I wish to develop a platform for geophysical work. The problem is that suitable geophysical receivers are copper coils with a weight in excess of 5kg - with ancillary electronics the total payload would likely be 10kg.
In addition, an air coil receiver would need the largest possible cross sectional area to be carried horizontally, whilst a ferrite core receiver would be a longish (0.6 m) cylinder to be carried vertically.
Model airplanes are generally smaller than this, whilst ultralights/para-gliders are considerably larger. Does anyone have any suggestions for a suitable airframe to get started with?