paddywil
|
| posted on 31/10/15 at 06:42 PM |
|
|
Once I've added a it more to them I will - I'm at exactly that point now, working out the shape for the frame that will accept the front
wishbones and coilovers
|
|
|
|
|
Neville Jones
|
| posted on 2/11/15 at 01:36 PM |
|
|
Sam,
Progressive collapse means permanent deformation, yes, yes, yes. Unless it's a spring.
If you'd had a router anywhere near a panel with ali skins and ali core, you'd know the result. You really haven't done it, have
you? Otherwise, you'd know all about the mess that ensues.
Your knowledge exhibited here re composites goes along with that shown for ali.
As an architectural technician you are probably OK. As a designer with composites, your recommendations are irresponsible to the point of
recklessness.
Anything can be made look good in a design, but properly engineered is something very different. Without knowing the materials hands on, you can never
fully appreciate the limitations and possibilities, and the nuances in manufacturing with them.
Stick with houses, and you won't kill anyone, maybe.
Cheers,
Nev.
|
|
|
BenB
|
| posted on 2/11/15 at 02:05 PM |
|
|
I was going to suggest having a look at
http://www.stuart-taylor.co.uk/gallery/f1-67/
I know Ian was working on that when I was building my car in his garage. Nice looking car, suspect it might be £££.
|
|
|
Sam_68
|
| posted on 2/11/15 at 02:41 PM |
|
|
Neville,
G'day, me old cobber.
I'm not going to waste further time or energy on you, since you're obviously intent on trolling. These will be my final words in response
to any post you make on this forum:
No, I've not used a router on ali skinned panels, nor would I try, but on composite skinned panels they work just fine. You're right about
the benefits of working with materials hands-on to get a grasp of their characteristics, and I've done exactly that with small-scale test
fabrications, but...
...one of the advantages of rout-and-fold is that all I have to do is send off the relevant CAD files to a supplier, and they send back panels
accurately cut and routed to my designs for neglible cost, so why on earth would I want to take the risk of ruining an expensive panel by making an
error myself, trying to do a whole tub, less accurately, by hand?
With ali skinned panels, they can be drilled or milled with normal machine tools, but again it wouldn't be something I'd do at home when
there are companies who will do the job for you, much more quickly, accurately and cost-effectively, using CNC controlled machinery.
Progressive collapse does not mean permanent deformation.
It's really very basic materials science, so if you don't understand it (as you either clearly don't, or are pretending not
to in the interests of trolling), then you have no business designing anything, but if it's the former then I suggest that you go away
and learn the meaning of the terms 'elastic deformation', 'plastic deformation', 'yield strength' and
'ultimate strength'.
Bottom line is that between yield and ultimate failure, materials permanently (plastically) deform.
Steel has quite a large band between yeild and failure, so there is a large possibility of it ending up permanently deformed in a way that can
exacerbate injury - a buckled tube can trap you and the deformed end of a failed tube can cause very nasty penetrative injuries.
Composites, particularly carbon fibre, have a very narrow band between yield and ultimate failure.... they pretty much go from elastic strain straight
to failure. With honeycomb composite panels, the honeycomb tends to provide sufficient support to the skins to ensure that they disintegrate
(not permanently plastically deform) progressively from the point of impact back, absorbing energy as they go.
Hope that helps clarify. 
|
|
|
paddywil
|
| posted on 2/11/15 at 03:14 PM |
|
|
quote:
Originally posted by BenB
I was going to suggest having a look at
http://www.stuart-taylor.co.uk/gallery/f1-67/
I know Ian was working on that when I was building my car in his garage. Nice looking car, suspect it might be £££.
That is beautiful 
|
|
|
paddywil
|
| posted on 2/11/15 at 03:33 PM |
|
|
*update*
I've taken the decision to move away from the original monocoque design and instead build a space frame. One of the main reasons for doing this
is to enable easy FEA analysis, as well as solving some of the other design issues I'm facing.
|
|
|
Neville Jones
|
| posted on 2/11/15 at 04:23 PM |
|
|
quote:
Originally posted by paddywil
*update*
I've taken the decision to move away from the original monocoque design and instead build a space frame. One of the main reasons for doing this
is to enable easy FEA analysis, as well as solving some of the other design issues I'm facing.
