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Old 10-17-2020, 05:42 PM   #51 (permalink)
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So i overcame the math anxiety and used the power equation from "The Leading Edge" by Goro Tamai To calculate power requirements. Given a gross weight of 300 lbs or 1335 N and 0.40 square meter frontal area, at 30 mph and the Cd of 0.3 the power needed is about 360 watts. This is about 1/3 less than an bare bike and an adult rider with a Cd of 0.60.

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Old 10-18-2020, 03:39 PM   #52 (permalink)
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Subscribed. If you include my daily paper route that I did by bicycle, I have about 5 decades of bicycle commuting experience. As the OP has stated “If it were easy, everyone would be doing it.” There are a number of design considerations that make reducing aero drag on a bicycle very difficult. Aero drag on a Battle Mountain streamliner can be very low but they are totally impractical to ride. A faired recumbent trike can strike a good balance between function and low drag but you add weight, length and perhaps some issues with visibility. Adding a fairing to an upright cycle can add frontal area in crosswinds. I did the bulk of my commuting with a drop bar bike which allowed several hand positions including getting flat and low when confronted with strong winds.

I look forward to your progress with this.
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Originally Posted by freebeard View Post
The power needed to push an object through a fluid increases as the cube of the velocity. Mechanical friction increases as the square, so increasing speed requires progressively more power.
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Old 10-19-2020, 01:51 PM   #53 (permalink)
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It surprised me to see that rolling resistance was as much as a factor with common mountain bike tires. I calculated 175 watts for tires, tubes, and max weight. Air pressure of 65 psi is often recommended for these tires. Next tests will be for a reinforced front piece.

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