How much is a "point" of downforce?

[Giblet]

Well I think it is just a way to avoid placing an understandable measure on it that others would relate to.
This is to make it difficult for the FIA to define a set maximum for regulation.
An old saying of mine. Bulls--- baffles brains covers it.

If that's the case, why would Mcbeath in Racecar Engineering use points of DF as a reference in articles about modifying 30 year old racecars

This is interesting, I might be completely wrong about a point being an arbitrary number, but applying a modern method or unit to 30 old racecars doesn't mean the unit was specifically used back in the day. If a wing was used all year, and it had only 5 positions to adjust to, maybe that was a point, and modern times and methods have applied solid math to quantify a point.

I find it interesting as well that drivers would come in to the pits in the 80's and 90's and ask for another turn or half turn of wing on the radio, meaning the ratcheted adjustment. I doubt the driver had done the conversion in his head, but new from experience that 2 turns was too much of a change, so maybe 1 was going to help the balance.

[MikeFromCanada]

Found this on F1.com interview with Paddy Lowe. Thanks for the headsup on the post raymond

Q: Jenson Button has suggested you were ‘30 points’ behind Red Bull in terms of downforce and that it would take six or seven races to make up that deficit. Do you agree with that analysis and can you explain what ‘30 points’ means?

PL: A point is Formula One code for a hundredth of a fraction of ‘cl’, where ‘cl’ is the downforce coefficient. Physically a Formula One car has a downforce coefficient of let’s say 3 to 3.5. So 30 points would be 30 hundredths which would equate to 0.3. So 30 points might be getting on for 10 percent of the downforce on an F1 car and that could be worth about a second a lap.

[speedsense]

How about this as a reason, aero sensors are scaled a 0-1 in almost all cases, yet read to .01..... so 30 clicks on a scale of 1? As a dag makes tons of sense..

Proof is always available in the data logging system

[Crucial_Xtreme]

Another description of aero points & downforce points

[Pierce89]

Well I think it is just a way to avoid placing an understandable measure on it that others would relate to.
This is to make it difficult for the FIA to define a set maximum for regulation.
An old saying of mine. Bulls--- baffles brains covers it.

If that's the case, why would Mcbeath in Racecar Engineering use points of DF as a reference in articles about modifying 30 year old racecars

You tell me?

because as stated earlier 1 point is 0.01 in the CL

[raymondu999]

Found this on F1.com interview with Paddy Lowe. Thanks for the headsup on the post raymond

Q: Jenson Button has suggested you were ‘30 points’ behind Red Bull in terms of downforce and that it would take six or seven races to make up that deficit. Do you agree with that analysis and can you explain what ‘30 points’ means?

PL: A point is Formula One code for a hundredth of a fraction of ‘cl’, where ‘cl’ is the downforce coefficient. Physically a Formula One car has a downforce coefficient of let’s say 3 to 3.5. So 30 points would be 30 hundredths which would equate to 0.3. So 30 points might be getting on for 10 percent of the downforce on an F1 car and that could be worth about a second a lap.

Yeesh. I can't believe I missed this. So it's in terms of Cl then...

[gixxer_drew]

Honestly sounds like BS to me. An arbitrary measure. Could be whatever units you want. Pounds, kilos, some dimensionless measure...

This is correct, mostly. The term "point" is used for all sorts of things, although usually its some reference to a change in coefficient at some quantity of decimal place. Can be 0.001 or 0.00001 what you call it is up to you. I've seen different conventions for how many decimal places depending on the application. Aircraft guys use one order of magnitude smaller than I use.

[PNSD]

Some of us have always said it is in terms of Cl.

Those of you with an aerospace background will know 1 drag count is equal to 0.0001 Cd. So it's was only natural to assume F1 use a similar convention for Cl, or downforce.

[shelly]

Found this old (2011) comment by paddy lowe on formula1.com, via the autosport forum, where they were discussing alonso drs failure:
http://www.formula1.com/news/interviews ... 12144.html
http://forums.autosport.com/index.php?s ... &start=240

Q: Jenson Button has suggested you were ‘30 points’ behind Red Bull in terms of downforce and that it would take six or seven races to make up that deficit. Do you agree with that analysis and can you explain what ‘30 points’ means?
PL: A point is Formula One code for a hundredth of a fraction of ‘cl’, where ‘cl’ is the downforce coefficient. Physically a Formula One car has a downforce coefficient of let’s say 3 to 3.5. So 30 points would be 30 hundredths which would equate to 0.3. So 30 points might be getting on for 10 percent of the downforce on an F1 car and that could be worth about a second a lap. I don’t agree that we have that deficit to Red Bull. I think that we’ve been quicker than them in the last few races - in race trim. Our car’s actually outperforming them at that point of the weekend. Clearly in qualifying we’ve got quite a gap to make up. What exactly it is and how that advantage is gained by Red Bull we don’t know, but we’re working hard to find the performance, particularly in race conditions. I think we can play to our strengths and win races by being quicker on Sunday and having a good strategy.

