jcarleto
04-25-2011, 06:42 PM
To say that I am remarkably disappointed is perhaps the understatement of all understatements. The long and short of it is that I am back in rebuild mode, due to a critical failure in today's test flight. Before we get started, let me say that I am quite fine and no persons nor property were damaged in any way as a result of my unscheduled off-airport landing.
Those who follow my exploits know that I just put the Bulldozer back into service after a lengthy rebuild due to a keel crack caused by taxiing into a hole. In addition to replacing the keel, I replaced both masts, changing from collapsible 2-pice to solid 1 piece masts and made various adjustments to systems for either weight reduction or improved operation or performance (for example: changing from cable to hydraulic brakes).
I had already planned to do an extended test period of not less than 20 hours to accommodate the changes. Up to today, I had been pleased to find only a few minor adjustments and changes to trim to make things settle down. The overall performance was significantly improved over the original iteration and it looked like smooth sailing.
Lewis Gulley joined me at the airport this morning, as I was finalizing the SWR setting for the new antenna. I also had a loose ground wire in the strobe that I had to straighten out. Afterward, we both looked the machine over and virtually ran out of things to check. At this point, I had about 12 runway circuits and about 10 landings behind me for 2 hours of flight time. I'd fly off some more test time after lunch.
There was a nice 8-10 knot direct crosswind after lunch, so I decided to fly circuits with low passes. I flew two normal patterns. Everything was fine. Speeds were consistent, engine instruments were exactly as before. I decided to fly an extended pattern. The runway is surrounded by a wall of thick trees, so we generally fly a tight pattern just past the runway apron above the edge of the trees. By extended, I mean more like a FW pattern...about 1/4 mile past the end of the runway, then left about a 1/4 mile and so on. This puts one at "the other side" of the trees.
I started getting the idea there was something wrong as I climbed out past the end of the runway. I had throttled back to 4500 RPM, and it now showed 4400. I added a bit of throttle, thinking that the quadrant had vibrated back. It eased back to 4500. A moment or three later, it was back at 4400. I added throttle again, noticing that my quadrant was further forward than it should be. I said, "Back to the airport." I was over the trees.
Then my decision was made for me. There was a loud crack and some vibration. My power was gone, but the engine was running. I also had some stick shake. I never get stick shake. First things, first. I picked my landing target. Then I took inventory. I looked back at my prop. It was smaller than it should be and shook a lot if I added any power. OK, something went through the prop. I killed the engine. Rotor and rudder control was good...so...I'm landing in someone's front yard. I wonder if they have any tea.
It was tight, but I made a pretty good landing. They didn't have any tea, but were kind enough to let me sit on the porch and wait until Lewis got there with a trailer. Judging by the number of cameras, there are no doubt some pictures all over the web of my machine sitting in this guy's yard. His first question was, "Why did you land here?" I told him I didn't have a lot of choice and thanked him for not having more trees than he did.
So, what happened. Apparently, and further inspection is necessary to be certain, the starter bracked failed. It is a bracket integral to the Bob Kopp redrive, that holds the starter in position to contact the flywheel. The loud crack was the starter coming loose and contacting the prop. I may have a 4 blade PowerFin hub for sale, without blades, if it passes a dye check. My rotors are suspect. There are some suspicious dents on the bottom. Given that I experienced rotor shake in flight, some prop pieces may have gone through. I may have gotten a slight tail support strike on landing, though I didn't think the landing was hard. I did bend my nose-wheel bracket. I suspect my nose-wheel may have been turned sideways by the grass, as it is free-castoring wth a very light spring and I let the machine roll a moment on touchdown before I stopped it.
So...I have 3 knowns and an unknown. I know I will have to get a new prop..and am seriously considering a Tennessee prop. I am pretty sure the rotors will have to be replaced, though that is not absolutely certain yet and I must replace the nose-wheel bracket. The unknown is back at the starter. I won't know more until I get it apart.
A lot of people have advised me not to post. I understand that. I suppose there is more risk in going public with one's issues than with one's triumphs. However, in this instance I believe I did everything as properly as I could have done and caused no harm (other than to my wallet).
I believe testing is vital and that examples such as this should be made public to underscore just how vital it is to do significant testing. I truly wish that more people posted for issues with machines that we never hear about unless there is an injury or worse. But, as I said, I understand why they do not. It is difficult not to feel personal failure in a situation like this and that is an embarrassment.
I'll close with a sincere thank you to Rick Abercrombie, Steve McGowan and Lewis Gulley for all their knowledge and information and for instilling in me the need to constantly practice emergency procedures. By the way, lots of others have been singers of the same song and I do not mean to short-change anyone for the help and guidance I have received along the way...the list of people who preach practice of technique and emergency procedures is simply too long to list here.
