An Encyclopedia of the History of Technology part 36. This one of a kind encyclopedia presents the entire field of technology from rudimentary agricultural tools to communication satellites in this first of its kind reference source. Following an introduction that discusses basic tools, devices, and mechanisms, the chapters are grouped into five parts that provide detailed information on materials, power and engineering, transportation, communication and calculation, and technology and society, revealing how different technologies have together evolved to produce enormous changes in the course of history | PART TWO POWER AND ENGINEERING Early development At the time about 1900 to 1910 that engineers started seriously to consider the gas turbine as a candidate prime mover neither the necessary understanding of turbo-machinery fluid mechanics nor satisfactory materials were available. Nevertheless the advantages of the gas turbine were such that a number of machines were constructed and operated notably by Armengaud and Lemale 1903-6 Holzwarth 1908-33 Karavodine 1908 and Stolze 1900-4 . The Armengaud and Lemale gas turbine and that due to Stolze used the constant pressure heat addition cycle while the Holzwarth and Karavodine turbines used the constant volume heat addition cycle. A significant feature of these machines was the use of water cooling of the expansion turbine in order to decrease the amount of air that would otherwise have been required in order to control its inlet temperature. Holzwarth s was the most successful of the early gas turbines and a number of versions were built between 1908 and 1933 under his supervision. The final model a 5000kW machine was built by the Brown Boveri Company and placed in service in a steelworks at Hamborn Germany in 1933. This experience apparently demonstrated to Brown Boveri the superiority of turbines based on the constant pressure combustion cycle and led to their involvement in the development of this type the company was to become one of the major contributors to gas turbine technology. 1933-1946 beginnings of the modern gas turbine There was a substantial hiatus in gas turbine activity following the early attempts to construct the machines described above while efforts were made to develop high efficiency compressors with an adequate compression ratio at least 4 1 . In addition during this period as a consequence of their work with Holzwarth s Hamborn gas turbine the Brown Boveri Company took an important step toward the development of a practical gas turbine based on the constant pressure heat addition cycle. It was
