Hi Randy
Quick word on power, lowell uses an X5 motor, they are big motors and can easily take a lot more than 500W infact there are people on here pumping 3.5KW in to them and they are working fine and do climb hills well, D has been climbing those hills with one for a year with no motor burn ups or controller failures.
The thing that concerns me with your system is 2 fold, the chain noise must be quite considerable as you are turning it at the motor at 3000 rpm or so, this will always be noisy and noisier as the chain wears, secondly its not very finger or clothing friendly either.
Also if you get a puncture its a lot more hassle getting the wheel off with 2 chains to get on, you also dont mention in to the cost factor the geared hub, these are very expensive and as I said previously require some engineering skills to graft the sprockets on.
I think your system is a good idea in general but there are downsides to it, here is the way i see it.
Randy Bike.
Pros
Efficient, good hill climber with good efficiency, powerful, fast
Cons
Noisy chain drive, tricky to setup, relatively expensive c/w geared hub, not very stealthy esp. on an island where e-bikes are illegal, may not fit all frame types easily, not available as an add on kit anyone can buy.
Brushless Hub Motor
Pros
Available! easy to fit, good range of motors to suit requirements, silent, easy to fit front or rear, cheap, no moving parts or noisy chains, powerful, fast.
Cons
High power motors are heavy, unless geared not as good at hill climbing as geared motors, not as efficient as geared systems.
I think thats a fair assessment Randy, the noise and stealth factor are very important for people I know this having been on the boards for such a long time, no matter what chain you use its going to be noisy, the xlyte motors are near as damn it silent, also like I said stealth, this is important esp when you are running high power.
I like your system and you are right in a lot of what you say but for the majority the hub motor is a much simpler solution, of course a multispeed geared brushless hub motor would be the killer!
I am going to have a go at a version of your bike Randy as I agree with a lot of what you say, and I think it will be fun to have a go to see if it lives up to the hype.
Knoxie