Those who follow my exploits know that I just put the Bulldozer back into service after a lengthy rebuild due to a keel crack caused by taxiing into a hole. In addition to replacing the keel, I replaced both masts, changing from collapsible 2-pice to solid 1 piece masts and made various adjustments to systems for either weight reduction or improved operation or performance (for example: changing from cable to hydraulic brakes).
I had already planned to do an extended test period of not less than 20 hours to accommodate the changes. Up to today, I had been pleased to find only a few minor adjustments and changes to trim to make things settle down. The overall performance was significantly improved over the original iteration and it looked like smooth sailing.
Lewis Gulley joined me at the airport this morning, as I was finalizing the SWR setting for the new antenna. I also had a loose ground wire in the strobe that I had to straighten out. Afterward, we both looked the machine over and virtually ran out of things to check. At this point, I had about 12 runway circuits and about 10 landings behind me for 2 hours of flight time. I'd fly off some more test time after lunch.
There was a nice 8-10 knot direct crosswind after lunch, so I decided to fly circuits with low passes. I flew two normal patterns. Everything was fine. Speeds were consistent, engine instruments were exactly as before. I decided to fly an extended pattern. The runway is surrounded by a wall of thick trees, so we generally fly a tight pattern just past the runway apron above the edge of the trees. By extended, I mean more like a FW pattern...about 1/4 mile past the end of the runway, then left about a 1/4 mile and so on. This puts one at "the other side" of the trees.
I started getting the idea there was something wrong as I climbed out past the end of the runway. I had throttled back to 4500 RPM, and it now showed 4400. I added a bit of throttle, thinking that the quadrant had vibrated back. It eased back to 4500. A moment or three later, it was back at 4400. I added throttle again, noticing that my quadrant was further forward than it should be. I said, "Back to the airport." I was over the trees.
Then my decision was made for me. There was a loud crack and some vibration. My power was gone, but the engine was running. I also had some stick shake. I never get stick shake. First things, first. I picked my landing target. Then I took inventory. I looked back at my prop. It was smaller than it should be and shook a lot if I added any power. OK, something went through the prop. I killed the engine. Rotor and rudder control was good...so...I'm landing in someone's front yard. I wonder if they have any tea.
It was tight, but I made a pretty good landing. They didn't have any tea, but were kind enough to let me sit on the porch and wait until Lewis got there with a trailer. Judging by the number of cameras, there are no doubt some pictures all over the web of my machine sitting in this guy's yard. His first question was, "Why did you land here?" I told him I didn't have a lot of choice and thanked him for not having more trees than he did.
So, what happened. Apparently, and further inspection is necessary to be certain, the starter bracked failed. It is a bracket integral to the Bob Kopp redrive, that holds the starter in position to contact the flywheel. The loud crack was the starter coming loose and contacting the prop. I may have a 4 blade PowerFin hub for sale, without blades, if it passes a dye check. My rotors are suspect. There are some suspicious dents on the bottom. Given that I experienced rotor shake in flight, some prop pieces may have gone through. I may have gotten a slight tail support strike on landing, though I didn't think the landing was hard. I did bend my nose-wheel bracket. I suspect my nose-wheel may have been turned sideways by the grass, as it is free-castoring wth a very light spring and I let the machine roll a moment on touchdown before I stopped it.
So...I have 3 knowns and an unknown. I know I will have to get a new prop..and am seriously considering a Tennessee prop. I am pretty sure the rotors will have to be replaced, though that is not absolutely certain yet and I must replace the nose-wheel bracket. The unknown is back at the starter. I won't know more until I get it apart.
A lot of people have advised me not to post. I understand that. I suppose there is more risk in going public with one's issues than with one's triumphs. However, in this instance I believe I did everything as properly as I could have done and caused no harm (other than to my wallet).
I believe testing is vital and that examples such as this should be made public to underscore just how vital it is to do significant testing. I truly wish that more people posted for issues with machines that we never hear about unless there is an injury or worse. But, as I said, I understand why they do not. It is difficult not to feel personal failure in a situation like this and that is an embarrassment.
I'll close with a sincere thank you to Rick Abercrombie, Steve McGowan and Lewis Gulley for all their knowledge and information and for instilling in me the need to constantly practice emergency procedures. By the way, lots of others have been singers of the same song and I do not mean to short-change anyone for the help and guidance I have received along the way...the list of people who preach practice of technique and emergency procedures is simply too long to list here.