On a clear sunny Groundhog and Super Bowl Day I went for the first test flight to set up SV-AP-Panel and AoA system.
Barometer was 27.81, OAT 54℉ on the ground, winds calm.
Equipment:
Scenario:
I flew back to my home airport (> 30 miles away) without further incident, did a full stall landing. The newly calibrated AoA and the stall warning agreed on the moment lift was lost. The engine ran fine during landing stall and taxi.
The electric fuel pump appears to be running fine, with good pressure at all times (although, I did not check it during the drop in RPM/rough running moments; only after stall recovery). The fuel tank was full at takeoff and I have no evidence of any leaks in the fuel system, but I have not yet removed the cowling or floor boards to do a full inspection. I completed last CI in late August and two carb floats were heavy, so I replace them with new.
I emailed Green Sky Adventures on Monday and am awaiting a reply. One local RV-12 owner with HACman installed has never noted any issues like this. Reading the install instructions and operational information (and warnings) however, engine stoppage from what they state are incorrect installations can occur. Obviously, I need to check the entire fuel system if I can't find an issue with the mixture controller. Carb floats seem always on the list of suspects. This doesn't seem like an ignition issue, however. Or does it?
I'm looking for suggestions. I do not want to fly the plane until this is resolved.
Barometer was 27.81, OAT 54℉ on the ground, winds calm.
Equipment:
2015 RV-12
ROTAX 912ULS
Dynon Skyview Touch with 2 axis-AP
SV-Knob Panel (installed 5/2019)
Gen3 HACman mixture control (installed 7/2019)
Silent Hektik VR (installed 9/2019)
SV-AP-Panel (installed 11/2019)
AoA retrofit kit (installation finished 1/28/2020 ? required removal of wings and fuel tank.
ROTAX 912ULS
Dynon Skyview Touch with 2 axis-AP
SV-Knob Panel (installed 5/2019)
Gen3 HACman mixture control (installed 7/2019)
Silent Hektik VR (installed 9/2019)
SV-AP-Panel (installed 11/2019)
AoA retrofit kit (installation finished 1/28/2020 ? required removal of wings and fuel tank.
Scenario:
In level flight at 6500 MSL, OAT 29℉, electric fuel pump on, HACman mixture set to full rich, I lowered engine RPM to 3,000 and began first stall to calibrate AoA. With RPM at 2500, nose up steeply and near the stall, the engine RPM fell and the engine began to run roughly. I lowered the nose right at full stall, logged the stall in Skyview (of course), lowered the nose, eased throttle forward then leveled out after full recovery. Engine recovered full RPM and smooth running, but only after 30-45 seconds of roughness with nose level.
I decided to add a second stall to the calibration. Entry to stall was similar, but of a longer duration and at full stall, RPM began to fall and in 2-3 seconds, the engine quit. By full recovery from the stall, the prop stopped. Initial attempts at using the starter failed to restart the engine. I did the usual system checks (fuel on, electric pump audibly clattering away and making good fuel pressure, all active engine monitors in the green, HACman still full rich) and began to set up an approach and landing at the paved airport less than 3 miles away. My altitude by then was over 5,000 MSL, about 3500 AGL. After several more attempts with the starter, the engine roared to life after about 3 minutes in glider mode. I re-established cruise RPM slowly and leveled off, only to have the engine quit again. This time it restarted within 10 seconds or so of running the starter.
.I flew back to my home airport (> 30 miles away) without further incident, did a full stall landing. The newly calibrated AoA and the stall warning agreed on the moment lift was lost. The engine ran fine during landing stall and taxi.
The electric fuel pump appears to be running fine, with good pressure at all times (although, I did not check it during the drop in RPM/rough running moments; only after stall recovery). The fuel tank was full at takeoff and I have no evidence of any leaks in the fuel system, but I have not yet removed the cowling or floor boards to do a full inspection. I completed last CI in late August and two carb floats were heavy, so I replace them with new.
I emailed Green Sky Adventures on Monday and am awaiting a reply. One local RV-12 owner with HACman installed has never noted any issues like this. Reading the install instructions and operational information (and warnings) however, engine stoppage from what they state are incorrect installations can occur. Obviously, I need to check the entire fuel system if I can't find an issue with the mixture controller. Carb floats seem always on the list of suspects. This doesn't seem like an ignition issue, however. Or does it?
I'm looking for suggestions. I do not want to fly the plane until this is resolved.