The big AeroCarb/AeroInjector thread

[sonex1374]

Paul,

My engine stopping on the first flight was a non-event. I had the idle stop screw set a little too low and the rpm was just ticking over. At the *really* low rpm settings the engine has a tendency to quit, so the solution was to slightly raise the idle speed (approx 1/4 turn on the idle stop screw). Coming down final the engine was fine until I pulled the throttle all the way back, and by that point I was looking good on the landing and the fact that the prop was slowing down and getting ready to stop wasn't really a concern, so I just let go to see what ultimately would happen. A quick adjustment (or two) solved that, and my idle speed is still about 800 rpm, slow enough for taxi and final.

[lpaaruule]

Jeff,

Thanks for the clarification. Knowing that you were in control of the engine basically until touchdown makes me feel better.

On the other hand I've bouced landings at the last second due to gusts while doing wheel landings in a Citabria, and it was a good thing I had full power available.

I'm trying to keep an open mind regarding the aeroinjector, and knowing that I'm basing my decision on facts is a great help.

[kmacht]

If you set the idle too low on an aerovee the engine will quit no matter what carb is installed. I found that my engine didn't like to idle below 1000 rpm until after I had 5 or so flight hours on it. I could easily taxi, stop, and land with it set at 1200 if needed. I think you will find the idle issue for the first few hours true for most aerovee owners.

Keith

[SvingenB]

I am confused reading this. I also read people readjusting it for summer/winter.

In a normal carb (Cessna for instance), you keep it full reach, then lean when needed (in cruise, when taxing for longer periods and so on). Does the aerocarb behave differently?

[radfordc]

I am confused reading this. I also read people readjusting it for summer/winter.

In a normal carb (Cessna for instance), you keep it full reach, then lean when needed (in cruise, when taxing for longer periods and so on). Does the aerocarb behave differently?

No. You start/warmup at full rich and takeoff/climb at full rich. Lean as needed in normal flight. Lean as needed at idle/low power after warmup.

I didn't readjust between summer/winter. In winter my EGTs were slightly higher...but my CHTs were lower due to cold OATs.

[Denny]

I have 64 hours on a conventional gear Sonex with the Aerocarb on a Jabiru 3300. It ran fine on the first start but would balk during the last 1/4” up to full throttle. After a lot of needle changes I discovered the mixture arm angle was too small which prevented full fuel flow. I also found the air filter supplied by Sonex was too restrictive. After changing to a K&N air filter and a properly adjusting the mixture arm I was able to get full throttle. The next mistake I made was assuming I should be able to set it for optimal mixture throughout the range from idle to wide open throttle. Yes, I even reshaped some needles. I had a push button style mixture control which was very difficult to fine tune. After changing to a vernier style mixture control and setting the needle for best full throttle at full rich mixture life has been good.

I can now climb several thousand feet at full throttle with perfect EGT's and CHT's. For cruise I pull the mixture until the RPM's increase and then turn the vernier knob to move the EGT's into the desired range (I like 600 to 640º C). This keeps CHT's in the 95 to 125º C range. If I turn too far and the EGT''s get too high (680º C) the engine will miss a beat and I turn out the vernier half a turn. For aerobatics I leave the mixture at full rich to accommodate repeated quick changes from idle to wide open throttle. For a one hour flight: four thousand foot climb at wide open throttle, cruise at 130 mph, 15 minutes of aerobatics, I burn 4.1 to 4.4 gallons of 100LL.

This is within 10% of the fuel burn a saw on my 65 hp Baby Ace for the same one hour flight with a 70 mph cruise. The Jabiru 3300 with Aerocarb is powerful, efficient, runs cool, and smooth.

Best Regards,

Denny
#879

[bakfly]

Hi All
I have the AeroInjector on my Aerovee 2.1. For the first 10hrs or so with needle #2, I was not able to adjust the needle to run it correctly for WOT and idling. When it was running ok WOT it was not idling properly. Sonex advice me to change to #2.5 needle. This make running on WOT much to rich while it idled ok. After changing back to needle #2 from 2.5, the idling problem was really bad. The mixer control has to be pulled out almost until the fuel was almost totally cut off.
Leaning the needle didn't help and making the Engine running to hot.
Due to desperation I decided to measure the 1, 2, 2.5 and #3 needles slope high at 5mm intervals, length of slope from the tip and the needles diameter.
I came to an interesting conclusion.: the slope of needle #2 and 2.5 are the same until about halve way from the tip. I was puzzled why the engine did not idle properly with needle #2 and did idle well with #2.5.
After measuring the diameter with a micrometer I found the problem. The diameter of the #2 needle was 0.05 mm smaller than #2.5.
Needle #2 is 3.14mm while needle #2.5 is 3.19mm. That means on idle, fuel is leaking passed the needle and make it rich without be able to lean.
After putting a new #2 3.19mm needle in the AeroInjector and after some adjustments it is like a different Engine.
The engine has now done more than 30hrs and it is running beautifully on Idle and WOT. I only lean the mixer control out during cruise to get better fuel economy. I am now very happy with the Aerovee and the Injector.

Cheers,

Peter.
Sonex #1430 Aerovee 2.1

[jerryhain]

Has anyone tried using a wideband O2 sensor to help them sort out their carb? I use it to tune carburetors on cars all the time. Set the idle mixture for 14.7 and the power valve/secondaries up to the 12s to make more power. I can get any carbureted car past emissions if I can get the idle set to 14.7. I'd be very interested in knowing what an engine that's already set up correctly and runs well is reading when it's lean of peak.
I'm going to the workshop next weekend so I might ask about it while I am there.

[lpaaruule]

I second that question about the O2 sensor. I had thought about setting up one myself. I used to work at a place that would use an ETAS Lambda meter ( http://www.etas.com/en/products/es63x.php ) for the wide range sensors (also called linear O2 sensors).

This guy is tuning his turbo Jabiru with something like the ETAS: https://www.youtube.com/watch?v=lAnAx9x9Dng

I've also seen much cheaper DIY versions, and automotive kits.

[rizzz]

Hmm this is very interesting.
Given from the results of the poll so far, most are happy with their AeroCarb but any tools/methods that help with tuning it would be of great value.