HARDWOOD RECORD 



September 10, 1918 



Bataan mahogany which also comes from a Philippine province. The 

 propeller is 9.5 feet in diameter with a 5-foot pitch. The tips are of 

 brass, fastened with screws soldered In place. 



On April 13 the propeller was run for 3 hours and 10 minutes on 

 Liberty engine No. 43. The average speed was 1550 r. p. m. and the 

 maximum speed was 160S r. p. m. at the beginning of the run, falling off 

 to 1374 r. p. m. at the end of the run. After this run the propeller was 

 allowed to stand in a horizontal position until April 15. On April 17 

 the propeller was again run for 2 hours at an average speed of 1607 r. p. m. 

 April 18. the propeller was placed on the roof of the laboratory, in order 

 to determine the effect of exposure to the weather. It was allowed to re- 

 main there 40 hours. During the greater part of this exposure test a 

 light rain was falling and for a short time it rained very heavily. 



The propeller was then sent to the Anacostia station where it was kept 

 until May 21. During most of this period It was kept on a rack in a 

 vertical position, but for a short time, it was mounted on an R-6 sea- 

 plane on which it was run 15 minutes in the air (at about 1700 r. p. m.) 

 and 23 minutes on the beach (at about 1500 r. p. m.). 



At the end of the series of tests above described, the measurements 

 were tabulated on a large sheet and the differences between the original 

 measurements and the measurements after each test were computed. 



A summary of the tests above described follows ; 



Test 



No. Time of Start. Time of Close. 



1 Apr. 3, 1918 Apr. 3, 1918 Measurements of new propeller. 



2 Apr. 13, 1918 Apr. 13, 1918 Ran 3 hrs. 10 min. on Liberty. 



3 Apr. 17, 1918 Apr. 17, 1918 Ran 2 hrs. on Libertj. 



4 Apr. 18, 1918 Apr. 20, 1918 40 hrs. on roof of laboratory. 



5 Apr. 20, 1918 May 21, 1918 31 days at Anacostia, including 15 



min. run in air and 23 min. run beach. 



No change in any of the dimensions, greater than the unavoidable error 

 in measurement could be detected after any of the tests. The only defect 

 noted during the whole series was one slight crack in each blade after 

 test No. 4 the exposure of 40 hours in the rain. The cracks were in 

 glued Joints and extended from the brass tips for a distance of about 18" 

 toward the hub. They were located at about the middle of each blade, 

 on one side only. These cracks were slight openings of the glued Joints 

 due to the exposure to rain, and were not over 1/64 inch wide and Vt inch 

 deep. They did not appear to Impair the strength of the blade and this 

 was borne out by the fact that the propeller stood up well in the subse- 

 quent tests in flight. 



As far as can be determined in the laboratory, tanguile mahogany is 

 suitable for use as a propeller wood and is apparently equal to true 

 mahogany for this purpose. 



H. S. McDewell. 

 Ter C. F. Taylor 



The second report, under date of July 26, 1918, was made by the 

 Forest Products Laboratory, Madison, "Wis., and appears in sub- 

 stance below: 



U. S. DEPARTMENT OF AGRICULTURE 



FOREST SERVICE 



Date, July 26. 1918 Project No. Misc. N D 



Forest Products Laboratory, Madison, Wisconsin 



MECHANICAL PROPERTIES OF TANGUILE (No. 3667) 



True African 



Mahog- Mahog- 



Tanguile any any 



Ref. No. Prev. Prev. 



Average Values No. 3667 Tests Tests 



Moisture— Per cent 1 17.3 15.0 15.0 



Specifle Gravity — Volume as tested 2 .542 



Specific Gravity — Oven dry volume 3 .577 .54 .50 



Shrinkage, In Volume — Green to Oven dry 



— Per cent 4 



Shrinkage, Radial — Green to Oven dry — 



Per cent 5 3.8 3.5 4.8 



Shrinkage. Tnn:;.'iiti:il ilroen to Oven dry 



—Per r..i,l 6 6.5 4.2 5 5 



Fibre Stress :,i l': I, "ij's. '[.er Sq. In 9 7260 7000 7100 



Modulus i.r KiiiiliMr l.l.s. pi^r Sq. In 10 10730 10000 10400 



Modulus of lObisti.ilv—liHiO Lbs. per Sq. In. 11 1460 1300 1400 



Work to E. L.— inch— Ll)s. per Cu. In 12 2.1 '2,2 



Work to Maximum Load — Inch-Lbs. per 



Cu. In 13 10.1 9.1 10 3 



Impact Bcndinr/ — ^0-Pound Hammer 



Fiber Stress at E. L.— Lbs. per Sq. In 17 11060 10920 11800 



Modulus of Elasticity— 1000 Lbs. per Sq. In. IS 1818 1580 1610 



Work to E. L.— Inch-Lbs. per Cu. In 19 3.8 4.2S' 4.8 



Drop causing complete failure — Inches.... 20 35 26 22 7 



Comp. Parallel to Grain 



Crushing Strength at E. L. Lbs. per Sq. In.. 23 4430 4415 

 Maximum Crushing Strength — Lbs. per Sq. 



In 24 5930 5500 5100 



Modulus of Elasticit.v— 1000 Lbs. per Sq. In.25 1710 1525 

 Comp. Perpendicular to G-rain 



Crushing Strength at E. L. Lbs. per Sq. In.. 26 1113 1000 '. 



Hardness — Ball Test 



End— Lbs 27 775 1049 



Radial— Lbs.— Side 28 



Tangential — Lbs 29 858 860 7 h 



Shearing strength 



Radial — Lbs. per Sq. In. Parallel .30 



Tangential— Lbs. per Sq. In. to grain 31 1294 1420 127u 



Note — Specific gravity and per cent of moisture in all cases based on 

 oven dry weight. Per cent of shrinkage in all cases based on green or 

 maximum dimensions. 



Prepared by F. L. F. Checked by C. B. D. 



Conservation Is a Question of Value of Materials 

 to Be Conserved 



There has been a good deal of agitation in this country in favor 

 of conservation and very much against the wicked, dollar-chasing 

 lumberman. No one suffers from waste in the woods more than 

 the lumber operators, for they pay for the trees and pay for the 

 cost of clearing the waste from the cut-over lands and for the 

 timber destroyed by fires orfginating in slashings. Lumbermen 

 have repeatedly and frankly expressed themselves as heartily in 

 favor of conservation, but have denied that the mere fact of their 

 owning the trees makes it imperative that they jeopardize their 

 businesses by carrying on their operations in a maimer that would 

 aid conservation from a theoretical standpoint but would prove 

 disastrous to the lumber industry. 



There are exceptions to the general case, but these exceptions 

 definitely prove the lumbermen's contention, for they are made 

 possible only because of the high price of the materials involved. 



The average tree is cut with a reasonable stump height that 

 eliminates from the first log lengths the undesirable wood structure. 

 On the other hand, in the production of walnut veneers and lumber, 

 gnarled wood found at the base of the butt log is often due to the 

 particular growth and color characteristic of the most valuable part 

 of the tree. Therefore, the walnut stump is cut practically on a 

 level with the ground, and, in fact, is frequently dug up and shipped 

 minus the roots right along with the butt logs. This is possible 

 only because a sufficient return can be gotten for the product to 

 justify the expense of utilizing the whole of the tree. 



CONSERVATION IS POSSIBLE ONLY WHEN IT IS GOOD BUSINESS, 

 A WALNUT BUTT IS USUALLY CUT LOW. 



