Motor, horsepower, 80: revolutions per minute, 1,277.
Diameter of propeller, 8 feet.
Load of 39 gallons gasoline, 2½ gallons oil.
Flying radius with normal equipment, two persons, 300 miles.
Maximum altitude obtained with this model at San Diego, 13,000 feet.
Wing-spread, tip to tip, upper, 38 feet, 10 inches; lower, 34 feet, 10 inches.
Supporting area, upper, 139 square feet; lower, 165 square feet; total, 364 square feet.
Length of fuselage from rear of propeller hub, 21 feet, 6¾ inches.
Data from Major F. P. Lahm, Signal Corps, U. S. A.
Dated May 9, 1916.
Fig. 14. “Trimming” a Tractor in Leaving the Ground
Photographed October, 1915
Military Tractor No. 50 just before leaving the ground. In gusty weather the mechanicians steady the ends of the lower planes, sometimes turning it by holding one edge and pushing the other. In the photograph the mechanicians are giving the airplane steerageway to the right.
Fig. 15. Military Tractor No. 50 Just Leaving the Ground
Photographed October, 1915
Before attempting to leave the ground there is always considerable jockeying for a favorable head-wind, and the photograph shows Instructor Brindley maneuvering for a favorable pointing.
After leaving the ground, the wind, so long as it is not gusty, makes no difference to the pilot.
