To paraphrase NASA, gentlemen, we have IGNITION.
Latest run on no ether fuel is here.
http://www.youtube.com/profile_videos?user=hopeso
I'm a little pressed for time so this'll be brief. More later.
It appears that the heat sink worked in the fashion I had hoped. It allowed the engine to run cooler, and thus nearer to the start compression than before. That in turn brought the idle adjustment within range and now we have a solid top end, a solid idle and good transition. One out of three times, rapid acceleration produced a flame out. These issues smooth out in the air so I'm hopeful and will fly the plane tonight.
To be posted to YouTube later, is a run with 30 ether and the usual suspects. The difference was that the engine WOULD start on just three or four prime runs. Hot starts were a cinch. The real deal here is that the compression and needle settings were the same as with no ether. I'm having trouble believing that so I'll be double checking during another session. The other difference was that the ether did help the idle sound smoother but only after a small tweak.
So far, it's looking more and more that ether may NOT be necessary. We just need to design the engine to use an all kero fuel. A good ignition improver is essential, along with adequate cooling for the higher temperatures the all kero generates. You don't even need ether in your prime. At least not on THIS engine, this one time.
That LM head suits helis but looks goofy on an airplane. And here I was, turning down the fins. Bad science, I should have known Norvel knew what they were doing.
It also appears that running cooler, as some of my other experiments have implied, is not a bad thing. Too hot is definitely bad, cooler seems to be OK.
And, for those of us that fly in the winter, I've noticed that engines seem to run better in the cold. Higher air density, more mix in the combustion chamber to be sure but there could be another factor.
Next session will be to go back to the stock head on a hot day like today and try again and document any diferences.