OBSERVATION OF NOVEMBER 20, 1891.OBSERVER, S.P.L.LOCALITY,UPPERHALL,SMITHSONIANBUILDING.No. 30.Single wings.No. 31.Superposed wings.CPm1516.5cm.CG115151517cm.CFw1528cm.Length (without fender)120cm. =3.94ft.120cm. =3.94ft.Width over wing tips120cm. =3.94ft.120cm. =3.94ft.Weight of rubber (72 grammes in each tube)144gr. =0.32lbs.144gr. =0.32lbs.Total flying weight (including tail)432gr. =0.95lbs.506gr. =1.11lbs.Turns of rubber3030Diameter of propellers37cm. =1.21ft.37cm. =1.21ft.Width of propellers7cm. =0.23ft.7cm. =0.23ft.Pitch of propellers50cm. =1.64ft.50cm. =1.64ft.Area of wings (each 992 sq.cm.)1984sq.cm.=2.13sq.ft.Each pair 1984 sq.cm.= 2.13 sq.ft. Total 3968 sq.cm.= 4.26 sq.ft.Area of tail373sq.cm.=0.40sq.ft.373sq.cm.=0.40sq.ft.Area of wings and tail in No. 30, 2357 sq. cm. = 2.53 sq. ft. 2.53 sq. ft. ÷ .95 = 2.7. Therefore, there are 2.7 or nearly 3 square feet of sustaining area to the pound.
Area of wings and tail in No. 30, 2357 sq. cm. = 2.53 sq. ft. 2.53 sq. ft. ÷ .95 = 2.7. Therefore, there are 2.7 or nearly 3 square feet of sustaining area to the pound.