needle points south

[Guest ridgell]

if the needle points north, this works;(A:GPS WP BEARING, radians) (A:PLANE HEADING DEGREES GYRO,radians) -but what if the needle points south ?(its a multi function RMI, and for nav1,nav2,adf, i use a southern pointing needle...(radials) i want a smooth sweep to new course directions, so i need to use the same needle referance)

[phjvh 0]

Hi,Just an idea, did you try to add some amount of PI?So like:(A:GPS WP BEARING, radians) (A:PLANE HEADING DEGREES GYRO,radians) - pi + (or any combination, like: pi 2 / + , etc.) Hope it helps,Jan"Beatus ille qui procul negotiis..."

[Guest ridgell]

(A:GPS WP BEARING, radians) (A:PLANE HEADING DEGREES GYRO,radians) - (>G:Var1) (G:Var1) 3.141592654 - (>G:Var1)i know i can shorten that useing registers, but i see the vars better, and i worked this over many many times!i kept useing rnor, i knew i had to add/subtract 180 degrees to compensate for the needle being upside down. the reason it was up side down was to keep from doing the minus 180 on radials (nav1/nav2/adf)...but the bearing works the other way. i thought that the thing might run over 360 degrees or less then zero and would need normalizing. what happened is that it was only good through 1/2 the circle, and 180 degrees off through the other 1/2useing the rnor * tried dnor with degrees as well* after decideing i was going to have to qualify the larger intity the bearing or the plane gyro heading...i removed the rnor and added the equation to a test gauge *digital reading* and to my surprise.it worked...the rnor was killing the deal....go figure (make sense now, rnor was cutting it in half...but hind sight always works that way!) thanks for the reponce