Turf vs Dirt question

[raybo]

Originally Posted by Cratos

Raybo,

The following information is what you requested and I will later post layouts of both Evangeline Downs and Delta Downs:

Evangeline Downs

1 Mile Dirt Track
Stretch Length = 1,200 Feet
Distance Around Turns = 1,319.30 Feet
Turn Radii = 419.8 Feet
________________________________________

Delta Downs

3/4 Mile Dirt Track
Stretch Length = 660 Feet
Distance Around Turns = 992.6 Feet
Turn Radii = 316 Feet

Thanks! If my calculations are correct, the centripetal force needed to be applied by the horse in order to remain in the same path (on the rail) and at the same speed, assuming an 1100 lb horse and jockey and a 50 fps velocity:

Delta Downs = 1201.904523 N
Evangeline Downs = 904.7208892 N

Differential percentage between the two tracks: 75.27% (Evangeline requires about 25% less centripetal force be applied by the horse than Delta.)

[raybo]

Originally Posted by Cratos

Most NA racetracks have a 2 degree slope near the rail in the straightaway for drainage and the banking on the turns is between 4-1/2 degrees to 6 degrees.

I don't understand your question; please explain further

The straightaway requires no centripetal force be applied by the horse, as there is no centrifugal force (inertia) when traveling in a straight line, unless there is a cross wind blowing in the straight, which would cause the horse to apply centripetal force (to the left or the right, depending on wind direction) in order to remain running in the same path.

[raybo]

Originally Posted by raybo

Thanks! If my calculations are correct, the centripetal force needed to be applied by the horse in order to remain in the same path (on the rail) and at the same speed, assuming an 1100 lb horse and jockey and a 50 fps velocity:

Delta Downs = 1201.904523 N
Evangeline Downs = 904.7208892 N

Differential percentage between the two tracks: 75.27% (Evangeline requires about 25% less centripetal force be applied by the horse than Delta.)

Adding to the above quote, the 25% less force needed at Evangeline, doesn't tell the whole story. The length of the turns being longer at Evangeline means that at Delta that force is not applied as long as at Evangeline, so it appears that the total amount of force might be equaled out somewhat by the shorter turn distances at Delta. But, at Evangeline the ease of attaining a higher speed in the turns would seem to translate into more easily attaining faster speeds in the straights (faster exiting speed from turn to straight), which are also longer than at Delta. Overall times, for the same horse, should be faster at Evangeline versus Delta?

So, if the surface resistances are similar at both tracks, Evangeline should be more speed favoring, generally, than Delta, and that somewhat explains why the public does better at Evangeline.

[Cratos]

Originally Posted by raybo

The straightaway requires no centripetal force be applied by the horse, as there is no centrifugal force (inertia) when traveling in a straight line, unless there is a cross wind blowing in the straight, which would cause the horse to apply centripetal force (to the left or the right, depending on wind direction) in order to remain running in the same path.

I understand this, it is very simple; what is to be. understood is friction, not wind force. Aerodynamic Drag and the COF are the critical factors in this calculation.

[cj]

Just an update, currently working on new speed charts with quite a different span. Using 140 point scale ala TimeformUS, it takes 22 seconds to span that range on dirt, only 11 on turf at the distance of a mile. It is actually lining up very nicely with actual race results, particularly when I also adjust the scales further by pace.

[lansdale]

Originally Posted by steveb

No I had nothing to do with them, except that I did work for them, as distinct from working 'for' them.
Stuff that they could not do themselves at the time.
He had me on a retainer at one stage is all, so that he could call me up whenever he wanted something done.
They probably had lots of people in the same boat that I would not know about.

I have always worked for myself, except for a bit after entropy, where I was in a team, but I quickly discovered that teams and me are incompatible.
I like being in charge, thus it did not work out with the team and I walked away from it, and walked from racing as well, to pursue other things in life.

As for the states, I have never studied the racing there, so I am in no position to comment.



I best say that I am only good at times stuff and what can be derived from times data, the rest of it I am probably no more clued up than anybody else.

Although I don't really care about racing these days, there can be no denying that it makes you think long and hard.
I just got sick of it ruling my life.

Thanks for the informative reply. Many of the profiles of Woods have described the contributions of people like yourself to the efforts of his handicapping team - sounds like you were something like a subcontractor. Woods seems to have employed a considerable number of such people, who would send him data by both e-mail and snail mail. Very interesting stuff.

It sounds like you're much happier now, being out of the game altogether. Still, grateful to have the benefit of your insight into the game here.

Cheers,

lansdale

[lansdale]

Originally Posted by classhandicapper

This is the kind of thing that I've mentioned in the past where I think non modelers might have a temporary edge over modelers. People that manually handicap races, sift through results charts, watch replays, etc... get so familiar with the horses and what's going on at their track, they pick up on these things immediately and adjust.

Obviously there are flip side disadvantages, but I thought that was an instructive story.

I'd be willing to bet they'd have some problems with the trainer factor in the US also. There are cycles where certain trainers get so hot (or cold) and form so explosive the cynical mind can't help believe it has more to do with the vet being used at the time and what's in the hay than the horses or trainers.

Hi CH,

I'm not sure that there is as much of a difference in the data being used by traditional handicappers (non-modelers) and those using computer models. Traditional handicappers create a model, but it's mental, informal, and subjective. Those constructing mathematical models are creating something that is formal, objective and tested.

