ASME

Rapid development of aircraft design in the 1930s required many related innovations, including propeller design. The hydromatic propeller by Hamilton Standard marked a significant advance over the counterweight-type, controllable pitch propeller. The first test flight of the prototype took place in 1938: the public demonstration was made by a United Air Lines DC-3 over New York City on April 6, 1938. It played a distinguished role in allied combat aircraft in World War II.

During the 1920s, Edwin A. Link was employed in his father's organ building and repair business. He obtained his pilot's license in 1927 and became convinced that a mechanical device could be built as an inexpensive method to teach basic piloting. Link received three patents on his flight trainer (No. 1,825,462, March 12, 1930; No. 2,244,464, June 3, 1941; and No. 2,358,016, Sept. 12, 1944).

Wind tunnel testing of aircraft models is essential to determine aerodynamic parameters such as lift and drag. The 5-foot Wright Field wind tunnel is an early example of the modern wind tunnel, well known from the early 1920s to the late 1950s for its contributions to research and the development of nearly every major aircraft and associated hardware used by the US Air Force and its predecessor, the Army Air Service.

Smaller and cheaper than a triple-expansion vertical engine, the horizontal cross-compound pumping engine, Pump No. 2, ran at relatively slow revolutions and was considered the height of engineering from the 1890s to World War I. This pumping engine at the York Water Company was built by the Worthington Pump & Machinery Corporation, Snow-Holly Works, Buffalo, New York.

The convenient dry-copying process for printed pages is among the truly revolutionary inventions of the century. In 1937 Chester Carlson, a New York patent attorney, developed the concept of applying an electrostatic charge on a plate coated with a photoconductive material. On November 22, 1938, Carlson dusted powder dyed with evergreen spores across an exposed plate and transferred the imprint to the surface of a paper.

The 1905 Wright Flyer III, built by Wilbur (1867-1912) and Orville (1871-1948) Wright, was the world's first airplane capable of sustained, maneuverable flight. Similar in design to their celebrated first airplane, this machine featured a stronger structure, a larger engine turning new "bent-end" propellers, and greater control-surface area for improved safety and maneuverability.

Stationary steam engines, once the prime movers of industry, powered trains, ships, and mills in an age when there was no electric power. By the 19th century, American industry, especially in England, was rapidly outgrowing the capacity of the ater power that had been its principal prime mover. The need for a new power source inspired an intense development of the steam engine, the work of inventors directed mainly at imporving fuel efficiency by reducing steam consumption. The leader in this effort was George H.

The Wilkinson Mill, situated on the west bank of the Blackstone River in Pawtucket, was built between 1810 and 1811 by machinist Oziel Wilkinson. Constructed in stone rubble, three and one-half stories high, the mill played a critical role in the history of textile technology, in steam power generation, and in the development of the machine tools industry.

The history of this foundry, which was the oldest malleable iron company in continuous operation in the United States for many years, was inseparable from that of the small town of Westmoreland, where neighbors and workers kept time by the foundry bell. The firm was founded as Oakhill Malleable Iron Company in 1833 and was established under its present name in Westmoreland in 1850. Erastus W. Clark, who along with his brother-in-law Abel Buell brought the foundry to Westmoreland, ran the ironworks until 1871 and was the first of six generations who still own and manage it.