# Calculating the height and width of a rocket for drag

While messing around with making a little rocket launch simulator, I seem to have hit a slight wall with finding the relevant information in order to calculate the width and height of the rocket for drag purposes.

I have found a lot about calculating a rocket's width to a degree, but nothing really that I have found goes in to much detail about its width and height together throughout launch. Take Falcon 9

With a launch height of

71 m (233 ft) with payload fairing

And a width of

3.66 m (12.0 ft)

The fairing is wider than the stages

5.263 m (17.27 ft)

While there are various websites out there that try to explain the solution, I am struggling to unable to understand their solutions. With Falcon's measurements, how am I able to calculate them to its surface area?

• Consider it as a group of cylinders and (maybe) cones; the surface area of those are easy to calculate. In my sim I don't use surface drag, just cross-sectional drag; that's even easier. Jan 23, 2019 at 17:36
• @RussellBorogove How could the length of a rocket go into the drag calculation? I have tried to look up how length would be applied, but have found virtually nothing at all. Jan 23, 2019 at 23:56
• Have you checked a resource such as Glenn Research Center’s? From my dynamics courses, we generally didn’t worry too much about length when it came to drag, but you could calculate the surface area exposed at whatever angle you choose and add that to the drag force acting upon the fairing. Jan 24, 2019 at 3:11
• @Snoopy Not sure if I am just overlooking something, but I am unable to find the answer to my question in regards to both length and width on there. Jan 28, 2019 at 22:05
• Perhaps this will help - read the thesis, particularly Section 3.4. Jan 29, 2019 at 6:39