What about imposing a drag limit in aero rules?

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PlatinumZealot
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Re: What about imposing a drag limit in aero rules?

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The thing with measuring the drag via the drive-train is that you have to account for the rotational inertia of the wheels at anytime the car is accelerating and tyre slip and such. The rotational inertia of the driveline might have to be measured before each session for each car. For example by using some sort of dyno or onboard sensors while the car rolls through a range of speeds.. doesn't have to be high speed. It can be done at low speed.
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bill shoe
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Re: What about imposing a drag limit in aero rules?

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PlatinumZealot wrote:The thing with measuring the drag via the drive-train is that you have to account for the rotational inertia of the wheels at anytime the car is accelerating and tyre slip and such. The rotational inertia of the driveline might have to be measured before each session for each car. For example by using some sort of dyno or onboard sensors while the car rolls through a range of speeds.. doesn't have to be high speed. It can be done at low speed.
Total net longitudinal drag over a lap would be average torque (force) over a distance, it would end up being a work limit with units of Joules. I'm thinking as I go. Two approaches-

If you limit the average drag over a lap, then you measure drag from start line to finish (same) line. The speed across the line will be similar both times so the net change in wheel rotational intertia over the lap will be close to zero. It would probably be simpler from a regulatory point of view to just ignore it. This probably requires inboard rear brakes so that brake (negative) torque is included at the drive hubs. We already have partial inboard braking in the form of MGU-K braking.

Or you could allow outboard rear brakes and only measure positive torque from the driveshaft. Then it probably makes sense to use spec rear wheels to eliminate insane spending on rear wheels that were slightly lighter.

What are implications of measuring all torque (pos and neg) over a lap vs. only considering positive torque?

rjsa
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Re: What about imposing a drag limit in aero rules?

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The amount of practical impossibilities piled up here is overwhelming.

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PlatinumZealot
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Re: What about imposing a drag limit in aero rules?

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bill shoe wrote:
PlatinumZealot wrote:The thing with measuring the drag via the drive-train is that you have to account for the rotational inertia of the wheels at anytime the car is accelerating and tyre slip and such. The rotational inertia of the driveline might have to be measured before each session for each car. For example by using some sort of dyno or onboard sensors while the car rolls through a range of speeds.. doesn't have to be high speed. It can be done at low speed.
Total net longitudinal drag over a lap would be average torque (force) over a distance, it would end up being a work limit with units of Joules. I'm thinking as I go. Two approaches-

If you limit the average drag over a lap, then you measure drag from start line to finish (same) line. The speed across the line will be similar both times so the net change in wheel rotational intertia over the lap will be close to zero. It would probably be simpler from a regulatory point of view to just ignore it. This probably requires inboard rear brakes so that brake (negative) torque is included at the drive hubs. We already have partial inboard braking in the form of MGU-K braking.

Or you could allow outboard rear brakes and only measure positive torque from the driveshaft. Then it probably makes sense to use spec rear wheels to eliminate insane spending on rear wheels that were slightly lighter.

What are implications of measuring all torque (pos and neg) over a lap vs. only considering positive torque?
I was thinking of something simpler... measuring the inertia of the driveline on a dyno then derive power needed to accelerate the driveline. Subtract this value from a torque and rpm sensor. This will give the power at the wheels.

Since the Original poster said this is done for road relevance somewhat - Let us assume drag at the contract patch will be included into the Total drag. So all that is left now since we have the power to the contact patch and the car velocity from ground sensors.. the drag on the car can be calculated.

This will have to be done in some form of practice session under controlled conditions, say, before qualifying, so the driver doesn't lose to much mass and the fuel mass is known.

With that said I have a new idea!

It might be cheaper to just get a pickup truck, a tow cable and a load sensor.. Tie car to pick up truck... then pull away with the car in neutral! This will include driveline drag so if you want to exlude that... then mount the car on some FIA regulated dollies and pull away!
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bhall II
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Re: What about imposing a drag limit in aero rules?

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PlatinumZealot wrote:It might be cheaper to just get a pickup truck, a tow cable and a load sensor.. Tie car to pick up truck... then pull away with the car in neutral! This will include driveline drag so if you want to exlude that... then mount the car on some FIA regulated dollies and pull away!
Better yet...


bill shoe
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Re: What about imposing a drag limit in aero rules?

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Simplify. The "Efficient Chassis Formula" would be:
1. cars must meet current safety requirements,
2. basic rules to maintain open cockpits and open wheels.
3. measure torque at drive hubs as a means of regulating/limiting chassis energy.

