planning own car project
Discussion
I am planning on building my own car from fresh, commencing the build in the next year or so. Initially I want to read up on the subject, design the chassis and make a build plan before getting stuck in.
How do you go about designing the car from scratch ? I have an idea in my mind how it should look, general size etc. But is there any good books or articles to read to cover some of the following:
wheelbase
track/width
expected weight
occupancy / passenger space
height
wheel size
engine / layout
bodywork material + fitment
doors
chassis material / construction
suspension donor or bespoke
gearing / gearbox / drive train
IVA compulsory features.
I expect people will think I am copying Rob, but I did speak to Dom9 about this many months before Rob realised his blog. I want to build a kei car sized group c replica, with the body shell being made from lexan (much like an r/c car)
Is the Kimini book worth buying ? Are there any other books that would be worth reading ?
I want to get some CAD software to plan out the chassis - is SketchUp fit for the purpose or is there another cheap alternative such as turboCAD ?
How do you go about designing the car from scratch ? I have an idea in my mind how it should look, general size etc. But is there any good books or articles to read to cover some of the following:
wheelbase
track/width
expected weight
occupancy / passenger space
height
wheel size
engine / layout
bodywork material + fitment
doors
chassis material / construction
suspension donor or bespoke
gearing / gearbox / drive train
IVA compulsory features.
I expect people will think I am copying Rob, but I did speak to Dom9 about this many months before Rob realised his blog. I want to build a kei car sized group c replica, with the body shell being made from lexan (much like an r/c car)
Is the Kimini book worth buying ? Are there any other books that would be worth reading ?
I want to get some CAD software to plan out the chassis - is SketchUp fit for the purpose or is there another cheap alternative such as turboCAD ?
sorry cant help with most of your queries, but the lexan bodyshell is a great idea. Dont know if youve seen Tony Shutes Lotus Expose, which has a clear lexan bodyshell?
i spent many years in the RC racing trade working for importers and distributors, and hada fair bit to do with the better bodyshell moulders. Whilst all your test body 'pulls' can be made with cheap material, the final vac forming using lexan will need someone extremely well versed in polycarb vacuum forming and have a machine capable of varying the heat across the material span (or you end up with a thick roof and wafer thin sides!).
also note the lexan itself must be dried very thoroughly and carefully or it blisters (attracts water when stored in sheets). Also the usable temp range of lexan is very narrow, too cool and it wont pull, too hot and it goes thin or blisters badly.
Upside is when finished you can paint it on the inside and it wont scratch off from the outsdie, just liek an RC car!
its incredibly strong and resilient too, ideal if you have an 'off'...
as for chassis/suspension design, there are a plethora of books, Adams, Stanniforth (good informative read) and also a bike engined car book by Tony Pashley, all wortha shot imho
Good luck, will watch with interest.
CNH
i spent many years in the RC racing trade working for importers and distributors, and hada fair bit to do with the better bodyshell moulders. Whilst all your test body 'pulls' can be made with cheap material, the final vac forming using lexan will need someone extremely well versed in polycarb vacuum forming and have a machine capable of varying the heat across the material span (or you end up with a thick roof and wafer thin sides!).
also note the lexan itself must be dried very thoroughly and carefully or it blisters (attracts water when stored in sheets). Also the usable temp range of lexan is very narrow, too cool and it wont pull, too hot and it goes thin or blisters badly.
Upside is when finished you can paint it on the inside and it wont scratch off from the outsdie, just liek an RC car!
its incredibly strong and resilient too, ideal if you have an 'off'...
as for chassis/suspension design, there are a plethora of books, Adams, Stanniforth (good informative read) and also a bike engined car book by Tony Pashley, all wortha shot imho
Good luck, will watch with interest.
CNH
I thought 'kei car' might be a typo, but googled it and now there is another piece of knowledge in my already full brain (I wonder what got pushed out to make room for it?). Anyway, my biggest concern would be the room for the occupants, inasmuch as there isn't going to be any if the car looks like a Group C car and is noticeably smaller than a full size car.
Cabin and legroom is a major problem in this type of car, and to make the overall size smaller than what we would think of as a full sized car, well I for one don't see how it could possibly be done, unless it's only intended for unusually small adults. Sorry if I've misunderstood the intention, though.
Cabin and legroom is a major problem in this type of car, and to make the overall size smaller than what we would think of as a full sized car, well I for one don't see how it could possibly be done, unless it's only intended for unusually small adults. Sorry if I've misunderstood the intention, though.
dtmpower said:
Maybe with a less bulbous roof - yes the cabin will be very small... 1 seat , 2 at a push.
