Beginner's Guide to Propulsion
Forces in a Climb
Answers

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1. Assuming the angle of ascent is a constant, find the angle the plane must use to achieve this height at this distance--to the nearest degree.
   The angle should be rounded to 10 degrees.
   
2. a. Find the thrust for a Boeing 737-200 airplane.
   Thrust is 66,300 N per engine. Total thrust is 132,600 N.
   
   b. What is the take off weight of the plane?
   Takeoff weight is 107,020 lbs, or 476,071 N.
   
   c. Use the first equation on the Forces In A Climb page to find vertical net force.
   Use 519,154 N as the lift and 25,957 N as the drag.
   L cos 10 + F sin 10 - d sin 10 - W = ma (vertical)
   519,154 cos 10 + 132600 sin 10 - 25957.7 sin 10 - 476,071 =
   53,713 N = net vertical force ( 511,266 + 23,025 - 4,507 - 476,071 = 53,713 N )
   
   d. Use the second equation to find the horizontal net force, use lift and drag from part c above.
   F cos 10 - L sin 10 -D cos 10 = ma (horizontal)
   132,600 cos 10 - 519,154 sin 10 - 25957 cos 10 = 14,873 N (horizontal)
   ( 130,585 - 90,150 - 25,562 = 14,873 N )
   
3. Divide your net force from 2c and 2d by the weight of the airplane to get the vertical and horizontal acceleration in "g's" (ratioed to gravitational acceleration).
   The vertical acceleration = .113 g's

   The horizontal acceleration = .031 g's

   Note to teachers: You may extend this assignment by going to Newton's Second Law.

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