Yamaha Genesis Snowmobile engine:
Rotary Forum has had extensive discussions of and by folks
who have adapted the Yamaha Genesis 3 or 4 cylinder snowmobile engines for use
in gyros. The links below are to the latest and apparently more available
adapter called ?Skytrax?by it's creator Neal Jenkings. This
allows a Rotax C box to bolt up to the 4 cylinder RX-1 years 2003-5 The cost is
$1500 for the adapter and then the C Box needs some machining (which the
fabricator will do for shipping costs). Neal is using carburetors on his
autogyro.
Here is one of the most recent Rotary Forum discussions
http://www.rotaryforum.com/forum/showthread.php?t=37557&page=5
Here is his you tube video of how to bolt up the conversion
adapter and the C box.
https://www.youtube.com/watch?v=r8UXxcV1CFQ
There are several threads on the Rotary Forum. I have read
some of them and will summarize. The 3 cylinder is much harder to adapt, spins
slower about 8700 rpm and makes 120 hp carbs, 130 hp EFI. There are various
adaptions of the 3 cylinder, but it seems to be on a custom basis.
The 4 cylinder RX-1 revs to 10,700rpm and makes up to 150 hp
is the R1 motorcycle engine adapted to snowmobile use with a CVT. This required
an internal reduction of 1:1.19 and a harmonic balancer. The cover for the
balancer and
reduction Skytrax replaces allowing the C box to bolt to the engine. Another
fabricator designed and marketed a two piece plate that can be adapted to any
gearbox. I believe this costs $1300. I am not sure of availability.
These are used snowmobile engines which cost $2000-$4500.
There is debate on the suitability of the C box for the RX-1 given it?s 150
peak hp and high rpm. The weight of the RX-1 FWF (or FW rearward) seems to be
about 165-170 lbs including fluids, radiator and everything else. There are few
hundred hours on the Genesis engines aero converted. I don?t recall I think the
3 cylinder engines had more air time.
Motus
VikingAircraft lists the Viking 135 for about $20,000. This
is the Motus aero conversion. There is very little info on their site
http://www.shop.vikingaircraftengines.com/Viking-Engines_c15.htm