EDIT: sorry, I see now that I have posted again the interview Mikefrom canada posted in 2011

[eslam1986]

it is different number for every team , in ferrari each 4 point = 0.1 sec , in maclaren each 5 point = 0.1 sec , this info from last year .

[turbof1]

Important thing to know: does the number mutate in time inside a specific team? I mean I readed 2 different measures for point of DF for Mclaren:

-5p/0.1s
-25-30p/1s
Those are 2 different ratios. Could be that one of the 2 explainations is faulty.

[shelly]

The important thing to fix is that the point is a convention that has a physical meaning.
You express downforce in N - it is a force; if you divide downforce by dynamic pressure (http://en.wikipedia.org/wiki/Dynamic_pressure)
You get a number for Scz (downforce coefficient times reference area => Scz unit is m2 in SI - surface times pressure gives force). This number gives you the downforce capability of the car. Whitmarsh said in the interview that typically a f1 car has a Scz of around 3-3.5 - I would rather believe the reference value given by Imanengineer (in his post here: http://www.f1technical.net/forum/viewto ... 41#p414341): 3.5-4.5.
Then a point is conventionally for most teams 0.01, like explained above. Maybe some teams use 0.001 as a point, or use a different reference S.

The relationsip between point and laptime is not that linear - it depends on the track. You can run a simulation, like machin does, and see the effect of laptime for a car with 30 points of downforce less and every other characteristic equal: at monza you wheel get a certain delta, and at spa it will be different.
Then if you have a more sophisticated simulation tool you can put not just a number, but its split contribution between front and rear - on some tracks a 10 point gain at the rear will give you more advantage (rear limited tracks).

[turbof1]

The relationsip between point and laptime is not that linear - it depends on the track. You can run a simulation, like machin does, and see the effect of laptime for a car with 30 points of downforce less and every other characteristic equal: at monza you wheel get a certain delta, and at spa it will be different.

Yes I know. The important thing to notice though is that MW used the point DF/seconds ratio as an average over all tracks. That does alllow you to stick a number in seconds on it, also averaged over all tracks.

Then if you have a more sophisticated simulation tool you can put not just a number, but its split contribution between front and rear - on some tracks a 10 point gain at the rear will give you more advantage (rear limited tracks).

Do know though that a gain at the rear must be roughly equated by the same gain at the front, and vice versa. Else your aero balance is messed up. Small variations exists of course, but this is true for every circuit out there. Common sense does tell that gains at the front and rear are the same, and that normally should be at other teams as well.

(btw, +1 for the excellent explanation)

[shelly]

Important thing to know: does the number mutate in time inside a specific team? I mean I readed 2 different measures for point of DF for Mclaren:

-5p/0.1s
-25-30p/1s
Those are 2 different ratios. Could be that one of the 2 explainations is faulty.

I think that the 2 different ratios are due to the non linearity of the delta-downforce/delta-laptime relationship. Downforce affects the car acceleration capability (longitudinal, centripetal, combined): there are several non-linearities involved, so it is reasonable for me to think that the effect of 10 points more (with respect to a baseline) is more than double than the effect of 5 points.

[Pierce89]

Important thing to know: does the number mutate in time inside a specific team? I mean I readed 2 different measures for point of DF for Mclaren:

-5p/0.1s
-25-30p/1s
Those are 2 different ratios. Could be that one of the 2 explainations is faulty.

I think that the 2 different ratios are due to the non linearity of the delta-downforce/delta-laptime relationship. Downforce affects the car acceleration capability (longitudinal, centripetal, combined): there are several non-linearities involved, so it is reasonable for me to think that the effect of 10 points more (with respect to a baseline) is more than double than the effect of 5 points.

Shelly is right. The time comparisons are just used to help the fans understand. 1 point is .01 of cla(coefficient of lift times frontal area). Its just the common convention. I even worked on a small regional stock car team that uses it. In the interview with Paddy Lowe, it seems clear to me that he said 1 point was .01 one of cla and then just uses the 30 points/1 second bit to help fans understand the worth of 30 points in the DF regime F1 cars run in . Because tires don't gain grip in a linear way as load rises, 30 points would be worth more time in a lower DF formula. This could explain why in 2010 Whitmarsh said 25 points/ 1 second, then in 2011 with more baseline DF(because of the more powerful ebd) Lowe said 30 points/ 1 second.