PIREP - 1977 Grumman Tiger, O360
From: Larry Tatsch, Princeton NJ
Aircraft: Grumman Tiger Date: August 5, 2019 at 8:55:40 AM MDT
After gaining a bit of experience with my SureFly electronic magneto installed a few weeks ago, I'm posting my experiences from a flight Sunday. On this flight, I took the time to lean aggressively and was amazed with the results. I was clearly in the lean-of peak regime. Here are the particulars: Aircraft: 1977 Grumman Tiger, O360; TSMO, 420; Port and polished Lycoming cylinders; Fine wire plugs. Flight Conditions: 7500 ft.; OAT, 10C Altimeter 29.93; Approx. gross weight: 1990 lb. (pilot plus one passenger) Engine Conditions: CHT - hottest cylinder (#4): 380F (using EI gage) Typical would be 395. TAS: 130 kts RPM: 2600 (corrected for 75 RPM low tach reading) Fuel flow: 8.3 GPH (EI) The engine ran fairly smoothly at this low fuel burn. I was able to reduce fuel burn to about 8.0 gph and still have reasonably smooth operation, but with additional reduced power. I can't give pre- SureFly conditions because I could never lean to such a degree. But to give an idea, I could typically cruise at 130 kts TAS, burning around 9.5 gph at 7500 ft, at std temp and leaned to slightly rich of rough operation.
I don't understand what it is about the advanced, more powerful spark that allows LOP operation, but as reported by others, it clearly works. Another benefit is much faster cold starts (not much difference with a hot start). Needless to say, I'm totally pleased with my SureFly. It should pay for itself in short order.