You seem to think that people like Benter are not compiling data from results charts or watching trips, but actually he had a large staff working for him doing exactly these things - he had three people alone watching trips and scoring their effect.

Also, you seem to believe that the Woods interview is referring to the effect of short-term track biases, but what it is describing is a change in a long-term change in the track configuration, similar in its effect t a lengthening of the stretch or a change of track surface-type. All models that I know of are seeking such long-term factors - I think people like sjk could confirm this.

Cheers,

lansdale

[Cratos]

Originally Posted by lansdale

Thanks for the informative reply. Many of the profiles of Woods have described the contributions of people like yourself to the efforts of his handicapping team - sounds like you were something like a subcontractor. Woods seems to have employed a considerable number of such people, who would send him data by both e-mail and snail mail. Very interesting stuff.

It sounds like you're much happier now, being out of the game altogether. Still, grateful to have the benefit of your insight into the game here.

Cheers,

lansdale

Lansdale, you and Magistri Ludi are class acts; I truly enjoy reading the posts by the two of you.

[steveb]

Originally Posted by lansdale

Thanks for the informative reply. Many of the profiles of Woods have described the contributions of people like yourself to the efforts of his handicapping team - sounds like you were something like a subcontractor. Woods seems to have employed a considerable number of such people, who would send him data by both e-mail and snail mail. Very interesting stuff.

It sounds like you're much happier now, being out of the game altogether. Still, grateful to have the benefit of your insight into the game here.

Cheers,

lansdale

thanks.

they would send me the data, and then i would send them the answers that they needed, but derived from their data rather than mine.
would be from countries that i had no interest in myself, so they had to supply it.
email only basically, and a private part on asian racing forum that the public couldn't see.

actually i still think about racing, but i no longer let it dictate my life.
so i am probably wrong when i say i have no interest.
i am not interested in betting on racing these days, but i still like the intellectual challenge i suppose.

[Cratos]

Originally Posted by steveb

thanks.

they would send me the data, and then i would send them the answers that they needed, but derived from their data rather than mine.
would be from countries that i had no interest in myself, so they had to supply it.
email only basically, and a private part on asian racing forum that the public couldn't see.

actually i still think about racing, but i no longer let it dictate my life.
so i am probably wrong when i say i have no interest.
i am not interested in betting on racing these days, but i still like the intellectual challenge i suppose.

Horserace handicapping to me is similar to chess; the intellectual challenge is difficult to divorce yourself from.

[raybo]

Originally Posted by cj

Just an update, currently working on new speed charts with quite a different span. Using 140 point scale ala TimeformUS, it takes 22 seconds to span that range on dirt, only 11 on turf at the distance of a mile. It is actually lining up very nicely with actual race results, particularly when I also adjust the scales further by pace.

Are those ranges from 1 to 140, or do they go negative at some point? And, is it a linear relationship between dirt and turf times, or non-linear?

[raybo]

Originally Posted by Cratos

I understand this, it is very simple; what is to be. understood is friction, not wind force. Aerodynamic Drag and the COF are the critical factors in this calculation.

Yes, I know that "wind force" actually affects the mass moving through surface air, which contains various particles of varying direction, speed, and density. I would think that the most critical factors (at ground level), in horse racing anyway, would be the magnitude of the wind/force, and its direction in relation to the direction the horse is running.

[Cratos]

Originally Posted by raybo

Yes, I know that "wind force" actually affects the mass moving through surface air, which contains various particles of varying direction, speed, and density. I would think that the most critical factors (at ground level), in horse racing anyway, would be the magnitude of the wind/force, and its direction in relation to the direction the horse is running.

The difference here is that in the turns you have a "collision" so to speak of forces with the side force and the horse's turning force and that is the major cause of increased energy expenditure by the horse exponentially.

In the the straight, you have the "sail affect" on the horse which incrementally changes the horse's instantaneous speed by the wind force, but the track's racing officials would probably never allow racing to continue if the the wind force became higher enough to change the horse's speed as it would in the turn.

You can perform a calculation with calculus to see the difference and I don't think the surface of contact on the horse would be great enough to equate the two.

Also the aerodynamic drag is a greater culprit to the horse in the straight than the turn because of the greater speed typically performed by the horse in the straight.

[Cratos]

Originally Posted by raybo

Are those ranges from 1 to 140, or do they go negative at some point? And, is it a linear relationship between dirt and turf times, or non-linear?

It wouldn't be linear because the "spring back" forces between the two surfaces caused by the different COF of the two surfaces are nonlinear.

[raybo]

Originally Posted by Cratos

The difference here is that in the turns you have a "collision" so to speak of forces with the side force and the horse's turning force and that is the major cause of increased energy expenditure by the horse exponentially.

In the the straight, you have the "sail affect" on the horse which incrementally changes the horse's instantaneous speed by the wind force, but the track's racing officials would probably never allow racing to continue if the the wind force became higher enough to change the horse's speed as it would in the turn.

You can perform a calculation with calculus to see the difference and I don't think the surface of contact on the horse would be great enough to equate the two.

Also the aerodynamic drag is a greater culprit to the horse in the straight than the turn because of the greater speed typically performed by the horse in the straight.

I was referring to "in the straights" rather than in the turns. And, I agree that drag is the significant factor in the straights, due to the higher speed in straight line running. Drafting can reduce that, depending on which direction the wind is coming from, and what position in the draft cone the horse is positioned in.