Wishbones attachment question !

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firasf1dream
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Joined: Fri Apr 18, 2014 8:26 pm

Re: Wishbones attachment question !

Post by firasf1dream » Sat Jul 26, 2014 9:00 am

ok thanks so it's simply a flexible wishbone :D
but how do they change the angle of these wishbones when needed, the angle with the reference plane on which sits the car if we're looking at the car from the front ?

xpensive
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Re: Wishbones attachment question !

Post by xpensive » Sat Jul 26, 2014 9:06 am

A slightly more elegant flexure joint, note that only the joint is flexing and not the wishbone;

Image
"I spent most of my money on wine and women...I wasted the rest"

marcush.
268
Joined: Tue Mar 09, 2004 3:55 pm

Re: Wishbones attachment question !

Post by marcush. » Sat Jul 26, 2014 10:26 am

Image

a rear one but ver neat Installation doubling up as damper mountingpoint.

firasf1dream
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Joined: Fri Apr 18, 2014 8:26 pm

Re: Wishbones attachment question !

Post by firasf1dream » Sat Jul 26, 2014 10:37 am

you mean the joint at the end of the wishbone right ? the titanium part ?

zonk
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Re: Wishbones attachment question !

Post by zonk » Sat Jul 26, 2014 11:20 am


mep
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Location: Germany

Re: Wishbones attachment question !

Post by mep » Sat Jul 26, 2014 11:46 am

firasf1dream wrote:ok thanks so it's simply a flexible wishbone :D
but how do they change the angle of these wishbones when needed, the angle with the reference plane on which sits the car if we're looking at the car from the front ?
The suspension kinematics are defined in the early design phase and then usually stay for the whole season. The outboard points (at the upright) are easier to be adjusted. A change of the inboard points requires a new chassis or new gearbox. The setup is adjusted at the upright, simply by replacing shims which are placed under the brackets where the wishbones are attached to the upright. However these only affect how the wheel is positioned to the ground. So parameters like chamber, toe, track (with rim spacers). The kinematic itself can not be changed! This requires manufacturing of new parts with different geometries. Due to the F1 regulations the wishbone shape also needs some reworking when a kinematic point is modified otherwise they can become illegal.

firasf1dream
1
Joined: Fri Apr 18, 2014 8:26 pm

Re: Wishbones attachment question !

Post by firasf1dream » Sat Jul 26, 2014 3:03 pm

guys, my problem here is where to put the axe or screw that will enter the joint of the wishbone and attach it
so here are pictures of my design so far i made it vertical, the joint, which gives a bigger movement which doesn't sound right but give me ur opinion please

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marcush.
268
Joined: Tue Mar 09, 2004 3:55 pm

Re: Wishbones attachment question !

Post by marcush. » Sat Jul 26, 2014 3:13 pm

it´s not the whole wishbone whish is bending ,it is just the end piece which is flexible (think of a thin blade). The design is a compromise of Installation stiffness and resistance to buckling especially under braking loads so you don´t want the flexy part to be too Long to avoid unwanted Suspension movement .

I do not agree with Mep These Points are fixed or set in Stone . You can of course specify multiple attachment variants in your original design without any compromise .It´s not like you have to cut a serious hole into the tub to allow for adjustability -if done correctly all you Need is a pit in the outer Shell were your alternative Suspension pickups will all fit in -allowing for considerable Change in antidive geometry and also movement of rollcentre Position .

your Picture will lead to bigger ball Joints to be needed as the main load (brake force) will be in axial direction for the Joint -

>putting a hole into the tub is always something to avoid<

firasf1dream
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Joined: Fri Apr 18, 2014 8:26 pm

Re: Wishbones attachment question !

Post by firasf1dream » Sat Jul 26, 2014 3:35 pm

ok great so i simply make a ball joint to make it a bit of flexibility between the wishbone and the tub and the cut that will be in the tub should be with a small angle to make the wishbone goes in angle to the reference plane when placed on ground ?

and about the screw that will go into the ball joint and attach the wishbone where it sould be, if not in the bulkead then it should be inside when open the cover will see it for the upper wishbone ?

and for the lower wishbone it goes from the bottom of the bulkhead up ?

marcush.
268
Joined: Tue Mar 09, 2004 3:55 pm

Re: Wishbones attachment question !

