Well, I've been busy in the garage practically the whole month of July...
I bet my partner €100 that I would finish all the mods before 31st of July. That didn't happen. So I lost.
I'll try and post some photos soon.
Previously I thought I'd just do a partial belly pan, partial meaning < 1.5 m². Now I am getting close to 3.2m². The target is to make about 4.0m² totally flat. Or as best as possible.
I have literally spent HOURS under my van pondering the best way to block off the remaining gaps. There's a mighty cavern behind the fuel tank, then another one behind the rear axle where the spare tyre went. I previously did a lousy attempt at both. Even though both bits stayed bolted on, I wasn't happy with it as I knew I could do much better.
So I thought I might as well just do the whole darn lot and be done with it.
I have a strong background in Materials Science so I had to do this properly...
I've used a
combination of materials for this project:
I like to experiment with things, like a lot of forum members...
- Firstly, 6x 85mm wide powdercoated alloy extrusions (2 metres long). I have put 3 down each side of the van, I'm using fibreglass tape & polyester resin to hold them adjacent to each other... I have pop-riveted some steel 90° brackets to the car (stainless rivets), then the alloy bits are bolted on to the brackets with stainless M6 harware (pan heads on all the bolts
). These sections effectively close of a gap (chambers really) about 12" deep along both sides of the van.
- I've got about 7 or 8 anodised aluminium extrusions for the mid-section closest to the exhaust, both sides. These contraptions have a fluted bottom & are held together by a few "L" shaped alloy struts. At the moment I'm using high-temperature epoxy to hold this altogether, so there are no bolts to interrupt the air flow...
Some pieces are fine, but other bits don't come into contact with the L bar so I'll have to glue on some more reinforcements. Once again, these have M6 stainless harware that mount onto an aluminium sub-structure.
- Then theres 2 homemade fibreglass composite sandwich panels. First one is about 1m x 1m. Second one is about 0.9 x 0.8m. I'm using a single layer of 500g/m² fibreglass on each side with standard epoxy resin. I was vomiting the morning after I used the polyester resin, so never again.
NOTE: Epoxy doesn't give off no where near as much of an odour as it cures. I bought this from a composites store. Now if I can get this here on the tiny island of Tenerife, you can get this anywhere in the USA. As they are essentially a wholesaler, it is MUCH cheaper than the equivalent materials in Bunnings, Home Depot or whatever. I actually returned €15 worth of expoxy (in 200ml tubes or something) and got 3kg worth for just over double that amount... Price of raw fibreglass was 1/4 of that in "Leroy Merlin" (Spanish equivalent of home depot).
I have used prefabricated steel tablelegs for the carriers, 10cm & 15cm long. That's about how deep the gap is in the middle.
- I modified the existing rear axle by placing a PVC sewerage pipe over it (the strongest grey version). The closet I'll come to a boat tail is on the rear axle.
- Last but not least. The pièce de résistance (which isn't made yet). I had previously had a go at smoothing out the plastic engine cover underneath the front of the car. That, along with the sound insulation, made it too heavy, and the rear half basically fell down over the first speed hump. Not good enough Les!
This van sees speed. So looking at all the uneccesary holes and what not, I've decided to make this into a TOTALLY flat underbelly for the engine. The best part is that I have already bought 1 square metre of carbon fibre for this...
This cost €40 for 1.25 x 1.0m so is actually fairly reasonably priced. There is 1kg of epoxy resin left over. So I plan to make what is called a "hybrid composite". That is something using more than one reinforcement material... in this case it will be two layers of fibreglass and the final carbon layer. I'm pretty sure that'll be plenty strong & stiff enough. I still have to optimise the shape of this part. More on that to come...
MOST IMPORTANTLY, NO CLOROPLAST!
Well actually, I used a similar product (clear polycarbonate sheeting) for the cores of my sandwich panels. The extra 4mm thickness they provide separates the two skins of fibreglass and provides even more stiffness.