parallel rulers การใช้

• A parallel ruler-equipped drawing board.
• Each set extends its surfaces, mounted like parallel rulers, above and below the wing.
• GRP ailerons were used and there were Schempp-Hirth spoilers, each pair extending out of its wing above and below on frames like parallel rulers.
• The wings of the Breguet 900 were straight-tapered, with squared off DFS type but were later replaced by Schempp-Hirth parallel ruler action brakes.
• The Rh鰊bussard is an all wood and airbrakes rotating out of both surfaces on a common span-wise axis at about mid-chord and finally with parallel ruler action Schempp-Hirth brakes mounted just behind the spar.
• Later that year, Stephens'Ink company advertisements featured not only inks and wood stains but also patent propelling pencils, parallel rulers, and stamp and label dampers, and claimed patronage by Prince Albert and other European royals.
• The two properties, conformality and straight rhumb lines, make this projection uniquely suited to marine navigation : courses and bearings are measured using wind roses or protractors, and the corresponding directions are easily transferred from point to point, on the map, with the help of a parallel ruler or a pair of navigational protractor triangles.
• The Koa
  ava was commissioned by the Yugoslavian Aeronautical Union and built at the Ikarus factory to replace the pre-World War II Kranich II aircraft . It is a wooden glider, covered in a mixture of plywood and airbrakes on each wing but these were replaced on the second aircraft with Schempp-Hirth parallel ruler action brakes.