F1Technical Overtaking Working Group

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
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WhiteBlue
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Re: F1Technical Overtaking Working Group

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There is plenty of experience that indicates to instability with cars going airborne if they rely on ground effect/diffusors and not on wings. You find more of this in LMPs than in F1 because F1 is fundamentally wing friendly due to their usefullness for billboarding.

F1 should allow movable / elastic wings with sufficient safety against failure and do away with most aero rules by defining a minimum ride height and maximum downforce. 1,25 metric ton was proposed in the past and it should be a good figure. Nobody has ever opposed that.

And generally one has to accept that overtaking will allways be more difficult in an open wheeler on a road course than a touring car on an oval.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

rjsa
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Re: F1Technical Overtaking Working Group

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WhiteBlue wrote:There is plenty of experience that indicates to instability with cars going airborne if they rely on ground effect/diffusors and not on wings. You find more of this in LMPs than in F1 because F1 is fundamentally wing friendly due to their usefullness for billboarding.

F1 should allow movable / elastic wings with sufficient safety against failure and do away with most aero rules by defining a minimum ride height and maximum downforce. 1,25 metric ton was proposed in the past and it should be a good figure. Nobody has ever opposed that.

And generally one has to accept that overtaking will allways be more difficult in an open wheeler on a road course than a touring car on an oval.
When was the last time a F1 flipped?

And how again is that you enforce maximum downforce?

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WhiteBlue
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Re: F1Technical Overtaking Working Group

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Theissen was quoted here on F1technical
"When it comes to overtaking maybe we had expected a bit more from the new regulations. In the area of cost-saving, I think the progress has pretty much met expectations. The aero restrictions we currently have, however, are not as tight as we thought they would be, so I think we could do more."
That sounds to me like BMW want to cut downforce possibly by deleting the DDD loophole.

On the issue of limiting downforce by technical means there are several ways which all requires the measurement of downforce or ride height. Previous discussions here on F1 technical have resulted to agreement that it is feasible. So I would not go into details there.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

DaveW
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Re: F1Technical Overtaking Working Group

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Scarbs,

Brilliant post. My peculiar bias would lead me to suggest that if both of the suggestions in the last bullet were implemented, the four preceding suggestions would be unnecessary. Keep up the good work.

SoftBatch
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Re: F1Technical Overtaking Working Group

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So what would have happened at Turkey if Vettel had the movable front wing?. He was much faster than Button at the time.

Before changing anything they should setup a test with two cars from a team with all of the OWG advancements and start them nose to tail telling both drivers to race for position. Then swap the starting positions and try it again.

Michiba
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Re: F1Technical Overtaking Working Group

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how about bring back bodywork/aero bits on the car? Eg delta wings, horns, etc. As I understand it, these were flow conditioners to optimise air flow over the body. Surely these would reduce any deleterious effects of dirty air from a car in front. The were only banned for aesthetic reasons in the first place (and personally, I think has worked as this years cars look much sleeker).

DaveW
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Re: F1Technical Overtaking Working Group

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WhiteBlue wrote: F1 should allow movable / elastic wings with sufficient safety against failure and do away with most aero rules by defining a minimum ride height and maximum downforce. 1,25 metric ton was proposed in the past and it should be a good figure. Nobody has ever opposed that.
Using aeroelastic deformation to modify aero loads is clever, efficient & dangerous. I believe that the last is the reason it has been discouraged.

A minimum static ride rule is not the most brilliant concept, IMHO. It is used in a number of race series, is demonstrably ineffective, but making it so compromises suspension set-up. Arguably, therefore, the principal effect of a minimum static ride height rule is to make race vehicles less safe than they might have been.

Downforce is difficult to monitor by measurement, I think. If the requirement is to limit cornering speeds, then D/F coefficent through corners is, perhaps, more relevant than maximum downforce. I can't help thinking that any rule that relied on measurements controlled by a race team would be of doubtful effectiveness.

Apologies...

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WhiteBlue
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Re: F1Technical Overtaking Working Group

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DaveW wrote:
WhiteBlue wrote: F1 should allow movable / elastic wings with sufficient safety against failure and do away with most aero rules by defining a minimum ride height and maximum downforce. 1,25 metric ton was proposed in the past and it should be a good figure. Nobody has ever opposed that.
Using aeroelastic deformation to modify aero loads is clever, efficient & dangerous. I believe that the last is the reason it has been discouraged.

A minimum static ride rule is not the most brilliant concept, IMHO. It is used in a number of race series, is demonstrably ineffective, but making it so compromises suspension set-up. Arguably, therefore, the principal effect of a minimum static ride height rule is to make race vehicles less safe than they might have been.

Downforce is difficult to monitor by measurement, I think. If the requirement is to limit cornering speeds, then D/F coefficent through corners is, perhaps, more relevant than maximum downforce. I can't help thinking that any rule that relied on measurements controlled by a race team would be of doubtful effectiveness.

