36 replies to this topic

[johnnycomelately1]

Regarding Mercedes, does anyone think that a FRIC system between front and rear aero downforce is being used?

[smitten]

What evidence have the scrutineers missed which you have seen?

[johnnycomelately1]

What evidence have the scrutineers missed which you have seen?

not being suspension based, would it be illegal if it existed?

Front and Rear Inter-Connected Downforce, dynamically.

[gruntguru]

How would such a thing work? The DF is where it is. No way you can change the F/R distribution mechanically.

[johnnycomelately1]

How would such a thing work? The DF is where it is. No way you can change the F/R distribution mechanically.

with respect, you could be very mistaken.

just consider what i have written and take the wording literally

[gruntguru]

Call me dumb but you will have to explain what a DF FRIC does.

[johnnycomelately1]

Call me dumb but you will have to explain what a DF FRIC does.

GG, i imagine (being the operative word here) substituting the wheel generated forces of FRIC with downforce, thats all.

maybe its impossible .

i was just looking at why the mercedes chassis performance is so good

[desmo]

Just as a crazy thought experiment--it's obviously not a practical idea-- imagine a front wing on a lever with the downward aero force fed into a slave cylinder rigidly mounted to the sprung chassis.  This pressurizes a hydraulic circuit that is connected to slave cylinders rigidly mounted to the chassis above the rear suspension pushing downward through a telescopic sprung link on the rear wheel uprights.  Or even simpler, if perhaps more bizarre, imagine a front wing mounted on a long lever with its pivot behind the rear wheels and simple links feeding the downward force from the wing transmitted through the lever into the rear wheel uprights.  

 

Do these:  A- do nothing to alter the F/R DF balance because the none of the monkey motion and links change the fact that the front wing is at the front, B- have a real but minuscule and negligible effect or, C- have a potentially significant effect on F/R DF ratio?

 

[blkirk]

Just as a crazy thought experiment--it's obviously not a practical idea-- imagine a front wing on a lever with the downward aero force fed into a slave cylinder rigidly mounted to the sprung chassis.  This pressurizes a hydraulic circuit that is connected to slave cylinders rigidly mounted to the chassis above the rear suspension pushing downward through a telescopic sprung link on the rear wheel uprights.  Or even simpler, if perhaps more bizarre, imagine a front wing mounted on a long lever with its pivot behind the rear wheels and simple links feeding the downward force from the wing transmitted through the lever into the rear wheel uprights.  

 

Do these:  A- do nothing to alter the F/R DF balance because the none of the monkey motion and links change the fact that the front wing is at the front, B- have a real but minuscule and negligible effect or, C- have a potentially significant effect on F/R DF ratio?

 

 

A free body diagram says that the reaction forces at the tires would not be affected by all that monkey business.  The only factors that have a significant effect on contact patch loads are the location of the center of gravity, the location of the center of pressure, and the height of the center of gravity times acceleration.

 

Sometimes those values can change rapidly and cause transient effects in the system that really do matter (just ask Fat Boy), but I think that's beyond the scope of the thought experiment.

[johnnycomelately1]

Just as a crazy thought experiment--it's obviously not a practical idea-- imagine a front wing on a lever with the downward aero force fed into a slave cylinder rigidly mounted to the sprung chassis.  This pressurizes a hydraulic circuit that is connected to slave cylinders rigidly mounted to the chassis above the rear suspension pushing downward through a telescopic sprung link on the rear wheel uprights.  Or even simpler, if perhaps more bizarre, imagine a front wing mounted on a long lever with its pivot behind the rear wheels and simple links feeding the downward force from the wing transmitted through the lever into the rear wheel uprights.  

 

Do these:  A- do nothing to alter the F/R DF balance because the none of the monkey motion and links change the fact that the front wing is at the front, B- have a real but minuscule and negligible effect or, C- have a potentially significant effect on F/R DF ratio?

 

i reckon you are about a quarter the way there (on the right path)

[johnnycomelately1]

A free body diagram says that the reaction forces at the tires would not be affected by all that monkey business.  The only factors that have a significant effect on contact patch loads are the location of the center of gravity, the location of the center of pressure, and the height of the center of gravity times acceleration.

 

Sometimes those values can change rapidly and cause transient effects in the system that really do matter (just ask Fat Boy), but I think that's beyond the scope of the thought experiment.

blkirk,

interesting analysis

there is no scope

fric works

its just substitution, isnt it?

who is Fat Boy?

