All linen used in airplane construction should be of the following specifications:
Free from all knots or kinks.
Without sizing or filling.
As near white as possible.
Weight, between 3.5 and 4.5 oz. per square yard.
Strength as per Government Specifications.
Inspection of Wood.
All wood should be inspected before varnish is applied.
Is grain satisfactory?
Are there any sap or worm holes?