from the GNU version of the Collaborative International Dictionary of English
- adj. Having two surfaces; -- said specif. of aëroplane wings or aërocurves which are covered on both sides with fabric, etc., thus completely inclosing their frames.
Sorry, no etymologies found.
Last year Lilienthal chiefly experimented with double-surfaced machines.
'The object of making these double-surfaced machines was to get more surface without increasing the length and width of the machine.
'Herr Lilienthal kindly allowed me to sail down his hill in one of these double-surfaced machines last June.