F1 currently has limits on instantaneous fuel flow (100 kg/hr), and overall fuel use during race (100 kg). Simply add on (or replace with) limits on instantaneous energy flow (power in W), and overall energy use during race (energy in Joules).

The current fuel flow limits relate to how efficiently you create the energy. The chassis limits would relate to how efficiently you use the energy. Current rules are a bit odd because they dictate efficient powertrains to motivate really inefficient chassis. The current cars are tiny 1-seat things that get 7-8 mpg!! This is terrible. I'll be impressed when they go that fast and get 20 mpg. No reason they can't.

Instrumentation is current technology.

bhall II
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Re: What about imposing a drag limit in aero rules?

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bill shoe wrote:2. basic rules to maintain open cockpits and open wheels.
Those are far and away the most inefficient components of the car. Combined, they reduce downforce and contribute nearly 40% of the car's total drag. Without a willingness to abandon such concepts, I don't think there's any point to this exercise.

Image
via formula1-dictonary.net: Insight into aerodynamics basics – downforce and drag breakdown into major components. (From "Aeronautical Journal Jan 2013", courtesy of Willem Toet, Head of Aerodynamics, Sauber F1 Team, Sauber Motorsport AG)

That said, and though I don't agree with the specific idea presented here - I think it would be a needlessly complicated addition to regulations that are already fraught with complication - I do think changes should be made for the sake of improving aero efficiency.

For instance, it's 1,000% pointless for current cars to run an airbox, given a forced-induction power unit. While replacing it with a simple roll hoop wouldn't necessarily reduce total drag, it would drastically improve the efficiency of the rear wing, which in turn would have the same effect on the diffuser, and it could potentially reduce lift created by the chassis. If introduced with a lower rear wing, the cars would see a further improvement in underbody efficiency and a reduction in parasitic drag. In both cases, weight and CoG would be lowered, too.

Image

It's been said F1 continues to mandate airboxes for ad space and aesthetics, but there's plenty of room for logos, and it's been ages since the cars looked good.

bill shoe
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Re: What about imposing a drag limit in aero rules?

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bhall II wrote: Those are far and away the most inefficient components of the car. Combined, they reduce downforce and contribute nearly 40% of the car's total drag. Without a willingness to abandon such concepts, I don't think there's any point to this exercise.
So it's not possible to reduce aero-drag while maintaining open wheels and open cockpits?

Get rid of wings, add lots of underbody tunnel downforce, put fairings ahead of wheels such as Formula E (front wheels), or Indycar (rear wheels). I'm not an Adrian Newey, but I think I just greatly reduced drag while maintaining downforce.

Greg Locock
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Re: What about imposing a drag limit in aero rules?

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You are both right, i think. using bhall's excellent graphic, get rid of both wings, save 50% of the drag, and downforce, then double floor and diffuser downforce, to compensate, which'd increase the drag by 10%, so you'd end up with all the downforce for 60% of the drag.

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Andres125sx
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Re: What about imposing a drag limit in aero rules?

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Also, a drag limit would necessarily imply a standarization in aero configurations. Today there are several configurations depending on the track, Monaco aero package is very different to Monza aero package. That would be finished, but I wouldn´t see it as a bad thing, but the other way around.


I´ll never agree on a motorsport where engine is more limited than aero, and currently engine is very limited with very controlled upgrades (tokens), so I don´t see any reason aero couldn´t be the same

And it would work to control costs too. Lately people complain a lot about 30 million PUs, but I don´t see that same people complaining about the hundred millions aero costs....



BTW I also said some time ago wings should/could be removed. For series like FE it should be mandatory, as efficiency there is basic, but watching at the useful graph Bhall posted, wings could be removed in F1 too

bhall II
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Re: What about imposing a drag limit in aero rules?

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Not to go too far down the cost rabbit hole, but it should be noted that engine development tends to be vastly more expensive than aero development.
bill shoe wrote:So it's not possible to reduce aero-drag while maintaining open wheels and open cockpits?
I didn't say it's not possible; I just don't understand the utility of a plan to improve aero efficiency that ignores the worst offenders.

If it's for aesthetic reasons, I suppose I can understand that. But, if the push for better efficiency means I can no longer enjoy the blissful symphony of hyper-fast NA machines screaming around a circuit, then I think it should also mean you can no longer enjoy the traditional look of the cars.