Apologies...
Static or dynamic load testing can easily take care of structural integrity concerns of elastic rear wings. A main reason for not going that route was the continous concern of curbing excess performance under the concord rules. They could never agree to anything and often performance curbing had to be brought in on safety grounds. So the FiA wisely always kept a safety concern open althoug everybody who has been in an aircraft during major turbulences knows that elastic design can be very safe. In a 747 you can watch the wing tips make vertical movement of 10-20 m. Or watch the drooping wings of a B52. They had to fit ancillary wheels to keep the engines from hitting the runway so elastic was the design. I never heared of a wing coming off such a bomber under regular flight conditions.

Actually I was thinking about monitoring downforce by measuring ride height as one of the alternatives to eventually control downforce. With spring rates known a point can be made that ride height is functionally linked with downforce although this is obviously a different function on each car.

A more interesting alternative is measuring vertical force at every corner of the car and correcting inertial forces by accellerometers. The SECU should be capable of doing this. We have diskussed this in a previous thread sometimes and nobody came up with obstacles that couldn't be resolved.

I think that the teams simply prefer to exploit the chaos of ever changing "boxes" of aero restrictions. It is so nice to blame the FiA for all problems that arise from this crude method and by juggling the boxes around you can eternally create new configurations on which to waste more billions for meaningless aero research. If the teams were working against a fixed maximum downforce they would at least contribute to fuel efficiency by every bit of improvement they find. With fixed downforce the only way to get more performance by aero is to reduce drag which then reduces fuel consumption and improves overtaking.

Originally the 2009 rules were supposed to be introduced in 2008 with the expiry of the old Concord Agreement. The draft 2008 rules had a mandatory downforce limit of 1.25 metric tons. The teams opposed this rule and set up the OWG to show they could do much better. It initially cost a lot of time because they had to do some practical reasearch to prove a concept. They did that and it was clear that they would interprete the 1.25 ton very liberally and the rule would be pushed back one year to 2009.

They defined the concept of the new front wing, the new rear wing and the diffuser where rear wing and diffuser would be decoupled. Then instead of keeping the downforce rule they went ahead with another foolish "box rule" which they promptly got wrong. The DDD loophole was created and words of warning by Ross Brawn were disregarded.

The next step in this perverted development was the annoucement by Red Bull that they managed to join the diffuser and the rear wing wash once again by the latest Newey design. We have gone full circle and nothing of the original brief of reducing downforce and turbulence remains. Red Bull pays Newey 9 mil $ salary to play the foolish box game. I wish the teams would at least acknoledge that they simply got it wrong with the OWG process. If you measure downforce now in max configuration I bet we are back to 85 or 90% of 2006, which is way off target.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

DaveW
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Re: F1Technical Overtaking Working Group

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WB: Oops. The logic you present for ensuring the stability of flexible wings is, if you will forgive me, exactly why they are dangerous. Aerofoil divergence is a "critical point" problem caused by the coupling between aerodynamic forces and aerofoil displacement. You are certainly correct about the flexibility of aircraft wings, but much technology lies behind their design. As a matter of fact, the Wright brothers were not the first to launch themselves into the air in a powered aircraft. Langley preceded them by a few years (with a monoplane). The problem was he knew nothing about wing divergence & ended his flight in the Potomac river. Monoplane wings had a reputation for being dangerous (e.g. Fokker DVIII(?) monoplane that killed a few WW1 pilots) until the early 1930's when Duncan finally solved the problem. You might like to browse through a very old, but venerable, book called (I recall) Aeroelasticity by Bisplinghoff, Ashley & Halfman. Anyway, more recently, Jacques Villeneuve experienced a spectacular rear wing divergence failure in (I think) a BAR vehicle in Australia.

Apologies again, but spring displacement would not be an accurate way of estimating downforce, for a couple of reasons.

The first is because bump stops are often used to limit spring travel at high speeds. Bumps stops are also used to control sprung mass rake (incidence) in order to manage the build-up of downforce (& hence drag) at high airspeeds. Another problem to be addressed by your concept, perhaps.

The second reason is because damping style can be (is) used to control the average platform ride height on track. NASCAR is the most outrageous example - they use rebound damping to haul down the sprung mass on-track to the point where the front springs become coil-bound.

Having said all that, I can't disagree with your sentiments.

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WhiteBlue
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Then we are apparently in agreement on the main issue. F1 isn't short of technology and should have no fear to aspire to safety challenges as seen in the aircraft industry. That is where most of the manufacturing technology comes from. Some of our most knowledgeble members here are working in the aircraft industry. Much of the deformation and dynamic behavior of composite parts is subject to computer aided design and simulation. Teams nowerdays make suspension elements from composites which are also sometimes subject to elevated temperatures from exhaust gas. I would think that is a simillar challenge to dynamic safety. If derformation becomes legal engineers may even use very different structures which will not have to satisfy the old tests anymore but more meaningfull tests designed to avoid structural failure or deformation with loss of aerodynasmic functionality.

