Is there any specific location on airframe for gaining higher drag? I have a model rocket and I want my rocket to reach specific height above the ground level. As soon as desired height is reached, an air brake (umbrella type) is allowed to deploy. In order to have higher drag, what is the best position for the air brake? Will I obtain same drag if the air brake is below or above the Center of Gravity (CG)? Is Cd different for different locations of the air brake (having same surface area)?
Note: Although this question is about a rocket, this really has to do with aerodynamics.
If you want to arrest ascent you put the airbrake behind/below the CG.  Keep in mind the rocket will tend to remain flying &quot;nose first&quot;, which may affect parachute deployment (from nose) on the way down.
Notice the Space X Falcon 9 has theirs near the nose allowing the rocket to descend tail first, and are only deployed once the rocket has coasted to maximum altitude, slowed down, and has begun to fall. Nearer to the ground, you use retrorockets and/or parachute.
For a high altitude sounding rocket, it may be preferable to delay parachute deployment, lest the wind carry it too far away from the launch point.