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

Kent, you make some good points and in general I agree with you, but I
would like to make some exceptions and expand a little on the point you
are trying to make.  In a little over a year of flying I have
experienced all of the following failures:

broken alternator mount (7hrs)
cracked aluminum coolant line (48 hrs)
cracked oil cooler (50 hrs)
broken turbocharger(70 hrs)
bad relay in the EC2 resulting in
broken PSRU (all at 145 hrs)
broken alternator tension arm (unknown)
worn out fuel pump (147 hrs)
and broken/stuck side seals (150 hrs)

All were either caught on the ground, were gradual failures, or
otherwise did not prevent further flight under power.  Only the turbo
failure required a precautionary landing.

Those failures all fall into the category you are talking about, except
the side seal issue which was such a soft failure mode that I was
probably flying with it for quite some time but never knew.

On the other hand, I feel that despite the lack of thousands of flying
hours, my fuel system is far safer than that in any Mooney or Cherokee.
The NTSB files are FILLED with cases of vapor lock that my system is
essentially immune to.  It is not as if I totally designed it myself.
The basic design of high pressure fuel pumps close to or inside the
tank, aircraft quality plumbing, regulator and return line is tried and
true with many more hours of operation than all Cherokee and Mooney
systems combined.  Throw in a redundant fuel pump, improved system
monitoring, and elimination of carb ice with the use of fuel injection
and there is no doubt that my fuel system is far safer than the GA fuel
systems, and especially safer than standard GA systems installed by
other amateurs in their experimental aircraft.

Likewise, the engine mount can be an issue but as far as I know has
never cause a problem on any rotary aircraft.  If properly challenged
during fly-off, the chances of failures occurring later diminish rapidly
with every hour flown.

Electrical and flight control systems will essentially have the same
failure rate on rotary aircraft as on other experimental aircraft.

All in all, after the first couple hundred hours the inherent durability
of the rotary will begin to overshadow the remaining shortcomings that
occur as a result of having a unique installation.

Case in point:  Given the fuel system and engine durability advantages
there can be little doubt by now that Tracy's RV-4 is more reliable than
any lyc powered RV-4.  Serious flaws in his installation would have
surfaced by now.

I plan to get to that point some day as well :-)