Modified ROTAX 670 snowmobile engines by "Rotax Rick" being used for aviation.
In an effort to help other rotorcraft guys & not see them experience the frustration & lack of flying time due to engine problems & catastrophic failures, think twice about using the Rotax 670 engine that is modified & promoted by a certain fellow in Florida that goes by the name "Rotax Rick" (not his real name).
Our out-going PRA chapter president installed one purchased from RR on his Sport Copter Vortex. After many hours of flying it around Oregon & Washington (as well as in Utah during ROTR), the many issues he has experienced have caused him to give up on that engine. Excessive fuel consumption is another, additional issue. He related to me he was getting 7+ gph fuel consumption. He is an A&P, and does his own engine work, so he hasn't returned his engine to RR, as others have.
Years ago in our local PRA chapter, we had another chapter member use the 670 engine on his KB-2 gyro. He used it stock as it came from the snowmobile application, & not from RR. He like the idea of 90-95 hp, but didn't care for the sharp jump in engine rpms as it comes onto it's power band. He claimed to have tamed it to run more like an four cycle engine's power band by adding a regular automobile muffler downstream of the Rotax tuned one.
This fellow had taught himself to fly a gyro over a period of many years, and wasn't around w/ us for very long after he achieved soloing himself, as he died w/in months of being diagnosed w/ massive lung cancer. Any guesses as to his very heavy tobacco usage?
Glenn Kerr in Utah installed one 670 from RR on his Butterfly gyroplane, & experienced three seizures while flying it (one each in Utah, during ROTR, in California during the KBFFI, & in Indiana during the PRA convention. The failure in Utah occurred just after he set down on the runway, while the
California one was just off the El Mirage dry lake bed recreational area onto a dusty two-track, & the Indiana one was into a soybean field about five miles west of the Mentone airport.
The other two were emergency landings, & he executed those well. They are documented from his videos he posted on his youtube channel. He sent his engine back to RR to be redone each time, & gave up after the third episode.
I was told that one of the RR 670 engines was found to have gasket sealer used as glue inside it (!), as well as RR sent it back after "rebuilding" it w/ the cylinder head was severely damaged from a prior seizure! RR had been quoted as saying the reason why he had sent it back "rebuilt" to the customer w/ the head damaged, and not replaced/repaired, was that the customer had cost RR too much $$ to correct it! UNBELIEVABLE...
Mentone area bean field emergency landing:
El Mirage dry lake emergency landing:
Also, known is that Mike Boyette installed one of these 670 engines from RR on his Dominator gyro & it had to be rebuilt by RR @ some point. The reason why is unknown to me, but I can imagine it revolves around the same issues others have had w/ their 670 engines sold to them by RR. Perhaps Mike can chime in here re: his 670 engine experiences.
These examples are only failures I know of. I suspect there have been others that I do not have any knowledge about. RR has marketed his modified 670 engines to the airboat & airplane crowds. Almost 100% of those engines that I know about that were purchased from RR have failed.
There is an exception that I do know of: One bought from RR that was flown on a Dominator-style gyro in Louisiana w/ no apparent issues.