An OF fan has how many radial arms that are 100 mils apart and cover 1,600 mils?

To determine the number of radial arms on an OF (Observation Fan) fan that are 100 mils apart and cover a total of 1,600 mils, you can start by understanding how the spacing and coverage work together.

1,600 mils of coverage divided by 100 mils per arm gives you the total number of radial arms. The calculation is as follows:

1,600 mils ÷ 100 mils = 16 arms.

However, when considering the structure of the fan, it’s crucial to include both the starting arm and the terminating arm. Essentially, the count of radial arms is represented by the sections they define, meaning you have an additional arm after the first one. Therefore, when you include the starting point and the point where coverage ends, the total arms in the fan are 16 sections plus 1 for the starting arm, leading to a total of 17 arms.

Thus, the answer is 17, explaining why it is defined that way in this context.