Why is rail running faster?
- Thread starter oxford
- Start date
Bouncing off the rail as you try and go strait down a track that is not perfect with other cars dirty air down a transition will be slower than a car that hugs a rail and does not hit the rails back and forth scrubbing speed each time. The wheels ride the crease of the rail and track minimizing the friction. This is my newbie understanding of it. I have tried both ways and there is no contest a rail rider wins more consistently, you may get a lucky run with a strait car but overall you will be consistently faster with a rail runner. Many times logic, physics in this hobby fool us. At times we don't take into account uncontrolled conditions.
By forcing your car into the rail it does a couple of things. 1 it reduces friction by only having the inner edge of your DFW touching the rail. 2 prevents your car from getting the shimmy and banging into the rail back and forth down the track. 3 also prevents your rear wheels from making contact with the rail. It's all about friction reduction. Friction < Speed
V
Vitamin K
Guest
No disagreement with what's been posted so far. The way I explain rail-riding is as follows:
- The car needs to contact the rail at some point in order to guide its path. It is impossible to run a car straight down without ever hitting the rail.
- If the car strikes the rail at random, you have two problems: One is that the heavier-weighted rear wheels can possibly touch, and since weight is a component of the friction equation, these do massive damage to your speed. The next problem is that you'll carom off of the rail and back the other way, and get into a zig-zag pattern, thus reducing the efficiency of your travel direction.
- So instead of trying to avoid the rail, we instead decide to use it to our advantage, by arranging the wheels so that only the inner edge of the front wheel actually contacts the rail, and then adding a bit of steer-in so that the car naturally wants to move this front wheel edge to the rail. In exchange for minor penalties brought on by the lightly-loaded front wheel contacting the rail, we are rewarded with straight travel down the track, and the inability of the rears ever to touch the rail.
- The car needs to contact the rail at some point in order to guide its path. It is impossible to run a car straight down without ever hitting the rail.
- If the car strikes the rail at random, you have two problems: One is that the heavier-weighted rear wheels can possibly touch, and since weight is a component of the friction equation, these do massive damage to your speed. The next problem is that you'll carom off of the rail and back the other way, and get into a zig-zag pattern, thus reducing the efficiency of your travel direction.
- So instead of trying to avoid the rail, we instead decide to use it to our advantage, by arranging the wheels so that only the inner edge of the front wheel actually contacts the rail, and then adding a bit of steer-in so that the car naturally wants to move this front wheel edge to the rail. In exchange for minor penalties brought on by the lightly-loaded front wheel contacting the rail, we are rewarded with straight travel down the track, and the inability of the rears ever to touch the rail.
oxford said:
For some reason, the physics guys always miss rail riding. I believe this is because they are focused within theory where perfection is attainable.
Rail riding is all about accepting imperfection when it is beyond your control, and instead focus on what you can do to minimize the impact. I've taken this as an important life lesson from PWD.
oxford, don't forget that a lot of scout races score by time. Whether it's an average of the runs or the cumulative time, consistency is a big plus in my book. Riding the rail can make a car more consistent and that might just be the edge a racer needs to get the win. If the racing is really tight, every .001 you can get on every lap matters.
LightninBoy said:
HurriCrane Racing said:
bracketracer said:
Obsessedderbydad said:
You all have it wrong and John never said that. It's rail running...
I guess today I just like running with sharp knives in my hand. (or is it riding with sharp knives?)
<But I really do think LB's response was very insightful>
V
Vitamin K
Guest
As a "physics guy" I can add to this for all:
1. rail running = rolling friction against the rail, not sliding friction. The fact that none of the wheels stop turning means no energy is wasted trying restart wheels that bumped.
2. 3 wheels is also faster than 4 due to less starting inertia
3. LB and Bracket already explained #3 /images/boards/smilies/wink.gif
1. rail running = rolling friction against the rail, not sliding friction. The fact that none of the wheels stop turning means no energy is wasted trying restart wheels that bumped.
2. 3 wheels is also faster than 4 due to less starting inertia
3. LB and Bracket already explained #3 /images/boards/smilies/wink.gif
No no no no, it is faster because the wheel contact on the rail heats the wheel in turn heating up the oil in the wheel bore causing a thermoduplicotic reaction forcing the enlarged mononucleoplatlets in the oil to harden causing the wheel to run faster and create a slight odor.
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