Not only does he design and make his own recumbents, he has developed a power assist methodology that's a right fit and use of appropriate technology as he succinctly explains below:
The idea of power assist for a bicycle is to add a motor while retaining the functionality of the bicycle. A power assist is for use on steep hills where it is most needed and turned off where pedal power alone is adequate. It differs from traditional mopeds which are small motorcycles and can't be reasonably pedaled without the motor.To retain bicycle function the power unit must be light weight and not impede pedaling when not being used. It's possible to maintain light weight since the power requirements are quite small. An average rider can provide some 75 to 100 watts of power on a continuous basis (8 hours). An assist providing this power would be adequate and it shouldn't provide more than two or three times this power lest it overpower the rider. My wife and I like touring, self supported bicycle tours. We're usually getting away for a trip of several weeks to a month each summer. I became interested in power assist for touring. I thought it would be wonderful to turn those 10 mile, 7%, 3+ hour pain-ridden climbs into 1+ hour more pleasant climbs. I was right, it is wonderful. We had also found ourselves planning tours and side trips around the terrain rather than where we'd like to tour and what we'd like to see. Having power assists allows us to tour many more places and take all the side trips we'd been passing up.For touring a gasoline engine is the only reasonable alternative. The other common option is electric which is a good alternative for around town and commuting. Electric assist tends to be heavier for the power output but reasonable systems can be built. However, for touring where the hills are much longer (read mountain passes) and electricity isn't always available for charging, gasoline wins out. Gas is readily available on the road and we can also use it in our stove in a pinch.
Finding a small low power gasoline motor is a trick though. The smallest available are string trimmer motors of about 20 cc displacement. These develop about 1 HP, or 750 watts. This is more, and thus heavier, than needed but again is about the smallest available. For my assists I decided to use a Honda 22cc four stroke string trimmer motor. It is a little heavier, and more expensive, than similar two stroke engines. However it is much cleaner, a little quieter and doesn't require a gas/oil mixture. So far I've been very happy with the choice.
Needless to say, I am a huge fan of this kind of thinking. It represents a well reasoned and clearly articulated use of appropriate technology that easily recognizes when enough is enough.
Hats off to Professor Currin for following his own bent. His website can be seen here
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