I see.That's a business decision, not a technical one, I imagine.
Yeah, Fara, please, if you read it, I'd like to hear your opinion on Constant Speed (or Variable Pitch) prop on gyros, please.Maybe Fara can answer about his company thinking
From what I have heard from some people who flew J-2, it was a marginal performer so it may have benefitted more with an adjustable or constant speed prop. I do not think vibration in the prop should have anything to do with if pitch is adjustable in flight. I have to honest and say I have not tested service ceiling with adjustable props and compared it to fixed pitch prop. I would guess it would be better with adjustable prop. But climb performance and cruise performance is simply better because you can grab full power and best of torque curve in cruise both. You can get full power with a ground adjustable prop as well unless you have a non-linear torque curve like with 915iS if you set your prop to be a climb prop. It just means you accept a compromise in cruise. Or you can pitch more towards cruise and not get full power for climb. Usually settling in the middle and getting decent climb and decent cruise. But from what I have seen you cannot expect much more than 5-7% increase on top end speed and similar increase in climb rate over a properly adjusted ground adjustable prop on Rotax 9xx series engines.On the old Lycoming-powered McCulloch J-2, the three blade metal Hartzel constant speed compared to the 2 blade wooden Sensinich fixed pitch offered a significant increase in ceiling, gross weight, and climb rate, while reducing cruise vibration and slightly helping fuel consumption. All of the 18As came with a constant speed prop, although some were two-blade and some three.
The prop wasn't an additional vibration source, but running at 2350 rpm instead of 2650 rpm made everything quieter and smoother with a less "buzzy" feel. The O-360 is much calmer if you slow it down a bit.. I do not think vibration in the prop should have anything to do with if pitch is adjustable in flight.