915is Updates in the Kitfox?

[brandonschmit]

Now for the single lever control..
This is an interesting subject. It is NOT being proposed in the ASTM or even through the FAA.. it is being talked about and politically pushed in certain circles. No light in sight that I have seen. We can all agree that the CS props should be allowed with the Light Sport and hopefully someday the FAA will catch up to the future.
The single lever is not Rotax.. It is actually a governor that is electronically controlled (instead of cable controlled). The only Engine Management Unit (EMU) that controls the governor currently is the Stock Flight Systems EMU for the 912iS and 915iS. Rotax, MT and Stock work closely on this program.
Yes the prop can still be cable controlled as any Hydraulic CS prop.
I'm sure there will be more developments regarding the single lever.. for the 915iS it is currently an MT prop, Electronic Governor and the Stock Flight Systems EMU. I suspect AirMaster will have a prop and I know there is another that may be available in the Fall. Hopefully Garmin, Dynon, GRT, MGL will come on board with the software to control the electronic governor.
I should mention the the 915 can be operated with a fixed pitch but one would not be able to take advantage of the full potential of the engine.

May I ask a newb question? I see that the 915 has the same exact bore and stroke on its pistons as the 912/914 engines. Does this mean the only way the new 915 is making more HP is that it's going to higher RPM's versus the 912/914? Hence your statement that a fixed pitch prop wouldn't take advantage of the engine's HP because it's essentially the same engine and has roughly the same HP/torque curves at the lower RPM's as the 912/914? The only way to take advantage of the higher horsepower at higher RPM's is to keep the engine spinning at the high RPM's and adjust the pitch of the prop for max thrust during takeoff and max forward speed at cruise? I did read an article on the SeaReys that said cruise RPM was 4800? So that actually seems lower than normal cruise RPM? If it's making more power due to higher boost/more oxygen in the fuel/air mixture, then why isn't a fixed blade prop going to work if the RPM range is the same? That's where I'm getting confused. Is it due to the changed reduction unit? Why would they change that if so?

Thanks,

Brandon