Formula For Climb Gradient
#21
Gets Weekends Off
Joined APC: Apr 2007
Posts: 456
Thanks!
#22
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Joined APC: Aug 2007
Position: Corporate Captain
Posts: 164
Sure!
For example, if you have a rise of 500 feet per mile, and the run is one nautical mile, you divide rise over run, move the decimal over two places (x 100) and then you have a gradient.
A good rule of thumb is to take the gradient times your groundspeed to have and estimated climb rate in feet per minute. Or, you can look at the rate of climb table in the front of the Jeppesen (tables and codes) book.
I'm dusting off my trigonometry here, so mathematically the vertical distance that you are climbing equals the sine of 8.23 times the opposite over the hypotenuse: take that distance and divide it by 360 to arrive at feet per minute.
For example, if you have a rise of 500 feet per mile, and the run is one nautical mile, you divide rise over run, move the decimal over two places (x 100) and then you have a gradient.
A good rule of thumb is to take the gradient times your groundspeed to have and estimated climb rate in feet per minute. Or, you can look at the rate of climb table in the front of the Jeppesen (tables and codes) book.
I'm dusting off my trigonometry here, so mathematically the vertical distance that you are climbing equals the sine of 8.23 times the opposite over the hypotenuse: take that distance and divide it by 360 to arrive at feet per minute.
Last edited by geosynchronous; 05-05-2009 at 04:00 AM.
#23
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Joined APC: Dec 2008
Position: E-170 Airbender
Posts: 341
that better be a chick's a$$
#25
#28
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Joined APC: Feb 2020
Posts: 1
then fpm = feet_in_one_minute * gradient
ex: 450 fpm, 150GS
find how many feet traveled over the ground in one minute: 150kts/60' = 2.5 NM * 6000 = 15000ft traveled over the ground in one minute.
then
Gradient = 450ft/min/15000 = 0.03 * 100 = 3% gradient
so 3(gradient) * 150(GS) = 450 ft/min
or 0.03(before the multiplication) * 15000(feet traveled in one minute) = 450ft/min
whichever you like
#30
Closer to a 4.7% Angle but the fpm is correct