Counter Rotating Brakes Vid

[GAMBLER]

video:
http://www.reverserotatingrotors.com/media/test.wmv

more info:
http://www.reverserotatingrotors.com
link to patent:
http://patft.uspto.gov/netacgi/nph-P...S=PN/6,918,467

[Just Riding Along]

Wow. "Increase unsprung weight now, ask me how!"


How about just going with some real brakes, BrakeTech?

[Still SP3]

A highly professional video with some of the best narration I've heard in a while. Sure to sell lots.

[Dezmo]

hrmm, ever heard of gyroscopic precession billy? without getting into a pile of physics, its what makes motorcycles lean into corners.

now what happens when you take about half that force and reverse its effect? hmmmmmmmm

[speedkills]

I have to hand it to them at least they're thinking out of the box. It's a great way to neutralize the gyroscopic effect. To bad about the increased unsprung weight and parasitic frictional loss.

[Dezmo]

Originally Posted by speedkills

It's a great way to neutralize the gyroscopic effect.

Uhm, you want some gyro effect, otherwise you have a bike that stops fabulously, but wont turn at any speed.

I would wager that with a lightweight mag or CF wheel and those brakes, there wouldnt be enough positive gyro effect to turn the bike.....not only is it less effect, but its having to overcome the negative effect of the brake rotors.

We wont even get into how much smaller the rotors are than stock

[banda]

Originally Posted by Dezmo

hrmm, ever heard of gyroscopic precession billy? without getting into a pile of physics, its what makes motorcycles lean into corners.

now what happens when you take about half that force and reverse its effect? hmmmmmmmm

Common misconception - I don't fault you for repeating it. Someone somewhere tried to connect the old "twist the spinning object, and the force is redirected through 90 degrees" freshman physics lesson with the behavior of motorcycles on the road, and they stopped there at the thought experiement.

It's not true. Motorcycles handle just fine even when you go to great lengths to cancel out the rotational inertia of the wheels.

Motorcycles tend go in a straight line becuase of the castor effect of the contact patch of the front wheel being behind the axis of the steering head - "trail".

Motorcyles don't lean because they are turning, but rather they turn because they are leaning - the tires are narrower in diameter at the edges than they are in the center, causing them to roll in an arc when leaned over - like a styrofoam coffee cup lying on its side. Coning.

Rotational inertia has nothing to do with the physics of motorcycling except for the fact that a wheel with a greater moment of inertia takes more energy to start and stop, and a heavier wheel requires more spring and damping force to keep it in contact with the road. But that's not what makes a motorcycle balance or turn.

[249]

I am not good at physics type stuff, and it may be that I mis-read your post.

But- I've gotta believe that gyro effect of wheels increases stability. Why is it easier to balance a motorcycle going 10 mph than one at rest?

[Dezmo]

Kevin Cameron wrote a whole column about this, I wish I had a link to it.
He basically explained that rotating mass of a front wheel has to be above an ideal percentage of total bike mass, otherwise it will not have enough steering effect. Cameron's example was a goldwing with lightweight sportbike wheels. Most bikes' stock wheels easily exceed this level, and thus they turn just fine. Lightweight wheels (on a sportbike) reduce the percentage, but its still above the ideal percentage.

I agree 100% that precession does not make the bike turn, precession makes it lean, leaning makes it turn, which is what I said in my 1st post

[banda]

Kevin Cameron, brilliant as he is, is just wrong about this.

The Wright brothers (bicycle makers before anything else) were the first to describe the physics of single track vehicles and how countersteering makes bikes turn.

What happens when you yank the wheel of your SUV to the left while driving? The body rolls in the opposite direction, to the right. That's just disconcerting in an SUV, but on a motorcycle, the effect is to roll the bike onto a coned part of the tire... that's how the corner is initiated.

Gyroscopes got nothing to do with it. To prove it, motorcycles have been constructed with counter rotating sub wheels to cancel out or even override the gyro effect. Guess what. They still turn just like a regular motorcycle.

Gyro shmyro. Even Kevin Cameron can make a mistake.

[banda]

Originally Posted by 249

I am not good at physics type stuff, and it may be that I mis-read your post.

But- I've gotta believe that gyro effect of wheels increases stability. Why is it easier to balance a motorcycle going 10 mph than one at rest?

At rest, there is no force straightening out the front wheel. When you get moving, the trailing contact patch exerts a torque about the steering head that that counters any difference between the yaw of the front wheel and the direction of travel.

Front wheels on a grocery cart point any direction they feel like when it's not moving. Once the cart is moving, they point away from the direction of travel. Same thing on a bike.

[Dezmo]

Originally Posted by banda

At rest, there is no force straightening out the front wheel. When you get moving, the trailing contact patch exerts a torque about the steering head that that counters any difference between the yaw of the front wheel and the direction of travel.

Front wheels on a grocery cart point any direction they feel like when it's not moving. Once the cart is moving, they point away from the direction of travel. Same thing on a bike.

this is all very correct, but it has nothing to do with what initiates a turn. And anyone who thinks that a spinning wheel doesnt impart some stability via gyroscopic effect is a fool.

And sorry banda, but I gotta go with kevin on this one, his rep has a smidge more cred than yours

[Gog]

I was scribbling some quantum notes to myself
.

I was musing that


keeping in mind


it's obvious!

!!!!

But thats just a hunch.

