Propellers of Minimum Induced Loss, and Water Tunnel Tests of Such a Propeller

The fundamental vortex theory for a single rotation propeller with a finite number of blades is reviewed. The theory leads to the specification of a radial distribution of bound circulation on each blade for minimum induced loss, analogous to the elliptic spanwise distribution of bound circulation on a wing for minimum induced drag. A propeller designed in accord with this theory has been tested in a water tunnel where it exhibited high efficiency in spite of localized cavitating flow. A knowledge of the flow field for an optimum propeller is of value to the airframe designer seeking to maximize the performance of the airplane-propeller combination

Minimum Vertical Tail Drag

Tail size requirement calculations are presented for a vertical tail performing a coordinated turn reversal at corresponding load requirements with minimum tail drag

Preservation of wing leading edge suction at the plane of symmetry as a factor in wing-fuselage design

Most fuselage geometries cover a portion of the wing leading edge near the plane of symmetry, and it seems reasonable to expect that a large fraction of the leading edge suction which would be developed by the covered wing at high angles of attack is not developed on the fuselage. This is one of the reasons that the Oswald span efficiency factor for the wing body combination fails to approach the value predicted by lifting line theory for the isolated wing. Some traditional and recent literature on wing-body interference is discussed and high Reynolds number data on wing-body-nacelle drag are reviewed. An exposed central leading edge geometry has been developed for a sailplane configuration. Low Reynolds number tests have not validated the design concept

Design of Propellers for Motorsoarers

A method was developed for the design of propellers of minimum induced loss matched to an arbitrary operating point characterized by disc loading (thrust or power), air density, shaft speed, flight speed, and number of blades. A consistent procedure is outlined to predict the performance of these propellers under off design conditions, or to predict the performance of propellers of general geometry. The examples discussed include a man powered airplane, a hang glider with a 7.5 kW (10 hp) 8,000 rpm engine, and an airplane-like motorsoarer

Trim Drag in the Light of Munk's Stagger Theorem

Munk's stagger theorem holds that the induced drag of a multiplane is independent of the streamwise position (the stagger) of its lifting elements so long as the gap/span ratios and the element/element lift ratios are specified. In particular, a monoplane-tailplane or a monoplane-foreplane (canard)arrangement can be regarded as a biplane of zero gap and the trim drag due to tailplane download or foreplane upload can be readily calculated. The trim drag penalty is the same for both configurations. Relations are given for trim drag estimates for various practical arrangements

Maria E. Larrabee Letters

Typed copy of letter dated June 18, 1906 which is Mrs. Larrabee's response to George J. Backen's invitation to attend Old Settlers Reunion, has brief mention of their life in Foster County, including the births of two sons, mail delivery between Jamestown, N.D. and Fort Totten. Handwritten letter, dated Nov. 11, 1960, from Ralph Miller, Fargo, to Leonard Sackett which mentions the Old Settlers Association, their picnics, and a Captain Warren

The Use of Local Photographic Material in the Development of Social Studies Units for the Intermediate Grades

There has been a double purpose in preparing and writing this thesis. One purpose was to meet the needs of the teachers and pupils of North Central Washington for materials to be used in carrying out local units in the social subjects fields. A second purpose was to provide for the interests that children have in other cultures, such as the study of American Indian life; of information and data concerning pioneer life, and to foster and appreciation of what the generation before has done to make life in North Central Washington what it is today

Physical Electronics

Contains reports on three research projects

Physical Electronics

Contains reports on four research projects