Document ID: chunk:federal_register_of_legislation:F2007L04873:body:0:p3
Version: federal_register_of_legislation:F2007L04873
Segment Type: other
Provision Reference: 
Character Range: 5246–7837

stated on the approved drawing, the allowable tolerances on angles, chords, maximum thickness, diameter and track must be as follows:
Angles      1 throughout the inner third of the blade length.

            ½ throughout the outer two-thirds of the blade length.
Chords      1 mm for chords up to 50 mm increasing by  0.5 mm for each 50 mm of chord, or part thereof, in excess of 50 mm.
Maximum    ± 0.5 mm for thickness up to 10 mm increasing by ± 0.2 mm for each 10 mm, or part thereof, in excess of 10 mm.
Diameter   ± 5 mm.
Track      ± 1 mm for propellers of up to 1.5 m diameter, increasing by ± 0.5 mm for each 1 m, or part thereof, in excess of 1.5 m diameter.
Plan form  For propellers of up to 1.5 m in diameter, a tolerance of 2 mm is allowed on the distances (as given in the approved drawing) between the trailing edge of all sections (except that nearest the tip) and a datum plane containing the axis of the bore and the centre line of the section nearest the tip. This tolerance may be increased by ± 1 mm for each 1 m, or part thereof, by which the diameter exceeds 1.5 m.

8 Protective treatment

       8.1The propeller must be finished in accordance with the instructions specified on the approved drawing.

       8.2The bore and bolt holes must be protected with paint or suitable varnish.

       8.3Where lacquering is to be used:

       (1)The surfaces of the propeller prior to lacquering must be smooth, even, dry and clean. Any small depressions remaining after the propeller has been rubbed down with fine sand paper may be filled up with plastic wood.

       (2)To prevent "blushing", the lacquering must be done in a dry shop free from cold draughts, at a temperature of from 20C to 30C.

       (3)On completion of the lacquering, the propeller surfaces must be smooth and entirely free from bubbles and pin holes and the film of lacquer must be between 0.10 mm and 0.15 mm thick.

       8.4Where fabric covering is to be used:

       (1)Fabric intended for covering propeller blades must comply with a specification approved by the Director. The covering for each blade must be in 1 piece and must extend to a position as stated on the approved drawing.

       (2)The covering process must be carried out at a room temperature of not less than 20C and the room must be free from draughts.

       (3)After being allowed to dry for at least 12 hours, the fabric covering must be given 1 coat of undercoating varnish complying with a specification approved by the Director.

9 Metal sheathing

       9.1The metal sheathing, if specified, must