Reliably enough to convert a good chunk to high(er) compression?
Well... You'd have to try. The engine ended up on a crap airframe, so it's hard to say. And the fact that there's a known correlation between engine compression and the amount of nitro you need, and that no one else has done this, suggests that there's something about it that maybe doesn't work for all engines all the time.
I have a bunch of stuff between .049-.15, and a Fox .35. I like the idea of a higher compression engine running the same stuff the Fox likes.
Could this work for reedies, Medallions, and a bunch of Norvels .061?
How much did you have to take off the head?
I assume you did it on a lathe.
I actually made a custom head (on a lathe) that used a regular glow plug. I made it crazy-high compression, then adjusted the compression with shims until it actually ran right. (I did find out that an overcompressed reed-valve engine will pretty much run through a tank while bouncing its prop back and forth against the compression bump -- that's not
useful information, but hey, now it's known!).
If I were going to do it again I'd use a turbo plug
like in this article.
Or check with
this guy to see if he makes high-compression heads. I suspect the answer is no, but hey -- you can ask.
So experimentation may be in order. I would expect that if you did find it practical, you'd need to plan on shimming the head for different weather conditions, and that may be more of a bother than just getting 25% nitro fuel.