[desmo]

So assuming a high mid-mounted wing, using that FBD it would make no difference whatever in terms of F/R aero balance whether the downforce load was routed into either the front or rear uprights?

[gruntguru]

Correct.

 

The vertical force vector (sum of vehicle weight and aero DF) is where it is. The FR tyre normal force distribution cannot be altered by a mechanism within the car (one that doesn't exert any new force on the environment). Ditto the LR distribution.

 

The only thing that can be altered by suspension systems including FRIC is diagonal distribution.

[Greg Locock]

(sorry gg beat me to it) In side view draw two wings with downforce, and weight at the cg, and downforce from the body. Upward forces at two axles. That's it.

 

However if you were to feed wing force into the unsprung mass then you could jack the sprung mass, changing its rake and hence the pitch of the wings and the ground clearance, and hence alter the aero in various ways.

Edited by Greg Locock, 11 July 2015 - 05:12.

[johnnycomelately1]

is it possible that these are incomplete representations of the force vector situation?

[johnnycomelately1]

this picture started my thoughts about front rear aero dynamic balance

[Greg Locock]

is it possible that these are incomplete representations of the force vector situation?

Vertically? No, that's it. You could add some drag due to aero in the x direction, which would change the F/R balance a bit, but I don't think it wouldn't change much as you pitched the body.

[Kelpiecross]

Just as a crazy thought experiment--it's obviously not a practical idea-- imagine a front wing on a lever with the downward aero force fed into a slave cylinder rigidly mounted to the sprung chassis.  This pressurizes a hydraulic circuit that is connected to slave cylinders rigidly mounted to the chassis above the rear suspension pushing downward through a telescopic sprung link on the rear wheel uprights.  Or even simpler, if perhaps more bizarre, imagine a front wing mounted on a long lever with its pivot behind the rear wheels and simple links feeding the downward force from the wing transmitted through the lever into the rear wheel uprights.  
 
Do these:  A- do nothing to alter the F/R DF balance because the none of the monkey motion and links change the fact that the front wing is at the front, B- have a real but minuscule and negligible effect or, C- have a potentially significant effect on F/R DF ratio?
 

Interesting idea. But as everybody else says the DF stays where the wing is. In the case of the long lever arm with the pivot point behind the rear axle and the vertical link attached to the body - the lever/pivot/link system essentially is solid and becomes part of the car's chassis - so the wing is just mounted in an odd way and the DF remains where it is under the wing.

However in the case where the pivot is mounted on the chassis and the links to the top of the upright it appears to be a slightly different situation - there being some movement allowed in the system - pushing down on the wing would produce a torque about the solid rear links causing an upward force on the pivot point and thus the chassis. But after the various components reached a steady (non-moving)state the situation would revert to the previous arrangement of all the wing etc. components mounted on the chassis.

[johnnycomelately1]

just found this, it may be of interest:-

http://www.thisisf1....-up-front-axle/

[smitten]

just found this, it may be of interest:-

http://www.thisisf1....-up-front-axle/

 

 

Auto Motor und Sport correspondent Michael Schmidt revealed that the suspicion is that the W06, by way of an unexplained trick, is able to be “pumped up” for the optimal balance between high and low-speed corners.

 

In other words: we have no evidence what so ever, but if they did have a magic trick.....

[gruntguru]

The discussion in previous posts of mechanisms connecting the aero elements to the suspension would of course allow the ride height to be dependent on downforce. Unfortunately that is against the rules which prohibit such interconnection.

[johnnycomelately1]

The discussion in previous posts of mechanisms connecting the aero elements to the suspension would of course allow the ride height to be dependent on downforce. Unfortunately that is against the rules which prohibit such interconnection.

this has got nothing to do with ride height as such.

its interesting that McLaren made this mistake for years , focusing on ride height to make their aero work while the whole car didnt

dont forget the interconnection

[johnnycomelately1]

In other words: we have no evidence what so ever, but if they did have a magic trick.....

yes it is a bit like that, maybe smoke and fire thing

[johnnycomelately1]

Just as a crazy thought experiment--it's obviously not a practical idea-- imagine a front wing on a lever with the downward aero force fed into a slave cylinder rigidly mounted to the sprung chassis.  This pressurizes a hydraulic circuit that is connected to slave cylinders rigidly mounted to the chassis above the rear suspension pushing downward through a telescopic sprung link on the rear wheel uprights.  Or even simpler, if perhaps more bizarre, imagine a front wing mounted on a long lever with its pivot behind the rear wheels and simple links feeding the downward force from the wing transmitted through the lever into the rear wheel uprights.  