About the best decision you could have made.
Sam, when something deforms 'plastically', it deforms permanently. like plastic, and doesn't go back to where it was. Elastic
deformation means like a spring, and deforms and goes back where it was. Or that's what I was taught in my first year of my engineering degree!
Stick to your houses, there'll be less to worry about.
Cheers,
NEV! not my mate who told me about you.
You managed to upset the gumleaf mafia, and are being very carefully watched. Bullshite detectors at full power.
[Edited on 2/11/15 by Neville Jones]
|
|
|
Sam_68
|
| posted on 2/11/15 at 05:13 PM |
|
|
quote:
Originally posted by Neville Jones
Sam, when something deforms 'plastically', it deforms permanently. like plastic, and doesn't go back to where it was. Elastic
deformation means like a spring, and deforms and goes back where it was. Or that's what I was taught in my first year of my engineering degree!
Quite right, Neville. Which is exactly as I explained above.
But if you'd made it to the second year of your engineering degree, you'd have discovered that, ironically, steel has a much larger range
of plastic (permanent) deformation than carbon or glass reinforced plastic.. as I said above, CFRP deforms elastically, then fails. It has a
negligible plastic region.
Best dig out your old textbooks?
But thanks for such a clear admission that you're trolling n behalf of your 'mate' Rod - I'll bring it to the attention of the
management.
|
|
|
Neville Jones
|
| posted on 3/11/15 at 10:55 AM |
|
|
Get a real life, Sam, and stop pulling the same stupid garbage that I'm told you did on the Oz site.
We could argue semantics on the mechanical properties of materials all day long, but the the members on here are a lot less gullible, and a good deal
smarter than the few who took notice on the other forum. Mild steel can stretch quite a way, but try high carbon and alloyed steel. Same goes for
most other common metals. Please, don't go through them one by one, and show me how wrong I am and right you are. Just plain stupidity.
Make all the sarcastic and nasty comments you want, it still doesn't make your suggested build methods less dangerous.
I'm told that a couple of Signatory Engineers on the Oz forum, made it very clear that a chassis built with your suggested materials and
methods, would never be allowed on the public road. The builders on here made that distinction for themselves.
Thermoplastic honeycomb for a core material, you've got to be joking! Melts when it gets hot! Matey showed me the rest, but it'd be
wasting good forum space to repeat it.
Nev.
[Edited on 3/11/15 by Neville Jones]
|
|
|
paddywil
|
| posted on 3/11/15 at 12:29 PM |
|
|
Thanks for that nev,
I decided to move to a space frame on the basis of my own research, not from any thing on here...
If we could keep thsee posts on topic I'd be very grateful - this is not the place for those arguments.
|
|
|
russbost
|
| posted on 3/11/15 at 01:56 PM |
|
|
Isn't it odd that whenever Sam gets involved in a discussion it seems to end up as a spat!
I could obviously have taken offence to being told that I'm obviously in the wrong business, after all I've only spent virtually all of my
life since age 14, building, racing, designing, working on & being thoroughly involved with cars of all descriptions & such things as road
legality & MoT, SVA/IVA/MSVA tests, so after all what the heck would I know about anything? But, no, life is too short, I had my rant the other
week, which no doubt some of you witnessed or took part in! So I will now remain calm & placid!
Sorry Sam, but I'm with Nev regarding plastic deformation etc. & I think if anyone is trolling it is you yourself by splitting hairs &
playing semantics - if something, whether steel or composite, deforms progressively it is almost certainly going to stay permanently deformed (&
permanently damaged/weakened) unless it happens to be a spring! or in a very mild impact; such as of a plastic bumper or something similar even then
although the outer skin may return to shape the foam beneath the skin will be permanently damaged & would not behave in the same way in a future
accident/deformation. In the instance of a tub such as that described, a relatively minor impact could leave the tub unusable as I don't see how
you could ever cut a damaged section out & replace it to give the same strength as the original, so whilst it MIGHT prove relatively strong &
safe it might not prove very economic. With a steel spaceframe or an aluminium monocoque unless the damage was catastrophic the damaged area could
fairly easily be cut out & replaced
When we are talking about a tub constructed as you suggest with the route & fold route I think; one, it is an extremely dangerous process for
someone to undertake with no prior experience, I don't mean that the process is dangerous, I mean the end result would be likely to be dangerous
as it would be almost impossible to know how good a job you had made of the assembly process; & two, unless you had access to CAD, particular
skills in the right areas & understood EXACTLY how to use the process & materials I think it could very easily finish up as a right mess - I
mean, if we stick to an area you actually are familiar with, would you suggest someone with no prior experience should design & build their own
house?
