My solution to the flexi-wings

[marekk]

Mandated porpoise nose? No thanks

Why not ? it's a circus anyway

[bettonracing]

I don't undersatnd how they can test with Newtons, instead of kgs. Surely 200N load is only the same as 20kgs?

F=ma

If F = 200 and a = 9.81ms2 for gravity, the surely they are only testing with a 20 kg load.

If so how about a wing test that uses a realistic load?

Likely to allow the FIA to conduct the tests horizontally. I'm not sure how the tests are conducted now, but at least the option is there if they so desire. Also, specifying the test with a nominal gravity figure, but conducting the tests in varying gravity fields (~9.78 to 9.82) may result in a demand for further clarification.

Regards,

H. Kurt Betton

[DaveW]

Last time I looked, a Newton was a unit of force & a kg was a unit of mass. I don't think either is affected by gravity (even on the moon). It follows that a test force should be defined in Newtons, not kg (in SI).

[bettonracing]

Last time I looked, a Newton was a unit of force & a kg was a unit of mass. I don't think either is affected by gravity (even on the moon). It follows that a test force should be defined in Newtons, not kg (in SI).

Read Martin Keene's post. A mass applies a force due to gravity.

Regards,

Kurt

[Ciro Pabón]

aeroelastics are huge right now watch the dream liner on take off see the wing tips curve up this is to simulate a wing end plate but with less drag its far from a dead tech area.

Sure, flyn, you are absolutely right, but how it is related with a different aerodynamic regime, like the one F1 car engineers confront?

Perhaps you think FIA intents to have these gadgets in regular cars some day? They say no.

Perhaps this research could be helpful in high speed trains, the only objects in transportation I can think about right now that have a similar aerodynamic regime, but I also think that's not Ferrari, Mercedes, Red Bull or McLaren goal.

There is a kilogram-force unit, Dave, as you know. You can use any unit, but engineers will stick to SI, as you say.

Gravity can be important for some measurements. In my country, the variation in gravity causes you to have an error of + or - 20 meters in height from the Caribbean to the Amazon, if you stick to GPS data. The first time I made maps of the Magdalena River Valley, in some parts the river went uphill (to my surprise) because it has such a low slope (300 meters of fall in 1.000 km, that is, 0.03% slope).

Gravity model for my country. You correct your GPS readings by the amounts indicated in this map



From Pole to Equator you have a difference in gravity that is around 0.5%. From sea level to 2000 meters of height, you have a difference of 0.1%, roughly speaking. Mountains and the such can throw local gravity around 0.01%.

So, if you go from a race in the Equator at 2000 meters (Bogotá) to a race in the Pole at 0 meters, you can have a variation in load (assuming the wing is tested with weights) of 0.6%. In 500 newtons that is a change of 3 Newtons.

That's not at the root of the problem of flexi wings, which is to give an unfair advantage to some teams that have developed wings that deflect in a non-linear way.

Kurt, I think FIA (if it deems gravity a problem) could use quartz load cells.

[DaveW]

[Read Martin Keene's post. A mass applies a force due to gravity.

I did, actually. Martin Keene was correct. Roughly, anyway, because 1 N of force will, by definition, accelerate 1 kg of mass at 9.80665 m/sec/sec in the SI world. It will do that anywhere. It is a conceptual error to assume that the force required to support a mass exposed to an arbitrary gravitation field will be constant, as you pointed out. Ciro's suggestion of measuring force with a load cell should suffice (though I would suggest a transducer having better stability that a piezo-electric device).

Ciro: Apologies, but GPS uses triangulation to determine position relative to some datum. The system is not good at estimating height (ellipsoid, geoid, or surface) for various reasons, including the fact that a receiver can't "see" satellites below the horizon. Absolute accuracy is affected by many variables, but they will (should) not include local variations in gravity. For more info, see here.

[flynfrog]

Ciro-

Its no more relative than any other part of F1 Ferrari has used the tech on their road cars.

[bettonracing]

I did, actually. Martin Keene was correct. Roughly, anyway, because 1 N of force will, by definition, accelerate 1 kg of mass at 9.80665 m/sec/sec in the SI world. It will do that anywhere. It is a conceptual error to assume that the force required to support a mass exposed to an arbitrary gravitation field will be constant, as you pointed out. Ciro's suggestion of measuring force with a load cell should suffice (though I would suggest a transducer having better stability that a piezo-electric device).

