Today I tried the Enya #3 hot plugs in the 42 GP and in the ASP 108. It made a difference on both engines but it made the biggest difference on the 42GP. That engine is ready to FLY. There is no difference on the top end with the glow driver on or off, and no difference in the idle, transition, and midrange with the glow driver on or off. I still don't know the rpm difference between glow fuel and the 2:1 E85/glow mix, but I know one thing, it sounds smooth and there's noises coming off the MA 10x6 prop tips which indicates supersonic tips. That GP42 is no fancy powerhouse but I'd say the gerbil inside is giving it all he's got. Darn my tach it picked a bad week to die on me. I ordered a new tach from Tower Hobbies, they were only $16.

The ASP 108 with Enya #3 plug on the E85/glow mix still has a few hundred rpm difference on top end between glow driver on and off. The transition and midrange improved a lot, although it still is having a slight hesitation on the transition with the glow driver off. This all indicates the plug is still not hot enough. It would definitely be flyable with on-board glow, but even a GP3300 cell at 4 amps is only about 45 minutes flying time if used full time, which it would need. I'll bet that somewhere out there is an ultra-hot glow plug in the 1/4-32 size. Tower lists about 100 glow plugs from 10 different manufacturers. Maybe one of those plugs will be hotter than the Enya#3.

I also tried a used and abused OS F plug on the ASP 108, which didn't do as well as the Enya#3 plug. There was slightly more rpm drop with the glow driver off at top end and the transition wasn't as good. I didn't try the OS F in the GP 42, it wouldn't light enough to run. Admittedly it wouldn't light before I put it in the ASP 108 but I pushed the coil down a little to get it lit for the experiment. That OS F was a used plug with a disconnected coil, and it really wasn't a fair comparison to the other plugs because the coil was not in good shape. But I really don't think the OS F is the answer, it's a medium range plug. It does have the extended nose to shield the element, so that's helping it work better than a regular medium plug. I have some other four-cycle plugs like the YS 4-cycle plug. That's probably a colder plug though, because YS recommends 20% nitro for their engines.