You could possibly say much the same about an aluminium monocoque in that there a whole bunch of unknowns unless you've had experience designing
one previously, however, it's a lot easier to know whether you've made a good job of bonding & rivetting a couple of ali panels
together & a lot less potential for getting it wrong
With a spaceframe there are a whole bunch of designs which can be copied/changed to suit your requirements.
My point about safety is that the design doesn't have to be as lethal as the original "half tubs" were, such as the one you
pictured. The structure could be "wrapped around" to construct an upper half to the monocoque which would not only be a lot stronger, but
also a lot safer, whilst still maintaining the period look & feel of the car, it's not that I have an aversion to risk, but I DO have an
aversion to stupid or unnecessary risk!
To get back to the OP's original questions, I think if going for a period feel then why waste money on anything other than a VW transaxle with a
"flipped" crownwheel, or if you don't mind destroying the period appeal then go for the Audi v6, which I believe has a very short
transaxle, thus keeping it within the original dimensions I would imagine - not speaking from experience here
Perhaps if we could all actually stick to trying to assist the OP with his questions rather than spending our time slagging one another off &
banging the drum in regard to our own personal preference then perhaps that would be beneficial all round?
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
paddywil
|
| posted on 3/11/15 at 03:49 PM |
|
|
Thanks
If anyone happen's to know what it takes in either the way on adapter plate or modified bell housing to adapt a zetec engine to either of those
gearboxes id be grateful
|
|
|
Ugg10
|
| posted on 3/11/15 at 04:35 PM |
|
|
The adaptor plate I suspect may be the easier bit, next you need to check what spline the gearbox input shaft has and whether there is a clutch
plate/clutch housing combination that can be used with the engine flywheel, the final part is the diameter of the end of the gearbox input shaft and
whether it will fit with the engine spigot bearing cavity (Zetec is 22mm cavity and 15mm shaft IIRC with the stock pinto spigot bearing). For the Audi
box, if you are lucky you may be able to find a combination of a Audi pressure plate (thickness and diameter) that will fit with a ford zetec/pinto
housing that can work. If not you may be able to get the flywheel drilled to accept the Audi clutch (pressure plate and housing).
Other stuff to think about is where the starter is and whether the bell housing needs modifying to make this fit and whether the release bearing (or
hydraulic release mechanism) will work with the adaptor in place.
Best bet is to gather info on the engine and gearbox options (search for clutch parts on ebay, they often give diameter and spline info) and see if
you can come up with a combo that does the job.
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
|
|
|
paddywil
|
| posted on 3/11/15 at 06:12 PM |
|
|
Thatnks! Thats the most useful post so far haha! I'll start searching and see what I can come up with!
|
|
|
russbost
|
| posted on 3/11/15 at 08:36 PM |
|
|
I'm no expert on Ford engine/gearbox combinations, but I'm certain the Kent engine has been fitted to the VW transaxle from the beetle
& surely the Kent & Zetec can be fitted to the same Type 9 Ford boxes? It would therefore seem exceedingly likely that the Zetec could be
fitted to the VW transaxle with the same combination of clutch & possibly flywheel? Personally I've always felt the Zetec was very
over-rated & feel the Duratec is a much better bet, would have thought if you could fit one then the other would fit
In the VW camp I'm sure the 2.0 injected Golf lump both NA & turboed has been fitted to the beetle transaxle which might suggest that
VW/Audi engines MAY be somewhat interchangeable, but no idea if that extends to the V6 engine/box being transposable with any other VW/Audi lumps let
alone Fords
If it was me I would look around the internet for what HAS been done before & how much difficulty it involves, but unless you particularly feel
the need for something newer than the beetle transaxle (or transporter if more power is involved) then that seems the most obvious route. If, for
whatever reason, you opted for the much newer Audi transaxle (is that available as a 6 speed anyone?) then surely easiest & most economic route
would be to go for the complete V6 or V8 package from Audi complete with all the anciliaries etc. rather than attempting to re-invent the wheel
There is another option of course which would be to go for the 5cyl Audi turbo & transaxle from something like the old Audi 100, dirt cheap, loads
of power but very heavy - they used this setup in the back of the Edge Devil, but I believe the car weighed around 750kg all up, probably not quite
the svelte result you would be hoping for
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
twybrow
|
| posted on 3/11/15 at 10:57 PM |
|
|
quote:
Originally posted by Neville Jones
Get a real life, Sam, and stop pulling the same stupid garbage that I'm told you did on the Oz site.
