To account for the loading effect, both propellers were load tested at the 

 various test conditions in uniform flow. To eliminate the gage response to pressure, 

 2-mil thick Mylar tape was applied over the gage holes. Pressure calibrations were 

 conducted with the taped over gages, resulting in a reduction in gage sensitivity to 

 less than one percent of the sensitivity without the tape applied. Rerunning the 

 test matrix (shown in Table 5 in uniform flow) with the tape applied over the gage 

 holes provided a direct measure of the loading effects on gage output. The gage 

 signal due to loading was nondimensionalized in the same way as the original 

 pressure signal and represented as a pressure coefficient. This coefficient is 

 defined as the loading pressure coefficient. Its mean value is C '. 



V = V (1/2PV R 2) 



where p T is the measured pressure signal produced when the gage holes were covered 



with tape. 



Figure 7 shows the variation of C T for each gage over a range of J for inflow 



pL 



speeds listed in Table 5. Each figure shows all repeat runs at each condition and a 



third-order least-squares polynomial fit through the measured values. From Figure 7, 



the repeatability observed was good with C T varying by +0.01 for repeat conditions 



pL 



at constant J. Certain gages (at the inner radii) had substantial loading coeffi- 

 cients at design J with large variations over the range of J measured. To correct 

 the measured pressure for loading effects at a given J, the polynomial describing the 

 loading coefficient for each gage was solved and subtracted, 



"C T (J) = A + BJ + CJ 2 + DJ 3 

 pL 



C (J) = C (J) - C (J) 

 pcor p pL 



where A, B, C, D, are the polynomial coefficients. This corrective procedure 

 eliminated the loading effect on most of the gages over the range of test conditions. 



13 



