Jag V12

Great thread, I've read the entire thing in the past two days or so. I did notice a potential issue though with your design. Heat exchangers (radiators/intercoolers etc.) as a general rule of thumb work best when the air entering is high pressure and low velocity. An easy way to achieve this is with a diffuser type shape in from of the heat exchanger. I noticed you mounted the fans on the front of the intercoolers. I believe that they would work more efficiently on the back surface instead.

I know it is a bit late now but in regards to some of the vehicle dynamics concepts discussed here the best source is Race Car Vehicle Dynamics by the Milliken brothers. A fantastic source on most issues and one of the best places to start for ideas such as Ackerman and suspension design.

Specifically speaking, the answer to the Ackerman question is the ever present engineering response..."it depends". At lowers speeds Ackerman is preferable to deal with the difference in slip angles. However at high speeds it is not. Some racing applications even use reverse Ackerman!

In terms of suspension the unequal length double wishbone is a nice way for a good all around set up. I could bore everyone here with details but I'll refrain. If you want more information I'll be happy to contribute.

Keep it up, a great read!

 

Nick,
The progress you have made is outstanding, kudos mate and I cant wait to drive her LOL!!!!

tex

 

I don't have much experience with polyurethane foam especially in regard to durability so I can't answer that question. Sorry!

In terms of suspension set-up what seems to be the problem or question? I had a brief look at the pictures you posted. If you want I can run down the general steps you'd take in a suspension design in terms of sizing control arms, scrub-radius, caster etc.

And by pop over if you meant stop by in person I will actually be in the UK for the majority of this summer.

 

Nick,

I don't see why you should use generic aerosol expanding foam, known as "crazy foam" by the lads on site. It is used for countless void filling applications in construction and is supposed to be a permanent material. Frankly it is over used and frequently misused. But even if it does degrade it won't be very soon, you could rake out and loose bits and inject some more.

Notes:
1) I'd buy something of a reputable brand, or at least recommended by your local builder merchant as 'exterior' use.
2) This stuff expands slowly and beyond your best guess, anything up to 10x from start volume (some claim 30x). I guess at two 750ml cans to fill each one of those cills...
3) Thick masses can take days to cure enough to be able to cut it back neatly, so don't rush it. Might be better to fill in two layers, picking the previous one with a big nail to get continuity.
4) A lot of the brands actually like a little bit of moisture on the surface they are bonding to, so a light mist from a trigger dispenser might help (CHECK).
5) They can generate a small bursting force if contained, so be careful if your GRP sections are very thin as it might conceivably bow the surface.



David

 

Sorry, never had to use expanding rubber... Your guess is as good as mine on the rubber.

Nonetheless the aerosol foam should be good option for the cills, or any GRP panel void you are trying to bulk out. I would stress that big volumes take a long time to cure (days), but once set you will be able to cut through with a hacksaw blade and you will see the Aero type consistency. Cut it too soon and you will find a gloopy mess in the middle.



David

 

Nick,
I owned a body shop in the states for over 20 years, so I will chime in. I would get a few estimates of how to proceed from the local body shop talent pool. They can give you many good pointers to make the body finishing process successful. They will be impressed and enthusiastic about your project.
looking good so far.
Jon

 

Flowcoat is much like paint but goes on thicker. It will need alot of sanding etc to get any uneveness out of it. Biggest problem you will have is with "waves", that is the panel may not be perfectly flat. Much like paint too, the better the surface preparation, the better the finish. Looking good by the way. Good progress!

 

Flow coat (gel coat) is typically used with female mold fabrication. (think boats for example) The flow coat is sprayed first into the waxed female mold, and then fiber glass resin and matte or cloth is applied over it. Once the body is removed from the mold, the float coat is now the outer surface, and is what would typically be painted, unless the flow coat was color impregnated.

Nick has made his body from a male mold, so flow coating would be pointless. It's time to straighten out the waves and imperfections with bondo, and then a primer / paint system.

 

Yes HID Xenon lamps require self levelling and headlight washers. Which means front and rear ride height sensors, control box and levelling servos and a washer control so they wash every 6th windscreen wash. This would get checked at the SVA. Quite a lot of hassle.

David.

 

HI Nick
The square fuel rails are not 100% full proof at stopping fuel vaporization when hot. [ i had this problem with my car and it had the square rails]. Jaguar used the air con. circuit, to cool the fuel, to stop this.[ air con was not fitted to my car]. I think you can buy an inline fuel cooler for the jag V12. as the guy i sold mine to said he had done this, I can make enquires if you want?
Grant

 

Nothing tricky then?

There's an option, or retro fit on the F40 using pnuematic cells inside the shock absorber to raise the nose... and the Veron uses axial hydraulic rams to alter the spring platform on the coil over units to control its ride height.

Without using high end technology I think your need something that would move your top suspension mounting down, thereby forcing the front suspension down (relative). I suspect the looseness in the top mounting would causes vibrations and loose handling unless meticulously engineered. ie: you will be attatching your spring damper to a point that is no longer solid.

I could sketch a mechanism, but I don't think it would be pleasing in practice and might mean chopping your mountings and some chassis parts.


An alternative might be...
Your chasis already seems to have a nice 100-150mm clearance, so it is only your nose spolier that is in danger. Set your front clamshell hinge on a raising mechanism, to kick the nose GRP up for speed bumps.


On a positive note, the nose overhang is very short, so any air splitter will not be quite so vulnerable... the longer the nose, the worse this gets.


David.
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You may want to check the solution RCR cars has for their SuperLite coupe. (I am not sure if registration is required)

It is a lift kit that can raise/lower the car from inside.

http://www.gt40s.com/forum/rcr-forum-rcr40-rcr70-p4-mkiv/26269-s-l-c-lift-kit.html

I think the pricing is fairly reasonable.

John

 

How about using the Citroen system? Although it's quite complicated, the bits will be cheap from a breakers yard, and lets face it, youv'e managed to create the whole car by yourself, so i'm sure you could make it work!
It's coming along nicely by the way!

 

Nick,

There's your answer, a concentric hydraulic ram, exactly the same as the Veyron - although hopefully cheaper. Now you just need to get your cheque book out.



X19er,

PS: I'm ex- x1/9 owner as well! Very underated little car, but I shall not say more about the x1/9 as I don't want to go 'off-thread' here.


David

Ferrari Owners' Club (308GTS)
X1/9 Owners' Club (none -ahhh)
Jaguar Enthusiasts' Club (XJ8 - x350)

 

Any updates!

 

Hi Nick,

Sorry to hear about the job stuff. Hope it gets sorted quickly so you can concentrate back on the car.

See you around !

Rgds

Maz