just about done with the chassis in cad now, looks pretty good to me but you never know so looking for opinions on what ive got please.
ive colour coded the tubes for the type used to make it easier for me.
the key is-
orange = 16g square
red = 16g round
dark blue = 20g square
light blue = 20 round
basically 'hot' colours are heavy and cold colours are light gauge and all is 1 inch tube.

the calculated weight of the tubes alone was 51kg, but in cad they all merge into each other so i can probably deduct a fair bit from that, at least enough to allow for welds and brackets etc so well call it a straight 50kg for now. whetter it is accurate or not only time will tell!

here are the pics-


colour coded

and-



colour coded again

these not colour coded ones might make it a bit easier to understand, and also show the engine and driver position and msoem of the wishbone mountings.



isometric


side


top

ill hope fully be able to get the garage reorganised this coming week and get a flat base built so start the fabrication. and get some quotes for the steel, but i need to be carefull with my money at the mo cos im self employed and my current contract is coming to an end so well have to see how work goes.

Cheers,

Russ.

ps- obviously there are bits to add on at the front for impact protection etc and bodywork mouting points etc. and also bear in mind that most of the cockpit area will be stressed skin as well.

looking good Only thing I have to add is the joins near the front where you have about 10 pipes coming into one point look like they would be difficult. Im no welder, but if you can achive that I'd be well impressed....

cheers mate. that joint at the fron does look a bit daunting but shouldnt be too much of a problem if im carefull with the order i put the tubes in, and just take them one at a time. but they dont necesarily have to hit at that exact point, infact the outer ones will probably be better moving in a bit so they join a bit further up the adjacent tube to give more clearance when the front whels are on full lock, but ill cross that canyon when i come to it anyway!

looks good. re the many tubes to one joint, presumably you could just put the diagonals inte other direction within some of the quadrilaterals that are being triangulated? I would have guessed rigidity would be the same, just the feeding of loads through the chassis might change slightly.

The only other thing I would do differently is the roof, but presumably you want an open or targa type roof? I see you've used a wide bar to get the strength but standard size members at either side would be lighter and stiffer imho.

keep up the good work though...

Ned.

Generally looks good..

My only comment is that there seems to be a few rectangles that are braced with two diagonals (giving an X) when in practice just one diagonal would be fine.

It is easily done...I know, I do it....but it is worth a look.

Regarding the muti-tube joints...that should not be a problem...as you say, it is a matter of getting the sequence right.

cheers for the comments lads, ned- im not totally happy with the roof either and will probably change it tbh, the only real reason i did it that way was to get gull wing doors cos i think it might be a tight squeez if they are any smaller, but ill see how feels as im building the chassis.

alan, your probably right, it just seems like it would transmit loads more equally that way, it doesnt really cost much extra in weight and if you look closely at the way ive done it you get 2 tetrahedrons for the a little more than the price of 1 if that makes any sense. plus it also keeps the tubes a bit shorter which is usually a good thing.

cheers again,

Russ.

I'll just chime in with my standard comment:
Make sure that you have a windscreen that fit your design before you start welding !

Cheers

thanks, i plan to use a lancia stratos windscreen, and have been sent a cad drawing (made on one of those laser pointer plotting things so should be accurate) by a member of the lancia stratos builders forum. which is what you see in some of the above pics. good point tho!

With just a quick look I think it looks quite good. Might I suggest that you build it out of balsa sticks next? Having a physical model to twist and bend will do wonders for your understanding of the stresses involved. I built about 6 models, each one a refinement of the previous. It worked well for me. Plus now I have some cool little balsa frames hanging on my wall that I can talk to people about...

theres a funny story there steve- about a year ago now, i was still at my last job in a wood working shop and weas at the same stage as i am now with my would be bec. i couldnt be arsed with going out a buying balso so i spent about 3 hours at work ripping down pices of 3x2 to make 3mm square sticks! the really funny bit is the saw blade was 4mm thick so i actuall wasted more tree than i used! hehehe.

i think i will probably do a model now you mention it. itll be a couple of weeks before i can start the reall thing anyway. my next task is to finish building my fishmouting tool.

Cheers,

Russ.

quote:

---

Originally posted by suparuss
my next task is to finish building my fishmouting tool.

---

There's a fine balance building tools, raising the following points:
1. What's your time worth?
2. What are you building, a car, or tools?
3. How long will it take?
4. How much could you have accomplished had you been working on the car instead.

Just pointing out what I went through myself...

quote:

---

Originally posted by kb58
There's a fine balance building tools, raising the following points:
1. What's your time worth?
2. What are you building, a car, or tools?
3. How long will it take?
4. How much could you have accomplished had you been working on the car instead.

Just pointing out what I went through myself...

