C150 EXPERIENCED NMAC WITH BIPLANE AT 52I UNCTLED ARPT.

Narrative

STUDENT AND I WERE PRACTICING SOFT FIELD TKOF AND LNDGS ON GRASS; RWY 27 AT 52I (GROSS FIELD; PINCONNING; MI; THE ONLY RWY). WE HAD DEPARTED IN CLOSED TFC WITH NO OTHER TFC SIGHTED OR HEARD ON CTAF (122.9). ON MIDFIELD DOWNWIND WE OBSERVED A SMALL BIPLANE COMING RIGHT AT US ON A XWIND FOR THE SAME RWY. IT APPEARED HE DIDN'T SEE US (WE WERE RIGHT IN FRONT OF HIM; NO VISIBILITY STRAIGHT AHEAD IN A PITTS TYPE SINGLE PLACE; AND I'M A PITTS S2B PLT SO I'M FAMILIAR WITH THIS TYPE OF ACFT) AND HE DIDN'T RESPOND TO RADIO CALLS. HE TURNED ONTO A DOWNWIND RIGHT BEHIND US (ESTIMATE 100 YARDS; SLIGHTLY ABOVE US) AND I IMMEDIATELY BROKE OFF DOWNWIND TO THE R; EXITING THE PATTERN IN A DIVING TURN TO ABOUT A 150 DEG HDG AS I ASSUMED THE ACFT WAS SETTING UP A DOWNWIND AND DIDN'T SEE US -- HE WAS EXACTLY WHERE YOU'D EXPECT HIM TO BE FOR DOWNWIND; IN CLOSE TO THE RWY (ABOUT 1/2 MI S OF THE FIELD). I COULDN'T GO L BACK ACROSS THE FIELD AS HE WAS JUST INSIDE US IN THE PATTERN AND THAT WOULD HAVE PUT US IN FRONT OF HIM. WE LOOKED BACK; NOW AT ABOUT 600 FT AGL AND SBOUND; AND HE WAS RIGHT BEHIND US; CHASING US. WE MADE A TURN BACK TO THE E; NOW ABOUT 2 MI S OF THE FIELD; AND HE AGAIN FOLLOWED US; VERY CLOSE. HE DID NOT RESPOND TO CALLS ON 122.9 OR 122.75. WE ENTERED A R 360 DEGS; HOPING HE WOULD FLY BY AND NOT FOLLOW US AROUND. WE LOST SIGHT OF HIM IN THE TURN. AS WE ROLLED OUT; AGAIN EBOUND AND WELL CLR OF THE PATTERN NOW TO THE SE; HE FLASHED BY 100 FT OR SO DIRECTLY IN FRONT OF US IN A L TURN -- I COULD ABOUT SEE THE PLT'S NOSE -- R TO L; WHICH MEANS HE MUST HAVE TRIED TO FOLLOW OUR R TURN; THEN CUT BACK ACROSS IN FRONT OF US ON A NORTHERLY HEADING. WE IMMEDIATELY WENT STRAIGHT TO THE FIELD AND LANDED; AS IT WAS OBVIOUS HE HAD NO INTENTION OF LNDG AND WAS CHASING US -- AND HE DIDN'T FOLLOW US DOWN. AFTER LNDG WE AGAIN SPOTTED HIM; OVERHEAD THE FIELD SBOUND AT ABOUT 1000 FT AGL; AND HE DIDN'T COME BACK. I CONTACTED LANSING FSS IMMEDIATELY AND RPTED THE INCIDENT. I RECOGNIZE THE ACFT. AS I DESCRIBE IT TO OTHER PLTS THEY HAVE DISTINCTLY REMEMBERED IT; BUT DO NOT KNOW THE PLT. IT IS DEFINITELY NOT A PITTS; BUT IS ABOUT THE SAME SIZE AS AN S1 SERIES PITTS. I DON'T KNOW THE N NUMBER OR THE HOME ARPT FOR THE ACFT; BUT I AM LOOKING AT THIS TIME AND HOPE TO BE ABLE TO RPT THE ACFT IDENTITY TO THE FSDO.