Ciro: Apologies, but GPS uses triangulation to determine position relative to some datum. The system is not good at estimating height (ellipsoid, geoid, or surface) for various reasons, including the fact that a receiver can't "see" satellites below the horizon. Absolute accuracy is affected by many variables, but they will (should) not include local variations in gravity. For more info, see here.

It sounds like we're all saying the same thing: A test using a 20kg weight (instead of a specified force) will need to specify a gravitational constant, which will need to be accomodated during the test.

Regarding GPS, the receivers used to plot the map Ciro posted are likely are surveyor grade units which use fixed-location correction methods (e.g. cell towers or reference stations) to achieve the sub-meter accuracy required for such work. The Garmin receivers posted in the link You provided are, as You correctly stated, horribly inaccurate for the work Ciro described.

The non-linear characteristic Ciro mentioned means if the FIA wants to ban flexi wings, they will likely have to specify an unusually high test force (beyond the expected aero loads), or some kind of on-track minimum height. Personally I say leave the test at 500N and let the other teams catch up, then ban it when the entire car starts flexing.

Regards,

H. Kurt Betton

[bot6]

I don't undersatnd how they can test with Newtons, instead of kgs. Surely 200N load is only the same as 20kgs?

F=ma

If F = 200 and a = 9.81ms2 for gravity, the surely they are only testing with a 20 kg load.

If so how about a wing test that uses a realistic load?

They don't put a weight on the wing. They use a hydraulic ram to be able to measure the applied load more precisely.

Easier to work with Newtons in that case. Also, it enables to use the same gear for vertical and horizontal tests, with the same calibration. Saves time.

[raymondu999]

I have a question, if anyone is able to answer. Do they:

a) hang a load from the endplate
b) place a load on the endplate
c) put a load distributed across the wing's plane
d) hydraulic press to press on the endplates
e) hydraulic press to press on the whole surface?

I was thinking that those would probably produce different results as the torque (or moment ) would be greatly different.

[shelly]

Testing procedure for wing flexing is recalled in scarbs blog.

Basically they apply load on two circular areas at some defined x and y positions; matching with endplate shape is obtained with a jig which is provided by the team.

The most interesting point is that proof loading is asymmetrical, i.e. testing is performed first on one side, than on the other; whereas on track the wing is always loaded on both sidesm, even if not always in a perfectly symmetrical way (e.g. cornering and other cars' wake intersection).

[myurr]

Although I don't think it's been confirmed, it is believed that the test is also carried out on a bench with the middle part of the wing supported, rather than with the nose attached to the car. So any flexing in the mountings will not be measured.

[Martin Keene]

I don't undersatnd how they can test with Newtons, instead of kgs. Surely 200N load is only the same as 20kgs?

F=ma

If F = 200 and a = 9.81ms2 for gravity, the surely they are only testing with a 20 kg load.

If so how about a wing test that uses a realistic load?

They don't put a weight on the wing. They use a hydraulic ram to be able to measure the applied load more precisely.

Easier to work with Newtons in that case. Also, it enables to use the same gear for vertical and horizontal tests, with the same calibration. Saves time.

Ok, but the principle still applies. They are testing the flex of a device which can produce several hundred kg's of down force with a 20kg mass.

It's not exactly a representative test is it. If they won't to ban flexi wings, which I don't believe they should, it is a very useful and relevant technology, then they need to increase the load substainally.

[bettonracing]

FYI as of last year (during the peak of "flexi-wing-gate"), the test has been 500N/ 50kg. Also keep in mind that while aero @ high speed may exert more total load on the front wing, aero loads are better distributed across the span of the wing than the (relatively speaking) point loads of the test.

Regards,

Kurt

[volarchico]

As a simple and rough aerodynamic comparison:

Downforce coefficient: 2 (probably on the low side considering ground effect, multi-element, etc)
Wing area: 1.08 m^2 (a bit of a guess, 1.8m x 0.6 m?)

At 99 km/hr, you get downforce of approximately 1000 N. This would be equivalent of hanging 500 N on 1/2 the wing (double it for the full wing).

They spend a significant time above 100 km/hr I'd say! What's the speed around the slowest corner?

At 300 km/hr, you get over 9000 N!