New tech: Counter Rotating rotors - Sportbike Forum: Sportbike Motorcycle Forums
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post #1 of 43 (permalink) Old 02-17-2006, 08:11 AM Thread Starter
 
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New tech: Counter Rotating rotors

http://www.reverserotatingrotors.com/


Neat and simple idea. Cancel most of the gyro forces of the front wheel.
The only disadvantages I can see right away are increased unsprung mass and increase cost/complexity.

Still very neat.



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post #2 of 43 (permalink) Old 02-17-2006, 08:53 AM
 
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It doesn't go into any detail on how this is achieved and the associate weight increase over conventional rotors.

Not too good for the track I would think. A sudden increase in gyroscopic forces as the rider brakes midcorner is just another handling issue for racers to contend with.

Still, good to see that some are thinking outside the square...
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post #3 of 43 (permalink) Old 02-17-2006, 08:58 AM Thread Starter
 
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Why a sudden increase?

I'm willing to bet the system uses several gears in a planetary arrangement inside the hub to spin the rotors the opposite direction of the wheel. The rotors will always spin in the opposite direction wether the brakes are applied or not. The gears will have to be strong enough to withstand braking forces. Additionally gear lash may play some interesting affects here.

Now, with different gear ratios it should be possible to spin the rotors fast enough to cancel the gyro forces of the front wheel entirely. I doubt anyone would do this, but if they were, I would think the bike would no longer countersteer. And then what?



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post #4 of 43 (permalink) Old 02-17-2006, 09:04 AM
 
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I can see ballance issues. Your bike remains upright under motion due to these gyroscopic forces. It will always return to upright position out of corners simply by relaxing your pull on the handlebars. If that effect is taken away, what you are left with, IMO, is the ballance of a bicycle at 3mph... with speeds in excess of 180MPH. I, for one, would rather fight the gyroscopic effect in the corners than to have to worry about the ballance ALL the time. I like releasing my grip on the handlebars to readjust my backpack or sit straight up going down hills from time to time.
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post #5 of 43 (permalink) Old 02-17-2006, 09:26 AM
 
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Quote:
Originally posted by Vash

The rotors will always spin in the opposite direction wether the brakes are applied or not.
Once the brakes are applied (slowing the speed of the disc rotation) there would be a change (increase) in gyroscopic force.

This one's best left to the bmw engineers to sort out...
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post #6 of 43 (permalink) Old 02-17-2006, 10:05 AM Thread Starter
 
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Quote:
Originally posted by Cammo
Once the brakes are applied (slowing the speed of the disc rotation) there would be a change (increase) in gyroscopic force.

No it wont. Gyroscopic force will always vary with the square of rpm. The only thing is with this system (if its dont like it think it is) you are also making negative percent gyro force. Assume wheel A makes X*mph gyro force. This same wheel is equiped with counter rotors, that have their gearing set to 75%X*mph. Now the wheel only makes 25%X*mph of the gyro force. The force produced still varies with the square of the speed, but its devided by 4 (In a perfect universe where this thing has 100% efficiency). This should answear both concerns. It is essentially the same thing as fitting wheels that are 4 time lighter.
Oh, one more possible issue. Set the power settings on this thing too high, and you risk overheating your brakes, requiring bigger rotors. Bigger rotors will further increase unsprung weight. And the whole system should have considerable rotational momentum, which should decrease the brakes efficiencies somewhat.



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post #7 of 43 (permalink) Old 02-17-2006, 12:36 PM
 
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When I see their prototype is in demand by fellow racers then I will realize they are in the right. Presently I do not feel this is the answer.

Still I will admit that I can be wrong. Like when they were sending the factory 'works" Matchless 500cc Scrambler they offered it with this & that. One I turned down was swinging arm rear suspension in preference to ridgid rear end.

I know this sounds crazy yet for anything like leaf spring rear end suspension, torsion bar rear end suspension, hub suspension or springer suspension they all twisted like a snake as you came out of the corners & turned up the wick.

By next year (being '50) we brought in a few of these scramblers with s/arm rear end suspension. In a race I was outdoing every one, but being just a Club event we had Senior with Expert racers & I noted this one Senior chap was coming down some parts almost as fast as I was.

After the race I borrowed his & realized it was easier to handle on the flat parts, same with uphill, some of the burms & ESPECIALLY coming downhill. So contacted the makers & they sent me the complete kit to make the change.

So yes that 2" of so called travel in the rear with the nick named "jam pots" made a big difference & from then on it was used on most bikes to even some yrs later one S/A rear end suspension was used on Observed Trials irons.
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post #8 of 43 (permalink) Old 02-17-2006, 12:51 PM Thread Starter
 
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post #9 of 43 (permalink) Old 02-17-2006, 01:57 PM
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Quote:
Originally posted by Vash
when in doubt, read the patent
sounds like its going to be heavy.

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post #10 of 43 (permalink) Old 02-19-2006, 12:29 PM
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I understand the concept but...






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