GB596302A - Improvements in or relating to a system for determination of the longitudinal position of the center of gravity and the gross weight of a craft afloat, such as a seaplane - Google Patents

Abstract

596,302. Computing-apparatus. MARTIN CO., G. L. Dec. 8, 1944, No. 24628- Convention date, Dec. 1, 1943. [Class 106 (i)] [Also in Groups XX, XXXIII and XXXVIII] Means for computing the longitudinal centre of gravity and gross weight of a craft, such as a seaplane, while afloat comprises means for determining the draught at two or more spaced points and charts or indicators for obtaining approximate and then more accurate estimates. When a cap 11, Fig. 2, is removed the water passes up a tube 7 to raise a lioat 12 and project a scale 10 to indicate the draught at the point concerned. From the sum of the draughts at front and rear of a flying boat, an estimate of the gross weight is obtained from the lower part of the chart, Fig. 5, assuming the centre of gravity to be placed at a certain value of mean aerodynamic chord (M.A.C.). By taking this estimate of gross weight and the difference of draughts, a revised centre of gravity is obtained from the upper part of Fig. 5 and successive approximations in the lower and upper parts of Fig. 5 finally give agreement as to the values of the centre of gravity and gross weight. In Fig. 6, the water from outside the hull, enters a chamber 17. The chambers 17 of the fore and aft points are connected to pressure gauges, one of which adds and the other differences the pressures, Fig. 7. The dials 18, 19 of the gauges are rotatable by knobs 29, 32 so that successive approximations can be made before arriving at the correct values of the centre of gravity and gross weight. The gross weight, in a modification, may be estimated from the pressure in a single pressure chamber located amidships. The connections to the pressure gauges may be broken by a cock 37 (Fig. 7, and Figs. 10, 11, not shown), except when readings are being taken. In Fig. 12, the pressure chambers are replaced by floats 51<1>, 52<1> actuating potentiometers 45, 46. A fourpole switch 47 in position A connects the potentiometers in series to indicate the gross weight on meter 48. In position B, the switch 47 connects the potentiometers in parallel so that the meter 54 indicates the centre of gravity. The dials are adjusted as before.