L17A PLT HAS GEAR UP LNDG AT OPF.

Narrative

I WAS FLYING DOWNWIND IN THE PATTERN; AT 1000 FT; WITH A HDG OF 090 DEGS. TWR HAD ADVISED OF A SIGN-TOWING ACFT DEPARTING. THIS AIRPLANE WAS APPROX AT MY ALT WITH A VERY LARGE SIGN TOWED LOW AND BEHIND THE ACFT. I KEPT CLOSE VISUAL TO SEE IF I WOULD SAFELY PASS IN FRONT OF THE ACFT AND DID NOT FEEL THIS WAS A GOOD AVENUE. SO; I CALLED THE TWR AND ADVISED I COULD DSND AND FLY UNDERNEATH. TWR ADVISED OK AND I IMMEDIATELY DSNDED TO APPROX 700 FT WHILE TURNING BASE. THE WINDS WERE OUT OF THE NW AT APPROX 10-15 KTS; SO I COMPLETED A TURN R ONTO FINAL WITH THE ACFT IN A CRABBING POS SO AS NOT TO BE BLOWN OFF COURSE FOR THE RWY. I HAD ALREADY MADE UP MY MIND AT THE BEGINNING OF THIS TKOF THAT I WOULD BE USING FULL FLAPS FOR LNDG; TO PRACTICE THIS TECHNIQUE. ON FINAL; I FOUND MYSELF APPROX 500 FT OVER THE END OF THE RWY; AT WHICH TIME I LOWERED FULL FLAPS AND HELD AN 80 MPH DSCNT. ABOUT 15 FT OFF THE RWY; I FLARED FOR A MAIN WHEEL LNDG AND SLOWED THE ACFT TO APPROX 50 MPH. EXPECTING A VERY SLOW AND SMOOTH ROLL ONTO THE RWY; I BELLIED THE ACFT IN AS THE GEAR WAS NOT LOWERED. THE ACFT DID NOT SUFFER SUBSTANTIAL DAMAGE. UPON REVIEW OF THE SIT; I BELIEVE 2 SCENARIOS WOULD HAVE PREVENTED THIS OCCURRENCE: 1) UPON COMPLETION OF PASSING UNDERNEATH THE TOW PLANE; CONTINUE ON AN EXTENDED DOWNWIND; REGAIN APPROX 200 FT OF ALT; AND RETURN TO MY CHKLIST; AS ON DOWNWIND THE GEAR WOULD HAVE BEEN LOWERED WITH PLENTY OF TIME FOR ALL PROCESSES TO HAVE OCCURRED. 2) UPON REALIZING THAT THE TWR HAD 2 ACFT INTERSECTING AT THE SAME ALT; REQUEST A 360 DEG TURN.