So aircraft fly "Rhumb Lines" just to use extra fuel.
No wonder so many go broke....Marum.
For your perusal:The Relationship between Latitude and the Nautical Mile. The Earth’s meridional circumference is calculated to be 40007.86 Km. which equates to 21604.2 nautical miles (n.m.). In other words, an angle of 360o at the Earth’s centre subtends an arc of 21604.2 n.m. on the surface of a meridian of Longitude which is by definition a great circle.
From the above, it follows that 1o measured along a meridian of longitude, will subtend an arc of: 21604.2 ÷ 360 = 60.012 ≈ 60 n.m. and 1′ will subtend an arc of: 60 ÷ 60 = 1 n.m
As calculated above, an angle of 1o at the Earth’s centre will subtend an arc of 60 n.m. along a meridian of longitude. Therefore, any point on the parallel of latitude 1o North will have an angular distance of 60 n.m. north of the Equator.
The angular distance between latitude 62o.8 N. and latitude 48o.5 N. is 14o.3. Therefore, the distance between these lines of latitude measuring due north or south along a meridian of longitude will be: 14.3 x 60 = 858 n.m.
Measuring the Distance Between Meridians of Longitude Along a Parallel of Latitude. We know that the distance between adjacent meridians of longitude at the Equator is 60 n.m. This is because the Equator is a great circle; parallels of latitude however, are small circles and this presents us with a problem. In the diagram, PBC and PAD lie on separate meridians of longitude.
The arc BA is the distance between these meridians measured along a certain line of latitude. The arc CD is the distance between the same meridians measured along the Equator. Clearly, the distance CD is much greater than the distance BA.
'Tis all smork and mirrors. Sines and cosines are like Crypyo Currencies, they are delusional.
Gadzooks....Marum
