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(Block 10) 



Task Area S0379-SL001 



Task 19977 



Work Units 1544-350 and 1544-296 



(Block 20 continued) 



The accuracy of the measured pressures was comparable to the 

 measured calibration accuracy, excluding unexpected loading effects 

 observed on some of the gages. 



The measured mean pressure distributions produced fair correlation 

 with predictions based on equivalent two-dimensional blade-section 

 methods at the design advance coefficient. The measured pressure 

 coefficients at certain blade locations were observed to be dependent 

 upon Reynolds number for a given advance coefficient. Boundary-lawyer 

 separation is thought to have caused the Reynolds-number effect. 

 These viscous effects were greater than previously anticipated. 



The variation of the mean pressure distributions with advance 

 coefficient produced the expected trends. At a given location, C 



generally varied linearly with advance coefficient with increased 

 sensitivity toward the leading edge. 



Measurements of the unsteady pressure were performed with the 

 propeller shaft inclined 7.5 degrees to the flow direction. Quasi- 

 steady predictions of the fluctuating pressures underestimated the 

 measured values by 30 percent to 50 percent, but generally followed 

 the measured fluctuation pressure distribution along the chord. 

 Over a range of advance coefficients, the quasi-steady predictions 

 matched the general trends in the measured fluctuating pressures. 



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