---

i dont have any plans im affraid. i started building it ages ago using an old jigsaw (thatll get you thinking!), ill not try explaining but ill post some pics later.
to answer kb- i love building/tinkering with things too so im building tools as well as a car! also with the amount of round tube i have in my chassis an accurate and quick way of cutting the tubes will invaluable, means i can concentrate more on building the car and less on standing at the vice all day with a file. especially if i build another later on.

russ.

quote:

---

Originally posted by Sven
... but then I like to tinker with stuff and the time spent tinkering is priceless whereas the time watching TV is worthless.

---

I didn't mean to put down anyone building their own tools, sorry. I've made my own too, but if we don't have a lot of time to work on our cars, it makes the time we do have very valuable. That said, yes, having a low-pressure, just-for-fun side project, one without the usual required accuracy, can be rewarding. How's that for a wishy-washy answer...

its ok, didnt think you putting anyone down. rorty is bang on though, my current situation is that i cant spend money on my project cos of uncertainties in work. so im spending some time getting a decent fishmouther together which will be fully adjustable for offset as well as angle which will save a hell of a lot of time. unfortunately spending no time on the car right now may come back and slap me in the face cos it looks like my next contract will be 12 hours a day 7 days a week meaning no time on the car for as long as the contract lasts. but then it does mean i will be able to pay off my credit cards and save for a good long spurt of car building during the obligatory 4 weeks off at christmas!

Darn you guys across the pond, with your six weeks (or more?) vacation each year!

well im self employed so can take what i want off but dont get paid for it. ive had 7 weeks off so far this year already (including christmas) but not by choice. things were a bit slow the beggining of the year so i was having trouble finding work, which i dont mind really, the key is to not let it stress you out and enjoy the time off while it lasts. the 4 weeks at christmas is pretty standard in the construction industry, not many people tend to work during the holidy month.

hi russ. any picture yet?! i need a notcher, im tempted to buy one but if its easy to make, i could always try! Alternatively, does anyone know a good supplier of tube notchers?

not sure if this is exactly what you ahd in mind joel-



god of all notchers



mmmm, adjustable


just about finished it today, just needs some vee thingies making for the tube to sit in and some sort of clamp. i will probably use one of those clamping pliers you can get with the bolt on the bottom for using on pillar drills etc.
i admit it is waaaay over the top, but it was fun to make and made use of some of the bits of steel i had laying around, and the old nackard jigsaw.

have you had the A-team in your garage

looks just about exactly what i need, but rather hard to make. Im going to attempt the tubemitre approach i think cheers for the piccy though!

hehe, i love it when a plan comes together!

rorty has some instructions on his site (think it was mentioned in this thread somewhere) on how to make one, not sure if thats the one you mean.

cheers,


russ.

Russ, surely a drill press would do all that your machine does plus a whole lot more?
How do you support the tube during cutting to prevent it dancing around and tearing the teeth out of the holesaw?
I admire any person who builds a contraption that works.

quote:

---

Originally posted by suparuss



just about finished it today, just needs some vee thingies making for the tube to sit in and some sort of clamp. i will probably use one of those clamping pliers you can get with the bolt on the bottom for using on pillar drills etc.

---

Seems I'm a half ass! At least you didn't call me a minotaur.

Looks good...... its also good to know at least I'm not the only one building a mid engine car from scratch.

I went a different route to yourself and employed someone to do the geometry and basic design... however I started with a wheelbase and width put my driving possition how I want it and we have grown the chassis from there.
I'm guessing mine will be around twice the weight of yours as its gona be Ultima size and taking a Twin turbo V12.


Could I ask were you plan to put the fuel cell.... or is it a small engined car so won't need a huge 90litre one like mine?

howdy andy, i think im going to put the tank just in front of the left hand rear wheel where there is a fair bit of space (i think thats where the ultima ones are mounted but they have one each side). itll be a special shape so ill either make it my self from stainless or have one made from ally (unless a find some money to invest in a decent ac/dc tig) the capacity wont need to be huge at the moment, the engine is only 2.2l and is pretty economical when you dont have a heavy foot. i hope you are gonna post us some pics of your chassis? what stage is it at right now?
it will also be interesting to compare torsional stiffness if you plan to measure it.

cheers,

russ.

ps- here is a preliminay design of the bodywork ive been messing with just to give an idea of what im aiming for.



body work (preliminary design)

havnt done much with the rear end yet though but it gives a general idea.

russ.

[Edited on 1/9/05 by suparuss]

Here you can see what I am doing re Fuel tank position,

The photo is of my early mock up, with a
a V shaped dummy fuel tank in wood (60 liter) mounted in chassis between passenger compartment and engine. Held into chassis by removable (from underneath) frame.

Cheers

Fred WB


General layout mock up

I'm about mid way through making the chassis, I still have some bracing at the front to do and have most of the rear to do..... but here is a pic I took tonight.








[Edited on 1/9/05 by andygtt]

[Edited on 1/9/05 by andygtt]