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The website seems to end with a 2015 electric unicycle but not continue on with covering that form factor. Maybe because most people don't refer to those as mon

by geor9e 3y ago

The website seems to end with a 2015 electric unicycle but not continue on with covering that form factor. Maybe because most people don't refer to those as monowheels anymore. http://www.douglas-self.com/MUSEUM/TRANSPORT/motorwhl/motorwhl5.htm#air http://www.douglas-self.com/MUSEUM/TRANSPORT/motorwhl/motorw... Also airwheel is kind of a random brand to showcase - Trevor Blackwell made an earlier one https://www.trevorblackwell.com/eunicycle https://www.trevorblackwell.com/eunicycle and Solowheel got the majority of the earlier patents (and royalties to this day). That form factor has come a long way since 2015 though. Check out this MotoGP style race, they're hitting 50+mph: https://youtu.be/fbX6qaWINBk?si=l2G0JnBxxCMP8a7e https://youtu.be/fbX6qaWINBk?si=l2G0JnBxxCMP8a7e I see them every day whizzing across San Francisco, especially on Van Ness passing all the cars. I know there's at least two shops in SF selling them, one in Potrero and one in Hayes Valley - https://alienrides.com/collections/electric-unicycles https://alienrides.com/collections/electric-unicycles - https://lastmilepev.com/collections/electric-unicycle-euc https://lastmilepev.com/collections/electric-unicycle-euc Unicycle seems to be the winner. The "wrap around the body" form factor seems doomed from a physics point of view. That big of a diameter has way too much leverage, and the person sitting inside has too little. So you end up doing a flip instead of stopping. As such, their required stopping distances are very long compared to unicycles which can stop as well as a bicycle, if the rider is skilled.

airstrike 3y ago
ok, that race video was as fun to watch as it was unexpected
dylan604 3y ago
> The website seems to end with a 2015 With the style of the website, I'm shocked it has anything after 2000
Panzer04 3y ago
I don't think (electric included) unicycles will ever have the same stopping performance of conventional vehicles - the center of gravity is just much further forward than in any two-wheeled vehicle. The requirements imposed by the balancing mechanism limits the possible braking force to how far behind the wheel a person can get. They can still stop plenty fast enough for most purposes, though, and it's a very natural action compared to almost any other vehicle. On wheel size - yeah, its the case that the smaller the wheel, the more responsive a unicycle becomes to torques applied by a person's body. It becomes a tradeoff between the resilience of a large wheel to bumps and terrain, and the responsiveness afforded by a tiny wheel (which takes less torque to apply a given forward/backwards force)
- geor9e 3y ago
  I disagree. Having a single wheel has the benefit of maximizing traction. With multiple wheel vehicles, if you apply the brakes to some wheels and not others, the tires lose traction. This is because those tires don't have enough normal force (weight) pushing them into the ground. I know my car only applies brakes to the front wheels. Any all-wheel-braking vehicle like a unicycle can beat my car to a stop, for that reason alone. It takes a sporty rider to be good at hard braking on EUC but I've seen them stop extremely fast. Especially some of the riders who race around manhattan. They have a handle on their EUC, and throw their entire weight behind the wheel in a crouch, like a cowboy bucking a bull. Their center of gravity gets near the ground. The motors on their wheels are extremely powerful, 10kW or more in either direction. It takes a skilled rider though. The main danger of super hard braking in the EUC community is the notorious "death wobble" that amateur riders sometimes get, where it starts oscillating right and left the harder you brake. Good riders grip things stiff enough to not have that issue though.
  - OrigamiPastrami 3y ago
    Having fewer wheels does not mean you have more traction - contrary to popular belief, a racecar can trivially out-brake a MotoGP bike despite weighing an order of magnitude more. The contact patch size matters more than the number of contact patches. This is ignoring the issue of perfectly balancing a unicycle to stop effectively, where just the time it takes to transition from leaning forward to backwards is a significant cost in time and distance for braking compared to any vehicle that has inherent lateral stability (such as a car or a motorcycle). > I know my car only applies brakes to the front wheels. I doubt this. What kind of car do you have? Almost all modern cars apply brakes to all 4 wheels. In most cars which have most of the weight in the front the brake bias is approximately 80% front and 20% rear. For mid-engine cars this usually shifts to 60% front and 40% rear. Some cars might be somewhere in between depending on their weight distribution. The limiting factor in braking is tires, and the way to improve that is by increasing the contact patch size - which is done by increasing tire widths, diameters, and the number of tires.
    - 3y ago
05 3y ago
In theory, the braking performance could be the same as the bicycle. In practice, the rider needs to guess the traction very precisely and to move their weight backwards to an angle just a smidge higher than arctan(static friction coefficient). Do you start to see a problem here? While the bicycle rider only needs to move their weight so that the combined center of mass is projected between the contact patches of the wheels during the deceleration, the EUC rider absolutely needs this to be as close to the contact patch as possible. Shifting the weight too far back means an almost guaranteed wipeout, and you don’t know if the road is squeaky clean or has some trace amounts of sand that would reduce traction, so any sane rider would err on the side of caution and under-brake to avoid falling on their back.
- loa_in_ 3y ago
  Did you ever ride on one? They brake using the motor so it doesn't wipe you out. At worst you stand on the ground, but mostly you just start riding backwards.
  - 05 3y ago
    I own one and I can assure you it’s very easy to fall on your back if you overestimate the friction when braking aggressively. Not even close to real life bike braking with disc brakes if you know how to transfer your weight properly (granted, a newbie would totally fly over the handlebars if they tried to brake to the limit without shifting their weight behind the seat..)
    - geor9e 3y ago
      Odd - I ride EUC and bike mainly, and bike is easier to skid on accident. Opposite experience as you. It makes sense too, since on an EUC 100% of the normal force is utilized for friction force. On a bicycle you can only utilize 100% if you're extremely good at applying the front and back brake at the perfect ratio to each other.
- geor9e 3y ago
  >arctan(static friction coefficient) >needs this to be as close to the contact patch as possible That's not true, or perhaps you mean something other than how those words are directly interpreted? Static friction force isn't an arctan, it's just the normal force (which is you+wheel weight) x the friction coefficient. That's the force that's slowing your motion. And being close or far from the contact patch doesn't affect that at all. Elaborate what you're thinking?

