Rhumbline track
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Rhumbline track
Q: From N65 00 E010 00 to N65 E052 00 on a rhumb line, what is the distance?
a 1065 nm
b 2283 nm
c 1700 nm
d 2520 nm
I got it to 2520 just by taking E52-E10.. but im not sure if this is right can anyone confirm?
Q: An aircraft flies from N32 00 E020 00 for 1200nm on a rhumb line track of 090, what is the longitude of the new position?
a E013 58
b E043 35
c E050 00
d E040 59
This one i calculated again just taking 1200/60 = 20 and adding it to E020 and getting E040.....
But it doesnt seam to be correct if i look at the possible answers.. can anyone help me here? Thanks in advance...
(Im abit unsure when the question says rhumbline track if i have to deal with convergency or not....)
a 1065 nm
b 2283 nm
c 1700 nm
d 2520 nm
I got it to 2520 just by taking E52-E10.. but im not sure if this is right can anyone confirm?
Q: An aircraft flies from N32 00 E020 00 for 1200nm on a rhumb line track of 090, what is the longitude of the new position?
a E013 58
b E043 35
c E050 00
d E040 59
This one i calculated again just taking 1200/60 = 20 and adding it to E020 and getting E040.....
But it doesnt seam to be correct if i look at the possible answers.. can anyone help me here? Thanks in advance...
(Im abit unsure when the question says rhumbline track if i have to deal with convergency or not....)
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concerning the 2nd question you propose:
If you keep a constant hdg of 090° means you're tracking a rhumb line and necessarily also a constant Latitude.
You need to use the departure formula which is:
Dep=ch long(in minutes ')*cos Lat.
1200nm=ch long(') * cos 32°
1200nm=ch long(')* 0.848
ch long(')=1200/0.848
=1415.1'
=23.58°
=23° 35' further east
new position: N32° (unchanged), E43° 35'
remember, the distance between two meridians spaced 1° is 60nm only at the equator, and 0nm at the poles. At 30°N is 60*cos30°=51.96nm , at 70°N is 20.5nm and so on.
ciao
If you keep a constant hdg of 090° means you're tracking a rhumb line and necessarily also a constant Latitude.
You need to use the departure formula which is:
Dep=ch long(in minutes ')*cos Lat.
1200nm=ch long(') * cos 32°
1200nm=ch long(')* 0.848
ch long(')=1200/0.848
=1415.1'
=23.58°
=23° 35' further east
new position: N32° (unchanged), E43° 35'
remember, the distance between two meridians spaced 1° is 60nm only at the equator, and 0nm at the poles. At 30°N is 60*cos30°=51.96nm , at 70°N is 20.5nm and so on.
ciao
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RP,
These questions both ask you for the rhumb line track along a line of latitude.
What they are after is the departure i.e. the distance between two points.
Departure = ChLong x Cos Lat
Q1. Departure = 42 (degrees between the two points) x Cos 65 (latitude)
= 16.9 (degrees at correct scale) x 60
= 1014 nm
I'd therefore go for answer a) as it's closest.
Q2. Here they want you to rearrange the Departure formula to obtain ChLong to find the new longitude.
Departure = ChLong x Cos Lat
ChLong = Departure / Cos Lat
ChLong = (1200 / 60) / Cos 32 (1200 is divided by 60 to get it into degrees)
= 23:35
So E020 + 23:35 = E43:35 which is answer b).
You use Convergency as soon as great circles are mentioned. Departure is used on rhumb lines.
Hope that helps.
SM.
These questions both ask you for the rhumb line track along a line of latitude.
What they are after is the departure i.e. the distance between two points.
Departure = ChLong x Cos Lat
Q1. Departure = 42 (degrees between the two points) x Cos 65 (latitude)
= 16.9 (degrees at correct scale) x 60
= 1014 nm
I'd therefore go for answer a) as it's closest.
Q2. Here they want you to rearrange the Departure formula to obtain ChLong to find the new longitude.
Departure = ChLong x Cos Lat
ChLong = Departure / Cos Lat
ChLong = (1200 / 60) / Cos 32 (1200 is divided by 60 to get it into degrees)
= 23:35
So E020 + 23:35 = E43:35 which is answer b).
You use Convergency as soon as great circles are mentioned. Departure is used on rhumb lines.
Hope that helps.
SM.
Last edited by SunderlandMatt; 8th Jun 2012 at 10:20. Reason: Edited to remove any mention of straight lines, as pointed out by W1.
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Rhumb Line may be a straight line on a Mercator Chart.
It is a line of constant bearing. So a line of Latitude is a Rhumb Line (and yes the equator is both a Rhumb Line and a Great Circle).
A Rhumb Line is NOT a straight line on the Earth, a Lamberts Chart or a Polar Sterographic Chart.
It is a line of constant bearing. So a line of Latitude is a Rhumb Line (and yes the equator is both a Rhumb Line and a Great Circle).
A Rhumb Line is NOT a straight line on the Earth, a Lamberts Chart or a Polar Sterographic Chart.
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A Rhumb Line is NOT a straight line on the Earth, a Lamberts Chart or a Polar Sterographic Chart.
