BEAVIS' White Track Car

[IanR]

off the chart awesome work on so many things... just wow

[beavis]

Like the seat Beavis - money well spent - just make sure you've got some nice thick steel plates under the mounting bolt points if you're not using the OEM ones. Will be interesting to see how the thing goes now with some power - should be a good thing.

Thanks, I'm happy to finally have a proper seat.
I'm actually looking at welding the seat brackets to the cage.... I figure its stronger than the sheet metal floor.

[MrsB]

better again (welding to cage or a plate running between the cage and welded to the floor as well

[beavis]

So we had our first trial with making the new wing.

The alloy plate is used for mounting the wing to the car, and for the wing endplates to attach to. However for this first test we decided to use some plywood as the plates cost about $50.


Weighing the foam core, it was under 290grams. (0.6pounds). We also used about 1.5kg of resin. The wing was cut to 1.4m span to match the car it will bolt to.


For this test piece, we opted for a few layers of fibreglass, a layer of plain weave carbon fibre and some strategically placed carbon offcuts for strengthening.
You can see our plywood end pieces in place


After layup, the wing was wrapped in plastic and returned to its original block to help with holding shape.


The whole block was placed in a bag. Vacuum pump hooked up. Start sucking.


After a few hours, we went to check the progress only to discover that the heat of the curing epoxy had exceeded the limits of the polystyerene. The end result was a very warped part.


So we need to find an alternative foam, or change the choice of resin, or change the process to reduce the heating effects... or some other alternatives which we have not pondered up yet.
We trialed the strength of the wing even in its deformed state. With near 200kg static weight in the centre of the wing, it did not flex, however any more than that and the wing started to fail.

Nonetheless, it was a good test.

[greenMachine]

Yes, a good test, lots to be learned.

Doing it that way (enclosing the workpiece in the foam from which is cut) gives no opportunity for heat to escape. That stuff (if it is the same foam as I have used in the past) is also not very heat-tolerant, so you have two strikes before you start. I think you will find that most 2-part epoxies generate a lot of heat as they cure, if you find one that doesn't please let me know!

Are you happy with the quality of the process (melting aside) with the sandwiching of the core in the two halves of the block? Did the pressure get transmitted to the skin OK, or did the foam absorb it?

Dow surfboard is what I use now for cores, stronger but heavier, and more heat tolerant I find. Have a look here, it is an aero modellers site but I get my cores from them - they supply a lot of these to racecar builders - an there is some useful info on the different foams around.

[lightyear]

That foam was normal polystyrene. I didn't think about what happens when it heats up. We trailed a second foam that is similiar, but much denser. We used a heat gun to see how easy it melted compared to the normal polystyrene, and found it much better. I am sure Brendan will update, but the 2nd wing didn't melt. We bagged it without the block of foam around it. I wouldn't call it a 100% success, but it is a very useable wing. It has cured, and we will do the minimum strength test - 2 people standing in the middle while the ends are supported by blocks of timber. Then it needs some sanding, resin brushed on, and more sanding, as the surface has the infusion mesh texture imprinted into it.

[greenMachine]

Thanks for that Lightyear, I look forward to anything Beavis can add.

[beavis]

We spent some time trying to find a foam supplier that would cut the shape for us. We were trying to avoid having to make our own hot-wire cutter.
Even with a CAD drawing supplied, many foam suppliers were incapable of cutting to our desired shape.
One supplier wanted over $400 for a pair of wings. However I think they priced it because they didn't want the work. Communication with them was atrocious.

In the end we found this guy who supplied us with cut to spec polystyrene for under $100 per raw wing foam. However his results were initially not very precise. In fact the first cuts we got from him were nothing like the supplied CAD, it's almost like he looked at the picture, and just randomly cut a roughly similar shape. We gave him a second chance and the results improved.

I think we can all agree that polystyrene is not the best choice of foam, but it is cheap and readily available.

[Okibi]

I wonder if you could cover the foam as a layer of insulation before applying the resin. Could do a test with an offcut.

https://youtu.be/qQdZoqbXJdM

[Apu]

Would it be easier to use balsa? Cut balsa blocks similar to the end plates but a couple of mm smaller to allow for balsa sheets, then lay the fibreglass and carbon over that. No issues with heat, and you can DIY it without having to rely on someone else to cut polystyrene.

[beavis]

Would it be easier to use balsa? Cut balsa blocks similar to the end plates but a couple of mm smaller to allow for balsa sheets, then lay the fibreglass and carbon over that. No issues with heat, and you can DIY it without having to rely on someone else to cut polystyrene.

I guess you can say 'there are many ways to skin a cat'.
It's quite possible to make a mould with something like balsa. We had considered making the wing in 2 vacuum infused parts with fibreglass moulds.
I guess the option we chose here was the 'easiest' in many regards.

We have started toying with alternative options and slightly different methods, already the results are improving.

[beavis]

Just a small update on things that aren't my car.

Had a visit from a 300+hp NB recently to help make an airbox and bracket for the COPs.
It was certainly interesting to get up close to a car running a turbo setup not too dissimilar to what I plan on using. Albeit this car is a little more beefy in the engine department.


Also visited Sandown raceway with the lightyear for a weekend of the state championships to enjoy the smell of fuel and rubber in the air and for an opportunity to get some inspiration and ideas on how to change/improve my own car.



With aero always on the mind, I really liked the many details of the Audi R8's. The design of the front end was awesome. One of these was for sale for only $150,000aud.


This sports sedan with its body removed offered a close up view of some sexy details not normally seen.

[beavis]

I forgot to post up the video i made of the wing.

https://www.youtube.com/watch?v=z00jNeLnx7U&ab_channel=BEAVISHSV


So needless to say, attempt 2 was much better than attempt 1.
This wing is strong, weighs about 2.7kg (~6lbs) and works well on the silver NB.
The gurney flap was cut down to about 4 or 5mm.

We will hopefully make another wing soon, however there is a good chance we may try a different method again.... and make a wider wing.

[IanR]

Looking forward to track results and breakdown... is there a mild version of aero bits for the fakers? Im id there is!

[MrsB]

looking good beavis be interesting to see how it goes on the new car