f1rocket
Well Known Member
Okay, this is the debate section, right? So let's entertain a discussion regarding alternative engine options.
I did a little research. I looked at all the RV accident reports for 2004 and pulled all the "engine problem" ones. I found 7 accidents. 5 of the seven involved Lycoming engines, 1 involved a Subaru, and 1 involved a Chevy V8.
Within those categories, I looked at final reports to see the root cause of the engine problem. On the Lycoming, 1 is a preliminary report so I don't know. 3 were caused by fuel exhaustion, 1 by a oil cooler line failure. None were caused by any internal engine problem. The Subaru went down due to vapor lock at cruise. The Chevy went down because of internal engine failure of the main bearings.
What can one derive from this? Not much really, but you can extrapolate some indications. When you consider the tens of thousands of hours put on Lycomings each year, it sure looks like the Lycomings are pretty reliable as long as you feed it fuel and oil. When you consider the very small number of hours put on alternative engines in a year, the picture is less rosy.
I guess that's my point. If you chose to drop an alternative engine in your RV, be sure you're willing to accept the proposition that you are a powerplant test pilot. Just because there's a few Subarus, Mazdas, and Chevys flying successfully, doesn't necessarily mean that your usage will be trouble free. There aren't enough hours put on these engine to derive any meaningful statistical conclusion as to their reliability. I'm not saying that they aren't reliable, and I'm not saying that they are. The point is there's no numbers to prove it one way or the other. If you can live with that, then go ahead and experiment.
One of the reasons folks choose the Subaru package, in particular, is cost. I suspect, but would like to see some hard numbers, that when its all said and done, you will likely have nearly as much money in a Subaru package as you will in a Lycoming. And don't quote me prices on the NEW Lycoming, because you're not getting a NEW Subaru either. You're getting one out of a salvaged automobile. When you consider resale value of your RV, I bet that Subaru will cost you much more money in the long run.
I'm a chicken, I admit it. When it comes to swinging the prop around, I don't mess around much. People have been trying to convert auto engines for aviation use since the 1960s. Personally, I don't think there's any magic out there to be uncovered. I have confidence in my building skills so I'm not afraid of pulling the wings off or losing my tail feathers. But when the prop stops turning, I have a big problem and a heavy glider on my hands.
I think there's more promise with newer designs like the diesel and turbine engine prototypes. In the meantime, I think I'll stick with what has a proven track record of reliability. I admire all you test pilots, and I hope your projects are very successful and safe.
I did a little research. I looked at all the RV accident reports for 2004 and pulled all the "engine problem" ones. I found 7 accidents. 5 of the seven involved Lycoming engines, 1 involved a Subaru, and 1 involved a Chevy V8.
Within those categories, I looked at final reports to see the root cause of the engine problem. On the Lycoming, 1 is a preliminary report so I don't know. 3 were caused by fuel exhaustion, 1 by a oil cooler line failure. None were caused by any internal engine problem. The Subaru went down due to vapor lock at cruise. The Chevy went down because of internal engine failure of the main bearings.
What can one derive from this? Not much really, but you can extrapolate some indications. When you consider the tens of thousands of hours put on Lycomings each year, it sure looks like the Lycomings are pretty reliable as long as you feed it fuel and oil. When you consider the very small number of hours put on alternative engines in a year, the picture is less rosy.
I guess that's my point. If you chose to drop an alternative engine in your RV, be sure you're willing to accept the proposition that you are a powerplant test pilot. Just because there's a few Subarus, Mazdas, and Chevys flying successfully, doesn't necessarily mean that your usage will be trouble free. There aren't enough hours put on these engine to derive any meaningful statistical conclusion as to their reliability. I'm not saying that they aren't reliable, and I'm not saying that they are. The point is there's no numbers to prove it one way or the other. If you can live with that, then go ahead and experiment.
One of the reasons folks choose the Subaru package, in particular, is cost. I suspect, but would like to see some hard numbers, that when its all said and done, you will likely have nearly as much money in a Subaru package as you will in a Lycoming. And don't quote me prices on the NEW Lycoming, because you're not getting a NEW Subaru either. You're getting one out of a salvaged automobile. When you consider resale value of your RV, I bet that Subaru will cost you much more money in the long run.
I'm a chicken, I admit it. When it comes to swinging the prop around, I don't mess around much. People have been trying to convert auto engines for aviation use since the 1960s. Personally, I don't think there's any magic out there to be uncovered. I have confidence in my building skills so I'm not afraid of pulling the wings off or losing my tail feathers. But when the prop stops turning, I have a big problem and a heavy glider on my hands.
I think there's more promise with newer designs like the diesel and turbine engine prototypes. In the meantime, I think I'll stick with what has a proven track record of reliability. I admire all you test pilots, and I hope your projects are very successful and safe.