ADVANCED INSTRUMENTATION FOR AIRCRAFT ICING RESEARCH

RESEARCH AND DEVELOPMENT OF ADVANCED LASER-BASED DIAGNOSTICSFOR THE DETERMINATION OF DROP SIZE SPECTRA AND LIQUID WATER CONTENT (LWC) FOR AIRCRAFT ICING RESEARCH IS PROPOSED. THISEFFORT WILL LEAD TO THE DEVELOPMENT OF INSTRUMENTS THAT ARE SUITABLE FOR OBTAINING RELIABLE DATA IN LARGE SCALE ICING RESEARCH TUNNELS AND AIRBORNE CLOUD MEASUREMENTS. SUCH DATAARE FUNDAMENTALS TO THE RESEARCH IN AIRCRAFT ICING AND ULTIMATELY, TO THE DEVELOPMENT OF ADVANCED ALL-WEATHER AIRCRAFT WITH EFFICIENT ICE PROTECTION TECHNOLOGY. AT THE PRESENT TIME, FLIGHT TESTS ARE REQUIRED IN ACTUAL ATMOSPHERIC CONDITIONS TO CERTIFY AIRCRAFT. THESE TESTS ARETIME-CONSUMING, RISKY, AND COSTLY. SIMULATIONS OF ICING CONDITIONS IN WIND TUNNELS HAVE NOT BEEN COMPLETELY SATISFACTORY. THE PROBLEM MAY BE TRACED TO THE INADEQUACY OF THE AVAILABLE INSTRUMENTATION. THUS, A PROGRAM IS PROPOSED TO INVESTIGATE THE POSSIBILITY OF UTILIZING THE RECENTLY DEVELOPED PHASE DOPPLER PARTICLE ANALYZER (PDPA) INOBTAINING THESE DATA. BECAUSE OF THE NEED TO MAKE DROP SIZEDISTRIBUTION AND LWC MEASUREMENTS WITHIN THE LARGE SCALE (6' X 9') ICING RESEARCH TUNNELS AND FROM AIRCRAFT, THE USE OF FIBER OPTICS PROBES WILL BE CONSIDERED. A FIBER OPTICS LINK WILL ALLOW THE USE OF COMPACT ROBUST PROBES THAT WILL BE IMMUNE FROM ELECTRONIC NOISE. CRITICAL QUESTIONS ON THE ABILITY TO COUPLE THE LASER BEAMS INTO SINGLE MODE FIBERS AND MAINTAIN ALIGNMENT IN ACOUSTICALLY NOISY AND VIBRATIONAL ENVIRONMENTS WILL BE ADDRESSED.