When I first thought about means of measuring downforce I was entirely fixed on force measurement, but some people told me that ride height was easier to use. If that is not true I can accept that without no problem. It appears that we still have the force measurement method and that may well be the way to go in the future.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

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flynfrog
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WhiteBlue wrote:Then we are apparently in agreement on the main issue. F1 isn't short of technology and should have no fear to aspire to safety challenges as seen in the aircraft industry. That is where most of the manufacturing technology comes from. Some of our most knowledgeble members here are working in the aircraft industry. Much of the deformation and dynamic behavior of composite parts is subject to computer aided design and simulation. Teams nowerdays make suspension elements from composites which are also sometimes subject to elevated temperatures from exhaust gas. I would think that is a simillar challenge to dynamic safety. If derformation becomes legal engineers may even use very different structures which will not have to satisfy the old tests anymore but more meaningfull tests designed to avoid structural failure or deformation with loss of aerodynasmic functionality.

When I first thought about means of measuring downforce I was entirely fixed on force measurement, but some people told me that ride height was easier to use. If that is not true I can accept that without no problem. It appears that we still have the force measurement method and that may well be the way to go in the future.
the test are not hard to figure out we do it on aircraft all the time. Find max load + safety factor apply for a set time. Do a damage tolerance test life cycle the part with know defects.

DaveW
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Re: F1Technical Overtaking Working Group

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Oh dear. WhiteBlue & flynfrog are ganging up on me, I am tempted to say with the confidence of youth, on a subject that is some way from from topic of this thread. However, I would like to have just one more attempt to explain myself with a simple analogy:

A straight tube required to carry compressive loads has two modes of failure. The first, a simple compressive failure, is predictable with accuracy assuming controlled end conditions and material properties. The second, a buckling failure, is an example of a "critical point" problem & is far less predictable. An aerospace designer would simply increase the diameter of the tube & decrease its wall thickness until a buckling failure ceased to be a realistic possibility. A race car designer, however, might see an opportunity in the post-buckling behaviour of the tube & attempt to use that to his advantage. Immediately he is on his own, with little or no past experience to call upon, so he had better know what he is doing.

Designing flexible wings is similar. An aerospace designer would consider the problem trivial & simply increase structural stiffness until he could design & test it reliably. Failing that simple solution, he would pass the problem on to specialists who would ask questions about elastic centres, centres of pressure, and centres of gravity. They would then perform complex calculations and become excited if the estimated critical airspeed was less than 50 percent greater than the maximum speed of the vehicle. In that event, incremental whole vehicle trials would be scheduled to compare reality with predictive models, gradually working up to cover the performance envelope of the vehicle. Arguably, perhaps in a roundabout way, FIA regulators simply took the view that this was unlikely to happen sensibly in F1, & so mandated the aerospace designer's solution.

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WhiteBlue
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Re: F1Technical Overtaking Working Group

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Do you seriously consider an elastic hinge to be more difficult to design that a rear suspension member or some of the carbon fibre composites of the wheel assembly? Those parts are primary safety components that are exposed to tremendous heat. Heat is another complication when you deal with polymeric matrizes. It causes non linear aging and premature failure if you do get your model wrong. Teams flux those components after every race and have very elaborate procedures to provide the required safety.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best .............................. organization, not to those with the biggest budget. (Dave Richards)

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machin
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Re: F1Technical Overtaking Working Group

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WhiteBlue wrote:There is plenty of experience that indicates to instability with cars going airborne if they rely on ground effect/diffusors and not on wings. You find more of this in LMPs than in F1 because F1 is fundamentally wing friendly due to their usefullness for billboarding.
I was under the impression from numerous articles in racecar engineering that the instability/airbourne experiences of LMP cars was due to the large flat underfloor area that these cars have had in the past, and how in extreme cases of yaw this flat area and the shape of the upper surface of the monocoque effectively creates a wing (with low pressure surface at the top). For this reason recent LMP rules have actually moved to INCREASE the downforce generated by the floor by ENFORCING a ground effect enducing shape.

I can see how extreme cases ground effect floors could be very unstable if the ride height changes dramatically... (e.g. if the throat of the floor becomes choked) the answer here is to ensure that the floor shape can't be this extreme (by carefully writing the rules).
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Re: F1Technical Overtaking Working Group

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DaveW wrote:WB: Oops. The logic you present for ensuring the stability of flexible wings is, if you will forgive me, exactly why they are dangerous. Aerofoil divergence is a "critical point" problem caused by the coupling between aerodynamic forces and aerofoil displacement.
This topic has also come up on the "ban wings" thread. viewtopic.php?f=1&t=7023

Are you saying that deformable wings are bad because the forces can suddenly flip, resulting in a near instantaneous loss of downforce?

I can see that happening if the wings flapped around like a badly trimmed sail, or a mast with subject to cross wind galloping. But that sort of scenario is also possible with a rigid wing that is very pitch sensitive on a car bouncing over kerbs?