Perhaps the severest and most exacting critic of aviation material is the aviator who has to fly the plane and fight with the equipment at the front. Brig. Gen. William Mitchell, then a colonel, was sent to France in 1917. He became in succession chief of the air service of the First Army Corps, chief of the air service of the First Army, and finally chief of the air service of the American group of armies in France. He commanded the aerial operations at the reduction of the St. Mihiel salient, where he gained the distinction of having commanded more airplanes in action than were ever assembled before under a single command. At St. Mihiel there were 1,200 allied planes in action, including, with our own, French, English, and Italian planes.

Gen. Mitchell, therefore, is a high authority as to the relative merits of air equipment from the airman's standpoint. In the spring of 1919, after a thorough investigation of the latest types of American planes and aerial equipment at the Wilbur Wright Field at Dayton, he sent to the Director of Air Service, Washington, D. C., the following telegram under date of April 20, 1919:

I recommend the following airplanes in the numbers given be purchased at once: 100 Lepere 2-place corps observation, 50 Loening 2-place pursuit, 100 Ordnance Engineering Corporation 1-place pursuit, 100 Thomas-Morse 1-place pursuit, 50 USD9-A day bombardment, 700 additional Hispano-Suiza 300-horsepower engines, 2,000 parachutes. All of the above types are the equal of or better than anything in Europe.

Mitchell.

Now, let us see some of the specifications and performances of these new models. The USD9-A, being the redesigned and improved De Haviland 4, may be given a place as a latest model. It is a two-place bombing plane of the tractor biplane type, equipped with a Liberty 12 engine and weighing 4,872 pounds, loaded with fuel, oil, guns, and bombs, and with its crew aboard. With this weight its performance record in the official tests at Wilbur Wright Field in Dayton was as follows:

Speed (miles per hour):
At ground121.5
At 6,500 feet118.5
At 10,000 feet115.5
At 15,000 feet95.5
Climb:
To 6,500 feet, time11 minutes 40 seconds.
To 10,000 feet, time19 minutes 30 seconds.
To 15,000 feet, time49 minutes.
Service ceilings (feet)14,400

The Lepere C-11, a tractor biplane equipped with a Liberty 12 engine, Packard make, weighing with its load aboard 3,655 pounds, performed as follows in the tests at the Wilbur Wright Field:

Speed (miles per hour):
At ground136
At 6,500 feet130
At 10,000 feet127
At 16,000 feet118
Climb:
To 6,500 feet, time 6 minutes.
To 10,000 feet, time10 minutes 35 seconds.
To 15,000 feet, time19 minutes 15 seconds.
Service ceiling (feet)21,000
Endurance at full speed at ground (hours)2.5

The Lepere carries two Marlin guns synchronized with the propeller and operated by the pilot and two Lewis guns operated by the observer. A total of 1,720 rounds of ammunition is carried.