. Shipbuilding and Shipping Record. PITCH RATIOS. September 6, 1917. SHIPBUILDING AND SHIPPING RECORD. 225 proppUcr? of small disc area ratio, of 1-5 pitch ratio working atabout 12 per cent, real slip ; (this, by the way, is almost impossibleto achieve in. actual practice). (3) Increase in disc area ratiobrings with it a decrease in efficiency. In this connection it isof importance to observe that screws of high pitch ratio seem tobe less affected in efficiency by increase in area than do ofSmaller pitch ratio. (4) Increase in disc area ratio has compara-tively little effect on the S v

---

. Shipbuilding and Shipping Record. PITCH RATIOS. September 6, 1917. SHIPBUILDING AND SHIPPING RECORD. 225 proppUcr? of small disc area ratio, of 1-5 pitch ratio working atabout 12 per cent, real slip ; (this, by the way, is almost impossibleto achieve in. actual practice). (3) Increase in disc area ratiobrings with it a decrease in efficiency. In this connection it isof importance to observe that screws of high pitch ratio seem tobe less affected in efficiency by increase in area than do ofSmaller pitch ratio. (4) Increase in disc area ratio has compara-tively little effect on the S value, except at high slip ratios. These cmves then show the potentialities of tluee-bladed modelscrews of wide variation in pitch and area ratio, and, if the law ofcomparison holds, of full-sized screws also. It should, therefore,be fK)ssible to forecast the performance of any full-sized proj^ellersfrom these model results, and also to determine the dimensions ofthe particular screws which will fullil stipulated conditions of power

---

Size: 2950px × 847px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondon, bookyear191