Robert Keighley wrote:

I've already decided on the rotary for an engine mostly for the
inherent safety characteristics that are touted in my research
- if the engine quits, it really doesn't "quit" more like
operates at reduced power and further, doesn't start throwing
parts out the side of the engine.  A smoother, quieter,
minimal vibration appeals as well.

Oh I wish that were true, but it's a dangerous assumption to make.  If
you study the NTSB statistics, you'll see that rotary engine aircraft
have a higher incident *rate* than Mooneys or Cherokees.  IMO, this is
not because of some problem in the engine itself, but in flaws in other
parts of the aircraft that are critical to continued operation of the
engine or aircraft.

For example, fuel systems in rotary aircraft are not as robust
(generally) as fuel systems in Mooneys & Cherokees.  Why?  Because
they're designed by amateurs and often assembled by beginners and
maintained by same.  (I should know: I am one!)

Bad mouth the certified aircraft all you want, they have one *huge*
advantage: they have hours and hours of engineers examining every system
trying to figure out how it can go wrong (and preventing that).

Botch the fuel system in your aircraft and I don't care how robust the
engine is: your plane is going down.

Botch the engine mount and encounter some rough turbulence: same.

Botch the electrical system: same.

Botch the flight surface control system: same.

Don't deceive yourself: build a rotary powered aircraft because you've
the time to spend and not the cash, or you want some special purpose
aircraft that isn't available as a certified aircraft, or you just want
to build an aircraft.  But don't think the finished product is likely to
be safer than a certified aircraft (statistically speaking).


Russell Kent

I am with Russell on this and that is why I am on here for seven years
no less. We are working towards making it safer.

Paul Lamar

To all,

Sorry if I may have overstated, and I don't want to be perceived as
bad-mouthing certified aircraft.  I agree that they are very reliable.
I wouldn't be buying a Mooney to continue flying with while building my
own plane otherwise.  My primary reasons for going on this journey are
1) satisfaction (I hope) of building it myself, 2) performance levels
per HP used 3) the learning experience of experimentation.  Hopefully,
this all comes with an aircraft that we can use to achieve our desired
mission.

I was referring to items that I have read about the engine itself.
Based on what I've read, oiling problem, apex seal failure, etc, the
engine typically does not seize up, or start throwing piston rods
through the oil pan (none to throw), or suck a valve (again, none to
fail).  In the incidents that I have read about, the engine usually even
continues producing a limited amount of power.

I agree with every point that you bring up about all the potential
issues and know that you only mention a few of the possibilities.  I
also expect it to be an interesting road ahead, and look forward to
learning a lot here and from any other sources that I can generate.

Thank You,
Robert E Keighley
Project Manager - IBM PMO
(913) 315-4697


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