Battle of the Enclosed SxS Gyros

[JEFF TIPTON]

The 150 horsepower I believe was to be six cylinder. It may have similar crankshaft problems as the Jabiru eight cylinder.

 

[JAL]

Guys, I have never understood Rotax. Less TBO than Lycoming for one.

Why would anyone want to run an engine at 5,000 to 6,000 RPM to run a prop at 2,000 to 3,000 RPM. Quite a bit of wasted energy, wear and tear, on an mechanical device that, is wearing itself out with every revolution of the crank.

Surely someone can engineer a much simpler design.

Runs slower so no gearbox is needed, air cooled to save weight, dual ignition for dependability, dual magnetos for redundancy, fuel injected for altitude changes. Wait, Lycoming has already done it. I guess the rest of the world needs to catch up.

Why use a Rotax?

I think you make a valid point but I think the main reason is that rotax 900 series run on mogas, in fact prefers it.

On the other hand the Lycomings need avgas. There are some models that have exemption and can on mogas but they don't like it is as much. Just like Rotax can run on avgas but needs more attention.

Most European flying is done away from airports with avgas bowsers and mogas is an extremely convenient fuel, you fill up at the local fuel station and you can get the fuel anywhere.

 

[PTKay]

....
On the other hand the Lycomings need avgas. There are some models that have exemption and can on mogas but they don't like it is as much. Just like Rotax can run on avgas but needs more attention.

Most European flying is done away from airports with avgas bowsers and mogas is an extremely convenient fuel, you fill up at the local fuel station and you can get the fuel anywhere.

Avgas is to go, sooner or later.
The experiments with lead free avgas are futile until now.

The future is mogas and diesel.

Certain breakthrough happened this year when Cessna started
offering 182 with SMA diesel. Over 100 OME already flying.

In the power class above 150hp there is no room for new gas engine.
Several new diesels are already on the market and more in development.
I think, this is the reason Roatx dropped the big gasoline engine. No future.

Chine will decide. They are not willing to start avgas production and
distribution there. They will go for diesel, aka JetA, available everywhere
and far cheaper.

 

[ckurz7000]

Living close to the Rotax company makes for some interesting rumor leaks that tend to have a somewhat higher than average truth content.

The 912iS is clearly designed to accommodate a turbo charger. This fall is the time frame I heard as the release date of a fuel injected 914 with 130 hp. The guys at ArrowCopter are expecting to get a one of the first engines for testing.

I'll report back when I know more.

-- Chris.

 

[Brent Drake]

Brent, could we stay apples-to-apples? No Rotax four-strokes failed at Mentone. At least one of the failures was a 582 heavily modified by someone other than Rotax.

The Lycoming LSA-class engine does not appear to offer true fuel injection as an option, only traditional or POSA carbs, both with manual mixture. It uses CDI, not magnetos. Compared to the 912 it's heavier, noisier, makes its max power at higher prop RPM, and is essentially the O-235 (certified 71 years ago) with some lighter weight parts.

Both technologies have their place for now. Lycoming and Continental have apparently determined that the mounting a serious challenge to the Rotax 912 in its power class would not produce enough return on investment. Likewise, Rotax parent company Bombardier had a 3.0L, 200-HP aircraft V6 (300 HP with turbo) ready for market five years ago, and decided the costs (especially insurance) of challenging Lycoming and Continental in the four-place aircraft market also would not pay off.

Paul One was a Rotax 912, one 582, and I think a 682? ( I know it was a 6 something).

 

[PW_Plack]

Paul One was a Rotax 912, one 582, and I think a 682? ( I know it was a 6 something).

Brent, if you can provide any details on the 912 failure, it would be valuable to know how it failed.

The other two-stroke was a "Rotax Rick" 670 which started life as a 582.