How to Calculate the Tail-Setting Angle

Fixed Tail-setting Angle

• 1

  Measure the height of the tail at the place where it meets the fuselage of the aircraft while it is parked.

• 2

  Measure the height of the tail's tip while it is parked.

• 3

  Measure the length of the tail from base to tip.

• 4

  Calculate the tail's sitting angle. This is done by determining the arctangent of the triangle formed by the tail with the ground. Subtract the height of the tip from the height of the base to get the height of the tail's rise or fall. (The number may be negative.) Then divide the result by the length of the tail. Use a calculator to find the arctangent (inverted tangent) of the resulting number. This is the sitting angle of the tail.

• 5

  Measure the height of the plane's nose and the length of the plane's body from nose to the base of the tail.

• 6

  Subtract the height of the base of the tail from the height of the nose. If the heights are the same, the fuselage is level and the sitting angle in Step 4 is the same as the tail-setting angle. If the heights are different, continue to Step 7.

• 7

  Divide the result of the subtraction in Step 6 by the length of the plane's body from the nose to the base of the tail. Use your calculator to find the arctangent (inverted tangent) of the result. This is the sitting angle of the plane's fuselage.

• 8

  Subtract the result of Step 7 from the result of Step 4 to get the tail-setting angle. If the angle is positive, that means the tail sticks up in the air relative to the fuselage. If the angle is negative, that means the tail points down relative to the fuselage.