12. FRESENIUS, R.: 



Schiffbau, Vol. 22 (1921). 



13. HORN, F.: 



North East Coast Inst., Vol. 54 (1938). 



14. DICKMANN, H.: 



Ingenieur Archiv, Vol. 9 (1938). 



Jahrb. Schiffbautechn. Ges., Vol. 40 (1939). 



5. Intern. Congr. of Appl. Mechanics, Cambridge, Mass. (1938). 



15. BASSIN, A. M.: 



Academii Nauk, No. 12 (1946). 



16. LEFOL, J.: 



Assoc. Techn. Maritime et Aeron., Paris (1947). 



17. MARTINEK, J. and YEH, G. C. K.: 



Reed Res. Inc., Washington, D. C, Rep. RR-815 (1953). 

 Intern. Shipb. Progr., Vol. 1 (1954). 



18. MARTINEK, J. and YEH, G. C. K.: 



Reed Res. Inc., Washington, D. C, Rep. RR-815B (1955). 



19. HUNZIKER, R. R.: 



Reed Res. Inc., Washington, D. C, Rep. RR-815B (1956). 



20. KORVIN-KROUKOWSKY, B. V.: 



Intern. Shipb. Progr., Vol. 1 (1954) and Vol. 3 (1956). 



21. BURGERS, J. M.: 



Kon. Academ. Wetenshapen, Amsterdam, Vol. 32 (1929). 



22. WEITBRECHT, H. M.: 



Jahrb. Schiffbautechn. Ges., Vol. 42 (1941). 



23. MANEN, J. D. van: 



Scheepsbouwkundig Proefstation, Wageningen, Rep. 100 (1951). 

 Intern. Shipb. Progr., Vol. 2 (1955). 



24. LAMMEREN, W. P. A. van, MANEN, J. D. van and LAP, A. J. W.: 



Intern. Shipb. Progr., Vol. 3 (1956). 



25. ECKHARD, M. K. and MORGAN, W. B.: 



Soc. Nav. Arch, and Marine Engin., New York, Vol. 63 (1955). 



26. HELMBOLD, H. B.: 



Ingenieur Archiv, Vol. 2 (1931). 



27. LERBS, H. W.: 



Hamburgische Schiffbau Versuchsanstalt, Rep. 254 (1945). 



28. BURRILL, L. C: 



Assoc. Techn. Maritime et Aeron., Paris, Vol. 54 (1955). 



DISCUSSION 



A. J. Tachmindji 



Dr. Lerbs has given us a very good summary of the fundamental and basic 

 work that has been done in the last few years in the development of propeller theory. 

 His personal work has contributed materially in the investigation of vortex theory 

 when the circulation distribution is considered arbitrary, and when the induced velocities 

 can be expressed in terms of induction factors. By means of this method it has been 

 possible to compare the validity of the circulation theory as derived by Betz's and 

 Goldstein's work for lightly loaded propellers where the condition of normality of 

 the induced velocity is assumed to hold true. The induction factors method, therefore, 

 gives a means of evaluating the applicability of the lightly loaded propeller theory to 



165 



