Fully Cavitating Propeller for a Hydrofoil Ship 



H 10OOlt>L0AD. C.P 2S% 



Fig. 22 - Test setup used in structural tests 



The principal conclusions resulting from the work on the simple blade 

 shapes were as follows: 



1. Blade sweepback has a significant effect on the stress levels in the 

 blades, and a judicious choice of sweepback can be made to minimise the stress 

 levels in critical areas of the blade or, alternatively, the sweepback can be 

 chosen to produce a reasonable stress distribution across the entire chord. Too 

 much sweepback is undesirable, however, since this can lead to an increase in 

 stresses in parts of the blade. The choice of sweepback is affected by the chord- 

 wise pressure distribution. 



2. Blade sweepback reduces blade deflections appreciably when compared 

 with unswept blades. However, introducing large sweepback for this purpose 

 can have an adverse effect on the blade stresses. 



3. Blade stress distribution and deflections are influenced by the chordwise 

 pressure distribution, as might be expected. The closer the section centre of 

 pressure is to the leading edge the higher are the stresses and deflections, 



4. Reasonable correlation exists between measured and calculated stress 

 distributions when simple bending theory is used. 



989 



