Suspension Wishbone Mounting

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
MoistureDaddy
MoistureDaddy
1
Joined: Sun Sep 18, 2022 7:05 pm

Suspension Wishbone Mounting

Post

Hello,

I am a bit confused about how various suspension elements interface with the chassis/other inboard suspension elements.

I have found this image (see attached) that illustrates the various methods I have seen used.

Method 1) Seems quite straight forward. The push rod seems to pass through a dedicated cutout and mount to the bell cranks using a traditional tie rod end.

Method 2) the lower wishbone has an aerodynamic airfoil profile which has a nicely blended interface with the chassis. However the blended piece seems to be rigid carbon. How does this allow for wishbone movement during suspension travel? Do these wishbones use some sort of tie rode mounting within the chassis? Is the blended covering/shroud flexible?

Method 3) the upper wish bone seems to be a flexible carbon blade that mounts directly to the outside of the chassis. Is this the case? No tie rod connection and movement during suspension travel allowed for by wishbone bending?

Image

Any insight into the details of the upper and lower wishbone connections in the image would be much appreciated.

Thank you

Just_a_fan
Just_a_fan
561
Joined: Sun Jan 31, 2010 7:37 pm

Re: Suspension Wishbone Mounting

Post

They use flexure joints instead of the old spherical joints.

An old post by Scarbs here shows the method used by Jaguar back in the day. Today will be a modern version of this system.

Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools." oh, and "The Dutch fans are drunk. Maybe"

Tommy Cookers
Tommy Cookers
592
Joined: Fri Feb 17, 2012 3:55 pm

Re: Suspension Wishbone Mounting

Post

Just_a_fan wrote:
Wed Oct 05, 2022 9:20 am
They use flexure joints instead of the old spherical joints.
An old post by Scarbs here shows the method used by Jaguar back in the day. Today will be a modern version of this system.
new to me ...
showing the flexure as an integral part of the wishbone - same width but about half the general thickness
that would make the flexure 8x as compliant - if with fibre layout as the general section and doing the same job
(but being near the fixing end of the force system the flexure part also 'sees' far more of the bending moment)

though haven't separate flexures (metal) been usual in F1 even since the Jaguar time ?

Just_a_fan
Just_a_fan
561
Joined: Sun Jan 31, 2010 7:37 pm

Re: Suspension Wishbone Mounting

Post

Tommy Cookers wrote:
Wed Oct 05, 2022 11:38 am
Just_a_fan wrote:
Wed Oct 05, 2022 9:20 am
They use flexure joints instead of the old spherical joints.
An old post by Scarbs here shows the method used by Jaguar back in the day. Today will be a modern version of this system.
new to me ...
showing the flexure as an integral part of the wishbone - same width but about half the general thickness
that would make the flexure 8x as compliant - if with fibre layout as the general section and doing the same job
(but being near the fixing end of the force system the flexure part also 'sees' far more of the bending moment)

though haven't separate flexures (metal) been usual in F1 even since the Jaguar time ?
I think metal ones are used where loads are higher - the wishbones see different loads depending on where they are on the car and whether the vertical loads are taken by push rod or pull rod systems.

Interestingly, this layout from the Mercedes web site appears to show rose joint type connections on the rear suspension:
Image

although they do say this, so all of the theirs are metal rather than the CF design seen in the Jaguar.
The parts of the suspension that are hidden inside the chassis are primarily metallic, whereas the elements that are in the airflow are mostly made from carbon fibre, only their joints or flexures are usually metallic.
Of course, they're not going to show anything that might be useful although it's an old design from a car that is now a museum piece.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools." oh, and "The Dutch fans are drunk. Maybe"

MoistureDaddy
MoistureDaddy
1
Joined: Sun Sep 18, 2022 7:05 pm

Re: Suspension Wishbone Mounting

Post

I've found this new image that seems so show that thicker wishbone elements having some sort of inboard mounting as well as some internal structural elements. (type 2 wishbone elements from the original image)

Image

The blended carbon portions between the chassis and wishbones still confuse me because they appear to be rigid carbon pieces, however that would not allow for any suspension movement. Maybe they can just withstand a certain amount of flex?

MoistureDaddy
MoistureDaddy
1
Joined: Sun Sep 18, 2022 7:05 pm

Re: Suspension Wishbone Mounting

Post

After some further investigation I found this post on the @scarbstech instagram account (see attached image) that shows metal flexures bonded to the ends of the composite wishbones, which attach to internal chassis mounts.

Not sure why some flexures are externally mounted, while others are internal, but I'll keep investigating.

thank you everyone for your replies.

Image

Just_a_fan
Just_a_fan
561
Joined: Sun Jan 31, 2010 7:37 pm

Re: Suspension Wishbone Mounting

Post

MoistureDaddy wrote:
Thu Oct 06, 2022 5:05 am
After some further investigation I found this post on the @scarbstech instagram account (see attached image) that shows metal flexures bonded to the ends of the composite wishbones, which attach to internal chassis mounts.

Not sure why some flexures are externally mounted, while others are internal, but I'll keep investigating.

thank you everyone for your replies.

https://imageshack.com/i/pnq1FOeYj
Some are mounted directly to the side of the tub and thus are "external". Others mount to the tub in places that are covered by aerodynamic fairings anyway and so are "internal".
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools." oh, and "The Dutch fans are drunk. Maybe"

AR3-GP
AR3-GP
79
Joined: Tue Jul 06, 2021 12:22 am

Re: Suspension Wishbone Mounting

Post

MoistureDaddy wrote:
Thu Oct 06, 2022 5:05 am
After some further investigation I found this post on the @scarbstech instagram account (see attached image) that shows metal flexures bonded to the ends of the composite wishbones, which attach to internal chassis mounts.

Not sure why some flexures are externally mounted, while others are internal, but I'll keep investigating.

thank you everyone for your replies.

https://imageshack.com/i/pnq1FOeYj
Some are "external" and some are "internal" because the points at which the control arm attaches to the chassis is a performance parameter.

johnny comelately
johnny comelately
75
Joined: Thu Apr 09, 2015 11:55 pm
Location: Australia

Re: Suspension Wishbone Mounting

Post

Is this a rear arm mount?
Image

Image