It's been a while since I looked at Homepower's marketplace page.
I'm a site member at Homepower and able to buy single or more archive issues, but apparently they've made an additional layer called "online member" which is a paid position and gets you a year's digital issue subscription. An additional $9.95 annual gets a print version mailed to your home.
I'm not surprised at this. Homepower used to be digitally FREE online for many years apparently subsidized heavily by the advertisers. But slowly and surely they've tightened the profitability screw and first charged for archive and then current digital issues. I guess you could say the free exchange of information has it's limits.
I have issue #104 in paper. Unfortunately this precludes me from "cutting & pasting" here online and since it is copywrited, I'd be subject to the force of law if I did so. As an ordinary member, however, you or I can get it for the cost of an digital archive issue which is only $5.
Burdon's Surplus Center has PM magnet motors which can be used for this. See
http://www.surpluscenter.com It almost doesn't matter which motor generator you choose providing it has the capability of 200 or more watts, and an output/input voltage greater than 12 volts - the battery will hold it in line voltage wise and the amount of push on the pedals will tell you if the pulley on the motor is too big or too small.
As an accessory to constructing the exercise bike which can be done from parts for less than $100, I might also suggest you purchase a digital watt-hour meter to track your output. A suitable meter can be seen at
http://www.rc-electronics-usa.com/ammeters/dc-amp-meter.html This is a product used with remote control racing cars but well suited to this use as well. The only downside to this meter is that it's "one-way" only. You have to wire it first between the generator and battery and then between battery and end use to fully track energy input and output to your system. Bogart Engineering's Tri-metric meter will do this and more and is a step upwards in convenience - but at considerably greater cost.
I've considered that at now middle age and survivor of a heart attack, that with this device I now have the ability to track and monitor my output capabilities over the remainder of my lifespan. The time and money to construct such a pedal powered generator might be a good investment in my health as well as the ultimate prep item.
See also
http://www.homepower.com/article/?file=HP106_pg108_Letters_2
Also google "Frank R. Leslie" and you'll see several articles of environmental/energy saving/green bent as well. Interesting guy!
Best,
Joe