... today's inlines ... give a smooth mesh without robbing any power.
The physics of an inline gearset will ALWAYS be less efficient than a sidewinder, with an anglewinder coming in better as the angle decreases toward having the armature shaft parallel with the axle. Part of an inline's power will always be pushing the crown gear toward the side, instead of rotating the axle. The anglewinder has less of this sideways push vector. A true sidewinder has none.
However, there are many other factors besides simple power transfer in determining whether a car is a winner. There might even be types of racing where the inline has an advantage. Looking at some of the magnet cars in the Marconi proxy race seemed to indicate that having a front-motored inline might have some advantages (to put more weight on the guide, and reduce weight far from the guide). Magnets then provided the rear-wheel traction without putting the motor and its mass on the end of a long moment arm. It was an interesting experiment.
As long as the classes don't mix inlines with angle/sidewinders, the power transfer deficit is moot.
Marcus P. Hagen -- see below, my five favorite quotes: applicable to slot cars & life in general.
[ "Everyone is entitled to his own opinion, but not his own facts.". . Daniel Patrick Moynihan ]
[ "Time is the best teacher. Unfortunately, it kills all its students.". . . . . . . . Hector Berlioz ]
[ "There is a very fine line between 'hobby' and 'mental illness." . . . . . . . . . . . Dave Barry ]
[ "Build what you like to build, they are all doomed." . . . . . . . . . . . . . . . . . . . . Prof. Fate ]
[ "The less rules the more fun. Run what you brung." . . . . . . . . . . . . . . . . . . . . . Larry LS ]