Narrative:

I departed runway 23 in my stinson 108-2 with 1 passenger. My destination was approximately 15 mi northeast; so I turned left crosswind and then left downwind on runway 23 to depart to the northeast. I was just clearing the pattern and at about 1500 ft AGL when I noticed a blur cross from left to right - likely a small bird. It appeared to fly right into the propeller arc and I immediately felt a thump in the airframe. There was no evidence of the impact immediately; but only seconds later there was a severe shudder from the engine and there was a significant loss of power. I immediately commenced a left turn to point back toward the runway and lowered the nose to capture best glide. I then announced my situation and intentions on the CTAF. Once I determined that I had sufficient altitude to make the runway I briefly troubleshot - moving the throttle brought almost no response from the engine; it continued to shake noticeably so I left it at idle. Rolling out on final I selected the first notch of flaps and maintained my glide speed. I made small s-turns approaching the threshold of the runway to work off a small margin of excess altitude and then selected full flaps over the numbers. As I touched down the propeller stopped turning entirely and I safely and uneventfully rolled out to the end of the runway. Postflt teardown of the engine revealed a failed valve in one cylinder that caused the subsequent failure of the piston in that cylinder.

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Original NASA ASRS Text

Title: STINSON 108 LOST POWER DURING CLIMBOUT AND RETURNED FOR EMER LNDG.

Narrative: I DEPARTED RWY 23 IN MY STINSON 108-2 WITH 1 PAX. MY DEST WAS APPROX 15 MI NE; SO I TURNED L XWIND AND THEN L DOWNWIND ON RWY 23 TO DEPART TO THE NE. I WAS JUST CLRING THE PATTERN AND AT ABOUT 1500 FT AGL WHEN I NOTICED A BLUR CROSS FROM L TO R - LIKELY A SMALL BIRD. IT APPEARED TO FLY RIGHT INTO THE PROP ARC AND I IMMEDIATELY FELT A THUMP IN THE AIRFRAME. THERE WAS NO EVIDENCE OF THE IMPACT IMMEDIATELY; BUT ONLY SECONDS LATER THERE WAS A SEVERE SHUDDER FROM THE ENG AND THERE WAS A SIGNIFICANT LOSS OF PWR. I IMMEDIATELY COMMENCED A L TURN TO POINT BACK TOWARD THE RWY AND LOWERED THE NOSE TO CAPTURE BEST GLIDE. I THEN ANNOUNCED MY SITUATION AND INTENTIONS ON THE CTAF. ONCE I DETERMINED THAT I HAD SUFFICIENT ALT TO MAKE THE RWY I BRIEFLY TROUBLESHOT - MOVING THE THROTTLE BROUGHT ALMOST NO RESPONSE FROM THE ENG; IT CONTINUED TO SHAKE NOTICEABLY SO I LEFT IT AT IDLE. ROLLING OUT ON FINAL I SELECTED THE FIRST NOTCH OF FLAPS AND MAINTAINED MY GLIDE SPD. I MADE SMALL S-TURNS APCHING THE THRESHOLD OF THE RWY TO WORK OFF A SMALL MARGIN OF EXCESS ALT AND THEN SELECTED FULL FLAPS OVER THE NUMBERS. AS I TOUCHED DOWN THE PROP STOPPED TURNING ENTIRELY AND I SAFELY AND UNEVENTFULLY ROLLED OUT TO THE END OF THE RWY. POSTFLT TEARDOWN OF THE ENG REVEALED A FAILED VALVE IN ONE CYLINDER THAT CAUSED THE SUBSEQUENT FAILURE OF THE PISTON IN THAT CYLINDER.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.