July 18, 2015
Guys,
N721WD at start of Phase I.
This is my story.
*I took-off at 9:30 local time on May 30, 2015 *for more Phase I hours (The Hobbs was 16.8 at takeoff). *My flight plan was to check out the AP systems and record cruise speeds at 5000 Ft. *
I activated the Dynon AP at 5000 Ft for the first time and it just worked. *I tried LEVEL , TRK & ALT and 180 Degree turn and everything worked as advertised.*
Since I had the AP working, I set up a racetrack parallel to the 22/04 runway at KMMV, *offset about 5 miles to the South. *I would fly west on a 220 TRK (Track) then hit the 180 *button (Reverses the Track 180 degrees) and fly back on the 040 TRK , repeat, repeat. *I set the rpm to 2200, allowed the AP to stabilize and recorded air speeds and fuel flows, repeated several times in a circuit then increase to 2300 rpm and repeat, then at 2400 rpm, then at 2500 rpm. *
I was nearing completion of the day and starting the final set of 2500 rpm laps, when all **** broke loose. *There was a loud bang and every thing started shaking violently. *
My Instructor?s training was to first point the nose to the nearest field, then go to Idle and finally establish best glide. *Then start to worry about what happened. *In less than 30 sec *Oil Pressure was at near zero . *I was still at speed and the prop was windmilling at about 2000 rpm. As the field looked far away, I increased the throttle to maintain the 2000 rpm and decided to let it run as long as it would and hoped it would not freeze up before I was down. *
The 35 runway at KMMV was nearly a straight shot from my location, but approximately five miles away. *I knew it was going to be close, but by increasing power to maintain the 2000 rpm it worked out. *I kept power on until I had the runway made, *then started dropping the flaps and touched down. *The engine did not freeze up. *When I stopped and got out, *oil was pouring out of the lower cowl. * After pulling the upper cowl the two large and gaping holes in both sides of the crankcase were very obvious. *The crankcases, the cam, the connecting rod for #3 all appear to be trashed. *I found several metal chunks on the Cyl fins. *Something flew out hard enough the break the Lightspeed ignition coil case which was mounted above the engine.*
Note: The crankcase hole beside the #4 Cyl.
Note: The hole in the crankcase above the #3 Cyl.
http://kmmvphoto.smugmug.com/photos/i-CN8nHwk/0/M/i-CN8nHwk-M.jpg
This photo shows the failed end of the Connecting Rod bolt. *Because the bolt backed out ~1/4 inch the failure plane is difficult to photograph.
This Photo shows the Connecting Rod Bolt that has backed out ~1/4 inch. *The photo is taken through the crankcase hole over #3 Cyl.
Note the remaining stub of the missing Connecting Rod ~ 1 inch tall.
Total Hobbs 18.4 hours at the end of the flight.
N721WD after the May 30, 2015 engine failure. The engine has been removed to return to Lycoming.
*It appears the #3 Connecting Rod Failed at 2500 rpm in level AP controlled flight. *I had been at 5000 Ft at 2500 rpm for ~ three minutes since the last control input by me. *
Bill
Guys,
N721WD at start of Phase I.
This is my story.
*I took-off at 9:30 local time on May 30, 2015 *for more Phase I hours (The Hobbs was 16.8 at takeoff). *My flight plan was to check out the AP systems and record cruise speeds at 5000 Ft. *
I activated the Dynon AP at 5000 Ft for the first time and it just worked. *I tried LEVEL , TRK & ALT and 180 Degree turn and everything worked as advertised.*
Since I had the AP working, I set up a racetrack parallel to the 22/04 runway at KMMV, *offset about 5 miles to the South. *I would fly west on a 220 TRK (Track) then hit the 180 *button (Reverses the Track 180 degrees) and fly back on the 040 TRK , repeat, repeat. *I set the rpm to 2200, allowed the AP to stabilize and recorded air speeds and fuel flows, repeated several times in a circuit then increase to 2300 rpm and repeat, then at 2400 rpm, then at 2500 rpm. *
I was nearing completion of the day and starting the final set of 2500 rpm laps, when all **** broke loose. *There was a loud bang and every thing started shaking violently. *
My Instructor?s training was to first point the nose to the nearest field, then go to Idle and finally establish best glide. *Then start to worry about what happened. *In less than 30 sec *Oil Pressure was at near zero . *I was still at speed and the prop was windmilling at about 2000 rpm. As the field looked far away, I increased the throttle to maintain the 2000 rpm and decided to let it run as long as it would and hoped it would not freeze up before I was down. *
The 35 runway at KMMV was nearly a straight shot from my location, but approximately five miles away. *I knew it was going to be close, but by increasing power to maintain the 2000 rpm it worked out. *I kept power on until I had the runway made, *then started dropping the flaps and touched down. *The engine did not freeze up. *When I stopped and got out, *oil was pouring out of the lower cowl. * After pulling the upper cowl the two large and gaping holes in both sides of the crankcase were very obvious. *The crankcases, the cam, the connecting rod for #3 all appear to be trashed. *I found several metal chunks on the Cyl fins. *Something flew out hard enough the break the Lightspeed ignition coil case which was mounted above the engine.*
Note: The crankcase hole beside the #4 Cyl.
Note: The hole in the crankcase above the #3 Cyl.
http://kmmvphoto.smugmug.com/photos/i-CN8nHwk/0/M/i-CN8nHwk-M.jpg
This photo shows the failed end of the Connecting Rod bolt. *Because the bolt backed out ~1/4 inch the failure plane is difficult to photograph.
This Photo shows the Connecting Rod Bolt that has backed out ~1/4 inch. *The photo is taken through the crankcase hole over #3 Cyl.
Note the remaining stub of the missing Connecting Rod ~ 1 inch tall.
Total Hobbs 18.4 hours at the end of the flight.
N721WD after the May 30, 2015 engine failure. The engine has been removed to return to Lycoming.
*It appears the #3 Connecting Rod Failed at 2500 rpm in level AP controlled flight. *I had been at 5000 Ft at 2500 rpm for ~ three minutes since the last control input by me. *
Bill