Mine is the local plane that will be testing the NTK sensor system Ross mentioned.
Prior Bosch 4.9 experiences:
- Generally, SDS system or not, the O2 sensor reliability seems to be more tied to the AFR (leaded fuel) environment it is being operated in, the lean side it likes, rich or over rich it don't like so much & won't last long.
- The sensor we had in Bill Beaton's supercharged IO-540 saw wide AFR swings, mostly on the rich side so his sensors were good for max 40 hrs, but that is notably extreme operations. In his calmer flying recently, the sensor is lasting much longer.
- While experimenting with my 6A (dual SDS 360), I got the Bosch 4.9 to go off line when I made the engine swing toward over rich in rapid change succession, I am able to reset it in flight so it flew on. With the fuel map now stabilized and with the same sensor, I now have 110 hrs out of it. It is now showing signs of giving out, but I can revive it by removing it and cleaning with a shot of aerosol brake cleaner and a blast of compressed air, again good for another 5 or so hrs. This plane has seen a fair amount of formation practice lately so it is subject to frequent AFR sweeps which I think, is also factoring into the O2 sensor longevity.
Ross & I are going to experiment next with the Ballenger AFR500 NTK sensor system, I will be installing it with a delay relay set to activate the sensor 25 seconds after engine start. As Ross said, we'll report back...