| 摘要 |
The aerial comprises at least one metal shaft (16a,16b) which is preferably cylindrical. The foot of each shaft is attached to the body of the craft to ensure it is orthogonal to the direction of displacement when the aerial is in use. A filament of material which is transparent to radiation and with diameter less than that of the shaft is wound around the shaft in a helical pattern. This causes a change from the laminar air flow past the aerial to turbulent air flow. The aerials may be arranged in pairs, so the two filaments wound around a pair of shafts have the same step between turns, and are wound in opposite directions. The filament diameter may be between 1/10th and 1/50th of that of the shaft. The resulting diameter of the filament is less than 1 mm, pref. between 0.5 and 0.8 mm.
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