Outer Structure

The fundamental task of the outer structure is to provide structural integrity, and to ensure a stable flight. Birkelands outer structure comprises two fiber-composite airframe sections, a nose tip, coupling tube, boat tail, and four symmetric, wedged trapezoidal fins. It is through the boat tail and aft airframe that the motor force is transferred to the rest of the rocket.

The forward airframe is made out of radio transparent fiberglass, whereas the aft airframe is made out of carbon fiber. Both sections are tapered, following a von Kármán ogive to minimize drag. The four fins are made of carbon fiber, and mounted to the bottom of the aft airframe with aluminum fin brackets. The nose tip functions as an aerodynamic continuation of the upper airframe, and is made out of aluminium to be able to withstand the high temperatures of super sonic flight.