chassis question

[Karam El Hady]

I'd like to ask if welding (the main hoop bracing and main hoop bracing support ) members in the the point in black circle instead of the point in red circle like pic is permissible and right ?
what i mean is welding on member like pic instead of welding at the end of member is permissible ?
1149

[Claude Rouelle]

I will let the rules expert answer your question but I can't help to ask you why you do not have all these tubes connecting to the same node. You just offer the chassis more chance for compliance

[Karam El Hady]

Hi Claude Rouelle

i made(upper maim hoop bracing support) member horizontal like pic because i fixed suspension point on it so now i related with plan i can't make the member higher to go the point in red circle
i didn't make the horizontal red member like this pic because it will prevent the chain that link the engine gear with sprocket to go through chassis ** the sprocket outside of chassis **So i made it higher to allow to the chain to go through
that why all tubes can't connect to the same node
1150

[Claude Rouelle]

I believe you fall in the trap of most new designers; you start to design (or worse manufacture) your chassis without having ALL drawings complete. The guy who thought about the space he needed for the chain did not communicate well enough with the guys who decided suspension pickup points and chasiis node.
If it is the same guy who does both work (you?) he did not put his thoughts together well enough

There are several more elegant ways to take car of both issues at the same time. usually it requires several chassis design iterations and some creative, non emotional thinking with several people together

Minimum nodes, minimum tubes and maximum triangulation is one of the ideas you want to keep in mind when you design the chassis.

[onemaniac]

Going back to the basics, Pat Clark's famous quote "A chassis is a bracket" should be the rule #1 for all chassis designers.
Have your sub system designs done (based on the overall design concept of course...), place them around the driver cockpit envelope based on the F:R and L:R weight distribution, CG height and Yaw inertia target. (just to be in the right ball park at this stage)
Once you've done that, design the "bracket" to hold them in place.
There will be of course more than a few iterations on both ends to make everything fit and comply with the rules.

This is just one of many approaches you can take so it's completely up to your own discretion.

[Jonny Rochester]

Karam,
Regarding your first image, this is acceptable and looks fine. All tubes inside the black circle need to be fully welded. This is in principle the same as the UTAS (and many other) chassis. The node in the red circle is not covered by rules, and you can do whatever you want. Some teams (UTAS) have an aluminium plate there.

With your second image, I believe that is OK as well.

[Jonny Rochester]

The next thing is to look at legal wall thickness of tubes.

In your second image, the coloured tube does not even need to be there (legally), so you can make it whatever you like.