Frictional accelerations greater than one G

[sophiecentaur]

On the lines of 'duck tape', I could suggest that, in order to get higher than g friction forces, you probably need even more engine power - to do the 'unsticking' as well as the accelerating.
There may be figures which show this. It's a bit like the 'design speed' idea with boat hulls; over a certain speed, a displacement hull needs wildly increasing powers to go faster and faster.

 

[Cleonis]

I was also going to ask the question: "What is the coefficient of friction of duct tape stuck to something, and how much force is required to peel it from the surface?"
Dragsters almost always do a burn out before the race, heating up the tires, making their surfaces fly paper sticky.

Then again, dragsters don't actually use that stickyness in the first meters.
In the first meters the tires are spinning furiously. In all other forms of car racing you lose acceleration if you have wheel spin at the start.

Are dragster tires shredded after a single run?

 

[xxChrisxx]

Q

Then again, dragsters don't actually use that stickyness in the first meters.
In the first meters the tires are spinning furiously. In all other forms of car racing you lose acceleration if you have wheel spin at the start.

Are dragster tires shredded after a single run?

Yeah, considering the engine basically needs a rebuild after each run (for a top fuel dragster) the life of a tyre is 1 run.

The aim is to get a slight amount of wheel spin on all starts, this is because if you don't the tyre can bite and it bogs the engine down.

 

[sophiecentaur]

Yeah, considering the engine basically needs a rebuild after each run (for a top fuel dragster) the life of a tyre is 1 run.

The aim is to get a slight amount of wheel spin on all starts, this is because if you don't the tyre can bite and it bogs the engine down.

So tyre = clutch, effctively?

 

[xxChrisxx]

So tyre = clutch, effctively?

Err, the line isn't as sharp as that. They usually have torque converters that are designed to lock up in a specific way to just make the tyre have a certain amount of wheel spin for best acceleration. This is so the driver can lauch at/close to full thottle.

If they get the clutch wrong for the conditions, the engine will either bog down (revs will drop off) or the tyres will just spin away. You can see when they get it wrong as the tyre screws itsself up, and the car bounces around wildly.

A drag tyre really is an amazing piece of kit. It not only has to act like a tyre, but acts like a secondary clutch and a gearing system as well.

Heres a nice viedo demonstating what I'm decribing.
http://www.youtube.com/watch?v=LNszt39F3ns&feature=related

 

[OmCheeto]

and just for the record, I did not write, nor did I check the wiki entry on friction before I made my post:

Coefficients of friction range from near zero to greater than one – under good conditions, a tire on concrete may have a coefficient of friction of 1.7.[citation needed]

When the surfaces are conjoined, Coulomb friction becomes a very poor approximation (for example, adhesive tape resists sliding even when there is no normal force, or a negative normal force). In this case, the frictional force may depend strongly on the area of contact. Some drag racing tires are adhesive in this way.

http://en.wikipedia.org/wiki/Friction"

I swear to god I didn't