[Just Riding Along]

Wow we've run off the rails pretty quick here. A lighter wheel is going to be easier for the suspension to control, and easier for the rider to steer.

Same for cars, motorcycles, bicycles, and so on. It's Got nothing to do with counter-steering.

Kludging in some crazy BAR style counter rotating gearbox to cancel torque or reduce inertia is just nutty when there are simple and reliable fixes like lighter rotors, or a lighter wheel.

The old saw about re-inventing the wheel is really lost on these guys.

[banda]

Originally Posted by Dezmo

this is all very correct, but it has nothing to do with what initiates a turn. And anyone who thinks that a spinning wheel doesnt impart some stability via gyroscopic effect is a fool.

Sure, rotational inertia has a stabilizing effect, but it's a minute component of what keeps a bike upright and tracking on its path. If you took gyroscopic effect away completely, the bike is still stable.

The castor effect of the trail of the front wheel has way more to do with it. If gyroscopic effect is so important, then let's see you ride a two wheeled vehicle with zero or less trail... with no hands! I'll spot you the heaviest wheels we can find, you'll still fall on your head.

Originally Posted by Dezmo

And sorry banda, but I gotta go with kevin on this one, his rep has a smidge more cred than yours

It's your right, and no one would blame you for listening to him instead of me. But you and I can prove him wrong with just a little bit of work.

[Dezmo]

Originally Posted by banda

Sure, rotational inertia has a stabilizing effect, but it's a minute component of what keeps a bike upright and tracking on its path. If you took gyroscopic effect away completely, the bike is still stable.

Do you mean the gyroscopic effect of the front wheel or the whole bike? A bike is essentially a giant collection of gyros. Crank webs, clutch baskets, sprockets, transmission gears, even camshafts to a small degree all contribute to a bike's gyroscopic stability.

Originally Posted by banda

The castor effect of the trail of the front wheel has way more to do with it. If gyroscopic effect is so important, then let's see you ride a two wheeled vehicle with zero or less trail... with no hands! I'll spot you the heaviest wheels we can find, you'll still fall on your head.

My 'fiddy' has about .9" of trail....its twitchy as hell (and I like it that way), but its most definately more stable once you get the wheelspeed up....over rough ground the slow and methodical method will put you on your ass, but crank it WFO and hang on for the ride, and youre all good. And were talking about a bike with 10" spoked wheels that might weigh 4lbs each with tires

[Old Baldy]

While I'd agree that wheel inertia has little to do with steering, other than the capability to quickly turn the front wheel at low speeds to initiate the counter-steer roll action - the amount of inertia has an indisputable affect on the STABILITY of the wheel.

Simply put, the lower the inertia of the front wheel, the easier that assembly can be flicked from side to side. That is physics. No argument about it.

Now, consider how this affects the ability of the front assembly to resist any headshake or tankslapper instability. My guess? Any geometry/tire/weight motorcycle configuration that is close to borderline stability can become unstable given a much reduced inertia/gyro force from the front wheel.

I'd agree that in a normal tire/rotor/wheel design, without any specifically designed counter-rotating mass, and even with very light components such as carbon wheels and brakes, there is enough inertia/gyro force from the whole assembly (especially from the tire), to not present a problem. But, purposely negate the gyro stability altogether? I'd want someone else to be testing that on a high-speed bumpy road under hard acceleration!

[Just Riding Along]

Interesting take on non-traditional geometry.

[PSk]

While this is a clever and interesting idea (I am not going to get into the 'does it work part', cause I simply do not know ... ) the last time somebody put something mechanical between a wheel and the brake ... things broke and brakes failed.

Ofcourse last time is a generalisation, but in the 60's Lotus in F1 and others tried to mount their front brake disks inboard to save unsprung weight ... this thus required 'brake' shafts to take the braking force out to the wheel, and they broke ... and thus had to be beafed up (negating a lot of the original advantage). BRM also tried to mount a single rear disc on the rear of the gearbox and thus brake through the gearbox and this caused dangerous failures.

Thus sorry I do not want gears to be the possible weak link on my bikes brakes ... I'll happily stick with 'button's and bolts/nuts. With this concept when you brake there is like 3 teeth taking all the braking load at any one time ... yeah should be okay, but then so should Lotus' and BRM's idea. I think once you over design the gears to ensure safety you will have made the assembly much heavier and thus will this reduce the effect they are after?

While the plantary (sp?) gear assembly is in the centre of the wheel it is pretty large and will have to be made out of some sort of steel ... as you beaf it up (for us scared riders ), it will get larger and heavier.

Just my ... on what appears to be a possibly clever idea, just a little risky.
Pete
ps: When hydraulic brakes were invented many did not quickly adjust to the idea because there was not a direct link from the pedal to the brakes ... ofcourse there really is, but apparently now companies like Bosch have been developing electrical brakes ... the reason why we probably won't see this is because I'm fncked it I am going to rely on a switch and actuator to brake my car ... it needs to be a direct link. Maybe this will change over time ... but it will take many years for Bosch (or whoever) to change our perspective and make people like me think of electrons as direct connections.

[Old Baldy]

Originally Posted by PSk

.....the reason why we probably won't see this is because I'm fncked it I am going to rely on a switch and actuator to brake my car ... it needs to be a direct link. Maybe this will change over time ... but it will take many years for Bosch (or whoever) to change our perspective and make people like me think of electrons as direct connections.

I'm kinda with ya, but have ya ever flown in a newish Airbus?