Increasing Conceptual Design Fidelity with Prebuilt Airfoil Databases

Abstract

Due to time and monetary constraints, the conceptual design process for new aircraft is typically limited to inexpensive low-fidelity methods. Unfortunately, these methods generally only provide the fidelity necessary to confidently go forward with a new design when they have been fitted to previous aircraft of the same type. The conceptual design process has difficulty producing accurate estimates of performance in unconventional aircraft. To remedy this, new methods must be developed that can produce higher fidelity results without a significant increase in cost. Here we present a method to do this in the aerodynamic analysis. First, we generate a large database of airfoils that are optimized using CFD to minimize drag in a variety of flight conditions that are likely to be seen on the wing of a subsonic transport aircraft. We then present methods to integrate these airfoils along an arbitrary wing to find the minimum possible drag. This process is meant to mimic the "expert designer" often pointed to in current correlation equations for determining the drag of a wing. Since the airfoils are generated before hand in a manner that is easy to parallelize, this process is not substantially more expensive than other methods for determining the aerodynamic properties of an aircraft at the conceptual level.