There is the option to just have one seat, certainly, but it's the length that will be the problem. Assuming you start with a footwell that's say 200mm back from the axle centreline, you will want at least 1200mm before you get to the bottom of the rear cockpit bulkhead, and if that bulkhead/engine firewall is vertical, as it often will be with a mid engined car (though not with a front engined 7 or similar), then a bit more again, say 1350 to allow for the seat backrest to slope back. The wheelbase on something like a Boxster is about 2400, so you can see why there might be a problem if the car you are making is going to be smaller.I'm certainly not saying it can't be done, though, just pointing out a potential problem
CNHSS1 said:
sorry cant help with most of your queries, but the lexan bodyshell is a great idea. Dont know if youve seen Tony Shutes Lotus Expose, which has a clear lexan bodyshell?
Yes, I did see it sometime ago. There was also an Escort body in multiple pieces CNHSS1 said:
i spent many years in the RC racing trade working for importers and distributors, and hada fair bit to do with the better bodyshell moulders. Whilst all your test body 'pulls' can be made with cheap material, the final vac forming using lexan will need someone extremely well versed in polycarb vacuum forming and have a machine capable of varying the heat across the material span (or you end up with a thick roof and wafer thin sides!).
also note the lexan itself must be dried very thoroughly and carefully or it blisters (attracts water when stored in sheets). Also the usable temp range of lexan is very narrow, too cool and it wont pull, too hot and it goes thin or blisters badly.
Upside is when finished you can paint it on the inside and it wont scratch off from the outsdie, just liek an RC car!
its incredibly strong and resilient too, ideal if you have an 'off'...
as for chassis/suspension design, there are a plethora of books, Adams, Stanniforth (good informative read) and also a bike engined car book by Tony Pashley, all wortha shot imho
Good luck, will watch with interest.
CNH
CNH - Thanks for all the info. I haven't even begun to think what/how the body will be constructed. I will start planning out the chassis and running gear and hopefully then, when I get to that stage. Put the body on like an r/c car. Painting the inside will be a bonus. What sort of thickness lexan would you think the body will need to be formed from ?also note the lexan itself must be dried very thoroughly and carefully or it blisters (attracts water when stored in sheets). Also the usable temp range of lexan is very narrow, too cool and it wont pull, too hot and it goes thin or blisters badly.
Upside is when finished you can paint it on the inside and it wont scratch off from the outsdie, just liek an RC car!
its incredibly strong and resilient too, ideal if you have an 'off'...
as for chassis/suspension design, there are a plethora of books, Adams, Stanniforth (good informative read) and also a bike engined car book by Tony Pashley, all wortha shot imho
Good luck, will watch with interest.
CNH
I used to race 1/10 IC cars back in the mid 90's. PB and BMT cars before moving into 1/10 touring cars. What companies were you involved with ?
I will get some books together and start reading up on the dynamics and the design.
singlecoil said:
dtmpower said:
Maybe with a less bulbous roof - yes the cabin will be very small... 1 seat , 2 at a push.
There is the option to just have one seat, certainly, but it's the length that will be the problem. Assuming you start with a footwell that's say 200mm back from the axle centreline, you will want at least 1200mm before you get to the bottom of the rear cockpit bulkhead, and if that bulkhead/engine firewall is vertical, as it often will be with a mid engined car (though not with a front engined 7 or similar), then a bit more again, say 1350 to allow for the seat backrest to slope back. The wheelbase on something like a Boxster is about 2400, so you can see why there might be a problem if the car you are making is going to be smaller.I'm certainly not saying it can't be done, though, just pointing out a potential problem
You do make a valid point. I see this as inspired by Group C. It's never going to be a Group C car, with Group C size and power !no idea re the thickness needed, you will have to discuss with your chosen vac former, but as i say use someone very conversant with polycarb as other vac plastics are a walk in the park compared.
i would have thought 3mm would be a good starting point though, although whether you would need say 5mm and 'pull' it thinner in places (vac machine with variable heating elements essential) i dont know. The trick is to make the body shape 'help' you. No large flat areas as they tend to flex and the car will sound like Rolf Harris's wobble board over every bump lol, constant curves or shallow angle spines, basically anything that will add mechanical strength to the shape rather than relying on the 'flat' strength of the material only. You can of course add internal ribs or stiffeners, but polycarbs a sod to glue properly. There are glues out there that will stick, often something like Tiger seal or similar is better though as it doesnt bond or bite into the surface weakening it. There was a product by Racers Choice iirc, that was to repair lexan. Basically it adhered but didnt attack and set like toffee, hard but slightly pliable.