We could argue semantics on the mechanical properties of materials all day long, but the the members on here are a lot less gullible, and a good deal
smarter than the few who took notice on the other forum. Mild steel can stretch quite a way, but try high carbon and alloyed steel. Same goes for
most other common metals. Please, don't go through them one by one, and show me how wrong I am and right you are. Just plain stupidity.
Make all the sarcastic and nasty comments you want, it still doesn't make your suggested build methods less dangerous.
I'm told that a couple of Signatory Engineers on the Oz forum, made it very clear that a chassis built with your suggested materials and
methods, would never be allowed on the public road. The builders on here made that distinction for themselves.
Thermoplastic honeycomb for a core material, you've got to be joking! Melts when it gets hot! Matey showed me the rest, but it'd be
wasting good forum space to repeat it.
Nev.
[Edited on 3/11/15 by Neville Jones]
Nev, you are full of it! Sam's explanation of composite behaviour is pretty much spot on and you then repeat one part of it and try to
discredit his post. You may well have hands on experience of composites, so my guess is at best you are a reasonable laminator, which explains your
lack of understanding of composite behaviour, and fracture/high strain rate failure. Go back under your bridge Calvinx/Ned/Syd.
|
|
|
Sam_68
|
| posted on 3/11/15 at 11:16 PM |
|
|
Sorry if this is off-topic, Paddy, but there are misconceptions being promoted here that are far from splitting hairs... we're talking very
basic, fundamental materials science and it's quite scary that they are apparently being misunderstood by someone who has designed and built
a car.
quote:
Originally posted by russbost....if something, whether steel or composite, deforms progressively it is almost certainly going to stay
permanently deformed (& permanently damaged/weakened) unless it happens to be a spring!
No Russ, really, it doesn't. Even Neville and I are in agreement on that!
With most materials, you get elastic deformation (your 'spring' ), then if you carry on increasing the load you get plastic deformation,
then you get failure...
The point at which you exceed elastic deformation is called the 'yield strength' and where it finally fails is the 'ultimate
strength'. The region between yield and ultimate failure is the zone of plastic deformation, and is where the material stays permanently
deformed ('bent' ).
For steel, this zone is fairly broad: the yield strength of mild steel is about 65% of the ultimate strength, so you've got a region of about
35% (over 1/3, in other words) of the material's total strength where it will plastically (permanently) deform. The high carbon and alloyed
steels that Neville mentions are elastic for about 85-90% of their ultimate strength, but of course we don't normally manufacture spaceframes
from high carbon or alloy steel, so that's pretty much irrelevant in the context of this discussion.
You won't find a yield strength listed anywhere for carbon fibre, because as I've said repeatedly above, to all intents and purposes it
does not plastically deform... its behaviour is elastic right up to the point of ultimate failure.
If you don't believe me, buy yourself a cheap carbon fibre fishing rod and see if you can put any sort of permanent bend in it without snapping
it: you won't. But right up to the point where it does snap, neither will it be permanently damaged or weakened, either (at least, not to
any significant extent).
quote:
Originally posted by russbost...In the instance of a tub such as that described, a relatively minor impact could leave the tub unusable
as I don't see how you could ever cut a damaged section out & replace it to give the same strength as the original, so whilst it MIGHT prove
relatively strong & safe it might not prove very economic. With a steel spaceframe or an aluminium monocoque unless the damage was catastrophic
the damaged area could fairly easily be cut out & replaced
Actually, it's completely the opposite.
Because CFRP skins do not plastically deform, the damage is essentially limited to the areas in which they have failed entirely, plus perhaps a little
beyond to take account of localised separation of the skins from the core. You cut out the obviously damaged section and bond in a new one.
