Information For Inspectors Of Airplane Wood

INFORMATION FOR INSPECTORS OF AIRPLANE WOOD - 1919 - CONTENTS . The strength of timber ..................................................... Xeaning of strength ................................................... Variability of the strength of wood ....................................... Wood nonhomogeneous ............................................. Variation of strength with locality of growth ......................... Variation of strength with posit. ion in the tree ........................ Variation of strength with rate of growth ........................... Variation of strength with amount of summerwood ................... Variation of strength with specific gravity .......................... Variation of strength with moisture content ......................... Defects affecting strength ............. . ............... . .............. Diagonal and spiral grain .................................... . ..... Compression failures .............................................. Brashness .......................................................... Decay ........................................................... Internal or initial stresses in wood ........................................ Wood fibers under stress in the tree .................................. Internal stresses produced during drying ............................ Initial stresses produced in assembling ............................... Recommended methods for determining working stresses for timber used in airplane construction .............................................. Nature of loading ................................................. Publications on the mechanical properties of wood ....................... Shrinka .g, e . ........... .... ................................................ Amount of shrinkage .................................................... Shrinkage of propeller stock ............................................ storage of st. ock before kiln drying .......................................... Rules for piling lumber and timbers .................................... Kiln-drying of wood ....................................................... Advantages of kiln. drying ............................................... The elimination of moisture from wood ..................... ............ Three essential qualities of the dry-kiln .................................. Defects due to improper drying ......................................... Case-hardening and honeycombing ................................. Collapse ................. .. ... . ... ............................ Brashness ......................................................... Testing of kilns for drying airplane stock ................................ Kinds of test. 8 .................................................... Instruments ........................................................ method. .......................................................... Preliminary tests ............................................... Current tests .................................................. Final tests ...................................................... Treatment of wood after removal fro nth e dry. kiln ...................... . Publications on kiln-drvine woods ...... - ............ ................. Pnge . 5 5 . 5 5 6 6 6 6 7 11 15 15 17 17 18 18 18 18 18 19 . . 4 CONTENTS . Changes of moisture in wood with humidity of air........................... Gluing of m. oods. ........................................................... Testing of animal glue for airplane propellers ............................ Rinds of tests ........................ .............................