Hmmm, well, I'll make a guess at this.... Let's say you're flying through a cloud and your engine is ingesting a certain volume of air...in that air, only a relatively small percentage of that total volume of air is actually water. Imagine if you took all those miniscule water droplets from the cloud and condensed them... I'm guessing you would end up with very little water. Remember a cloud isn't only water droplets, it's water droplets suspended in air.

Similar story for rain...the engine is ingesting many hundreds of cubic feet of air, of which only a small portion is liquid water.

I imagine if you put enough water down the intake the fire would go out, but I saw a show on TV about the testing the engines for the Boeing 777 had to be put through. They were run on the ground and water was sprayed into the intake at the equivalent of a tropical downpour... not even a hiccup.

That's it, that's my guess!

As to whether RC turbines would do as well...couldn't tell you, but I imagine they'd stay running in conditions that would have me running for shelter.