Bevel gears can be made with the centres in line or with off set centres. (The off set ones are also known as hypoid )
Theoretically a crown gear and parallel pinion isn't a very satisfactory gear arrangement because the teeth on the crown have to get closer together as they get nearer the axle, the teeth on a parallel pinion don't. That means the pinion teeth can only be the correct size for the crown at one diameter. Making both gears conical means they can be made so the teeth match properly across their complete width.
Bevels should be better and if you look inside how 1:1 car transmission turns the drive through 90 degrees and you'll find they almost always uses some variation on bevels.
Bevels have been used many times before on slot cars. Getting the length ways position of both axle and pinion correct is important to getting bevels working correctly, where as it doesn't matter much with parallel pinions. Crown gear and parallel pinion set ups seem to work well enough on slot cars whatever the theoretical disadvantages.
How well a particular make of slot car gear works largely depends on the quality of design, manufacture and materials rather than the basic type. Anybody like to offer any experience of Black Arrow
EDIT Looks like Bill and I were typing replies at the same time - fortunately we don't seem to conflict
Theoretically a crown gear and parallel pinion isn't a very satisfactory gear arrangement because the teeth on the crown have to get closer together as they get nearer the axle, the teeth on a parallel pinion don't. That means the pinion teeth can only be the correct size for the crown at one diameter. Making both gears conical means they can be made so the teeth match properly across their complete width.
Bevels should be better and if you look inside how 1:1 car transmission turns the drive through 90 degrees and you'll find they almost always uses some variation on bevels.
Bevels have been used many times before on slot cars. Getting the length ways position of both axle and pinion correct is important to getting bevels working correctly, where as it doesn't matter much with parallel pinions. Crown gear and parallel pinion set ups seem to work well enough on slot cars whatever the theoretical disadvantages.
How well a particular make of slot car gear works largely depends on the quality of design, manufacture and materials rather than the basic type. Anybody like to offer any experience of Black Arrow
EDIT Looks like Bill and I were typing replies at the same time - fortunately we don't seem to conflict
