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Bolt on front end subframe
MK9R - 15/12/09 at 04:17 PM

Thinking of replacing the front end of the chassis with a bolt on subframe so easily changeable after a racing incidents, and/or develop suspension. The plate between the existing chassis and subrame would be 5mm, bolted together with M12 and doweled.

Magenta = existing Fury Chassis
Cyan = added members to chassis
Red = bolt on front end
yellow lines are pick up points for suspension.

Note, the steering rack mounts and damper mounts are not shown

The reason the front subframe is higher is because its a racing chassis so has the raised suspension points and i want them to mount direct to the chassis rail

What do you think?








[Edited on 15/12/09 by MK9R]

thunderace - 15/12/09 at 04:27 PM

Magenta Cyan wtf are they lol

Staple balls - 15/12/09 at 04:32 PM

quote:
Originally posted by thunderace
Magenta Cyan wtf are they lol


Colours

MikeRJ - 15/12/09 at 04:33 PM

The 5mm plates seems unnecessarily large and heavy. Something like a small bit of 3mm plate would likely suffice if you could create a rigid mounting area with box sections.

Perhaps you could make the cyan parts out of wider box so you could weld in some mounting bosses/dowel locators and ditch the big plates entirely?

TimC - 15/12/09 at 04:37 PM

quote:
Originally posted by thunderace
Magenta Cyan wtf are they lol


A comment there from someone who clearly never had a CGA monitor. This used to be it - the only colours you could see on a PC!

MK9R - 15/12/09 at 04:39 PM

quote:
Originally posted by MikeRJ
The 5mm plates seems unnecessarily large and heavy. Something like a small bit of 3mm plate would likely suffice if you could create a rigid mounting area with box sections.

Perhaps you could make the cyan parts out of wider box so you could weld in some mounting bosses/dowel locators and ditch the big plates entirely?


Good point, could use 50mmx25mm box with crush tubes

Mr G - 15/12/09 at 04:44 PM

quote:
Originally posted by TimC
quote:
Originally posted by thunderace
Magenta Cyan wtf are they lol


A comment there from someone who clearly never had a CGA monitor. This used to be it - the only colours you could see on a PC!


Or someone who owned a ZX spectrum

adithorp - 15/12/09 at 05:02 PM

Can't see why not. Adds a bit of weight but if done right will add stiffness. If you put in dowels to locate it accuratly, you could remove/refit without having to recheck the suspension. Or you could have another front sub-frame complete and set up and just swap them over should you ever have damage at a meeting.

adrian

blakep82 - 15/12/09 at 05:19 PM

hmm, i wouldn't like it, but to be honest, i can't think of a reason why not lol
my head says it would be too wobbly, but all your suspension is bolted on anyway.

i would worry that the 3mm plate would be too bendy though, 5mm would be too heavy

rayward - 15/12/09 at 06:02 PM

as others have said, can;t see anything wrong with it, but don;t think i;d risk it myself,

my main concern would be the shear effect on the bolts/dowels if the font of the car was hit from the side.

are you using the car for racing ?, if so maybe worth finding a friendly MSA scrutineer, and getting his opinion on it ?

hth

ray

tegwin - 15/12/09 at 06:07 PM

In an accident wont the car fail at the weakest point?

Most likely the join between the two chassis parts?

sebastiaan - 15/12/09 at 06:08 PM

quote:
Originally posted by rayward

my main concern would be the shear effect on the bolts/dowels if the font of the car was hit from the side.


I'd think in a crash you'd want to get rid of as much parts (= kinetic energy!) as you can, so parts flying off would be a bonus?

