I’m the first non-builder owner of Sonex 0373, which I’ve been flying for a year now around south Chicagoland area.
It’s equipped with an AeroCarb and I’ve got a couple questions for the group.
Does anybody make seasonal mixture needle adjustments? If so, is there a best practice?
and
I believe I’m having the WOT power reduction / sputtering issues that I’ve read about. On climb out, if I pull the throttle back 5-10% get an extra 100rpm. Any common solutions to this?
Based on some of the ground runs I’ve done and EGTs I think the overall tune is pretty close.
Welcome to the forum! I’ve never made a seasonal adjustment, nor do I have WOT power reduction as some have reported. If you stay at WOT and lean it, can you get an RPM increase? I’m thinking it’s either got to be too rich or too lean, and if so that can be adjusted away.
The one problem I had was an engine that was pretty much happy, but in the winter I would go over redline on my EGT. I customized my needle and it worked pretty good.
What airport are you based at? We fly out of C77. NW extended Chicagoland.
Thanks for your thoughts Bryan, I see you’re in the area as well so that good to know you don’t adjust for the climate around here.
Im hesitant to lean at high power settings as a matter of programming from training and I have only the push button mixture control. I plan to swap in a vernier at some point. It pretty common to lean Aerovee/aero carb for power in climb near sea level?
I’ve never had to adjust for seasonal changes. I’m at sea level, but fly in the mountains when weather permits. Run a number 2 un-modified needle. Sounds like you are running slightly rich. I think if you lean the needle 1/8 to 1/4 turn, you might be fine.
Yes, definitely go to a vernier, much nicer control.
It’s not your father’s lycoming - Definitely need to lean at full power. I like to adjust the needle so it doesn’t run poorly at full rich, because that’s alarming. But the best power is always a little lean. I really like the AeroInjector because it’s light, simple, and it works. But the design is a compromise. With a linear taper needle, and a nonlinear throttle body for air, it can’t be perfect and the rest is up to you and the mixture knob. The other challenge is the front cylinders tend to run richer so those are the ones probably causing the stumbling. You lean until the back EGT is high but under redline, and the fronts will be good enough.
Rene’s thoughts are much the same as mine. I would start with 1/8 turn. In my Aeroinjector adjusting toolbox I usually use 1/8, or a tweak.
I’ve been to Lansing before, was helping a guy there with some advice. I did a couple of pattern laps with him too. I also see we connected via email about a year ago - glad you got your Sonex flying! Back then you were looking for training.
There is a ton you can do to improve the AeroVee. Mostly I would focus on cooling improvements. But it’s a pretty good package I think.
Welcome to the group! I have a vernier mix control, adjust for max power durring run-up, and am very considerate about cht/egt on climbout. have had no unusual problems yet, but still watch closely, I do consider my routine to be adjusting for seasonal changes here in N texas, which are…mostly!…not as extream as your climate area. If I remember right, I have a #3 needle, getting 4.5-5 gal hr cruise, but not at wot.
Yup! I ended up with Jeff Schultz for transition training. Without that training it would have been dangerous for me to figure out the airframe alone, way different that the Pa28s, C172s, C140s i trained in. His knowledge base and write ups are very helpful.
The machine i ended up with has needed a lot of little refinements here and there. The baffle setup leaves a lot to be desired, wasn’t even sealing against the cowling on the back fence and there are lots of gaps in the transition to the super tin. I’m working through the kinks. When secondaries are on, the CHTs climb pretty quickly to redline on high power settings, etc. Lots of little things need to be tuned up. I’m still noting all the trends, what the plane does and doesn’t like.
I’ll try leaning and maybe an 1/8 turn lean on the needle and do some testing, thanks yall.
The baffles are slowly coming together. The only overheating issue I battled early on was on climb-out. I had a CHT during mid-summer hit 415. I discovered if i turned off my secondaries, my CHTs would drop under 400 no matter what power setting or OAT. This started a process of retiming my secondaries, which i had some luck with. I upgraded from 10a to 20a alternator and have since got an updated set of secondaries that I have to install, top of my list right now. So it’ll need retiming anyway.
I’ve read a lot of the literature on cleaning up the cylinder heads. Schultz told me its good practice to have a second set on the shelf ready to go. I’m hesitant to start pulling the engine apart as it runs pretty good. Compressions are acceptable and theres nothing critical on the borescope images. When I inevitably pull the heads I’ll do some work cleaning up the castings. I picked up Tom Wilsons book on aircooled VW engines, so that will probably come in handy.
With the aerocarb on a vw we always had to lean about 1 inch out of the mixture control. But, it would cut out (too rich ?) pulling g’s into a loop. The cure was changing the aerocarb to a Rotec tbi, but even with that setup we always had to lean about 1 inch out to get best performance.