by geor9e 3y ago

airstrike 3y ago

ok, that race video was as fun to watch as it was unexpected

dylan604 3y ago

> The website seems to end with a 2015 With the style of the website, I'm shocked it has anything after 2000

Panzer04 3y ago

I don't think (electric included) unicycles will ever have the same stopping performance of conventional vehicles - the center of gravity is just much further forward than in any two-wheeled vehicle. The requirements imposed by the balancing mechanism limits the possible braking force to how far behind the wheel a person can get. They can still stop plenty fast enough for most purposes, though, and it's a very natural action compared to almost any other vehicle. On wheel size - yeah, its the case that the smaller the wheel, the more responsive a unicycle becomes to torques applied by a person's body. It becomes a tradeoff between the resilience of a large wheel to bumps and terrain, and the responsiveness afforded by a tiny wheel (which takes less torque to apply a given forward/backwards force)

geor9e 3y ago
I disagree. Having a single wheel has the benefit of maximizing traction. With multiple wheel vehicles, if you apply the brakes to some wheels and not others, the tires lose traction. This is because those tires don't have enough normal force (weight) pushing them into the ground. I know my car only applies brakes to the front wheels. Any all-wheel-braking vehicle like a unicycle can beat my car to a stop, for that reason alone. It takes a sporty rider to be good at hard braking on EUC but I've seen them stop extremely fast. Especially some of the riders who race around manhattan. They have a handle on their EUC, and throw their entire weight behind the wheel in a crouch, like a cowboy bucking a bull. Their center of gravity gets near the ground. The motors on their wheels are extremely powerful, 10kW or more in either direction. It takes a skilled rider though. The main danger of super hard braking in the EUC community is the notorious "death wobble" that amateur riders sometimes get, where it starts oscillating right and left the harder you brake. Good riders grip things stiff enough to not have that issue though.
- OrigamiPastrami 3y ago
  Having fewer wheels does not mean you have more traction - contrary to popular belief, a racecar can trivially out-brake a MotoGP bike despite weighing an order of magnitude more. The contact patch size matters more than the number of contact patches. This is ignoring the issue of perfectly balancing a unicycle to stop effectively, where just the time it takes to transition from leaning forward to backwards is a significant cost in time and distance for braking compared to any vehicle that has inherent lateral stability (such as a car or a motorcycle). > I know my car only applies brakes to the front wheels. I doubt this. What kind of car do you have? Almost all modern cars apply brakes to all 4 wheels. In most cars which have most of the weight in the front the brake bias is approximately 80% front and 20% rear. For mid-engine cars this usually shifts to 60% front and 40% rear. Some cars might be somewhere in between depending on their weight distribution. The limiting factor in braking is tires, and the way to improve that is by increasing the contact patch size - which is done by increasing tire widths, diameters, and the number of tires.
  - 3y ago

05 3y ago

In theory, the braking performance could be the same as the bicycle. In practice, the rider needs to guess the traction very precisely and to move their weight backwards to an angle just a smidge higher than arctan(static friction coefficient). Do you start to see a problem here? While the bicycle rider only needs to move their weight so that the combined center of mass is projected between the contact patches of the wheels during the deceleration, the EUC rider absolutely needs this to be as close to the contact patch as possible. Shifting the weight too far back means an almost guaranteed wipeout, and you don’t know if the road is squeaky clean or has some trace amounts of sand that would reduce traction, so any sane rider would err on the side of caution and under-brake to avoid falling on their back.

loa_in_ 3y ago
Did you ever ride on one? They brake using the motor so it doesn't wipe you out. At worst you stand on the ground, but mostly you just start riding backwards.
- 05 3y ago
  I own one and I can assure you it’s very easy to fall on your back if you overestimate the friction when braking aggressively. Not even close to real life bike braking with disc brakes if you know how to transfer your weight properly (granted, a newbie would totally fly over the handlebars if they tried to brake to the limit without shifting their weight behind the seat..)
  - geor9e 3y ago
    Odd - I ride EUC and bike mainly, and bike is easier to skid on accident. Opposite experience as you. It makes sense too, since on an EUC 100% of the normal force is utilized for friction force. On a bicycle you can only utilize 100% if you're extremely good at applying the front and back brake at the perfect ratio to each other.
geor9e 3y ago
>arctan(static friction coefficient) >needs this to be as close to the contact patch as possible That's not true, or perhaps you mean something other than how those words are directly interpreted? Static friction force isn't an arctan, it's just the normal force (which is you+wheel weight) x the friction coefficient. That's the force that's slowing your motion. And being close or far from the contact patch doesn't affect that at all. Elaborate what you're thinking?