAM-ERIDS(tour/job shadow day)was working, i have my doubts on the current timetables. Radio navigation will be around for a while. 10 years at least. Did you get picked up yet? March will be my first panel.  (against the age limit). Should have started in my early 20's and not at 29.Thinking about finishing my Private and continuing on to ATP. I thought i would breeze into a slot here in Seattle. Low traffic levels apparently make this area highly desirable. Don't regret anything, though. |
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Just a thought.. So let's say the Earth is rotating at X mph. Wouldn't the atmosphere (and associated weather patterns) be rotating at the same speed? Thus negating coriolis?  That's all fine and dandy with a stable atmosphere. There is an airport not very far from here that if the conditions are right, I can take off in a Cessna 172 and climb to 500FT AGL, reduce power but maintain airspeed and be perfectly safe in the envelope of parameters of operation for the aircraft. But I can look at the ground and the aircraft is actually moving backwards in relation to the earth. I can ad power and put the nose down and land on the runway that I just took off from without making a turn, just maintaining a straight line. It's more fun in something like a Super Cub since they stall at a lower airspeed. |