Design of an Instrument for Measuring the True Vertical Velocity of an Airplane at Moment of Contact in Landing

Citation

Burger, Glenn William and Daniels, Jerry Forest (1947) Design of an Instrument for Measuring the True Vertical Velocity of an Airplane at Moment of Contact in Landing. Engineer's thesis, California Institute of Technology. doi:10.7907/R4C9-D634. https://resolver.caltech.edu/CaltechETD:etd-12032008-140606

Abstract

In the design of the Vertical Velocity Meter a survey was first conducted of the existing methods used to measure the vertical velocity of an airplane when landing. A study was then made of these methods and of other unsuccessful attempts to design a Vertical Velocity Meter to determine just why they were not satisfactory and in what way they might be improved.

It was decided to develop a design along an entirely different principle than any used before but yet one having basic simplicity. The one selected was based on the formula of velocity being equal to a distance divided by the time it took to travel that distance. To accomplish this a device was designed which consisted of two rods of different length which would strike the ground when the plane was landing, thus if the difference in length and the time between the striking of the two rods is known, the velocity at that moment would be determined.

Since it was impracticable to test this device on an airplane, a testing machine was constructed which would test both the strength of the rods and various timing methods. This machine consisted of a wedge mounted on the end of a whirling arm which would strike the rods and simulate the impact received during the landing of an airplane. Two timing methods were tried; a Miller Oscillograph with built in recorder, and a Cathode-Ray Oscilloscope with a camera to record the trace.

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