Forces applied to a leaning levitating bicycle

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Discussion Overview

The discussion revolves around the forces acting on a levitating electromagnetic bicycle, particularly focusing on the effects of leaning during turns. Participants explore the dynamics involved when the bicycle is at a 45-degree angle while considering the weight of the rider.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant describes the design of an electromagnetic bicycle that levitates over its wheels, aiming to reduce rolling friction by eliminating bearings.
  • Another participant proposes that the bike leans to achieve a net torque of zero from centripetal force and gravity, suggesting that the net force acts through the contact point on the ground, leading to a notionally zero side-to-side force.
  • A mathematical expression is provided to calculate the load on the axle magnets, incorporating centripetal force and gravitational force, though the participant seeks verification of this approach.
  • It is noted that in reality, side-to-side loads will not always be zero due to factors like acceleration and road conditions.
  • A different participant emphasizes that rolling resistance primarily arises from tire deformation rather than hub bearing friction, while also noting that air resistance is a significant factor in overall losses.

Areas of Agreement / Disagreement

Participants express differing views on the simplifications made in the model of forces acting on the bicycle. While some agree on the theoretical framework, others highlight the complexities and real-world factors that could affect the analysis, indicating that the discussion remains unresolved.

Contextual Notes

The discussion includes assumptions about the forces acting on the bicycle and does not resolve the complexities introduced by real-world conditions such as acceleration and terrain variations.

Qwerty42
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Hi!

So I'm building an electromagnetic bicycle where the frame is levitating over the wheels, thus reducing the rolling friction to almost zero by removing the bearings. Magnets have also been placed alongside the wheels to provide side to side stability. Black is the frame, red are the magnets on the wheel and yellow are the magnets attached to the frame to stabilize side to side movement from the wheel. Se the attached image. Since the wheel is held in place purely by magnetic forces, it can move if enough force is applied to it.

My question is: How much force would affect the axle magnet and side-to-side magnets when the bike is turning and thus leaning at let's say 45 degrees? Let's assume that the person riding the bike is weighing 50 kg.
linetrack.500.jpg


Thanks!
 
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I think bikes lean over so that the net torque on the bike due to the combination of centripetal force and gravity is zero. I think this means the net force on the bike and rider will be directed through the contact point on the ground. So the side to side force is notionally zero.

The load on the axle magnets is the vector sum of the centripetal force and the force due to gravity.

Cyclist.png

Using Pythagoras that gives

N =√{(mv2/r)2 + (mg)2}

where
m is the mass of the rider and bike
v = velocity
r = radius of the turn
g = acceleration due to gravity

Can someone check I have this right as it's been a long day.
 
Obviously the side to side load won't always be zero in reality but in that simplistic model it is. In the real world there is acceleration as the bike leans over not to mention bumps etc etc.
 
Qwerty42 said:
I'm building an electromagnetic bicycle where the frame is levitating over the wheels, thus reducing the rolling friction to almost zero by removing the bearings.
Rolling resistance comes mostly from the deformation of the tires, not from friction at the hub bearings. But most loses come from air resistance anyway.
 
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