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I think it's easy to assume that I advocate flying Subaru's. I don't.
Regardless who I'm talking to, it looks like the Lycoming is the least risk
decision. For now....I think that will change in a year or so because newsgroups
like this make it so easy for successes to be shared.
You bring up very important points. If you guys can develop robust
solutions for each of the challenges, then you can end up with a powerplant that
has some fabulous failure modes. Here is a great example, I suspect your
ECM shutdown risk is now somewhere around 1 time in 1000 (maybe 500) hours. But
with simple changes that make the system genuinely redundant, you
would automatically raise that to 1 time in 1000000 hours. That is fantastic for
a custom low volume ECM.
You describe each engine being different. That is a huge risk item.
Creative endeavors are always risky. As soon as someone comes up with an
optimized cnc manifold, your risks drop a little.
Optimized exhaust manifold, they drop some more. Optimized fuel pump
plumbing proven using facts( not theory BS) they drop more.
-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock
Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop
construct, Subaru install, Risk assessment, Glass panel design
info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
Welcome, Al...
Lets see if in the end IF the overall risk
ends up being greater or less.. I suspect that the TYPES of risks involved
will be somewhat different (as in - failure modes).. between the two engine
types..the other thing to keep in mind is that there is not a standardized
installation of the rotary package (not counting the powersport engine) so
there is likely a tremendous variability from engine to engine just among the
rotary types. I acknowledge that I may be trading one set of "known" risks for
another set of "unknown risks" but time will tell. In the meantime, I don't
plan on doing anything foolish, such as running with scissors.
Glad to
have you here,
Dave
al p wick wrote:
Allright. Hang me.
First, someone cross posted my email on the subject. Totally fine by me.
Second, I haven't seen any previous posts on the subject, so blast away!
I just joined. It may not be apparent, but my goal is to reduce flight
risks. Regardless of type of power plant.
My background. My entire work career dealt with failures. Day after day
investigating the causes for each failure. Huge variety. Mechanical,
electrical, systemic, you name it. More significantly, eventually I had
the power to change the response to failures. This allowed me to test my
theories on how to eliminate them. So there would be a failure, I'd
implement a change, then measure how often the failure occurred in the
future. Investigate, alter the solution, remeasure. There are all these
patterns to failures that we usually don't notice. It's remarkable.
When I first started looking into the rotary risks, I was shocked. I
thought "My God, I have to let these guys know!". But instead, I ignored
it for a few days,question my perception, then started the process of
measuring the risks instead of relying on impressions. I'm not done, far
from it. But it's so clear that the path most take is of extreme risk, I
thought it best to post what I had so far. I thought "maybe one or two
guys will read this and take more effective action at reducing risk".
I have already measured the Lyc risks. Yikes! Quite a bit higher than I
expected. They have significant crank, valve and head risk. The total is
1 failure per 1800 hours. This based on 49k flight hours in Cozy
aircraft over 5 year period.
-al wick
Artificial intelligence in cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru install, Risk assessment, Glass panel design info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
Homepage: http://www.flyrotary.com/
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>> Homepage: http://www.flyrotary.com/
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