Seat update....needs lots of adjustment

The seat is again proving to be a more challenging project than anticipated.

It has many rules governing it's position and size and so getting the belts to go through into the driver compartment is a tricky process. Also because we don't want to destroy the seat and cut holes where we don't need them it's hard to start to make cuts and holes when you really need the seat fully mounted in the chassis with a driver sitting in it to know exactly where these all go.

With the chassis unable to be soley used to mock this up at this late stage it is a bit of a guessing game, the solid works design used a model of a driver but there really is nothing liek the real thing so you can't trust this 100%.

Also makig life a little harder is the fact that the harness mounts are 30mm out of position due to a manufacturing error, it is too late to re-make these so we are using what we got but the seconday problems are just becoming a little be-motivating and slowing progress down.

I have decided that we are jst going to have t cut holes as best we can and keep cutting and shaping them till the seat sits right, we still have the mould so if need be we can add some patching to the composite lay-up later down the track once we know the belts will go where we want and comply with the rules.

Here is a few pics of the progress over the weekend...slow but now we have a pretty good game plan written down with a list of priorities to get done by our car launch this Friday, we just need it to be sitting in the car with belts through it so it looks the business, we can finalise the hard mounting points later.

Oh did I mention we all have exams over the next 3 weeks and the car goe on a truck to melbourne on the last day of exams ? This is the most fun you will have in you're engineering degree.



Above I use a drill bit that has the milling type teeth on it's shank so that I can easily cut complex curves. I start with lots of holes around the perimeter on the inside of where I want the final cut. I then mill between the holes joining them all up using the sideways cutting ability of the drill bit. Then I get a nice sharp half-round file and try to neaten up the edge. It works fairly well and is the most effective method I have found to do this type of work, I have been involved in the seat making in '08, '09 and this year so I'll building a knowledge of what NOT to do by making mistakes.....some would call it learning. Still got a lot to learn and still making mistakes but thats life, we do what we can.



Above test fitting the belt holes in the seat to see what will work and where we need adjustment. The lap belt holes (on the sides) should be ok I have marked where they need to be enlarged for the haress clips to fit through. The submarine (crotch) strap does fit through the opening but the belts will slightly rub on the seat at the moment which is no good, either have to cut the holes more to taper a slot towards the mount to enable a good angle of wrap around the drivers thighs or add a steel tube bar that just touches the underside of the seat, the belts would wrap around this so that they have a nice smooth radius transition up towards the driver, just have to ensure a good wrap around the drivers legs again though.

Design Blunders

Just a short on to remind everyone we are human and we are all still learning.

We make mistakes.

With a miscommunication / understanding of how a particular laser cutter programed their CNC input in the machine we ended up with a double size part. With tight deadlines and long leadtimes associated with this type of work we opted to have the re-make plasma cut to save time.

The second generation part is not as accurate and has been slightly welded incorrected we now have a snow-ball effect with the harness mounts not sitting in the designed location withing the chassis.

This actually has strict rules within the technical criteria of the FSAE competition and it had to be double / triple checked that our car would still be compliant. LUCKY the design had inplace a few backups for suck errors with multiple locations for the harness eye-bolts to mount, this accomodated for the new further back position in the chassis.

The part on the left is the marginall under-sized plasma cut part (fully tig welded up here) and on the right is the double size part that was incorrectly laser cut due to an error on our end. (the part on the right is only roughly welded together as a gimic to ourselves to show the error that was made)

Just a reminder to us to be extra cautious even in times when we are pushed to make the car ready on time rushing small things can create much more hassel.

Even the marginally uder-size plasma cut part means that it now sits 30mm further back in the chassis even though the difference from design size to manufactured part is minimal it can create a big impact.