when you are ready for the body and can get hold of him, Dale Epp, the owner and designer of Protoform bodies, now part of the Proline empire in the US, would be a useful contact, especially as hes a motorsport fan, he may be interested enough to give you some lexan tips.
as for my RC background i last worked for the Associated, Yokomo, RB Concept, Novarossi, Team Magic plus others UK distributor (about 9 years total). Raced every class over the years, although have a soft spot for 2wd elec off road, 1/8th IC circuit and 1/12th elec circuit, but nearly 20 years in the trade destroyed my hobby was got a normal job designing offices now and wont ever 'work' in my other hobby, hillclimb/sprinting ;-)
i would have thought 3mm would be a good starting point though, although whether you would need say 5mm and 'pull' it thinner in places (vac machine with variable heating elements essential) i dont know. The trick is to make the body shape 'help' you. No large flat areas as they tend to flex and the car will sound like Rolf Harris's wobble board over every bump lol, constant curves or shallow angle spines, basically anything that will add mechanical strength to the shape rather than relying on the 'flat' strength of the material only. You can of course add internal ribs or stiffeners, but polycarbs a sod to glue properly. There are glues out there that will stick, often something like Tiger seal or similar is better though as it doesnt bond or bite into the surface weakening it. There was a product by Racers Choice iirc, that was to repair lexan. Basically it adhered but didnt attack and set like toffee, hard but slightly pliable.
when you are ready for the body and can get hold of him, Dale Epp, the owner and designer of Protoform bodies, now part of the Proline empire in the US, would be a useful contact, especially as hes a motorsport fan, he may be interested enough to give you some lexan tips.
as for my RC background i last worked for the Associated, Yokomo, RB Concept, Novarossi, Team Magic plus others UK distributor (about 9 years total). Raced every class over the years, although have a soft spot for 2wd elec off road, 1/8th IC circuit and 1/12th elec circuit, but nearly 20 years in the trade destroyed my hobby was got a normal job designing offices now and wont ever 'work' in my other hobby, hillclimb/sprinting ;-)
Nice idea in principle but I seem to recall that polycarbonates are rather sensitive to hydrocarbons (petrol fumes etc;),What I do know is that when I was racing 1/12 scale a customers brand new Lexan chassis crazed just by being wiped over with an incompatible solvent in order to attach the servo tape!
Don't know whether the latest incarnations of these plastics have greater resistance to chemical attack, might be worth checking it out.
Don't know whether the latest incarnations of these plastics have greater resistance to chemical attack, might be worth checking it out.
Cad – possible worth a look, http://www.alibre.com.au
Solid works is popular for this stuff as well but it’s going to be a few thousand.
Tony Pashleys Book
http://books.google.com.au/books?id=cym6_H4qm8UC&a...
you sound like your wanting something similar to this.
http://www.kellforms.com/retoga/index.htm
Solid works is popular for this stuff as well but it’s going to be a few thousand.
Tony Pashleys Book
http://books.google.com.au/books?id=cym6_H4qm8UC&a...
you sound like your wanting something similar to this.
http://www.kellforms.com/retoga/index.htm
Auntieroll said:
Nice idea in principle but I seem to recall that polycarbonates are rather sensitive to hydrocarbons (petrol fumes etc;),What I do know is that when I was racing 1/12 scale a customers brand new Lexan chassis crazed just by being wiped over with an incompatible solvent in order to attach the servo tape!
Don't know whether the latest incarnations of these plastics have greater resistance to chemical attack, might be worth checking it out.
1/12th scale lexan chassis are going back a while, bet you remember silicone tyres and TEAC tyre additives too;-)Don't know whether the latest incarnations of these plastics have greater resistance to chemical attack, might be worth checking it out.
lexans(polycarbonates) dont like any solvents as such, but the paint barrier on the inside of the bodyshell helps to protect the material. In RC car terms, most are methanol engines which dont affect it anyway, but with the large scale petrol engines we just used to use a model aicraft fuel proofer over the top of the paint surface to seal (fuel proofer doesnt stick to lexan, so you have to put special paint on first which does adhere, then the FP will stick to the painted surface).
