Ski doo snowmobiles used their HAC and DPM system on sleds for about 10 years. I had a bunch of them and even added hac to a sled that didn't have it (just looked up the hac parts on the microfiche). Float bowl pressure regulation... worked really well but I did have some failures over the years. Default fail is rich.. which is good, but the sled would only pump about 40% power when it failed. Reasonable failure mode in a sled but not so much in a plane! Man, I dont know... an attempt to re-create a alt compensation unit in a 2 stroke would require tons of testing, fiddling, reworking, and possibly engine rebuilding if you mess it up and overtemp in the R&D process. Think I'd rather pick up a 600 etec and try to build a psru adapter plate for it! (Direct injection, "FADEC", and 120 HP)
I work with a lot of FAA guys and 99% of them have been true professionals, a pleasure to work with, providing valuable input and insight. As to the 1%, they are everywhere in life I guess! Sounds like the OP found some 1%"ers" who thought they had a chance to strut their stuff. Nicely handled by the way, no point in causing a fuss unless they started thinking they were going to hand out a violation... then I'd take the "yes sir" gloves off and dig into the regs and stand my ground. I have done that before and the situation quickly dissapated when they saw they were mistaken.
Ok guys, finally got to that rx-1 test running with 1 (and 2) of the 4 cylinders down: Yamaha RX-1 Performance Test on 3 cylinders: Ok, so part of my decision to go yamaha was that (since it does not have dual ignition) it would perform adequately on 3 cylinders if one were lost to a bad coil, spark plug, carb blockage, stuck/burned valve, etc. So I put the theory to test out on the snow today by pulling a coil lead off a cylinder. Results were better than I expected, with an easily started motor, good idle, and an estimated 80 hp output. Details of test: (All speeds are off the snowmobiles "dreamometer", which are accurate in comparison to one another, but all read high by approx 8%). 2005 Yamaha RX-1, 30 deg F day (heat wave here in MN!) through 2" of loosely packed snow. Top speed 78 mph with the #2 cyl coil unplugged. That compared to a MUCH lighter 2012 Ski Doo 600 ACE (60 hp 4 stroke). Top speed 64 mph. For the 100 lb heavier RX1 to go 14 mph faster than the ski doo in loose snow would probably take between 15 to 25 more HP. (Note that a lighter 90 hp ski doo I ride occasionally would have gone about 85 mph in those conditions) So I am happy in those results. The engine sounded and ran surprisingly well! And 80 hp would be plenty to fully operate my kitfox 5 which was designed to use an 80hp rotax 912 as the normal powerplant. Conclusion IMO is that dual ign is great, and would be preferred.... but it does only cover ignition redundancy. I prefer the yamaha (with it's extra power reserve) which could carry the day very well with ANY failure of power output from a single cylinder.
Running on 2 cylinders test: Test results running on 2 cyls (#2 and #3 coils unplugged): I'm really surprised by this one, started right up, idled fine on the all cyl idle stop, ran 53 MPH down the trail!! That's gotta be 50 HP! I was guessing it would have done less, but that would keep me in a gentle drift down in the plane... giving 10 times the options and time for a emergency landing. Really happy to see it perform like that!
Yep, I just added you over on the Yamaha Aircraft Conversions group. I am an admin over there... I go by "Anatoli". Glad to have you there Ian! Teal reccomended you and told me about your areas of expertise. As far as a modeled engine I know of no one who has done that yet. Morten Wiik has modeled up an engine mount, but it would be great if someone were to scan the entire engine someday. Put up a post about that on Facebook and we'll see if we can get a taker!
Yeah misrigged tail wheel on my KF2 handed me two loops in my first day (only two I've ever done... saving my next for a big audience at a fly in somewhere LOL ). A more experienced pilot could have powered out of what I continued to try to salvage that day, but I was too green, and the instructor next to me was giving little help. Mech and I figured out the misrig (in my case the old maule wheel would hit caster click out with 3/4 left rudder application.. and not re-engage. Brakes were too soft... pilot too green... instructor not teaching the critical point (power up the tail!).... perfect setup for having my ass handed to me LOL! A quick rigging adjustment and I was off knocking out my endorsement. I was lucky not to bend anything that day! And I brought that learning to my tailwheel flying in the years to come, which I was better off with when flying more expensive planes in the future.
I am very sure there is at least a provision to ferry a plane in to a facility to get an overdue xpdr cert done. Guess I would go along those lines. Mark it inop and to be recertifiied as soon as practical.