Vortex-generator specialist Boundary Layer Research has obtained a US Federal Aviation Administration supplemental type-certificate for fitting a pair of aft-body strakes to Beech Duke models 60, A60 and B60. The two 1.6m-long strakes, weighing a total of 3.4kg, are riveted to the underside of the aft fuselage. They are claimed to improve directional stability, reduce aft-body drag and reduce Dutch- roll oscillations, which are often felt in the back of the aircraft. Vortex generators and winglets have already been developed by the Washington-based company for the Duke and a tip-tank which will increase capacity by more than 110 litres is under development for certification in early 1997.
Source: Flight International