If you're stood by the side of the track though.... (and that is where the "do not lose wheels in a crash" rule in F1 comes from)

blakep82 - 15/12/09 at 06:10 PM

^ which would tug on the threads (and would do on heavy bumps, heavy braking etc), rather than through the thickest part of the bolt

quote:
Originally posted by rayward
my main concern would be the shear effect on the bolts/dowels if the font of the car was hit from the side.


if it was hit from the side, its pretty much screwed anyway though

smart51 - 15/12/09 at 06:13 PM

quote:
Originally posted by blakep82
i would worry that the 3mm plate would be too bendy though, 5mm would be too heavy


So you'd go for 4mm then?

blakep82 - 15/12/09 at 06:13 PM

quote:
Originally posted by smart51
quote:
Originally posted by blakep82
i would worry that the 3mm plate would be too bendy though, 5mm would be too heavy


So you'd go for 4mm then?


that would be too bendy AND heavy

rayward - 15/12/09 at 06:15 PM

quote:
Originally posted by blakep82
^ which would tug on the threads (and would do on heavy bumps, heavy braking etc), rather than through the thickest part of the bolt

quote:
Originally posted by rayward
my main concern would be the shear effect on the bolts/dowels if the font of the car was hit from the side.


if it was hit from the side, its pretty much screwed anyway though



fair comment, but i think i;d prefer it if the steering stayed as intact as possible right to the end

ray

blakep82 - 15/12/09 at 06:18 PM

quote:
Originally posted by rayward
quote:
Originally posted by blakep82
^ which would tug on the threads (and would do on heavy bumps, heavy braking etc), rather than through the thickest part of the bolt

quote:
Originally posted by rayward
my main concern would be the shear effect on the bolts/dowels if the font of the car was hit from the side.


if it was hit from the side, its pretty much screwed anyway though



fair comment, but i think i;d prefer it if the steering stayed as intact as possible right to the end

ray


ah, yeah, i was forgetting about what happens til the car comes to rest. you're right, it should really stay on

i was just thinking about what was said about replacing the damaged front. any impact is going to bend the mounting too.
the plates will get twisted, chassis tubes bent, so its never going to be a case of just bolting a new front end on

MikeRJ - 15/12/09 at 06:30 PM

quote:
Originally posted by blakep82
i would worry that the 3mm plate would be too bendy though, 5mm would be too heavy


3mm plate would certainly be too bendy if it was a couple of large flat plates bolted in the middle. A small bit of 3mm plate supported by box section around it's periphery would be very rigid.

boggle - 15/12/09 at 07:08 PM

you could use 3mm with a triangular press in the middle, or a slight rigid fold throu the center diagonaly...

you need some form of servo saver for the steering? maybe putting the removable section further back?

MikeRJ - 15/12/09 at 10:18 PM

quote:
Originally posted by boggle
you need some form of servo saver for the steering?


It's not a radio controlled car

Volvorsport - 15/12/09 at 11:13 PM

hmm , id came up with a design early in my chassis life so that i could convert it to composite chassis later on .

why not use the actual chassis tube section and dowel it tight with some high tensile bolts in the original chassis , you wouldnt need to make the 3mm mounting plates , and in my opinion not much weight gained and no less stiffness .

MK9R - 16/12/09 at 07:19 AM

quote:
Originally posted by Volvorsport
hmm , id came up with a design early in my chassis life so that i could convert it to composite chassis later on .

why not use the actual chassis tube section and dowel it tight with some high tensile bolts in the original chassis , you wouldnt need to make the 3mm mounting plates , and in my opinion not much weight gained and no less stiffness .


mmmm, interesting idea. When a chassis gets cut and shut it uses that principle, but obviously welded rather than bolted.

Guihanos - 16/12/09 at 09:28 AM

Does you modeling software has something like Cosmos in Solidworks? It could give you an idea of which aera will have the highest stress.

MK9R - 16/12/09 at 09:31 AM

quote:
Originally posted by Guihanos
Does you modeling software has something like Cosmos in Solidworks? It could give you an idea of which aera will have the highest stress.


No, its actually a CAD package for simulating robotic automation, bt has a simple modelling tool that i can knock stuff up in very quickily. It has Kinematics, but not stress evaluation

se7en - 31/12/09 at 07:01 PM

I have seen it done on F2 stock cars away back in the 80's. There is nothing new about this chassis.

IICR Audi did something similar with the Le Mans cars when the rear suspension/drive train was held on to the car by 4 bolts.

The only thing to keep in mind is a chassis is only as strong as it's weakest point.

skinned knuckles - 3/1/10 at 01:04 PM

interesting idea but cant see the real benefit.