CP-1 Plotter...Why does the "heading plotter" read in reverse??
 

Please forgive me if my terms are incorrect, I'm in a slow moving ground school and just trying to figure this out. I have a ASA CP-1 Plotter. I don't understand why the "heading plotter" appears be backwards. The degrees seem to decrease in the clocwise direction, as opposed to increasing. I've asked another pilot about why it doesn't increase and he couldn't give me an answer. If anyone could please offer an explanation, it would be greatly appreciated!!

:confused:

Well, sometimes you take bearing readings FROM and sometimes TO a reference point, station, etc...

Is it upside down?

No seriously, pull your plotter out, and take a look at it. I understand the logic of to and from. However, this doesn't make sense to me. Typically, ten degrees to the right would be either 10degrees or 190degrees (on the to&fro concept) but, if you read it 10degrees to the right on the CP-1...from a 360 or 180 heading, it reads 350 0r 170. I'm sure I'm missing something, either that or my not so stable ex who gave it to me, is trying to drive me nuts.

Whatever heading "makes sense" is the right one, keep it simple. If you are flying from Mexico to Canada, and the plotter says either 180 or 360, 360 is the only possible answer. Hope this helps. :eek:

Could somebody please pull out their plotter?!?!?!?!?!

R U serious?!?!? Haha!!! I hope you were trying to be funny!! Either that, or you just insulted me:eek: I think you were trying to be funny:rolleyes:

Lay your CP-1 on a chart, and align the center of the circle and the center number along a line of longitude (one that goes from North to South). The bottom edge of the plotter now lies along a line that runs East to West (true), or 090/270 degrees.


Rotate the plotter 10 degrees to the right (clockwise). The bottom edge now runs along a line that is 100/280 degrees. What number appears on the top index?



You can do the same thing along lines of latitude (East/West), but that method is less accurate due to the fact that such lines are not straight, they're curved. When you use them, the numbers on the index will center around 360/180.


Does that help?




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Yes it does. I'm away from my charts, so I'm still a little confused. However, the concept makes sense. Thank You!!

Figure out how to use a basic plotter or get a better ground school and/or a new CFI.