22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-6.6.3

PRECIPITATION DRAG OF SNOW AND STANDING WATER

M. Giesberts, J. Gooden
National Aerospace Laboratory (NLR), the Netherlands

Keywords: contamination, contaminated runway, precipitation spray, precipitation drag, snow, standing water, water spray model, contamrunway, amj 25x1591

Under contract with the European Commission (EC) Directorate General Transport (DG –VII) a consortium of Dassault Aviation, SAAB Civil Aircraft and the National Aerospace Laboratory (NLR) was to advice on the validity of the precipitation drag calculations in Joint Aviation Regulations (JAR) Advisory Material Joint (AMJ) 25X1591. The resulting project (CONTAMRUNWAY) contained both a theoretical study as well as the execution and analysis of test runs. NLR’s Cessna Citation II, a Dassault Falcon 2000 and a SAAB 2000 research aircraft were tested on a runway contaminated with either standing water or loose snow as part of CONTAMRUNWAY study. Unbraked rolling tests were performed through precipitation in order to obtain data on the precipitation drag. Hydroplaning phenomena were investigated during the tests in standing water. For both water and snow conditions the results indicate that the total precipitation drag for commuter and business type of aircraft is higher than the drag predicted by the theory in the AMJ 25X1591. Spray patterns observed during the water tests contacted the airframe considerably more than the AMJ 25X1591 assumed due to the smaller type of aircraft used.. Analysis of the snow results showed that the AMJ 25X1591 has a physically incorrect model for snow drag prediction. A new model is presented to replace the existing theory on snow drag prediction in the AMJ. This paper will discuss the preparation and execution of the flight tests, the results from the data collected and the theory developed.

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