By comparison, a steel spaceframe or aluminium monocoque can plastically distort over a much greater region than the area of the obvious damage. This
is usually not a huge problem in terms of the structural integrity, but it sure as hell is in terms of dimensional accuracy and
'straightness'- and it's the reason why any steel chassis needs to be checked for geometric accuracy and re-jigged after a
significant accident.
Are you old enough to remember the hoo-hah that Ford had with the early Sierras 'rippling' their floorpans in very minor accidents? That
was because of plastic deformation of the steel spreading along the whole length of the car as a result of very minor shunts...
quote:
Originally posted by russbost...When we are talking about a tub constructed as you suggest with the route & fold route I think; one,
it is an extremely dangerous process for someone to undertake with no prior experience, I don't mean that the process is dangerous, I mean the
end result would be likely to be dangerous as it would be almost impossible to know how good a job you had made of the assembly process; & two,
unless you had access to CAD, particular skills in the right areas & understood EXACTLY how to use the process & materials I think it could
very easily finish up as a right mess...
I agree with you entirely. Certainly on the basis of the very basic lack of understanding of materials and structures demonstrated on this
thread, anyone who is not absolutely certain that they know what they're doing should probably leave well alone.
That's not to say that the rout-and-fold can't be perfectly safe when designed and fabricated by someone competent, in line with basic
good principles of structural design and fabrication.
But yes, if you're inept and/or inexperienced with structural design, you're certainly better off sticking to a spaceframe: they're
a lot more idiot-proof.
You could, of course, physically test the end result, but I appreciate that's not common practice in the UK (I doubt you've got torsional
stiffness figures, or even an FEA estimate, for your Furore chassis, for example?).
Neville is, of course, dissembling wildly, and deliberately misrepresenting what I said.
I never recommended thermoplastic cores for a sandwich panel: just the opposite, I spent quite a bit of time stressing the temperature sensitivity of
even aluminium/nomex cores (due to the temperature limitations of the adhesives used to bond the skins to the core).
And I agreed totally, right from the beginning, with the (single as far as I can recall) Signatory Engineer who said that they would be very difficult
(but not impossible) to certify as amateur builds for road use in Australia, where rules are massively tougher and more bureaucratic than they
are here in the UK, and he agreed with me (he's a recent English emigre and is familiar with IVA) that the situation wouldn't be nearly as
difficult under UK regs.
The topic was a quite free-ranging, and at times slightly off-the-wall discussion of alternative materials and build techniques, but if anyone wants
to see for themselves what was really said, the link is here:
http://www.ozclubbies.com.au/index.php?/topic/11885-been-playing-around-with-a-new-cheap-clubbie-chassis-concept/
For what it's worth:
a) Sandwich panel monocoques have been certified under IVA here in the UK and;
b) Anyone on this forum building a 'book' Locost can be assured that their cars WOULD fail the Australian assessment, too: the chassis
lacks sufficient torsional stiffness to meet Australian regs.
...but beyond that, I'm not quite sure what Neville hopes to achieve by pretending that a discussion related to Australian regs has any
relevance to the quite different regulatory standards and means of assessment that apply here in the UK?
[Edited on 4/11/15 by Sam_68]
|
|
|
russbost
|
| posted on 4/11/15 at 10:59 AM |
|
|
Gahhhhhhhhhh! 
Which part of stop arguing & stay on topic do you not understand!
There are about 1001 things wrong with that last post which I am not going to respond to, I would suggest that Nev doesn't either
Sam, could you PLEASE make your posts less deliberately insulting, if you want to disagree with something someone has said, fine, but do it in a way
that doesn't include words like inept & idiot. It would appear to me that you may have great qualifications & can talk the talk, there
doesn't appear to be much evidence of walking the walk, that's not intended to be insulting, just how I am seeing what gets said
This is supposed to be a forum for people from all walks of life who can contribute in areas where they have knowledge &, one would hope,
practical skills. I've had tons of great advice regarding stuff like household plumbing & electrics from people with vastly more knowledge
than me which has been extremely useful, I would freely admit that I don't have much experience of composites, hence why I ask questions. I very
rarely disagree publicly with anyone on the forum, but you speak to people as tho' they are morons with no knowledge of what they are talking
about simply by taking a sentence & disseminating it into soundbites which then don't mean what the poster meant to say!
