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# Formula for X-Wind component

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Anyone have a formula to calculate an X-wind component on takeoff.I've been playing with this one, but it's not working out well. There is also the issue of magnetic variation, and I still need to work the GPS_MagVar into the formula.xwindcomponent = windspeed * sin ( windir - runwaydir ) ;//Where:runwaydir = runway * 10 ; // Example: Runway 34 = 340 windir = AMBIENT_WIND_DIRvar.var_value.n ; windspeed = AMBIENT_WIND_VELvar.var_value.n ;Cheers,Bryan

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Bryan,You have the right formula, but the direction values need to be in radians ,multiply by pi over 180 to get radians.xwindcomponent = windspeed * sin((winddir * pi/180)-(runwaydir * pi/180));RegardsErnie.

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Hi,You could just use the sim var AMBIENT WIND X, which gives the wind component on the X axis, in meters per second (for C gauges), or translable to knots units in XML.I believe positive values were for right wind and negative for left, or maybe otherwise, I'm not sure.Tom

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AMBIENT WIND X is described as being the wind velocity in the East/West orientation. This would be relative to the world and not the aircraft.

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Ernie,Thank you. The Radians were the missing link.My virtual FO can now correctly fill in the X-Wind Component field on his Takeoff Data card :-)Cheers,Bryan

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Ed, you're right. The variable I was thinking is AIRCRAFT WIND X.Tom

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• Tom Allensworth,
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