Jim,

Two things to try. A glow plug unergized and also one where you light the thing to get the engine running with less than ideal compression. Then you crank it down and away you go. Question is how.

Martin,

You're right, most model diesels run fine as long as you have good fuel and your compression seal is good. Just wondering though, if adding a hot spot might allow for the use of less ether (expensive and harder and harder to get) and an ignition improver, (not expensive but also getting harder to get).

What if, using a glow element of some sort in some kind of adjustable contra piston arrangement, you could eliminate or reduce the use and/or need for ether and ignition improver. Despite needing to light the damn thing, you'd get the benefits of kero combustion, with high compression ratios, driving insanely large props with stump pulling torque.

Yes, the element would get fouled but no catalytic action expected, just a glowing hot spot to initiate ignition more easily in the absence of a lot of ether. Could be that this hasn't been tried because of the seemingly insurmountable problem of a way to light the glow plug while retaining the adjustable feature of a contra piston.

What if you could also run glow fuel on the same engine but also be able to adjust the compression ratio to optimize power and efficiency? Just an exercise in what if and why not. Long winter coming, might just give it a go. Hey, remember Motorboy? If somebody had said he had a dieselized model four stroke, Ida said no way, can't be done. But it was done in a very unique and interesting way. And I had fun dieselizing my baffled piston Veco .19. No practical reason for it, just had to see if it could be done.

Actually, the impetus for this notion came from Ringwing who has a head for his soon to be received Norvel .074. I had encouraged him to use MEKP but his technical background and natural caution prompted him to suggest that I cease and desist. I've ordered his recommended Amsoil cetane booster but in the meantime, discussions of the need for a booster and also the need for ether led both of us to wonder how these ingredients might be minimized or eliminated. Imagine buying a jug of kero and 40W50 oil, totally cheap and going flying without all the hassle.

Another question. We normally just use our fuel to prime the engine and that works fine but what about using just ether with 25% oil as a priming mix? Might this allow a start using a lower ether content fuel? Or a start where your compression setting is way off, as in undercompressed? Just to get the &%#$@ thing going and fuel up the line?

Scorpio.

I saw a bit of a write up by Clarence Lee, I think, a few months back in RCM. Sorry, I can't find that issue off hand but I believe the thing is still available. Maybe just Google "Gadjet" and see what you get?