I would repectfully request that if you haven't got anything helpful to say in respect of what the OP has asked then it might be better to say
nothing ................
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
paddywil
|
| posted on 4/11/15 at 11:40 AM |
|
|
Right, I would appreciate it if we could have no more discussion about this argument, it's time to move on. For the sake of this build, the
argument has been useful, but from this point onwards, let's assume a few things:
I am going to use a spaceframe for this build
As much I would like this to be a replica, I am more concerned with the economics of this than historical accuracy.
I may in the future attempt a monocoque, but that's up in the air at the moment
What I would like input on is people's preference for fibreglass vs aluminium bodywork - going down the space frame root will require a large
amount of body work to achieve the desired shape... I have experience of both making Ali panels and making moulds for fibre glass, so that's not
the issue, I simply want to know what people in my place would choose.
|
|
|
Ugg10
|
| posted on 4/11/15 at 12:18 PM |
|
|
I WILL STICK TO THE SUBJECT IN HAND :-)
So.......
There are a couple of interesting threads that I hope you will have seen that might help in making the choice of skin -
Aluminium re-skin of a triumph GT6 - http://www.locostbuilders.co.uk/viewthread.php?tid=178173
Some of the craft in this piece of work is truly outstanding, IIRC there are some pictures of this guys trials car that was again aluminium skinned
that may be useful
Fibreglass build of a single seater car should buck and moulding processes - http://www.locostbuilders.co.uk/viewthread.php?tid=194783
Also T89 design of a single seater - more modern/formula type design but process may be useful -
http://www.locostbuilders.co.uk/viewthread.php?tid=195128
I suspect that the fibreglass route (depending on your skills with an English wheel) may be quicker and can cope with more complex shapes and you have
the chance of making another if your moulds are built and finished well but aluminium, particularly if left polished could be stunning to look at and
more authentic.
Tiger does a version of their Six (Seven?) car with an aluminium body if that is of interest - http://www.tigerracing.com/rs6.php
and......
I DID STICK TO THE SUBJECT !!!!!
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
|
|
|
twybrow
|
| posted on 4/11/15 at 12:51 PM |
|
|
quote:
Originally posted by paddywil
Right, I would appreciate it if we could have no more discussion about this argument, it's time to move on. For the sake of this build, the
argument has been useful, but from this point onwards, let's assume a few things:
I am going to use a spaceframe for this build
As much I would like this to be a replica, I am more concerned with the economics of this than historical accuracy.
I may in the future attempt a monocoque, but that's up in the air at the moment
What I would like input on is people's preference for fibreglass vs aluminium bodywork - going down the space frame root will require a large
amount of body work to achieve the desired shape... I have experience of both making Ali panels and making moulds for fibre glass, so that's not
the issue, I simply want to know what people in my place would choose.
Simple advice - don't underestimate the time and effort required to build patterns and tools of the desired quality. For a one off part, it is
very time consuming to do - for multiple/series parts, it makes perfect sense. You can of course speed up and simplify the process by using CNC to
machine plugs/direct moulds, but this will not be locost. You could even think about building the tooling by stacking up lots of machined profiles,
and then blending the surface with paste/filler - if this is an option for you, it would save time and may allow you to bypass the plug all together
(assuming you plan to design the shapes in CAD)....
I cannot help with comparing directly to making Alu parts, as this is not something I have done for anything more than a single fold/bend!
|
|
|
Neville Jones
|
| posted on 4/11/15 at 01:28 PM |
|
|
quote:
Originally posted by russbost
Gahhhhhhhhhh!
Which part of stop arguing & stay on topic do you not understand!
There are about 1001 things wrong with that last post which I am not going to respond to, I would suggest that Nev doesn't either
................
I understand your frustration Russ. The dear chap will twist each and every statement to suit his own ends and ego. He also doesn't appear to
know who all the signatories are on the oz site from what Bob tells me.
One-off grp bodywork...
Paddy, if you've done what you say, then what I'm writing below you'll have done and be familiar with. So please, excuse my words if
they seem patronising.
Start with foam from your local builders supply. You need the close grain sort of crumbly stuff, not expanded polystyrene.
