Mini Magnet (oz8421)

About this Plan

Mini Magnet. 48 inch wingspan magnet-steered glider. Slope soarer.

Quote: "If you have any sort of local slope, build this lightweight magnet steered glider. Mini Magnet, by Peter Dolby.

I am sure many readers will have heard of Magnet Steered Gliders even if never having seen an actual model, but for those who are not so familiar with the class here is a brief outline of some of the main aspects. Magnet models are free flight gliders flown from hillsides facing into wind and like hang gliders rely on lift created by the hill to maintain the flight. As the name implies a steering unit, using a bar magnet, is employed to correct any in-flight deviations from a straight into wind flight path.

The unit in principle is quite simple, a bar magnet is pivoted to act like the needle of a compass. This is mounted in the nose of the model directly under a fixed front fin, the magnet will naturally seek a north/south alignment, so with the model held in the direction it is intended to fly, the steering rudder is fitted to the magnet, in a neutral position, thus if the model is moved away from this line, the magnet will seek north turning the rudder for in-flight correction.

The torque produced by this action is very small, but is sufficient, providing bearing friction is kept to a minimum. This ability to self-steer keeps the model on its flight path into wind; so the art of magnet flying becomes one of pre-setting the flying speed, ie by adding ballast and generally trimming to match the wind speed on the day and so keep the model within the narrow band of lift on the hillside.

Mini Magnet. 'Mini' was built out of a desire for change, I have been flying magnet steered gliders for some years, and although FAI rules impose few restrictions on the design and size of models, the norm has tended to be of A/2 or larger areas. The potential of such a small model was a little unknown, so it was decided to make it as light as possible for use on calm days, when its performance could be more easily assessed. The models construction is quite simple and not too far removed from normal free flight practice, the only thing which warrants special attention are fin alignments and keeping the flying surfaces as warp free as possible.

The magnet unit as drawn is one produced in Germany but available from Trevor Faulkner, it is supplied complete with front fin and rudder and simply requires fitting to the model.

Covering is entirely lightweight Modelspan for wing, tail and most of the fuselage with just the area of the front pod covering in heavyweight Mode/span.

A fuse dethermaliser was used on the original model mainly to save weight, but the fuselage will easily accept a clockwork timer if preferred. Just a reminder to anyone using fuse, many hillsides are high fire risk areas in summer so always fit a reliable snuffer tube, better safe, etc.

Initial flights were made in about 5 mph winds after first establishing a flat glide over level ground. Early flights from the slope indicated that the model was more susceptible to ground level turbulence than its larger counterparts, and was easily thrown off line, this proved to be no real problem as the steering unit is effective enough to quickly correct this. The weaving pattern is reduced as smoother air is encountered as the model gains height... "

Scan from DBHL, cleanup by theshadow.

ref DBHL-5210.

Direct submission to Outerzone.

Update 13/02/2017: Added article pages, thanks to Algy2.

Supplementary file notes

Article pages.

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