Released Speedkraft Formula Ibishu 1.1

Hmm, interesting!

 

You could remove the pushrods and the suspension will behave in the exact same way, minus the missing swaybars. I tried this and got nearly identical handling and identical suspension articulation with the flexbodies flopping around. The suspension is even called "flexbody only" in the jbeam.

 

Yes. That's what I said.

 

Then you are misinterpreting what I am saying. The suspension articulation should be different between a standard double wishbone and a pushrod. With its current setup, it is no different from my backyard kart or DrowsySam's scarab in that the direction of forces from the "coilovers" is not longitudinal, but transverse and in no way follows the mesh. There should be some transverse forces from the pushrods rotating the knuckle, but it would not be anywhere near 100% nor at the angle it is currently.

My post was to point out that the pushrods are fake and only there for aesthetic purposes. A vehicle with pushrod suspension will have different handling characteristics than one with the suspension setup this vehicle currently has.

Edit: I actually really like this vehicle, I just think it's weird that the suspension type visible is not the one in use.

 

What pushrods give you is more control over the motion ratio of the shocks and that's pretty much it. While that can help with adjusting handling characteristics to be perfectly how you want, doing so requires a bunch of calculations and design time that I don't really want to put into a mod. Making a pushrod setup w/o properly designing it will often just give you worse results than simple double whishbone. A big reason for pushrods in modern single seaters is also packaging and aero, however that's not really an issue in beam.

Multilink has the exact same issue, in that while it gives more control, it requires a lot more thought in the design to not end up with something that just doesn't work right. You cannot eyeball something decent unlike with double wishbone.

The other issue is weight. The mod is not far from the limit in terms of how light I can make it before running into instability issues or bad handling due to a lack of rigidity. As suspension is kinda critical to a car's handling, the whole thing needs to be very rigid and therefore ends up with heavier node weight. The current setup has only a single node for the shocks on each end, while a basic pushrod setup needs at least 5 per shock, or 10 per side. You could reduce that number by reusing chassis nodes, but that's still more weight for, in the end, not a huge difference in handling.

The Formula Bee has a very hacky pushrod setup, but it's mechanically the only way to jbeam the monoshock setup that it has.

 

I guess my question would be, why jbeam the suspension if you aren't using it? I understand that the nodes are extremely light and only really there for the flexbody and I appreciate not wanting to go through the trouble of making it 100% accurate. However, there is more to suspension articulation than just the motion ratio such as the forces I alluded to previously. Plus the fact that the two shocks share a node, so the suspension arms aren't really separate since any sudden bump on one side will directly transfer the forces to the other side instead of doing so through the frame or the sway bars.

Trust me, I get how difficult it is to make something light as the backyard kart is still getting tweaked a year after I started on it. I just think it's strange to model one thing and jbeam a different thing.

 

The thing is that other than motion ratio curves, where you can have the motion ratio change exactly how you want as the suspension compress, a lot of the IRL aspects of pushrods (or motion ratios in general) don't really apply to beam.

The shock tower node is very rigidly fixed to the chassis, so hits from a single wheel will act on the chassis and not the other wheel.

It's not much different to the Apache where both shock tower nodes on the front end are connected to each other with a beam, which is pretty much what those buggies run on the front in terms of structure.

 

How would they not apply? I guess I may not fully understand how a pushrod suspension would functionally differ from a double wishbone aside from the position of the springs and the way the springs are compressed. Is it not just a coilover compressed using a lever of some sort?

Wouldn't they interact much less if they were set up with individual nodes? and especially using the visible setup? The way it is set up now, the forces from one wheel will not be diffused by the chassis at all before they reach the other side, whereas in the visual setup, the forces will have to move through the chassis alone before reaching the other side.

Adding on to this, the direction of the forces is going to be significantly different from the current setup if made to match the mesh. A bump would cause a large force on the x-axis initially, which would be partially absorbed by the chassis and then converted to the y-axis by the rotation of the bell crank. Currently, a bump causes forces on the chassis equally on the x-axis and z-axis at a point above the actual chassis. This causes not only the wheels to influence each other, but also magnifies the effect of any bump due to the suspension having more of a lever against the chassis due to the center node being as high as it is.

