PROPELLER 4661 
Y= 10 DEG 
NO SCREEN 
(FE, m)i/K(F, BAI d 
PROPELLER 4661 
v =0 DEG 
My, WITH SCREEN 
1.4 \ 
(FE, M)1/*(F, Mp1, d 
Fig. 6 — Experimental Variation of First Harmonic Blade Loads 
On Propeller 4661 with Advance Coefficient 
corresponding values at very large tip 
clearance ratios for Propeller 4402 with 
an inclination angle ~ of 10 degrees. 
Effect of Advance Coefficient 
Figure 6 presents the trends of the 
variations of the first harmonics of the 
Bree load components Fy, M 
and My with J for Propeller 4661 
aye the three primary experimental 
conditions described in the section on 
Experimental Conditions and Procedures. 
K(F/M)I/X(F,M)1,d 
PROPELLER 4661 
y= 20 DEG 
NO SCREEN 
In Figure 6 the force and moment 
components are nondimensionalized as 
follows: 
(Eee) 
ag x,y'1 
Meaehn @ = (2) 
pnV,D 
a af (My ys (3) 
ESD Sar 
pnV,D 
where the subscript 1 represents the 
first harmonic component, and Va = 
V(l-wym) is the speed of advance based 
on the volume mean wake. This form of 
nondimensionalization was used in part 
to verify Wereldsma's argument (12) that 
for a given propeller in a given wake 
pattern the circumferential variation of 
the hydrodynamic loading varies 
approximately as nVa; i.e., for a 
given value of nVaq the circum- 
ferential variation of hydrodynamic 
loading ts insensitive to J. This form 
of nondimensionalization is different 
only by a factor of the advance coeffi- 
cient, Ja, from the conventional form 
of nondimensionalization; i.e., 
Fx,y/en2p4 and My, y/en? 2p5. 
The conericrent: (EX, y)l 
and (mx,y)1 in Figure 4s are all 
normalize by the respective 
coefficients at design J to illustrate 
the relative sensitivity of the loading 
coefficients to J, for different wakes. 
The results presented in Figure 6 
show that in tangential flow ‘(px,y)1 
and (mx,y)1 generally decreases with 