 

Do these:  A- do nothing to alter the F/R DF balance because the none of the monkey motion and links change the fact that the front wing is at the front, B- have a real but minuscule and negligible effect or, C- have a potentially significant effect on F/R DF ratio?

 

i think along similar lines on how it would be achieved.

it could also be done via solenoids etc using signal to activate the hydraulics at the other end, would require mapping, modulation etc.

the big question is , if there was an hydraulic cylinder used when the delivered pressure was introduced would the top fixed point be counteracted adequately by the native downforce and gravity etc of that end?

[gruntguru]

this has got nothing to do with ride height as such.

"able to be “pumped up” for the optimal balance between high and low-speed corners"

Sounds like ride-height to me.

 

Adjustable ride height is something of a holy grail - much more important than you seem to think.

 

Anyway, my comment was about posts which suggested aero could be mounted on levers or linkages which also connect to the suspension and chassis. Such a device would be illegal.

 

 Si think along similar lines on how it would be achieved.

it could also be done via solenoids etc using signal to activate the hydraulics at the other end, would require mapping, modulation etc.

the big question is , if there was an hydraulic cylinder used when the delivered pressure was introduced would the top fixed point be counteracted adequately by the native downforce and gravity etc of that end?

You keep saying "it" without saying what you think "it" is.

 

I can tell you what "it" is not. "It" is not a means of altering the downforce distribution (without changing the actual lift of individual elements).

Edited by gruntguru, 17 July 2015 - 01:10.

[johnnycomelately1]

"able to be “pumped up” for the optimal balance between high and low-speed corners"

Sounds like ride-height to me.

 

Adjustable ride height is something of a holy grail - much more important than you seem to think.

 

Anyway, my comment was about posts which suggested aero could be mounted on levers or linkages which also connect to the suspension and chassis. Such a device would be illegal.

 

You keep saying "it" without saying what you think "it" is.

 

I can tell you what "it" is not. "It" is not a means of altering the downforce distribution (without changing the actual lift of individual elements).

"it" obviously refers to my approximate term  aero FRIC, the very name of the thread.

"it" is the transference of downforce to balance the car in a manner to produce stability for the driving characteristics during racing.

just like fric does with other forces, its a mechanism for transference.

 

you can do as much "telling" as you like but discounting the ability to distribute downforce is a mistake in my opinion.

the ride height factor is not what this is to do with, i do not mean for a second to say its not important, of course it is , but its not the point here. the interaction between the two factors (assuming aero fric is something tangible) would be whole other area for investigation.

the levers and linkages thing would be almost impossible installation wise in a race car, but hydraulic and servo even pneumatic would be quite feasible.

if i was in the position of development i would assign a team to investigate that for sure.

[gruntguru]

"it" is the transference of downforce to balance the car in a manner to produce stability for the driving characteristics during racing.

just like fric does with other forces, its a mechanism for transference.

What you are suggesting is physically impossible.

[johnnycomelately1]

What you are suggesting is physically impossible.

if you have two downforces working at once; 

and there is a discrepancy between evenness;

you have both exerting through say, an hydraulic mechanism(leave regulations aside for the moment);

you take the excess from one transfer to the other ,

it seems to me that equilibrium could be achieved?

because the receiving end can take the extra up till the point of equilibrium??

No?

if this is not the case, could you explain to this dunderhead where it would not work please

[gruntguru]

If you put a box around the entire car with just the aero and the tyre contact patches outside the box and applying forces to the box - add gravity and you have a Free Body Diagram.

 

If the box is not accelerating, the vector sum of all the forces must equal zero. This tells us the tyre normal forces are a function of the remaining force vectors only (gravity and aero), regardless of what is inside the box (aero FRIC or any other mechanism).

[Wuzak]

The only way an "aero fric" could work is with active aero - physically changing the front or rear wings to alter the level of downforce and/or the centres of lift and pressure. These are clearly illegal in most, if not all, forms of motorsport, and certainly is for F1. Save for DRS, of course.

