acceleration (V>0, n#0, P#0). Thus, one "true" acceleration run is rep- 
resented by five runs which simulate the proper time rate of change of V 
but not the proper time rate of change of n and P. The quasi-steady and 
unsteady acceleration simulations were for the same conditions, the only 
difference being that V=0 for the quasi-steady simulation whereas V>0 for 
the unsteady simulation. In general, P varies with time during a "true" 
acceleration run; however, for the acceleration run under simulation here, 
P was constant throughout the portion of the run simulated. 
For the unsteady acceleration runs, the carriage speed was manually 
varied with time in a carefully controlled manner. This was achieved with 
the aid of an inked pen on a two-dimensional Cartesian plotter. In one 
direction, the pen was controlled so that it moved linearly with time, 
and in the orthogonal direction, it was controlled so that it varied with 
the instantaneous carriage speed. When an acceleration maneuver was to be 
executed, the switch moving the pen with time was turned on and the car- 
riage operator manually varied the carriage speed so that the inked pen 
followed a prescribed velocity versus time curve. 
As discussed earlier, each of the three load-sensing flexures 
measured only two components of blade loading. Therefore, each of the 
experimental conditions described in Table 3 was run with each of the 
three blade loading flexures. 
The blade pitch was set by using a Sheffield Cordax 300 measuring 
machine. In order to change either the blade pitch or the flexure, the 
propeller had to be removed from the drive system. 
Air-spin experiments were conducted with all three flexures over a 
range of rotational speeds in order to isolate the effects of centrifugal 
and gravitational loading from hydrodynamic loading. Supplemental experi- 
ments were conducted to assess the influence of the downstream dynamo- 
meter boat on the flow in the propeller plane. These supplemental exper- 
iments consisted of wake surveys in the propeller plane at the self- 
propulsion point (Condition 1 in Table 3) with and without the downstream 
body, but without the propeller. These wake surveys yielded a direct 
measure of the change in the velocity distribution through the propeller 
16 
