SMT PLT FAILS TO EXTEND THE LNDG GEAR AND DAMAGES PROPS DURING SUBSEQUENT GAR.

Narrative

DURING A VFR APCH TO A LNDG AT THE NOORVIK ARPT; I FAILED TO COMPLETE THE BEFORE LNDG CHKLIST. THE APCH WAS MADE WITH THE GEAR UP. UPON PWR REDUCTION IN THE FLARE THE GEAR WARNING HORN SOUNDED. THIS IS A STEADY HORN IN THE SMT A IDENTICAL TO THE STALL WARNING HORN IN THE FIXED GEAR SMT B THAT I HAD BEEN FLYING THE DAY BEFORE. MY INITIAL REACTION WAS THAT IT WAS A STALL WARNING HORN AND WAS OF NO CONSEQUENCE. A SECOND LATER I REALIZED IT WAS THE GEAR WARNING HORN AND IMMEDIATELY APPLIED TKOF PWR. THE AIRPLANE HAD BY THIS TIME DSNDED LOW ENOUGH FOR THE PROP TIPS AND THE TRAILING EDGE OF THE LOWERED FLAPS TO COME IN CONTACT WITH THE GND. THE ENGS CONTINUED TO RUN SMOOTHLY AND THE SUBSEQUENT LNDG AT A NEARBY FULL SVC ARPT (OTZ) WAS UNEVENTFUL. I BELIEVE A MAJOR CONTRIBUTING FACTOR TO THE INCIDENT IS A GEAR WARNING HORN THAT IS IDENTICAL TO THE STALL WARNING HORN IN ALMOST ALL FIXED GEAR AIRPLANES. THE STALL WARNING HORN IN THE SMT A IS AN INTERMITTENT HORN. ALSO; THE GEAR WARNING HORN DOES NOT SOUND UNTIL THE THROTTLES ARE RETARDED TO ALMOST IDLE (12 INCH MANIFOLD PRESSURE). WITH ANY WT IN THE AIRPLANE; LNDGS ARE ROUTINELY MADE WITH 15 INCH MANIFOLD PRESSURE. THE PRIMARY FACTOR WAS; OF COURSE; FAILURE TO COMPLETE THE CHKLIST.