Accession Number : ADA140918

Title :   Studies of Contaminated Runways,


Personal Author(s) : Fristedt,K ; Norrbom,B

PDF Url : ADA140918

Report Date : Jan 1980

Pagination or Media Count : 60

Abstract : The report describes the friction forces acting in the tyre-ground contact area during braking and how these forces are influenced by different parameters. It appears possible to avoid most cases of water- and slush-planning by constructing the runways with a harsh microstructure and an open coarse macrostructure. The report contains comparative measurements between aircraft and brake number measuring vehicles equipped with different types of tyres. These measurements were mostly done during winter conditions. On runways with attached dry deposits, also compacted snow and ice at low temperature, the results show that current vehicles measure brake numbers representative of aircraft, even if large differences in parameter values between the vehicles and the aircraft exist. On attached dry deposits the brake number of a tyre is not seriously dependent of speed, inflation pressure, etc. On loose contaminations such as water, slush or wet snow on the contrary the brake numbers are speed dependent and are also influenced by the tyre inflation pressure, the geometry of the footprint and its deflection, the combined tyre runway drainage capability, etc. From the results it appears possible to get a reasonable correlation also in the latter case if such parameters as speed, inflation pressure, slip ratio are relatively equal in both the measuring tyre and the aircraft tyres.

Descriptors :   *Aircraft tires, *Runways, Contaminants, Snow, Ice, Force(Mechanics), Friction, Surface roughness, Microstructure, Braking, Transport aircraft, Test vehicles, Water, Field tests, Sweden

Subject Categories : Transport Aircraft
      Terminal Flight Facilities

Distribution Statement : APPROVED FOR PUBLIC RELEASE