Volvorsport
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| posted on 8/12/04 at 02:04 PM |
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Monocoque Tub
right , after i had a conversation with a fellow member last night , i got drawing some sketches of monocoque tub .
I tried to upload them but pencil doesnt scan so well .
Anyway , my idea is to seperate the engine and interior parts of the chassis - basically the engine bay will be finished off with a flat 5mm plate
welded across the frame to which the engine bolts , a 5 mm spacer on the crank to space flywheel back , and fit a small bellhousing for the clutch
from a 360 , enabling a rear gearbox
The passenger compartment will be GRP/kevlar/carbon in certain places , the rough side inside so that a full roll cage can be bonded onto it . the
centre tunnel bearing quite a bit of the strength
at the rear bulkhead , a renault 5 spd without nellhousing bolted to the bulkehead , with a bearing to support the input shaft - placement of such
gearbox so that both input shafts front to rear are the same height . That brings into question ride height becuase of placement on output flanges
relative to input shaft and crank distance from the sump bottom , altho a dry sump could cure it .
the gearbox will have a mini subfame which attatches to the topledge behind the bulhead and gives a place for wishbones to attach . front running gear
would be as normal locost .
so , couple of questions does anybody have a sump that sticks down further than the floorpan ?
Anybody know the track of an R21,25 espace etc .
ill see if ican get some sketches up later
what do people think ?
[Edited on 8/12/04 by Volvorsport]
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ettore bugatti
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| posted on 8/12/04 at 08:31 PM |
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Do mean the R5 transaxle of the first Renault 5?
Why not use the 360 transaxle?
Your propshaft tunnel have to be strong enough for bending, stress and torsion issues that the engine caused.
I dont see any advantages of this setup
greets Richard
PS: try www.carfolio.com for dimensions of the renaults
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krlthms
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| posted on 8/12/04 at 08:54 PM |
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quote:
Originally posted by ettore bugatti
Do mean the R5 transaxle of the first Renault 5?
Why not use the 360 transaxle?
Your propshaft tunnel have to be strong enough for bending, stress and torsion issues that the engine caused.
I dont see any advantages of this setup
greets Richard
PS: try www.carfolio.com for dimensions of the renaults
I think Volvosport means to use a 5 speed gearbox from Renault 21, 25, or Espace.
I think this semi-monocoque is a fantastic idea. It will at least in part solve many of the issues regarding driver/passenger saftey, and provide a
platform for exciting developemnts in suspension and drive train.
The issue about the rigidity of the proposhaft tunnel could be solved using a torque tube, rather than plain propshaft. In system, which is used in
front enegined Porsches and some Alfas, the shaft is enclosed in a solid tube that rigidly connects the engine in the front to the transaxle in the
back. This way the chassis is not torqued by the rear diff, but essentially the drivetrain "pushes" the engine, which
"carries" the rest of the car with it.
In any case, if I understand VS correctly, the front and rear subframes will be bolted onto the corresponding bulkheads in the tub, and since the tub
is a single piece, the loads will distribute over the whole structure.
Way to go Volvosport, I am very enthusiastic.
Cheers
KT
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ettore bugatti
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| posted on 8/12/04 at 10:21 PM |
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Ahah,
Now it becomes more clear.
Would be interesting to see the sketches
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Volvorsport
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| posted on 8/12/04 at 11:26 PM |
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yeah , if i attatch a prop that makes up for alignment a little bit .
the reason for not using the 360 transaxle is that the gears are mounted before the diff . the renault box is stronger and has the diff first which
means the gears wont be stuck in your hip and also , more weight over the rear wheels .
ill ask again - does anybodys sump protrude lower than the floor pan ?
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Metal Hippy
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| posted on 8/12/04 at 11:31 PM |
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I've never studied the undersides very closely, but on Locosts I thought they all did a bit?
Cock off or cock on. You choose.
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ceebmoj
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| posted on 8/12/04 at 11:45 PM |
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if you go to the BEC part ther are some nice pictures of a sump sticking out the botom of the chasy and a discuion about how much is safe and sump
cuting.
Blake
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MikeRJ
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| posted on 8/12/04 at 11:58 PM |
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Virtualy every Pinto engined locost I've seen has had the sump sticking below the floorpan to some extent, even with chopped down sumps.
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krlthms
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| posted on 9/12/04 at 02:49 AM |
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The Champion book says that the sump should not protrude more than one inch below the chassis.
The original Lotus 7 had 6 inches of ground clearance, but I think the figure is more like 4 to 5 inches for modern sevenesques.
