New track toy

[Jay]

As i said alot of little things happening but 90% of the stich welding is done so just waiting for a few more bits to arrive for engine then she will be in her new home.
Fingers crossed might be able to start throwing the cage in soon.

Heres a couple of pics of the welding so far.

[DJ.]

I'm sure there is a good reason, but why don't you weld all along the seams?

[b33fy]

I'm sure there is a good reason, but why don't you weld all along the seams?

My understanding Duncan is as follows:

Stitch welding prevents excessive build up of heat in one place which may distort the thin panels. You can spread the welding out and then fill in the gaps as the welds cool down.

If you want continuous, you just keep filling in the gaps. Not sure if the extra work gives that much greater strength though.

I'm sure Jay or Dick will be along to clarify.

[Wingco]

Same question from me Duncan, looking forward to the answer from Dick or Jay.
Mike i do understand what you are saying, that seems a fair answer to me.

[Dick]

As Mike has said its about heating things up to much and yes we could fill in all the gaps but then you would end up getting stress cracking . Ok if you have lots of money and are going to replace the shell after a season racing but for this project its a bit different.
Its stitched as we still need the car to move a bit its a bit like a squeaking gate never brakes or the wind on the reed or the mighty oak. If it was a new shell direct from factory with no sealer then we would do 4" welds on it and spaces. Its a tried and tested method . It would be nice to do the underside as well but this is a fun track day toy , Jay will be doing some bits under the car . We was talking things over today again . The front chassis where it joins at the bumper will have an extra bar welded in and an extra piece put in the rear. Two reasons for these are, firstly cars have a bumper bar behind the plastic this car wont. Second is the reinforcing bars fitted when new are a compromise on strength and look . This is about strength bugger the looks. Another bar will be placed from the bulk head to the tunnel and from the inner wings to the a pillar.
Jay will add photos as these things are done, Neil was given a short tour of what is what today.
Are all these things he is doing needed er maybe but its better to do them now than when its broken. Takes me back doing this sort of thing to shells.

[DJ.]

Thanks for the explanation
I take it when you mentioned cracks, that isn't the welds cracking, I assume it is where all the stresses caused by the seams not flexing end up causing the panels themselves to crack.

[Fury1630]

A monocoque depends for it's strength on defusing any loads throughout the structure, make one part of it too strong & the load will go to the weaker parts which will bend or break.

It's not an easy concept to grasp (took me a long time), but think of a balloon, you blow it up & the load is equally distributed, but if there's a thin bit you get a lump there. What Jay's done is to add strength to parts of the balloon so it can take more pressure without adding so much strength that the extra pressure breaks the existing thin bits.

Does that make any sense at all

[Dick]

A monocoque depends for it's strength on defusing any loads throughout the structure, make one part of it too strong & the load will go to the weaker parts which will bend or break.

It's not an easy concept to grasp (took me a long time), but think of a balloon, you blow it up & the load is equally distributed, but if there's a thin bit you get a lump there. What Jay's done is to add strength to parts of the balloon so it can take more pressure without adding so much strength that the extra pressure breaks the existing thin bits.

Does that make any sense at all

Yep in a nut shell that's about it .
Sorry for the squeaking gate / reed and oak tree thing seems not every one has heard of these stories

[Jay]

So all the stitch welding is finally finished now on to some support work from the b post to the front of the inner wings to stop this section from twisting.
But in better news, in order for the roll cage to be msa/fia approved you can either get the cage fitted at a approved place of they can send you some test pieces you have to put together then they load test those which then approves you to fit the cage.
The limit it has to reach is 10.5ton to be approved. Just got our result back. Result was 12.75ton before the weld broke. This has broken a record for them that has been standing for 2 years nearly. So well done Wilf get cracking. When the cage is fully installed and we get authorisation that means we are then a recommended installer.

[Fury1630]

^^ Excellent^^