A CL60 CREW; DEVIATING WX AT FL410; ENCOUNTERED HAIL; RESULTING IN A CRACKED OUTER LAYER OF THE L WINDSHIELD.

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AT FL410; ACFT CHALLENGER 604. WE KNEW THERE WAS WX IN THE AREA. WHEN WE SAW THE WX AHEAD; WE INITIATED A CLB TO FL410(ATC CLRED ALT) AND TRIED UTILIZING OUR RADAR. THE ACFT HAS ONLY 1 RADAR HEAD AND DOES NOT HAVE A STORM SCOPE FOR LIGHTNING DETECTION. THE RADAR WAS NOT DISPLAYING ANY WX; WHICH WE THOUGHT WAS STRANGE; SO WE BEGAN TO TRY DIFFERENT ANGLES AND DISTANCE. THEN 2 VERY SMALL RED DOTS PAINTED ON THE SCREEN AT ABOUT 50 MI AHEAD AND DISAPPEARED WITHIN A COUPLE OF SECONDS. WE WERE VERY SUSPECT OF THAT AND DECIDED TO TURN TO THE L; THE UPWIND SIDE OF THE SMALL AREA THAT HAD DISPLAYED THE RED DOTS. NOW ON A HDG APPROX 45 DEGS FROM OUR INITIAL COURSE AND LESS THAN 1 MIN FROM THE TIME OF THE TURN; WE WERE STILL NOT PAINTING ANY WX AND THEN STARTED GETTING HIT BY HAIL. THE L WINDSHIELD CRACKED AND SUBSEQUENT TURB AND STATIC OVER THE RADIOS. OXYGEN MASKS WERE PUT ON AND WE REQUESTED TO GET DOWN OUT OF FL410. THE FACE PLY ON THE WINDSHIELD WAS LOST (APPROX 18 INCHES BY 20 INCHES). WE DECIDED THAT WE NEEDED TO LAND ASAP. COMS WITH ATC AND MY COPLT WERE DIFFICULT BUT MANAGEABLE. TO MY KNOWLEDGE; THE COPLT NEVER DECLARED AN EMER OR SQUAWKED 7700 AND ATC ISSUED LOWER ALTS AND HDGS WHICH WE FOLLOWED. WE LANDED IN CRW AND WERE MET BY FIRE TRUCKS AND RESCUE VEHICLES. THE ACFT WINDSHIELD MAINTAINED INTEGRITY AND SECOND AND THIRD PLYS WERE OK. WE HAD NOT DECLARED AN EMER; BUT ATC DID PROVIDE PREFERENTIAL TREATMENT.