Luge runners

[Scotty11]

I'm a member of the US luge team. As the Olympics come up next year we are looking for a new type of material for our runners. If you're not familiar with luge it's a sport measured to the thousandth of a second (.000). The slider rides down an iced track which is chilled from 26 degrees to -20 degrees F depending on the temp. outside. The slider goes around banked corners where he/she and the sled will reach g forces up to 5g's. In that 5 g corner the 2 runners are contacting the ice with 2572.5N (newtons) a piece with a total of 5145N total. Obviously that's a lot of force which is creating a great amount of friction which is slowing us down. What we're looking for is a material we could put on our runners or a new material runner in order to reduce the co efficient of friction with the ice. What we do now is build an edge on our runners which adds grip but also adds friction because more runner is touching the ice. We make a fine balance between grip and friction so they're right on the edge. Another thing that would be helpful is a material that would heat up on the way down the track in order to create a thin layer of water which would reduce friction.

If you have any other ideas feel free to post them.

Thanks in advance,
Scott

 

[gr2vessels]

Hi Scotty,
My two cents;- make the runner face concave towards the ice, so you'll run two edges normally. Now, if you can fit between the runners a pair of elastic 'supports' made of spring steel, the runners will tend to spread in the corner under the given 5g load. Subsequently, the outer edge of each runner will lift off the icy surface, leaving only the inner edge to carve the ice. Obviously, this takes a bit of engineering and testing, particularly when the number of newtons you quoted are really depending on the rider(s) weight.
Hope this helps,
gr2vessels

 

[Neubaten]

I would like to add some considerations to the discussion:

-The formation of the water layer that acts as a lubricant between the interface metal-ice is largely caused by frictional heating. This is going to be more pronounced with the decrease of the temperature from 0ºC on.

-One can think that the formation of the water layer can be promoted as well by decreasing the contact surface, in order to elevate the pressure exerted. However the dominant effect for the water layer formation is frictional heating, and the coefficient of kinetic friction is independient from load, area of contact and speed of sliding, for common ranges.

-Metals of low thermal conductivity slide better, because of the above considerations. It is the most important factor when selecting a metal.

-Waxing reduces friction, but only for rough surfaces. Polished surfaces do not significantly slide better when waxed. The effect of waxing and polishing are less pronounced at ice temperatures lower than 0ºC.

 

[tomwalz]

We looked into this about four years ago for someone from the Olympic team. Nothing ever came of it.

What do the regulations say about the runners? Isn’t there something about not using anything on the runners?

If you could past a link to the regulations it would help.

Tom


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[Scotty11]

Hey Tom, Thanks for your reply and all others thank you.

Tom is correct there was a thread about 4 years ago:

http://www.eng-tips.com/viewthread.cfm?qid=118794

I have no clue who that person was and if he/she is still around on the team that is why I started a new thread. Also technology has changed quite a bit in 4 years so I wanted to get the latest ideas.


Rules can be found here. Regulations on the sled start on page 15 and diagrams can be found on page 20.

http://www.fil-luge.org/fileadmin/user_upload/Documents/IRO/IRO_2008_e_Final_versionSB.pdf

The building of the sled is pretty unregulated compared to bobsled and skeleton so there is a lot of room for different components.

Thanks everyone for their input!

 

[cloa]

Don't double post- red flag your post in ceramic engineering