PLT OF SMA REPORTS NMAC IN PATTERN WITH HELI FLYING NON-STANDARD RIGHT HAND PATTERNS AND NOT RESPONDING TO CTAF TRANSMISSIONS.

Narrative

I SET UP AND ENTERED A DOWNWIND APCH TO RWY 17. A HELI CALLED 'DEPARTING 17.' I THEN MADE A RADIO CALL THAT I WAS DOWNWIND RWY 17. I FLEW A TIGHT PATTERN (ROUGHLY 1/2 MI) TO AVOID A COLLISION IN THE TFC PATTERN; IF (I WAS UNKNOWN TO THE HELI'S INTENTIONS) THE HELI WAS GOING TO REMAIN IN THE TFC PATTERN. AFTER I TURNED AND THEN CALLED FOR THE BASE LEG; I HEARD THE HELI CALL DOWNWIND RWY 17 NONSTANDARD PATTERN WITH R TURN; WHILE I WAS IN A STANDARD PATTERN WITH L TURNS; BUT WAS UNABLE TO FIND THE HELI IN THE PATTERN. I THEN TURNED FINAL AND WAS ON A VERY SHORT FINAL WHEN I HEARD THE HELI MAKE A RADIO CALL FOR BASE RWY 17. I LOOKED OUT MY R WINDOW TO SEE THE HELI 500 FT AND CLOSING. THE COURSE WAS NOT COLLISION; BUT WAS TOO CLOSE FOR COMFORT. I MADE THE RADIO CALL FOR SHORT FINAL RWY 17; AND AS I MADE THE CALL; THE HELI PERFORMED A 360 DEG TURN IN THE PATTERN FOR SPACING. AFTER THAT; THE HELIS MADE STANDARD TFC PATTERNS FOR THE REMAINDER OF THE DAY. THE SITUATION WAS CORRECTED; BUT PART OF THE PROB WAS THE HELI PLT NOT LISTENING TO OTHER RADIO CALLS. I HAVE BEEN FLYING AT LOW COUNTRY REGIONAL ARPT FOR 3 MONTHS AND HAVE HAD AT LEAST 1 NEAR MISS (MOST OF THEM IN OR NEAR THE TFC PATTERN) EVERY MONTH. LOW COUNTRY REGIONAL ARPT IS A BUSY ARPT FOR ALL TYPES; CATEGORY; AND CLASS OF ACFT. I FEEL AN ATC TWR WOULD ALLEVIATE THESE PROBS.