KT
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Volvorsport
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| posted on 9/12/04 at 02:24 PM |
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ill figure that into my calculations , so if the thing weighs 500 kgs - i give it 200 hp - thats 400 bhp/ton - what do the modern c*******s have - or
to that matter what are all the LOCOSTS like .
i think 600 kgs for an all up build would be more reasonable , since it will have roll cage , and bodywork would be bigger . Me thinks ill have to
get me drawing board out , mind you , most of its in me head .
without reading the blue book - if my roll hoop is 360 degrees do my rear stays have to go to the floor like on the race locosts ?
[Edited on 9/12/04 by Volvorsport]
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Volvorsport
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| posted on 9/12/04 at 09:40 PM |
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well , the front tack of r21 is 1.54M so thats about right for a wide track locost .
Anybody have any firm knowledge on the power and torque that an r21 transaxle will break at , i have an idea , itll be ok for this app , but just for
future upgrades
www.dbsmotorsport.co.uk
getting dirty under a bus
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MikeRJ
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| posted on 9/12/04 at 11:13 PM |
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If this is the same gearbox discussed in
this
thread on GT40s.com, then quite a lot of power!
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Volvorsport
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| posted on 10/12/04 at 01:42 PM |
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yeah , thats what i thought, but was unsure , its either that , or i go for a hewland £££ , now to get one , thast half the problem
www.dbsmotorsport.co.uk
getting dirty under a bus
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krlthms
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| posted on 10/12/04 at 06:49 PM |
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quote:
Originally posted by Volvorsport
ill figure that into my calculations , so if the thing weighs 500 kgs - i give it 200 hp - thats 400 bhp/ton - what do the modern c*******s have - or
to that matter what are all the LOCOSTS like .
i think 600 kgs for an all up build would be more reasonable , since it will have roll cage , and bodywork would be bigger . Me thinks ill have to
get me drawing board out , mind you , most of its in me head .
without reading the blue book - if my roll hoop is 360 degrees do my rear stays have to go to the floor like on the race locosts ?
[Edited on 9/12/04 by Volvorsport]
The Robin Hood light weight aluminium monococque has the roll bar bolted to the top of the body:
http://www.robinhoodengineering.co.uk/
go to the "light weight" page; picture bottom right.
Cheers
KT
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Volvorsport
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| posted on 10/12/04 at 07:21 PM |
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its funny how they claim it to be the lightest combination available , then stick a pinto in it !
Thinking about it , i dont think i would use more than 25 kgs resin , at 2:1 ratio , that makes my chassis 37.5 kgs , obviously i dont expect it to be
that !! , i dont think itll be far off that robin hood
www.dbsmotorsport.co.uk
getting dirty under a bus
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imull
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| posted on 30/12/04 at 02:51 AM |
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the Clan Crusader (though not front engined) does not have a subframe as such for its steering/suspension.
There are steel plates as mentioned above bonded into the GRP tub. On the underside, there are pressed steel brackets (basically) that the suspension
acutally bolts to. Will try to get a picture if you want to see what I mean.
Composite (not metallic) monocoques are extremely strong and are much more resilient that a metal equivalent as they basically dont have an
'elastic memory'
in fact a Clan pushed the b pillar of a sunbeam into the tunnel without suffering more than a slight danage to the front corner on the Circuito f
Ireland in the early 80's...
will answer further in the next few days, been in the local for a wee shandy forwarn Mr Hoeseasons about the craic for this coming October and may
even get to meet you???
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Volvorsport
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| posted on 30/12/04 at 03:25 PM |
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ooh its quite possible !!! are you following me around
ill edit that and say , are you the chap from the motorsport forums ?
[Edited on 30/12/04 by Volvorsport]
www.dbsmotorsport.co.uk
getting dirty under a bus
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chrisg
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| posted on 30/12/04 at 07:12 PM |
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Did anyone answer the sump question?
I've just measured mine and the sump is 23 mm below the chassis and the lowest point on my car is the bottom of the bellhousing of the gearbox
at 26mm.
HTH
Cheers
Chris
Edit; The ground clearance on my(not very flat) garage floor is 98mm.
[Edited on 30/12/04 by chrisg]
Note to all: I really don't know when to leave well alone. I tried to get clever with the mods, then when they gave me a lifeline to see the
error of my ways, I tried to incite more trouble via u2u. So now I'm banned, never to return again. They should have done it years ago!
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Volvorsport
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| posted on 1/1/05 at 04:27 PM |
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thanks chris , your measurements have been duly noted .
oh and another thing , there was an FW400 brochure on ebay , i missed bidding on it - has anybody got said brochure - or pics they have . Im not
copying- just want to see if theres anything ive missed .
[Edited on 1/1/05 by Volvorsport]
www.dbsmotorsport.co.uk
getting dirty under a bus
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