When you assess risk, at some point you have to look at the whole
picture. Converting a rotary engine is extremely risky because there are
so many creative activities you are doing. Each has many potential
oversights, so the oversights occur. You have lot's of evidence that
describes this. The ratio of dead sticks, the number of alarm conditions,
whatever you choose. But you need the courage to face the truth. It's not
easy.

Sorry to say this al wick but I think you are on a fishing expedition of the first magnitude. That is I do not believe you are offering us specifics as to what you call risky installs. Your own subie can easily be defined as a "risky" install. In fact MOST of the Subarus had problems before Eggenfellner started to provide a FWF.

 You are trying to negate the fewer parts argument, which is ignorant at best. While a lower parts count doesn't insure a safer engine it is a MAJOR step in the right direction. The rotary engine IS an impressive performer. I am a Mech. Engineer and I'm am not piston phobic. I have been interested in all sorts of conversion engines, V-8, V-6, Flat 4 and 6, Rotary, et all. The more power you are attempting to provide the "riskier" the conversion. V-8's with reasonably redundant ECU have failed in many conversions. Several conversion firms have gone bankrupt trying to make a successful FWF package. So far NONE have succeeded with a program beyond 1 or 2 units! Quite a few V-8 conversions fail. Many Subaru conversions fail. In most cases sadly you can look under the cowl of most of the failed conversions and predict ahead of time that they WILL FAIL. The problem is that few people have experience working with anything as critical in execution as an aircraft. Simply put if you want to succeed you must use the best parts for the job throughout. It amazes me how cavalier many less informed people can be about wiring, cooling, (air or water), fasteners, rivets etc. Everything must be done 100% in it's turn before you can have any reliability. This is obvious, even naggingly so but too often people will take shortcuts on the items they "don't think are that critical." It doesn't matter what engine you use if you don't engineer the package well it will fail.

 

Powersport is selling a rotary that is flying in several aircraft, Mistral is CERTIFYING a rotary package with the help of Embry Riddle which is in flight test in a Piper Arrow now being flown. Tracy Crook is now racking up the hours in his second or third engine configuration with great success. Hell Tracy's biggest problem recently has been trying to find a muffler that will hold up. Please note that the muffler failing doesn't cause the engine to stop, in fact it's more of an annoyance. Paul Lamar may be easily offended, (ask several people on the flyrotary list), but he does hammer on the point that is most important in all engines that are converted for use in aircraft. That point is that the external supporting equipment has been the failure of almost every conversion. I would go further to say that this is true of almost any engine conversion. Very few engines that are used within their design limits fail in use. This is true of the rotary, the subaru, and even most of the V-8's.

 

Several of the people on the rotary list seem to know you and think well of your reputation, which is a good thing. So far in your posts I have read however, you have NOT SUGGESTED A SINGLE ITEM that has not been discussed on the fly rotary list prior to your notice. I.E. your systems should be redundant, big whoop that was a toughie to figure out. (Are you running two Subaru ECU's with the capability to switch between in the event of failure in your install?) In any engine installation there are risks which we seek to minimize. This used to be called common sense. I have always recommended to my friends that if they didn't have the ability to engineer all the subsystems themselves they were better off with a Lycoming or other proven system. (Although that is no guarantee of sure success) My rotary system will see at least 15-20 hours of ground test on an engine stand that includes the cowling and propeller and full power operation to test cooling and other subsystems. I'm tired of self anointed experts (or actual experts) sniping at a certain design without a true understanding of what they are trying to achieve. If fewer in-air failures of rotary powered aircraft is your only goal, great. Otherwise you are wasting archive space. If you can offer design assistance with parts we need like intake and exhaust systems bring it on.

 

If you exist only to criticize the efforts of others, without specifics, don't waste my time.

 

Bill Jepson

Rotary 20B conversion in process

Van's RV-10