WOOD ON THE WING 



585 



sticks," "vehicles" or "wood- 

 enware." In only one that 

 the writer has seen and he 

 has made a pretty thorough 

 search through them has 

 there been any mention of 

 airplanes, yet wood is the es- 

 sential material in their con- 

 struction. In other words, 

 airplane manufacture, upon 

 which the outcome of the war 

 is said to depend, was scarcely 

 mentioned in this series of 

 government reports issued 

 within the past five years. 



The one exception to the 

 general dearth of facts about 

 airplane manufacture was in 

 the report on the wood-using 

 industries of New York, is- 

 sued in 1913. It listed three 

 manufacturers who made 

 planes or their parts, and 

 gave the quantity of wood 

 used annually as 31,400 board 

 feet, of which spruce fur- 

 nished about half, the other 

 woods mentioned being ash, 

 yellow poplar, white oak and 

 hickory. The total cost of all 

 woods used was less than 

 $1,000.00, to be exact, $968. 



Compare these figures of 

 four years ago with the pres- 

 ent plans for 7,500,000 feet 

 of oak, and from 40,000,000 

 to 100,000,000 board feet of 

 spruce. 



It is difficult to state au- 



Copyright 1917 by International Film Service. Inc 



WOOD IN THE WING OF A WAR AIRPLANE 

 Spruce stands first in the kinds of wood demanded in airplane construction Practically all of the con- 

 struction is of built-up or laminated wood. One advantage of this construction is that the lamination 

 divides the stresses and prevents them from coming in full force on any one grain. Another advantage is 

 that the laminated stock can i)e built to form curves or can be bent to curves without splitting or weak- 

 ening the piece. This picture shows men at work making a wing for a Government war plane. 



thoritatively just how much lumber is going into air- 

 plane construction, because authorities disagree. One 

 statement which has official sanction is about as follows : 

 "The war is going to be won in the air. The program 

 calls for the construction of more than 20,000 airplanes 

 within twelve months." Since then it has been stated 

 that the estimates have been revised and it has been 

 a revision upwards. In another statement it is pointed 

 out that "each propeller uses 300 feet of lumber, and if 

 23,000 airplanes are built as proposed, and two propel- 

 lers are held in reserve for each machine, it will take 

 20,000,000 board feet for the propellers alone." This 

 corresponds to the 7,500,000 feet of oak for the supply- 

 ing of the blades actually needed for initial construction, 

 without allowing for reserve propellers. The govern- 

 ment now is using, according to another authority, some 

 3,500,000 feet of lumber for airplanes themselves, and 

 120,000,000 feet for aviation school cantonments with 

 an additional 22,000,000 for coastal airplane stations. 



Spruce stands first in the kinds of wood demanded in 

 airplane construction. Practically all of the framework 



is of spruce and it bids fair to hold its place, with a 

 possible supplementing by bamboo. Metal tubing has 

 been tried, but has not given satisfaction. 



The essential qualities of airplane woods include 

 straightness of grain, strength and lightness, and abso- 

 lute freedom from defects. The "struts" or upright posts 

 used in biplanes and triplanes are of spruce, as are the 

 supporting ribs in the planes themselves, and the beams, 

 running lengthwise. In these, in particular, the grain 

 must be straight, and must continue the whole length of 

 the piece without going across from one side to the 

 other, or without "running out." 



Practically all of the construction is of built-up or 

 laminated wood, in which thin layers are glued together 

 to form the part needed. That is, each post, beam, or 

 rib is made up of thin strips glued together. Except for 

 tacks used in covering the wing frames no nails are used, 

 because they make weak spots where they are driven. 



The laminated construction has many advantages. In 

 the first place, the smaller the pieces of wood that are 



