Aerovee turbo vs. O-200

I wonder if an Aerovee turbo is a reasonable substitute for a O-200A. They supposedly have the same horsepower rating, though vendor of the Aerovee Turbo claims that it does not lose power as fast when going up in altitude when compared to a naturally aspirated engine. I live at an altitude of about 4300 feet (about 1300 meters).

There is a partially completed Davis DA-2 for sale locally, without motor. That aircraft normally takes a O-200A, but I was wondering if a Aerovee turbo would work OK in that aircraft.

By the way, the Sonex looks a lot like the Davis DA-2. I wonder if the Sonex design was inspired at least in part by the DA-2.

Your best bet might be to checkout Sonexbuilders.net The very first AV turbos had some issues, but I’d like to think they’ve been resolved. But I don’t know for sure.

People with extensive experience with VW engines will tell you that 65 HP or thereabouts is about the maximum sustained power setting for the engine unless you want to overheat and cook it relatively quickly. Unless AeroVee could show data demonstrating they have solved that problem, I'd be leery of putting the Aerovee in an application that needs a hundred horsepower engine.

I built an Aerovee for a buddy. I was not impressed, and I would certainly not be interested in the turbo version.

I'm curious about this, as I've been eyeing a OneX build in the future. What did you find lacking in the AeroVee?

Hard to beat the reliability record of the O-200. It's tied (with the Rotax 912) for the lowest rate of mechanical issues in my 1998-2020 accident database. The auto-based engines have significantly worse rates. I have a relatively low number of Aerovee-powered aircraft accidents in my database (19), but the rates are quite a bit higher than the O-200.

Ron Wanttaja

Can you discern whether those accidents were caused by a failure of engine components or by an installation error (fuel system, wiring, etc.)?

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Originally Posted by Eric Page

Can you discern whether those accidents were caused by a failure of engine components or by an installation error (fuel system, wiring, etc.)?

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Usually, I prefer to have at least 40 or 50 accidents for reliable analyses. I've got only 19 Aerovee accidents in my database, but I'll give a summary.

My processes slice the cause information a number of ways... including builder, maintainer, or pilot error.

Of those 19 accidents, 15 involved a loss of engine power. This is about 79% of the accidents. This is high; the overall rate for homebuilts is about 33%, and the Rotax 912 is about 22%.

HOWEVER... that 15 includes failure due to ALL causes. Two were due to fuel exhaustion (not the engine's fault), another three involved builder/maintainer error relative to the engine. One of the accidents appeared to be related to the aircraft fuel system (reason undetermined), and another was the failure of a rocker arm (cause also undetermined).

For the eight remaining accidents, the NTSB was unable to determine the cause of the engine failure. It may be pilot-related, it may have been something with the fuel system, or it may have been a mechanical issue with the engine that the NTSB was unable to trace down. Sometimes, this is due to the damage caused by the accident, other times the wreckage permitted examination but nothing was found.

So out of those 19 loss-of-power accidents, the NTSB was unable to determine the cause for about 42% of them. This, in itself, is a high percentage. It's 9.8% for *all* homebuilt accidents, and 8.3% for the Continental O-200 and 7% for the Rotax 912.

It's likely some of those eight accidents were pilot related ("No, I didn't turn the fuel valve back on after the accident") or temporary conditions such as carburetor icing or vapor lock. But it's still, overall, a lot of power failures.

Again, though, this was a small sample set.

About a year ago, Mark Schaible at Sonex asked me for a full analysis of Sonex accidents. I obliged, and he posted the report to the Sonex forum:

https://sonexbuilders.net/viewtopic.php?f=41&t=6545

Ron Wanttaja

Thanks, Ron. I appreciate you taking the time to tease that info out of your database and type it up!

O-200 if you have the choice weight and size wise for your application. A friend has an turbo Aerovee on a Sonex. Multiple valve train issues including a precautionary partial power landing. I am not directly connected with the project, but I have been unimpressed with the support he has received from Aerovee.