4.7% F-15 Torsion
 
 

The following data was taken from a resent 4.7% scale F-15 wind tunnel test performed by the Unsteady Aerodynamics Integrated Product Team (UAIPT) at Wright Labs.  The head of the UAIPT is W. Calarese and the report number is WL-TM-97-3084.  The model was equipped with rigid and elastically scaled tails for testing effects of flow modification on tail buffet.  Figure 4 shows the 1st torsion mode RMS response of the elastic tail during a variation in angle of attack (AOA) at a constant tunnel speed.  The tail shows a peak torsion response at AOA=24°.  First torsion is also the mode reported to be excited in buffeting on a full scale F-15 by Tripplet, et al.  They reported similar responses with angle of attack change.  The frequency of the 1st torsion mode on the 4.7% scale F-15 is 190 Hz.     4.7% F-15 Bending

 
 
 
 F-15 Tail Buffet Alleviation Results
 
F-15 Velocity Spectra    Frequency vs. Velocity    Reduced Frequency
4.7% F-15 Torsion    4.7% F-15 Bending    Empirical Prediction vs. Test Data
Conclusions
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