The Use of Wheel Brakes on Airplanes

The results of tests to determine the effect of wheel brakes on the landing run of an airplane under conditions of load and at various wind velocities are presented

Drag of Prestone and Oil Radiators on the YO-31A Airplane

At the request of the Army Air Corps tests were conducted on a mock-up of the YO-31A airplane to determine the drag of the prestone and oil radiators. The drag of the airplane was determined with both radiators exposed on the lower surface of the fuselage; with each radiator exposed; and with no radiators. The results show that at 120 m.p.h the oil radiator accounted for 2.8 percent of the drag of the complete airplane; the prestone radiator 8.3 percent; and both radiators together, 11.8 percent

The Aerodynamic Effect of a Retractable Landing Gear

Tests were conducted in the N.A.C.A. full scale wind tunnel at the request of the Army Air Corps to determine the effect of retractable landing gear openings in the bottom surface of a wing upon the characteristics of a Lockheed Altair airplane. The tests were extended to include the determination of the lift and drag characteristics throughout the angle-of-attack range with the landing gear both retracted and extended. Covering the wheel openings in the wing with sheet metal when the wheels were extended reduced the drag only 2 percent at a lift coefficient of 1.0, which was assumed for the take-off condition. Therefore, the wheel openings in the bottom side of the wing have a negligible effect upon the take-off of the airplane. Retracting the landing gear reduced the minimum drag of the complete airplane 50 percent

The NACA full-scale wind tunnel

This report gives a complete description of the full-scale wind tunnel of the National Advisory Committee for Aeronautics

Effect of the Surface Condition of a Wing on the Aerodynamic Characteristics of an Airplane

In order to determine the effect of the surface conditions of a wing on the aerodynamic characteristics of an airplane, tests were conducted in the N.A.C.A. full-scale wind tunnel on the Fairchild F-22 airplane first with normal commercial finish of wing surface and later with the same wing polished. Comparison of the characteristics of the airplane with the two surface conditions shows that the polish caused a negligible change in the lift curve, but reduced the minimum drag coefficient by 0.001. This reduction in drag if applied to an airplane with a given speed of 200 miles per hour and a minimum drag coefficient of 0.025 would increase the speed only 2.9 miles per hour, but if the speed remained the same, the power would be reduced 4 percent

Grass Growth Profiles in Brittany

For farmers, knowing the local grass growth profile and the possible variations between years is very helpful in managing grazing. Indeed, the comparison with herd needs and anticipated farm cover change allows decisions to be made that will maintain the cover at the desired level. This paper proposes a ten-days grass growth profile corresponding to Brittany’s different conditions of soil, climate and pasture management

Pressure Distribution on the C-7 Airship

This investigation was made for the purpose of determining the aerodynamic pressure distribution encountered on a "C" class airship in flight. It was conducted in two parts: (a) tests on the tail surfaces in which the pressures at 201 points were measured and (b) tests on the envelope in which 190 points were used, both tests being made under as nearly identical flight conditions as possible, so that the results could be combined and the pressure distribution over the entire airship obtained