Hi again AMB,
I was loathe to mention the hydrophilic nature of methanol before as I know that some full size engines use a methanol/water mixture to boost octane ratings and thus power but what I don't know here is whether your engine ingested a homogenous fine 'mixture' or simply small and seperate drops of water that exploded into steam.

Isuspect the latter.

But there are also rare occurances of full sized diesel engines using water injection in the inlet manifold, but here it is done through the medium of an injector and thus is a fine mist as it is very easy to over hydrate a diesel. So my best guess is you got the combustion process interferred with by undispersed droplets that did not mix with the fuel and thats what caused the misfiring.

And Jim, what would you do if the rain storm you were flying in turned into a lightening storm? Ditch the model? (Have fun wrestling over that one!)