@sonhouse said
Sounds reasonable. Could the pulling effect be caused by the rather small size of the shroud? Suppose the shroud was ten times bigger with say 10 feet in all directions away from the bike, that should change the pulling effect if that is present, right?
Suppose we move the goalpost a bit: Now the track on the moon is magnetic like a maglev and the bike is maglev'd off the ...[text shortened]... force comes also magnetically. I wonder how fast she could go under those circumstances on the moon?
"Sounds reasonable. Could the pulling effect be caused by the rather small size of the shroud? Suppose the shroud was ten times bigger with say 10 feet in all directions away from the bike, that should change the pulling effect if that is present, right?"
I'm sure it would. From what I'm reading on the slipstream, a zone of low pressure is created behind the vehicle. The rear of the zone could be pushing her along a bit.
"Suppose we move the goalpost a bit: Now the track on the moon is magnetic like a maglev and the bike is maglev'd off the surface of the metal track so the pedals are now powering a superconducting alternator (virtually 100% efficient conversion of pedal power to electricity) and that energy now powers a linear electric motor while being suspended over the track magnetically and the drive force comes also magnetically. I wonder how fast she could go under those circumstances on the moon?"
Lets drop the maglev stuff because it is not intrinsic to the argument of what happens without frictional resistance of any type. Also, another thing that won't exist is a drive train that converts rotational motion into translational motion without any energy absorption of it own. For instance, even in your mag lev electrical motor drive some of the energy from your pedaling will be used to spin up the rotor.
However, since we are talking about riding bike on the moon in space suits...we can pretend.
Again this basically comes down to human physiology. I'm making an educated guess the best cyclist can sustain 250 W power output for like 4 hrs. If our cyclist has a mass of 70 kg and is beginning from rest and his/her output directly converts to translational kinetic energy then it works out to about 718 mph.
Obviously this strongly depends on the actual output and output duration of a rider.