Set up stations, or frames, with the shape you want at that point, fill in between with foam, and sand to shape. Sounds easy, but is messy and
itchy.
Fair it up with filler, then sand the thing withing a mm of oblivion. Give it a coat of 600csm, then fair this up. Over that goes a coat of primer
filler, or you can short cut the process and cover it with brown packing tape. Everywhere. Wax on that, then lay up your parts.
Depending on overlaps and fairness of whats underneath, then final article shouldn't need much filler to make it good for final paint.
I built a foiling moth hull(crazy little sailing things, look 'em up on Youtube) in carbon in the summer, just that way, start to finish in a
week. That shape is very simple, so I'd multiply by four ,at least, for the 32 shell.
Cheers,
Nev.
[Edited on 4/11/15 by Neville Jones]
|
|
|
Sam_68
|
| posted on 4/11/15 at 01:32 PM |
|
|
By the mid-60's, upper bodywork was in GRP, so that would be the 'authentic' solution and I'd have thought much easier than
alloy for some of the shapes? Also rather more tolerant of small knocks and scrapes?
The sill panels of the 'tub' were aluminium and, being single curvature, would be pretty easy to from from ali anyway. If you're
using a spaceframe, you'll be able to see these panels from inside the cockpit, so bare ali might look nicer than the rough face of a GRP panel?
|
|
|
russbost
|
| posted on 4/11/15 at 01:56 PM |
|
|
To add to the bodywork building scenario, when I did the original body for the Furore I was only ever intending building one car - for myself - it was
never intended to go into production!
I built the panels by first making a basic frame in 1/2" square tube to the size & shape of what I was trying to produce, shapes a lot more
complex than the Lotus 25 or 32, I then formed 1.2mm (IIRC) ali sheet around the steel to get the basic shape, where complex curves were involved I
just split the ali as necessary & folded it to shape, you can get within maybe 3mm or so like that & then just used filler with some chopped
fibreglass in to get it to the correct finished shape. Once at that stage the panel is ready for primer & paint. In a few areas, like the curve in
front of the screen, I went straight for fibreglass over the basic frame, supported with thin wire mesh during the forming process
The panels thus formed were still on the car several years later when it was sold, with very little deterioration, just one or 2 tiny cracks where I
should have put more support under the filler.
Nev, I'm slightly confused by the method you are describing, I've seen that method used to make bucks, but surely if you're making
finished bodywork aren't you going to have a ton of filling & rubbing down after glassing up over the packing tape stage or am I (as usual)
completely missing something?
Going back to the safety aspect, you can very easily extend the spaceframe up around the upper half of the tub which will not only increase stifffness
(at a very small weight cost), but will also greatly increase driver safety - pretty obvious that something like this is never going to be as safe as
an ordinary tintop, but I don't have a built in death wish & see no point in making it any easier to get flattened than necessary.
The upper "half" of the body could still be finished in fibreglass to get the required shapes, but if doing a one-off, much easier to
make this all part of the structure of the vehicle, just cut a "bonnet" aperture for access to steering, suspension, brakes, battery,
cooling etc.
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
Neville Jones
|
| posted on 4/11/15 at 02:22 PM |
|
|
Russ,
The amount of time and effort put into the fairness of that last csm layer, dictates how much filling and fairing is done on the final article.
Yes, the final surface will need a complete all over skim then sanding, but the choice of material makes a significant contribution. CSM will need a
good deal of elbow grease.
The moth hull was a 4x4 twill,(carbon in this case, but glass is easily had) which draped really easily over the plug. The filler was epoxy/balloons,
and when finished and sanded, prior to paint, very little of the balloons was left. Mostly small patches between the weave. This is countered by the
amount of resin that needs to be applied when using cloth over foam in a mould. With what I built, you just paint on some epoxy on the inside,(after
thorough dewaxing and sanding, before HE gets picky and pedantic) then in goes the foam then a layer of carbon over that. I should have taken some
pics, but this sort of thing is fairly routinely done around here, for one-offs, for many years, and isn't seen as out of the ordinary.
With the Lotus32 shape, the biggest problem in putting the car on the road will be headlight positions. Mounted up high, just inside the wings, might
work. I've seen that done before.
Cheers,
Nev.
|
|
|
|
