audi and kaipola ski jump advertisiement - climbing an icy hill

I saw this advertisement from Audi on their second records on driving up Kaipola ski jump in Finland. It was a rather impressive achievement and photos. I could not believe that a car can climb a hill with slope of 80 degrees, even on a regular ground (not icy road). When I dig out more information about the Audi advertisement, I read more detail information on how the car actually climbed up the hill. I would like to find out comments from the readers about driving up an icy snow hill with very steep slopes. My immediate questions are:

- Could you actually climb up a ski jump by the power of your car, from a stop, without slipping on an 80 degrees icy/snow slope?. In the Audi advertisement, they were using a winch in which the car could only goes up. There was a braking mechanism to prevent the car from slipping backward.

- If the above answer is no, then how many degrees of slope can a regular or 4WD car climb a slippery/ice hill slope? What about a regular, dry, soil or rocky slope?

- Is the wonder of such a climb a result of the high power car (big engine), the all wheel drive system, or the good quality gripping ice tires, or all of the above?

- On what icy slope is a car can actually stand still on without sliding down? I thought that a relatively small slope (with no friction because of ice) that a car can stand up on icy slope more than say 15 to 20 degrees ( 1V to 3H to 1V to 4H). .... or is the figure even lower, say 10 degrees ... or less?

- How many degrees slope that Land Rover brags about in their advertisement? Or a Hummer? I think they are on a regular, dry, rocky or soil ground, not snow or icy surface.

- How good quality ice or snow tires can reduce the slippage when standing on a slope? Will car using these tires stand up at say 25 or

30 degrees? I don't think there is any car on any tires that can stand still at a 45 degrees slope (1H:1V) . Correct me if I am wrong.

- If the Audi car shown in the ad does not have a winch, do you think it can climb that 80 degrees slope ? What happen it it accelerate first on flat surface until it achieve a very high speed? If it NOT on ice/snow slope, could a car (like an Audi AWD) climb an 80 degrees slope in a dry, rocky, rough surface?

- I assume that contributing factors for climbing are: adequate engine power, all wheel drive or 4x4, good gripping tires, weight of the car, and a good driver. Are there any other governing factors?

Would like to hear some discussion. Thank you!

Reply to
aniramca
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37.5 degrees actually.

Graham

Reply to
Pooh Bear

Cant be 80 degrees. That's absurd.

A quick Google found an interesting article:

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Reply to
223rem

And the explains the problem:

" is hard to believe that, after quite literally scaling new heights, he has just parked his Atlas Grey Audi A6 4.2 quattro 47 metres off the ground at an angle of 37.5 degrees and that is approximately equivalent to an 80 percent gradient."

80%, not 80 degrees.
Reply to
Alan Baker

I wonder if the AWD was really useful at that angle. RWD should have been enough.

Reply to
223rem

At this angle, in terrain (no snow or ice) you will need grip. Without AWD or 4WD you will be left with a spinning (rear) wheel. Kind regards, Erik-Jan.

Reply to
Erik-Jan Geniets

You really should study physics a little...

Reply to
Alan Baker

Thanks for the correction. I checked the ad again, and it was 80% grade.

37.5 degrees is more likely! It is still very steep, though

223rem wrote:

Reply to
aniramca

Not 20 minutes after my last post, I saw the commercial itself!

Reply to
Alan Baker

In a given distance it rises 80% of that distance. Tomes

Reply to
Tomes

Yes.

But the original poster said 80 *degrees*. He had clearly mistaken one for the other or heard about it from someone who'd been so mistaken.

Reply to
Alan Baker

So how did they get 0.8 from 37.5 degrees? Is that the tangent of the slope angle? It is close numerically, but it doesnt sound right, as it can exceed 100%. Or is the sinus? That doesnt match numerically with 0.8.

Reply to
223rem

Your observation is correct, it's the tangent function. Gradient is the ratio of vertical elevation -vs- horisontal displacement, and with slopes greater than 45 degrees the vertical elevation goes up faster - hence it is possible for gradient to measure past 100% .

For instance, the gradient of a ladder leaning against a wall can be several hundred %'s, and the gradient of an upright wall itself is as much as infinite... :-)

Cheers!

- Risto -

Reply to
Risto Lankinen

Why? We are talking about an angle of 37.5 degrees here which can be done with most 4x4's with low range T-case. On tarmac you will even succeed without spinning wheels. Kind regards, Erik-Jan.

Reply to
Erik-Jan Geniets

The message from "Risto Lankinen" contains these words:

Or possibly even negative if your builder's had one too many for lunch.

Reply to
Guy King

Percentage, as written down on the warning traffic signs (e.g.,

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and
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is defined as thevertical distance ascended (or descended) versus the horizontal distancetravelled, 100*b/a in the following diagram: /| / | c/ |b / | /____| a

This is the tangens of the angle between sides c and a. The gradient is also given as 1:X, but this is just the fraction b/a written as 1:(a/b).

Here's a table of some gradients in degrees and percentages, both rounded to 0 decimal places:

deg | perc. ===========

90 | infinity 45 | 100 31 | 60 30 | 58 27 | 50 17 | 30 14 | 25 6 | 10
Reply to
Jan Kalin

Pooh Bear, was motivated to say this in rec.autos.driving on Wed, 18 Jan 2006 01:41:37 +0000:

38.66 degrees (assuming I did the trig right)...
Reply to
necromancer

It's actually a lot of fun doing that!

We regularly used to take our Jeeps out to a local sand pit area before it closed that is challenging in the summer and run it in the winter. It is a blast and our 4x4's can climb wicked slopes in snow. Way more than 37.5 degrees.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
Reply to
Mike Romain

A slope *can* exceed 100%, because yes, it is the tangent of the slope angle. A 45 degree slope is 100%.

Reply to
Alan Baker

Your missing the point. At 37.5 degrees, almost the entire weight of the vehicle will be on the rear wheels. Take a wheelbase of 8' for example and assume a 50-50 weight distribution. If the centre of mass is located at 8/2 * 80% = 3.2 feet, then the entire weight of the vehicle would be on the rear wheels on a 80% or 37.5 degree slope.

Hence the OP was suggesting that only RWD would be necessary.

Reply to
Alan Baker

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