Choosing an engine for a Sonex A

[Skippydiesel]

Nah! - still looks like an AeroVee mount with the red adapter rails.

My Legacy has the original AeroVee mount - the bolts supplied with the adapter rails are for the latest B - they don't fit the A. I had to make interference fit plugs for the holes (which don't align with my Sonex supplied mount) & redrill off centre,for the correct size bolt hole. Can't understand why the mount was not made to a precise dimension.

Now that Sonex recognise Rotax they should come up with a specific mount as you say could be a Ring or hybrid.

[karmarepair]

Hello all, I'm building a Leagcy Sonex, and am in doubt about the engine for it; actually I have a Sauer 2200 with camshaft for lower rpm for max. torque,

If this engine fits your mount, it's a great choice. The AeroVee cam is not optimum for our use case, it is the mildest hi lift VW cam commonly available, the lobe centers, duration and overlap are optimal for about 4000 rpm. The bored and stroked Sauer should produce as good or a little better performance at the same RPM and with the same prop as an AeroVee.

]but have possibilities about getting an UL Power 350 or a Jabiru 3300.
My doubts are born from comments I have heard about different problems wit UL and Jabiru, mainly about cooling problems.

My conclusion is Jabiru Gen 4 ONLY. Some have had good experience with earlier versions. I've gotten the impression the UL is not the panacea Sonex hoped it would be. There are fewer of them out there. And a new one is more money than I have in my project, including my avionics.

[Skippydiesel]

"My conclusion is Jabiru Gen 4 ONLY. Some have had good experience with earlier versions".

You may want to be a bit cautious with your Jab recommendation: My local flying school - all Jab aircraft/engines - CFI (absolute Jab expert) not impressed with Gen 4. Don't have details just his disgruntled comment.

[karmarepair]

"My conclusion is Jabiru Gen 4 ONLY. Some have had good experience with earlier versions".

You may want to be a bit cautious with your Jab recommendation: My local flying school - all Jab aircraft/engines - CFI (absolute Jab expert) not impressed with Gen 4. Don't have details just his disgruntled comment.

I'll amend it then: if you must Jabiru....

I flew behind a 3300 in Jeff Schultz' airplane and I thought it was a terrific match, but when I asked him what he was going to do in 300 more hours when his Gen 3 needs a Top Overhaul he got a far away look.

[Bryan Cotton]

I flew behind a 3300 in Jeff Schultz' airplane and I thought it was a terrific match, but when I asked him what he was going to do in 300 more hours when his Gen 3 needs a Top Overhaul he got a far away look.

Thank you for reducing my Jabiru envy!

[BobDz]

At the risk of being tarred and feathered during my next visit to Sonex, I have to admit that the 120hp Covair is interesting. William Wynn makes a intriguing argument.

[pfhoeycfi]

I have the Aerovee Turbo on my Sonex B, approx 50 TT to date. When I was building I heard that the aero injector and timing was difficult to set up, that the engine would burp and that it would leak lots of oil. I simply followed the manual and none of that has proven true with my engine. I did have some temperature issues. Installing deflectors on the side openings increased the measured DP from air inlet to outlet and solved that issue. If I had to do it again I would install time-serts in the spark plug holes before assembling the engine. In the future I may consider splitting the exhaust assembly to make it easier to install and to make it easier to pull and re-install the heads. Lastly, I would install the oem coolant pump, not the copy. The copy didn't last more than a few hours. Otherwise my Aerovee Turbo performs as advertised.

peter

[robysonex]

Thanks for all the answer to my post; with all these I'm narrowing my choose between the Sauer (that I already have...) or the Jabiru 3300.

Will decide about which to use...

Thanks agin to all,

Roberto