Holloway, W. G.; Kumar, P. E.; Osbourn, W.
Abstract:
This note covers the development of two strain-gauge balances for use
on the Whirling Arm Facility of the College. The main requirements for
this balance were:- (a) to withstand 700 lbs of sideload without it
interfering with the lift, drag and pitching moment measurements, (b) to have
a high sensitivity without too heavy a structure. The balance originally
designed for this purpose proved to be unacceptable because of undue interference
due to sideload and the non-repetitive nature of its calibration
curves. With the information gained from this first balance a second balance
of exceedingly simpler design, was manufactured and was found to give good
calibration curves and sensitivity, with little interference from sideloads.
A trouble free method of recording the signals from the strain-gauge bridges
is being developed and should be operating within the near future.
It concluded that a new model, with its c.g. lying on the transverse
centre-line of the balance, will be needed if sideload interference is to be
further reduced.