Hey guys thanks for the replies.
Sorry for the late answers, I don't have internet at home yet and I hate typing text on my phone so much that posting here involves me typing up on my laptop, then bluetoothing a .txt file to my phone then copying and pasting the text...
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Anyway:
KB58, I may try to contact Caterham if I don't get any luck elsewhere. Though I haven't had luck asking other (kitcar) manufacturers for installation drawings/dimensions of their parts in the past. Also, and I know its a small risk, I don't want any vendors refusing to sell me a part after I've asked for the drawing for fear that I will reverse engineer it.
By the way, your book is what convinced me to use the fuel cell. Given I don't have the time, knowledge or tools to properly engineer the chassis to be as safe as a production car in a crash, I figured a bladder type fuel cell is going to at least reduce the liklihood of a fuel fire in the event of a crash.
I have had a look at the 10 gallon fuel safe cell that you used in your car but its too wide to fit behind the driver and in front of engine (unless I increase the wheelbase which I don't want to do so early in the design phase).
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Carguy123, Thanks for the interest. At the risk of shooting off topic, I will try to answer all of your questions.
The target mass you saw is in fact what I'm aiming for. I'm thinking of lowering it a little, but the car is essentially more like a Lotus Elise instead of a Seven. The lotus has an aluminium chassis too while mine will be steel. So I don't see it being realistic to make the car lighter than an Elise. The target mass (900kg/2400lbs) is with driver and full fuel tank. As I acquire parts and the design evolves, I will revisit the mass targets - which will mean another check of the tyre sizes.
The mass table you saw had only an initial set of data input and the part locations were pulled out of my... head. The design isn't detailed enough yet to know the CG loc of each part. Again, once I get hold of parts, and design my own parts in more detail, I will update the weights sheet to see if my target of 39%F mass dist is possible to reach.
The detail I'm going into is because I'm a nerd for this sort of stuff. I'm a suspension engineer by day and I actually enjoy the work so much that I fill my weekends with this kind of stuff. Every time I work on this project, I learn something new.
Regarding the Ultima windscreen, I was under the impression that it was their own design which the got E-marked as an approved windshield. But I'd be happy to find out if its possible to obtain elsewhere.
For the engine, I've gone for a transvere mounting simply because its less stuffing about. I literally pull the engine/gearbox from the FWD and drop it in the back of my car. I'm not an expert on engines so I didn't want to stuff about with expensive transaxle gearboxes and etc adapters. FWD engines are perfect for this because they have the gearbox and final drive all together with it. Probably the only mod I would consider is a dry sump to lower the CG (if the CV joints can handle it) and a lightened fly wheel to reduce mass.
Regarding the At-om handling, I would guess the unpredictability is probably down to an unsorted suspension, but the oversteer tendancy (which I hear is also a bit of an issue in the Elise) is largely linked to the rearward mass distribution. I hope to overcome both of these in the choice of tyre size and by engineering a decent suspension for it. Even with "sports" bushings in a suspension, the geometry requires a fair bit of thought to get the toe compliances to to the right things under all conditions.
Something I've learnt recently is that compliances (of toe camber etc) are made up of about 50% geometric effects and 50% from the bushing stiffness. A lot of people will design the geometry based only on kinematic targets for roll centres, anti lift/dive etc. With this approach, even with stiff bushings, the toe compliances are likely to cause problems because the geometry is imposing toe and camber changes in the wrong direction.
The chassis is still very much under development... but I want to keep the side intrusion zones as big as possible because I'm a better engineer than a driver. I'm bound to hit something at some point and the bigger the side impact structures are, the more energy they absorb.
I hope thats cleared everything up. If there is anymore interest, I will make a seperate thread like I've done on F1T.
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P.S. Back on topic - if anyone even has a clear picture of one of these tanks it would also be pretty helpful.
Cheers
Tim
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