Post by marcush. » Sat Jul 26, 2014 7:41 pm

firasf1dream wrote:ok great so i simply make a ball joint to make it a bit of flexibility between the wishbone and the tub and the cut that will be in the tub should be with a small angle to make the wishbone goes in angle to the reference plane when placed on ground ?

and about the screw that will go into the ball joint and attach the wishbone where it sould be, if not in the bulkead then it should be inside when open the cover will see it for the upper wishbone ?

and for the lower wishbone it goes from the bottom of the bulkhead up ?
no need for the ball Joint ,mate . the Teams just put a bolt through tub and wishbone -end of Story. The Minute anular movement (at least at the front of the car )is taken up by the flexure design of the wishbone end- that´s what we told you all the time...
look up this :
http://sulu.smpp.northwestern.edu/saved ... 27p788.pdf
https://ravensracing.wordpress.com/page/2/

and here a Picture from an MG-Lola LMP2 car with blade type lower Suspension wishbones .I know from first witness(one of the Drivers) those gave a very bad Feeling under heavy braking and Dyson (who campaigned two similar cars quite successfully in USA) modified to balljooint lower wishbones and cured that unhappy Feeling under braking ..They had confidence in redesigning the wishbone as a flexure joint .

firasf1dream
1
Joined: Fri Apr 18, 2014 8:26 pm

Re: Wishbones attachment question !

Post by firasf1dream » Sat Jul 26, 2014 8:22 pm

but i saw a car with ball joint

but ok way better without ball joint :D thanks a lot for the help :)

one more question i have : what is the angle of the slot or groove that the wishbone will go into in the tub ?

marcush.
268
Joined: Tue Mar 09, 2004 3:55 pm

Re: Wishbones attachment question !

Post by marcush. » Sat Jul 26, 2014 9:16 pm

firasf1dream wrote:but i saw a car with ball joint

but ok way better without ball joint :D thanks a lot for the help :)

one more question i have : what is the angle of the slot or groove that the wishbone will go into in the tub ?
you are the one designing it ,no?

look up this years cars obviously not even the very best in the trade agree on wishbone angles ...so it is something of a soft constraint in your design -go for roll centre location or maybe a aero Advantage or maybe Installation stiffness .Take your choice .Suspension design is like everything in mechanical Engineering a matter of trade offs most of the time striking the best compromise with as many winwin decisions as possible will result in a good design -if you have not missed the boat completely in other areas...the variety of designs hints at the answer ..not that important for Overall Performance,maybe? :shock:

firasf1dream
1
Joined: Fri Apr 18, 2014 8:26 pm

Re: Wishbones attachment question !

Post by firasf1dream » Sat Jul 26, 2014 10:12 pm

ok so i found out that the angle in regulation must be maximum of 5 degrees

here is my new design now what do you think ? but without an angle for now because i must see how to make a new reference plane with angle to be able to draw it on solidworks !

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firasf1dream
1
Joined: Fri Apr 18, 2014 8:26 pm

Re: Wishbones attachment question !

Post by firasf1dream » Sat Jul 26, 2014 10:39 pm

and here it is the final one with an angle
what do you think ?

Image

marcush.
268
Joined: Tue Mar 09, 2004 3:55 pm

Re: Wishbones attachment question !

Post by marcush. » Sat Jul 26, 2014 10:56 pm

the 5° is the angle of attack mate .you got it wrong :

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this reg is there to ensure wishbones are not used to produce downforce

why would you use the awkward bolt solution then there are neat alternatives which are much easier to manufacture as well?

your tub is missing the second bulkhead to Support the rear wishbone legs as well -make up your mind how to feed the force into the bulkheads .This is the critical part -Installation stiffness without adding mass