At Last!. I have started on my car ;-) PART 2

A spray booth would be nice, along with a wind tunnel and a rolling road, that would be most of my boxes ticked :)
 
Worked out how to activate the wing, now I need to harden up on the positioning.

Anywhere between the top and bottom image is possible. Top one simplest to make but bottom is best for downforce generation but difficult to attach securely.

To me, the middle three look the best and still work pretty well.

Thoughts?

 
You know Steve, I can't help thinking to myself how you are going to insure this car with a true valuation taking into account all of the hours spent making items by hand ?-/
 
Not easy. I will just make up a number and see what happens. I mentioned £75k last time I enquired and there wasn't a sharp intake of breath from the other end of the line :)

Can't take my time into account, otherwise we would be up in Bugatti territory :)
 
Well, I could always go somewhere else where I might be appreciated!

Novel indeed! Would you class War and Peace as a novel?
 
I'm a butterfly, flitting from idea to idea :)

I think I have worked out how to make the window frames, but it involves prepreg carbon and my oven isn't big enough. No problem, I will simply make a bigger one :)

Frame no problem.
Insulation no problem.
Fan assist no problem.
Heating and thermostat control I am still working on. I can get heating elements easily, but they all seem to be thermostatically controlled to 150 deg C and I need around 100.

This, for example:

http://www.ebay.co.uk/itm/191665719536

or this:

http://www.ebay.co.uk/itm/AC-220V-2...581208?hash=item43e028d518:g:shgAAOSwHnFVs9RY

Any heating engineers out there that can advise me on the best way to go? The box will be around 900mm x 700mm x 200mm in ply with Styrofoam insulation on the outside.
 
Dry run (no prepreg carbon) testing whether freezer bags work as vacuum bags. If they do it saves a lot of faffing about making bags with plastic and sealing tape. Seems to work fine.

 
With regard to rear wing design, I am now going with number 2.

DIY curing oven construction will be plywood box insulated externally with 50mm Styrofoam. Size will probably be around 900mm x 900mm x 200mm. This will be bib enough to accommodate the window frames but will no doubt prove to be too small very quickly but I will cross that bridge etc.

Heating will be by a pair of these, initially:

http://www.ebay.co.uk/itm/121733838869?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT



Controlled by this:

http://www.ebay.co.uk/itm/121366223748?_trksid=p2057872.m2749.l2649&var=420309324716&ssPageName=STRK:MEBIDX:IT

 
Right, anyone with any experience of working with prepreg please look away now :)

First attempt at using prepreg.

Carbon cut to size, a little bigger than mould to allow for pushing into cutouts.


Starting to apply CF


First mistake. CF not cut long enough. Oh, well, it will probably be rubbish anyway so no problem.


Add release film:


Then breather fabric which allows all of the air to be sucked out:


Vacuumed:


Placed in oven at 95 deg C for 6 hours:


Only 5 hours 37 minutes to go :)
 
Right, just removed from oven and mould.

Not as bad as I thought it would be but not usable without a fair bit of fettling. I didn't get the carbon tight enough into the corners. Hopefully next attempt will be better.

Weight? Just this side of nothing :)

Didn't realise that my mouse was so dirty!









 
Second attempt, almost a disaster. After talking to EasyComposites re temps and times I experimented with cure temps and times.

First, however, I tried a couple of different methods of applying the carbon. On half of the mould I cut the carbon into louvre sized chunks so the openings weren't covered. The other half I applied a strip that was only slightly wider than the louvre recess but covered the remaining four in one piece. For both methods I then applied a strip down the sides that overlapped the other layers. Did the same for the second layer.

Placed in cold oven and heated up top 85 deg C for 60 minutes. So far so good. I then increased the temp to 118 over 30 minutes. Looked Ok so went for dinner. However, when I checked an hour later the bag had melted! So, as a point of interest, self seal freezer type bags are only good up to around 100 deg C :)

Anyway, removed from mould and it isn't actually too bad. I had managed to get the carbon into the tight corners and they are pretty uniform. Resin hasn't flowed very well, due to lack of pressure I guess, but that will be cured when I use the proper bagging material (which I have plenty of, just trying to see if there was an easier way)



 
It's fine, thanks Os. Had to reinstall Windows 10 as it decided to log me in as an administrator which meant that I couldn't look at photos or use Edge. I couldn't get back to my login and even the KnowHow people at PC World couldn't help, other than suggesting that I restore the machine back to as shipped, losing all my data! I had to suggest that in older versions of Windows I could simply reinstall the operating system and not lose anything other that some installed programs. "Oh, yes, you could do that", he said!

Other than having to reinstall AutoCAD, Inventor and Office it was pretty painless and everything seems to be OK, at the moment.
 
Forth attempt at a wing vent is the best yet. It still have some imperfections but I may be able to hide those with paint :)

Photographing black items under artificial light is difficult so I will try again tomorrow.



 
Vent isn't quite ready for the final reveal so, in the meantime, I have been experimenting with window frame construction. I have been struggling with how to do it ever since I ditched the original frames and went to Lexan. However, this still needs support and I have been agonising on how to achieve this. Now that I have discovered prepreg I think my worries are over :)

To test my theory, I have made a pattern of the tightest bend on the frame and covered it in carbon. I will cure it tomorrow and reveal the result.

 
After 3 attempts using pre-preg carbon, I have managed to get a couple of vents out that are acceptable. Photo shows the final two, one as it came out of the mould and the other after fettling and painting.

Unpainted 51gms, painted 68gms. Whichever ends up heaviest will go on the passenger side to help even up the weight:) These will save over 1kg which equals around 1bhp/tonne

 
Didn't spend too much time fettling this as it is just a proof of concept part, but it seems to have worked. It is VERY stiff. The actual frame will be a little deeper and 4 more layers (this one has 8). This piece weighs 10gms, so I estimate that the final frame will be around 200gms.

 
Not a lot happening at the moment, but I have got the car back on the ground (well, actually on blocks). I can now level the chassis and try to sort out, as best I can, the crap body alignment. The wheels are just temporary ones until I finalise width and offset and order the new ones.

But first of all, I will have a clean up :)

 
Been doing some sums and I think that I will have trouble keeping the Elan below 700kg, as opposed to below 650Kg that I was hoping :-(

I suppose that I should take some consolation in the fact that it would have weighed over 850kg if I hadn't put it on a serious diet.
 
Started on rear damper cover and wheel tubs. I have been struggling on how to make it so decided to just start and work it out as I go along, as usual :)

 
In between blocking mouse entrances under the kitchen units and sorting out horse stable doors I managed to do a little more on the interior:

 
A little more progress. Rear wing support bracket and roll cage rear bar junction cover (where the bar passes through the carbon rear panel). Presently cooking at 95 deg C for 5 hours.



 
Wing bracket came out pretty well. Gave it a quick clearcoat just to see what the weave looked like, hence the bubbles :) Once it is sanded and painted it should look OK.



The cover for the rear roll cage bars and parcel shelf intersection came out reasonably. A little work and some paint will hide the imperfections. They will be glued to the roll bar with the joint filled but they will not be fixed to the parcel shelf in order to take into account any differential movement between roll bar and shelf.

 
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