The High Speed Water Tunnel three-component balance

An experimental program was initiated in the High Speed Water Tunnel to measure force coefficients for hydrofoils under cavitating conditions. This program necessitated either a new force balance or a major modification of the existing one. Various balance configurations and pressure seal designs which were considered are described. A balance modification design was selected which consists of an appendage bolted between the existing balance and the water tunnel working section. This appendage alters the basic geometry of the force balance so that the model is now mounted on a parallelogram linkage instead of on a simple pivoted lever. The addition of the parallelogram force table suspension to the old balance renders the modified balance unresponsive to moments which in the old balance, interacted with forces and resulted in errors in the force readings. This modification which is described in detail was accomplished and resulted in a successful force balance capable of accurate measurement of forces on cavitating and noncavitating hydrofoils; and, in fact, it is expected to replace the old force balance for all force measurement work in the High Speed Water Tunnel. The cost and construction time for the balance modification were considerably less than would have been required for an entirely new force balance of comparable accuracy and sensitivity

Burrowing apparatus

A soil burrowing mole is described in which a housing has an auger blade wound around a front portion. This portion is rotatable about a housing longitudinal axis relative to an externally finned housing rear portion upon operation of driving means to cause an advance through soil and the like. The housing carries a sensor sensitive to deviation from a predetermined path and to which is coupled means for steering the housing to maintain the path

Cold-air performance of a tip turbine designed to drive a lift fan

Performance was obtained over a range of speeds and pressure ratios for a 0.4 linear scale version of the LF460 lift fan turbine with the rotor radial tip clearance reduced to about 2.5 percent of the rotor blade height. These tests covered a range of speeds from 60 to 140 percent of design equivalent speed and a range of scroll inlet total to diffuser exit static pressure ratios from 2.6 to 4.2. Results are presented in terms of equivalent mass flow, equivalent torque, equivalent specific work, and efficiency

Soil penetrometer

An auger-type soil penetrometer for burrowing into soil formations is described. The auger, while initially moving along a predetermined path, may deviate from the path when encountering an obstruction in the soil. Alterations and modifications may be made in the structure so that it may be used for other purposes

Research turbine for high temperature core engine application. 1: Cold-airoverall performance of solid scaled turbine

A solid, half-scale model of a 50.8-cm (20-in) research turbine designed for a high temperature core engine application was investigated over a range of speeds and pressure ratios. The results of this test are presented. The effect of rotor blade twist was also investigated. At the design equivalent speed and specific work output, the total efficiency of the turbine with untwisted rotor blades was 87.1 percent; at the same pressure ratio the efficiency of the turbine with twisted rotor blades was 88.0 percent