Converting a MTB to E-Assist using cheap scooter parts
I am curious if anyone here has done this before. I have a cheap electric scooter I picked up from goodwill, and would like to use it's parts on another cheap 21 speed MTB I ride in order to make my commute manageable by bike. I'm currently waiting for the charger, so I can get a feel for how fast and how far the electric scooter can go before I decide if it is worth it.
My biggest design challenge I've found so far is how the motor will assist. The friction drive method seems fairly easy, but I don't think that is the best in the long run.
My next thought is one found on this site and a couple of other places is to use a flip flop hub, and with some customizing drive the left side of the rear wheel through a chain of some sort.
Finally, the other option I've come up with is mounting the motor in front of the pedal / gearing.
One worry for the second two solutions is the RPM of the motor versus the RPM of the tire. I know there has been extensive talk here about that subject, most of it going over my head. What do you think would be the easiest method to make this work? I'm trying to avoid welding, but it's doable since a welding shop is nearby.
Also, if anyone has done this before, I'd love your thoughts or pictures. Here is a picture of the scooter I am working on, even though it's pretty standard. Thanks!