It's only fair. :D

Besides, wheel covers don't necessarily have to be a pronounced addition. Something along the lines of the one below, but with more coverage and a Le Mans-style cutout to reduce lift, should suffice (if it can be made light enough to minimize the increase in unsprung mass).

Image

Covering the cockpit is an altogether different matter, though, and I won't even pretend to understand the safety aspects of it.

With regard to removing the wings: I think it would make the cars damn near impossible to balance, because there would be nothing to counteract the fore and aft movement of the cp, especially in traffic. It would also make the cars more sensitive to ride height variations. The loss of the rear wing in particular would reduce underbody efficiency, because the low-pressure wake it leaves behind helps to "drive" the diffuser, which in turn "drives" the floor. Ultimately, that means understeer through fast corners, braking instability into slower corners, and oversteer upon corner exit.

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Andres125sx
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Re: What about imposing a drag limit in aero rules?

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bhall II wrote:Not to go too far down the cost rabbit hole, but it should be noted that engine development tends to be vastly more expensive than aero development.
Where is aero department?

Also should be noted it was 2006, the last season with free engine develpment before the 7 seasons freeze, so that was NOT a standard season investment, but the contrary, an exceptional season where manufacturers focused on the engine because they will be using that same engine as it is for many seasons


Or in other words, poor example, wich is weird coming from you I must say

rgava
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Re: What about imposing a drag limit in aero rules?

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bhall II wrote:I didn't say it's not possible; I just don't understand the utility of a plan to improve aero efficiency that ignores the worst offenders.
The general idea is that better efficiency should meant less turbulent wake and improved overtaking oppotunities.
It's repeatedly said that current aero development is against overtaking opportunities. And to improve in this area cars should rely more on mechanical grip than on aero grip.
My idea is to find a way to reduce aero grip with reduced turbulent wake and improved efficiency.
McLaren mp4-X concept goes to wheel covers and close cockpit.
Red Bull X2010 also goes towards wheel covers.
Ferrari concept also partially covers the wheels.
It's interesting the technical discussion about how to possible measuring drag in a race event environment.
Some say that is too much difficult to enforce. I've to say that F1 already does a lot of things that are awfully difficult to do.

George-Jung
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Re: What about imposing a drag limit in aero rules?

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bhall II wrote:Since drag squares with speed, and the power required to overcome it is cubed concurrently, I think it's probably safe to assume designers already put forth considerable effort toward improving L/D ratio.

For instance, Lotus tried for years to implement a so-called "passive DRS" in order to shed induced drag at speeds beyond those for which downforce is necessary.

http://i.imgur.com/lxHA6HQ.jpg

And I remain convinced that Red Bull's flexible front wings were designed to shed induced drag through a progressive reduction in wing tip ride height that ultimately caused the force-enhancing tip vortices to burst.

http://i.imgur.com/WileXoF.jpg

Also note MP4-26's radically reduced sidepod frontal area and RB7's reduced rear wing frontal area. Both designs are entirely devoted to drag reduction.

So, I'm not really sure this is an area of performance that needs to be incentivized through regulation. For sure, downforce tends to come first. But, that doesn't mean drag is ignored.
Weren't the sidepods of the MP4-26 that way in order to get more air to the rear.. in order to create more downforce?

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FoxHound
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Re: What about imposing a drag limit in aero rules?

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bhall II wrote:Not to go too far down the cost rabbit hole, but it should be noted that engine development tends to be vastly more expensive than aero development.
Lurching ever forward unto the murky breach of the rabbit hole....

Red Bull have a team budget of $468m, the single largest budget in F1, and they do not build engines, currently.
http://www.crash.net/f1/news/221835/1/f ... -most.html

There is also the very public cost of engines to customers which is circa 20m, dependant on which Donkey you choose, or perhaps which Donkey chooses you.
Given Williams have a budget of around 190M a year, 20 million accounts for about 10% of their team budget. So naturally, these costs are dwarfed by costs elsewhere, at least if you are a customer.

Mercedes, Ferrari and now Renault will obviously need to research, design, build and supply engines. All of which are separate to team costs. Given that Mercedes are paying 400 employees at Brixworth, and 700 at Brackley, mostly well paid and sought after professionals, I'm going to propose that the costs are proportional. Factor in that they receive 20 million per team supplied, and the cost is reduced somewhat.

If not, and if the graph you presented is accurate, Ferrari and Mercedes would be reaching nigh on Billion dollar season spends, each.
Their team spends are proxy 400 million apiece, meaning the engine spend would another 50% to the total costs.

I don't buy that.
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