 

F1 wings do flex to change their aero characteristics, an issue which the FIA tries to fix using more stringent tests, but they are not interconnected.

[johnnycomelately1]

If you put a box around the entire car with just the aero and the tyre contact patches outside the box and applying forces to the box - add gravity and you have a Free Body Diagram.

 

If the box is not accelerating, the vector sum of all the forces must equal zero. This tells us the tyre normal forces are a function of the remaining force vectors only (gravity and aero), regardless of what is inside the box (aero FRIC or any other mechanism).

i roughly understand what you are saying, seeing as i am as aero as a brick.

but,,,the two sources of down force (i know there are others but) act outside of each axle and exert down force through the axles and then combined produce a centre of pressure

but... what i am saying is that the two individual sources of downforce have mount points and that is where the pressure can be sourced and distributed.

to me the limiting factor is the opposing force when the transferred force exerts downwards (it is not acting against a fixed object but gravity and the the other downforce,

the question is would the exertion produce an equal reaction with zero effect downwards

[Greg Locock]

As gg suggests, to understand why changes to the internal paths won't affect the tire forces you probably need to understand free body diagrams. These are not, at first, intuitive, luckily people with more patience than me have explained how to construct them. 

 

http://www.physicscl...e-Body-Diagrams

 

I'd add that in MIT's online Advanced Introductory Classical Mechanics course (highly recommended BTW)

 

https://www.edx.org/...s-mitx-8-mechcx

 

FBDs probably caused more head scratching or bad solutions among students than any other single concept except maybe orbital mechanics. 

[johnnycomelately1]

As gg suggests, to understand why changes to the internal paths won't affect the tire forces you probably need to understand free body diagrams. These are not, at first, intuitive, luckily people with more patience than me have explained how to construct them. 

 

http://www.physicscl...e-Body-Diagrams

 

I'd add that in MIT's online Advanced Introductory Classical Mechanics course (highly recommended BTW)

 

https://www.edx.org/...s-mitx-8-mechcx

 

FBDs probably caused more head scratching or bad solutions among students than any other single concept except maybe orbital mechanics. 

Thanks Greg, i will have a look

[johnnycomelately1]

As gg suggests, to understand why changes to the internal paths won't affect the tire forces you probably need to understand free body diagrams. These are not, at first, intuitive, luckily people with more patience than me have explained how to construct them. 

 

http://www.physicscl...e-Body-Diagrams

 

I'd add that in MIT's online Advanced Introductory Classical Mechanics course (highly recommended BTW)

 

https://www.edx.org/...s-mitx-8-mechcx

 

FBDs probably caused more head scratching or bad solutions among students than any other single concept except maybe orbital mechanics. 

is that one of the MIT open courses?

i understand forces in equilibrium and the vectors and forces involve d in these sort of static situations but the question remains for me:

the limiting factor is the opposing force when the transferred force exerts downwards (it is not acting against a fixed object but gravity and the the other downforce,

the question is would the exertion produce an equal reaction with zero effect downwards?

[johnnycomelately1]

more where there is smoke there is fire :

http://www.f1today.n...p-up-front-axle

[MatsNorway]

There is allways stupid conspiracies for the winner team. We had the same with Redbull. There is nothing illegal. Just clever understanding of the rules maximising the setup around it.

 

"Mercedes 'pumps up' the front axle for slow corners without having to sacrifice in the sharp forward angle for the fast corners."

 

If anything your links are kinda suggeting anti squat geometry at the front. But someone who actually knows setup can tune in and give a more qualified teory.

Edited by MatsNorway, 17 July 2015 - 11:54.

[johnnycomelately1]

There is allways stupid conspiracies for the winner team. We had the same with Redbull. There is nothing illegal. Just clever understanding of the rules maximising the setup around it.

 

"Mercedes 'pumps up' the front axle for slow corners without having to sacrifice in the sharp forward angle for the fast corners."

 

If anything your links are kinda suggeting anti squat geometry at the front. But someone who actually knows setup can tune in and give a more qualified teory.

i simply believe some type of aero fric can work to some degree.

maybe its the degree of effectiveness that is arguable.

illegality has not been mentioned here at all ( by me at least)

 

i would have thought that to talk about anti squat geometry would be too archaic and obvious ( maybe i give too much credit to the journos), i think maybe something more developed is at hand.

thats my opinion.