Badger_McLetcher
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| posted on 25/5/09 at 11:20 AM |
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Cabin space?
Hey guys, as I may have said before I'm now getting the chassis for my car designed. Unfortunately it's proving quite hard to package
everything, and I'm quite worried about cabin space.
At the moment it's about 50 cm per side with a drive tunnel of 22cm. However the footwells go down to 40cm and the whole thing is only 123 cm
long. Is this enough? The only way I can get more space is by moving the engine in front of the front axle (which I really don't want to do). Or
make people sit on top of the diff!
If disfunction is a function, then I must be some kind of genius.
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Mr Whippy
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| posted on 25/5/09 at 11:22 AM |
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quite amazing as the bonnet looks like its about 20ft long
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mr henderson
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| posted on 25/5/09 at 11:31 AM |
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Are you working with an existing body, is that the reason for the restrictions
From the legroom measurement, sounds like a child's car, so pedal power or 12v motor? 
John
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Badger_McLetcher
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| posted on 25/5/09 at 01:19 PM |
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Yeah, it's an existing bodyshell. The cars about 4 metres long, wheel base is 2.4 meters. The problem is that due to the width of the engine
(70cm) and the bodyshell the footwells can't be parallel. Take out the space for the diff and it becomes a big problem. I just don't want
to have to shift the engine overhanging of the front axle line, it's going to be unbalanced enough as it is!
TBH I'm beginning to think I'm either going to have to extend the bodyshell, find a narrower engine or just sell it and build my own
shell!
If disfunction is a function, then I must be some kind of genius.
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mr henderson
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| posted on 25/5/09 at 01:37 PM |
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Perhaps I missed it when you explained which engine and bodyshell you were using, but if you were to repeat that and maybe throw in a bit more detail,
someone might be able to suggest some alternatives.
John
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Badger_McLetcher
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| posted on 25/5/09 at 02:25 PM |
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Well the bodyshell is from a Lightning kit car, basically a C3 Corvette replica. I havn't got any clear pics of mine but here's a real
one: 
Mine's pretty much the same but 10cm shorter.
The engine is the 1uz-fe married up to a R154 gearbox (about 70*70cm for the engine and about 60 * 40 cm (tapered) for the gearbox).
Basically to get the engine behind the front axle line means the rear end of it is just below the windscreen, which pushes the gearbox right into the
cabin.
The passenger compartment is suprisingly narrow at 128cm, and about 140cm of floor space. However this is floor space, the seats can overhang the
rear of that to an extent. Currently the footwells extend 25cm in front of the bulkhead under the windscreen.
The blue lines are the current cabin area.
Any suggestions welcome!
Except those type of suggestions 
If disfunction is a function, then I must be some kind of genius.
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Badger_McLetcher
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| posted on 25/5/09 at 07:45 PM |
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Haha just noticed there's one on sale on Ebay!
Linky
If disfunction is a function, then I must be some kind of genius.
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Ninehigh
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| posted on 25/5/09 at 07:57 PM |
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123cm cabin long enough?
Let's say for the sake of average that your legs are as long as your body. Take off 10 cm for the seat back and don't take into account
that your legs will be bent slightly. 113x2 is 226. 200cm is about 6'6" so you're looking about being around 7 foot tall before you
get too big...
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ettore bugatti
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| posted on 25/5/09 at 08:57 PM |
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I think you wouldn't lose too much on inertia and weight distribution by moving the engine 5-10cm forwards.
Other options could be smaller wheels (more narrow)
clever rear suspension design.
Have a look in the Mazda Rx7 Sa22 or Porsche 924 these cars have a similiar wheelbase and package.
Good luck!
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Doug68
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| posted on 26/5/09 at 02:28 AM |
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Why can't you sit in it to work out if it going to work or not?
It's been my experience that the areas of the car that humans fit in are the hardest to work out through CAD. You need to build a mock up of
some sort to see if it'll work.
In my case I made some MDF seats for example to check to see if the ones I thought would work did (which they do).
My cabin is 1440mm long, but I also have the fuel tank in there and the seats have a 30 deg recline to the low roof line in the car.
[Edited on 26/5/09 by Doug68]
Doug. 1TG
Sports Car Builders WA
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hughpinder
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| posted on 27/5/09 at 12:06 PM |
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I built a plywood cabin and measured whats comfortable for me. From the lowest part of the seat (e.g closest to the front of the car) to the face of
the pedals is 43" (110cm approx). I am 5'11 tall. The cabin is 18.5" (46cm) wide and just ok for me. Don't forget a standard
chassis is only 42" wide and has the transmission tunnel in there too.
Regards
Hugh
Added top of seat is 5" further back, plus you need width/stroke of pedals... Width of cabin at pedal front is 17 inches.
[Edited on 27/5/09 by hughpinder]
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mr henderson
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| posted on 27/5/09 at 01:24 PM |
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If the 1230mm dimension is from the back of the cabin, at the base (I assume the back slopes backwards as it does on most sports cars) to the base of
the footwell, with no allowance yet made for pedals and seat, then that is a seriously short cabin.
I have a standard (MK built) Locost here at the moment, and that dimension is about 1430 and a Tiger Avon at about 100 mm less.
I know the cm is a popular measuring system, but shouldn't really exist, as the metric system works in steps of a thousand- millimetre, metre,
kilometre etc
John
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Badger_McLetcher
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| posted on 29/5/09 at 04:19 PM |
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Right after a bit of rearranging I've managed to gain about 18cm (I wonder how many blokes can say that!). Unfortunately it has meant shifting
forwards the engine 5cm effectively, which scuppers any push rod suspension and so rising rate 
Ah well, a small price to pay if I can actually fit into it!
Gonna take a couple of peoples advice this weekend and rip a chair out of my focus as a rough guide (though I'm pretty damned sure the base
will be far too high and my head will be straight out the roof!)
If disfunction is a function, then I must be some kind of genius.
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mr henderson
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| posted on 29/5/09 at 05:17 PM |
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Glad to see you've gained 180mm, but don't bother with the seat from a production car, use pieces of wood, Haynes manuals, cushions etc to
mock up the seat.
John
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Alan B
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| posted on 29/5/09 at 11:18 PM |
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John,
I totally agree.......I HATE cm measurement...
Alan B
quote:
Originally posted by mr henderson
If the 1230mm dimension is from the back of the cabin, at the base (I assume the back slopes backwards as it does on most sports cars) to the base of
the footwell, with no allowance yet made for pedals and seat, then that is a seriously short cabin.
I have a standard (MK built) Locost here at the moment, and that dimension is about 1430 and a Tiger Avon at about 100 mm less.
I know the cm is a popular measuring system, but shouldn't really exist, as the metric system works in steps of a thousand- millimetre, metre,
kilometre etc
John
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