Tapered Bores

[Al]

Hello All!

I recall looking at adds made in pre-wwii for cars and motorcycles. One feature that was praised and shunned was tapered bores.

I tried to find some info on tapered bores, but all I found was information about straight bores being tapered due to wear.

When intentional, what is the advantage of a tapered bore?
Is it wider near the head or the crank and by how much?
Does the taper go away when the engine heats up?
Was it intended for non-ringed pistons?

[GTSLOW]

Some RC car nitro engines have tapered bores, actually I think most do.