NO. 



3 



I.ANGLEY MEMOIR ON MECHANICAL M.h.ll! 



191 



square foot, has only 129 grammes drift, while the superposed one, while 

 supporting 0.125 pounds per square foot, has 255 grammes drift. More 

 over, the soaring speed of the single-tier wing is only 11.(1 feel per second, 

 while the superposed one requires a speed of L3 feet per second. 



As the superposed wing tested on November 30 was so weak structurally 

 that il could not be made to keep iis proper shape without adding an excessive 

 number of guy-wires, it was decided that it was not adapted for use on the 

 aerodrome, but before abandoning- it the partitions and strips were added and it 

 was again tested on the whirling-table on March 1, 1899, with the following 

 results : 



Weight of wing = 905 grammes; weight of guy-posts, etc., = 320 grammes; equivalent weight of 

 guy-posts, etc.. = 150 grammes applied at CP of the wing; equivalent load on the wing = 

 grammes = 2.321 pounds; area of wing = 21.S5 square feet; equivalent load on wins 

 pounds per square foot. 



Angle of 

 chord. 



5.0° 

 5.0° 

 5.0° 



10.11 



10.0 = 

 10.5° 

 10.5° 

 13.0° 



Revolutions ™^ f 



of turn- 

 table. 



10.875 



10.75 



10.75 



s.o 



8.0 



7. ST.". 

 7.875 

 7.0 



wing 

 (ft. per min.). 



1100 



1085 



10S5 



SOS 



707 

 797 

 707 



Velocity 

 < ft. per 

 secoud). 



IS. 35 

 IS. 07 

 IS. 07 

 L3.47 

 13.47 

 13.3 

 13.3 

 11.78 



Drift 



(grammes). 



250 

 250 

 250 

 250 

 250 

 250 

 250 

 250 



Drift 



(pounds.). 



o 55 

 o 55 

 0.55 

 0.55 



0.55 

 0.55 

 0.55 



Foot- 

 pounds 

 p. r sec, 

 BY. 



Kl.l 

 9.94 

 9.94 

 7.4 

 7.4 

 7 32 

 7.32 

 6 (8 



Calculated 

 Boaring 

 Bpe< 



rig 0.5 

 pour. ! 



sq. ft. 

 (ft. pel 



I 



39.19 

 39.19 

 29.226 

 29.226 



28 s.; 

 28.86 

 25.553 



An examination of the data obtained in this test shows the wing to lie of 

 slightly less efficiency than wbeu first tested. While it was considerably stronger 

 it was still too weak for use on the aerodromes. 



A second type of superposed wing, Plates i'.4 and 65, was therefore con- 

 structed and tested on the whirling-table on March 2, 1899, with the following 

 results: 



Weight of wing = 1025 grammes: weight of guy-posts, etc., = 320 grammes; equivalent weight of 

 guy-posts, etc., = 150 grammes applied at CP of the wing; equivalent load on wmg - 1175 grammes 

 = 2.585 pounds; area of wing = 21.85 square feet; equivalent load on wing = .11S3 pounds per square 

 foot. 



Angle of 

 chord. 



5.0° 



5.0° 



8.0" 



10.0° 



10.0° 



Revolutions 

 of turn- 

 table. 



11.025 



11.025 



10.5 



9.125 



9.125 



Velocity of 

 center of 

 wing (ft. 

 per mln.). 



1170 

 1170 

 1060 



919 



919 



Velocity 



ift. per 

 second I. 



19.5 

 19.5 

 17.7 

 15.3 

 15.3 



Drift 

 (grammes). 



250 



250 

 250 

 250 

 250 



Drift 



[pounds). 



0.55 

 0.55 

 0.55 

 0.55 

 0.55 



Foot- 

 pouuds 



per s< <■- 



1(1.72 



10.72 



9.75 



S.43 



8.43 



Calculated 



Boaring 



speed, 



carrying 0.6 



pounilfl per 

 sq it. 



I It. per sec). 



10.087 

 10 o 

 36 37 

 31.4 

 31.4 



During the tests on the whirling-table this type of construction seemed to 

 be exceedingly strong and stiff, and to be easily maintained in whatever posi- 

 tion it was placed. Tt was therefore thought that it would prove strong enough 

 for the aerodrome, and it was accordingly inverted and given a " sanding test ' 



