scope:

Description of Driving Event:

While testing at Mach 0.8 in the 16-ft Transonic Tunnel (16 TT), a full-scale F-15 inlet model separated from the sting. The model traveled downstream and impacted the catch screen and turning vanes. The impact resulted in total loss of the model and damage to the screen. Some debris passed through the screen and damaged the wind tunnel blades. The sting was also damaged.

An investigation team concluded that the aerodynamic loads on the model resulted in sting loads that exceeded the ultimate strength of the sting. Possible reasons the large loads occurred are: operating at a Mach Number not in the original test envelope, F-15 cowl traveled past intended angle, sting deflection, and dynamic loads.