 

Tbh @TrackpadUser would you mind me perform a V8/V10 swap on the Formula Ibishu and release it on the repo?

 

"Pushrod suspension" really just applies to how the springs are connected to your suspension. You can have a pushrod setup with pretty much any suspension design that doesn't depend on the springs to do anything other than control up-down movement. People have used pushrod suspension on live-axles, swing axles, multilink, double wishbone and probably other stuff as well.

It's main advantages IRL are :
-Packaging : You can fit the shocks in ways that might be better for your build. For example, hidden in the body of your single seater, or flat on the frame of your slammed pickup truck build.
-Aero : Kinda fits with packaging, and specific to single seaters, but instead of having a big shock in the wind, you just have a stick, with the shock hidden away inside the body.
-Fine tuning the motion ratio across the entire suspension travel.

Motion ratio is essentially the leverage of your suspension. 1 meaning that the shock compresses 1mm when the wheel moves 1mm. 0.5 means the shock compresses 1mm when the wheel moves 2mm.

You can get a smaller motion ratio through the following means :
-Having the shock be mounted half-way on your suspension arm instead of right next to the wheel
-Having the shock mounted at an angle
-Using bellcrank geometry on a pushrod setup to change the leverage.

A smaller motion ratio means :
-A shorter shock for the same suspension travel
-More loads on components with the
-The suspension is effectively softer for the same spring stiffness.

However like most things in suspension, motion ratio usually varies as the suspension compresses, especially because the angle of the shock changes compared to the direction the wheel is moving. In most applications you're will see the motion ratio get larger as the suspension compresses, meaning the suspension gets effectively stiffer. This is generally pretty good for things like road cars as it helps reduce the harshness of the bigger bumps. This is where a properly engineered pushrod setup truly shines, as it gives you a lot more control over that motion ratio curve.

However the "properly engineered" part is very important, else you get no advantage (with more complexity and weight, especially in the context of beamNG). This requires knowledge I don't really have, and it's not really something I'm interested in doing for the minimal difference it might have on handling.

As long as the shock mounting nodes are attached rigidly enough to the chassis that it doesn't move relative to the chassis, the whole chassis can be considered to be a single unit that moves as one.

My design works exactly the same way, but instead of the forces being transfered from one side to the other through a nearly perfectly rigid structure (the chassis), they're transfered from one side to the other through a perfectly rigid structure.

If you consider the chassis to be a perfectly rigid structure (which it kinda is as it's way stiffer than the springs), the wheel still sees the same force and force direction. It doesn't care if the shock is connected directly, sideways, upside down or backwards.

I haven't done a free body diagram in a while, but if I had 2 setups with the beam connected to the wheel (the red beam) at the same angle, one with said beam being the spring, and the other using that beam as a pushrod for a vertical pushrod setup, the reaction forces would be the same on that beam for both setups.

Putting it that high up was just a way to keep the motion ratio somewhat reasonable. The suspension setup was made taking into account the still fairly small motion ratio of the suspension.

As long as it doesn't look too hacky.

 

I actually managed to put the V8 model inside although with some scaling adjustments since it is too wide for the body, even in nodal positions I had to keep adjusting but still managed to pull through. The V8 has 2.4L and has 750 hp, my words are it will actively try to kill you before going into 4th gear (or 200+ km/h), it STILL has wheelspins at 200+ km/h despite me slapping on those meaty 18x12 rears racing slicks.

Tldr power =/= good

 

No steering wheel or dash could you help

 

Have you tried a 6 cylinder instead?

 

TrackpadUser updated Formula Ibishu with a new update entry:

Small fixes

Read the rest of this update entry...

 

nice mod. but since yesterday i seem to have a bug with a visual glitch going through the car. Can anyone relate or help?

Without echaust the problem seems to be gone.
I cleared cache already and deinstalled all existing mods i had

 

Same issue seems to happen on my end.

I'll try to see if I can fix it this weekend.

 

Also the tires dont have collision it can go through other cars!!!!
Edit: Can only go through same car

 

I think that's on purpose. I wouldn't know the exact purpose but its not a bug

 

Having the tires not crash in the car itself is just because I left it at the default setting, which is required for most cars to avoid the tires getting caught in body panels.

The fact that tires don't collide with other instances of the same car is weird