Ron Wanttaja wrote:
On Mon, 18 Feb 2008 11:38:29 -0900, "Ron Webb" wrote:

As for the safety record of Lyc vs others, I have to grant that I'd have to
pick my examples pretty carefully to find an uncertificated homebuilt with a
better record. Such examples exist. http://www.rotaryaviation.com/ for one.

I did a study of homebuilt accidents over a ~8 year period. Didn't have fleet
sizes for Lycosaur and Auto conversions, but instead looked at how often the
engine was the *cause* of the accident.

Out of 744 homebuilt accidents involving Lycoming, Continental, Franklin,
Jacobs, or Pratt and Whitney engines, 104 were due to some form of engine
failure.

Out of 219 homebuilt accidents in the same period involving auto-engine
conversions, 63 were due to engine failure.

Lycosaur: 14%
Auto Engines: 28%.

Offhand, I'd say the Lycosaurs are safer.

For the purpose of my analysis, I counted the following as "due to engine
failure":

Internal failures (pistons, cranks, etc.)
Fuel System on the engine side of the firewall
Ignition systems
Drive systems (e.g., PSRUs)
Oil System
Carburetor or fuel injector failure
Cooling system failure
Undetermined loss of power


Ron Wanttaja


I've followed your articles on accident stats for several years; thank
you for doing the research. I wonder, though, if your conclusion about
Lycs is really valid.

If we factor in the reality that Lyc installations are more or less
'standardized', with help almost always available from knowledgeable
predecessors, compared to auto conversions where each is nearly unique,
and we factor in the unpleasant fact (sorry guys) that many of the
people most willing to do an auto conversion are the least qualified to
tackle it, how much should we weight the percentages? Only if you add
the word 'installation' to each category can you reach the conclusion
that Lycs are actually safer, in my opinion.

What do you think?

Charlie