Petrol if in liquid form and left to sit in puddles on the lexan, will eat it, but vapour tends evaporate and have no effect anyway, even without fuel proof layer.
...and is this your car(d)?
Pic of a modded AZ-1, standard (if that's the right term for a mid-engined gullwing kei):
These are much rarer than Cappuchino's or Beats but a couple made it to the UK, so it might be worth checking for owners clubs for reference, as well as an image search you could also check for a scale model. As long as you weren't planning a V8 (or a straight 6
) packaging shouldn't be too much of a problem. Single seater would allow you to have inset cockpit so characteristic of Group C stuff, but kei cars typically tend to look a little narrow, so a modest width increase might allow inset and two seats.
ETA: thumbsnaps apparently down, will add images later
ETA: dimensioned views of AZ-1 & Honda Beat:
UK Kei club
http://keikarsinthepark.co.uk/index.php?board=14.0
Pic of a modded AZ-1, standard (if that's the right term for a mid-engined gullwing kei):
These are much rarer than Cappuchino's or Beats but a couple made it to the UK, so it might be worth checking for owners clubs for reference, as well as an image search you could also check for a scale model. As long as you weren't planning a V8 (or a straight 6
) packaging shouldn't be too much of a problem. Single seater would allow you to have inset cockpit so characteristic of Group C stuff, but kei cars typically tend to look a little narrow, so a modest width increase might allow inset and two seats.ETA: thumbsnaps apparently down, will add images later
ETA: dimensioned views of AZ-1 & Honda Beat:
UK Kei club
http://keikarsinthepark.co.uk/index.php?board=14.0
Edited by seansverige on Thursday 22 April 11:38
Edited by seansverige on Thursday 22 April 12:03
seansverige - thanks for the dimension drawing - should help me loads with me chassis planning
singlecoil - what's not to like about making a full size r/c car ! lightweight body. I almost want to make the car body less and then put the body on to drive it once I am in the car, sort of like a Funny car dragster.
singlecoil - what's not to like about making a full size r/c car ! lightweight body. I almost want to make the car body less and then put the body on to drive it once I am in the car, sort of like a Funny car dragster.
No worries. The AZ-1 is an old favourite, so digging up some more info on it was no hardship. Must admit I'd forgotten about AZ-550 (and it's kinship to the AZ-1) and the GReddy VI AZ1 is new to me. Bit more on both on this page: http://www.japancar.fr/forum/viewtopic.php?t=15535...
Unfortunately if the GReddy VI AZ1 uses the AZ-1's glasshouse then it's considerably wider -check out the door thickness below:
Unfortunately if the GReddy VI AZ1 uses the AZ-1's glasshouse then it's considerably wider -check out the door thickness below:
with vac formed bodies the labour costs to reproduce are minimal as theres no labour to layup like grp or carbon, and lexan after all is bullet proof in thicker forms (above 6mm iirc) and also used for riot shields, very very resilient, more like kevlar in fact.
and its different i guess
and its different i guess
dtmpower said:
singlecoil - what's not to like about making a full size r/c car ! lightweight body. I almost want to make the car body less and then put the body on to drive it once I am in the car, sort of like a Funny car dragster.
Nothing at all wrong with that, what I'm asking about is why Lexan instead of GRP? I know that Lexan is favoured for things like riot shields, but they need to be transparent, and resilient, neither of which (I assume) applies to your requirements. I don't have any specific knowledge of Lexan compared to GRP, but I would be surprised indeeed if it turned out that strength for strength Lexan was the lighter of the two. I assume Lexan is popular for r/c car bodies because it is strong compared to other materials that can be vac-formed, as opposed to strong compared to other materials that can be moulded.CNHSS1 said:
with vac formed bodies the labour costs to reproduce are minimal as theres no labour to layup like grp or carbon, and lexan after all is bullet proof in thicker forms (above 6mm iirc) and also used for riot shields, very very resilient, more like kevlar in fact.
and its different i guess
Oh I had grasped that the labour costs were lower, this is a subject that I am VERY interested in. However, when I looking into it I was put off by the difficulties of vac forming large areas, the need for careful temperature control and the amount of vacuum power needed.and its different i guess
I'm not attacking the idea by any means, I like it, but what I want to know is, it is feasible? Just because r/c models are made that way doesn't in itself prove that it is a good idea for a full scale car.
all fair points single coil.
i think in terms of it being the right material for production cars then its a definite no. Also for large unsupported largely flat panels, again no. It also has the disadvantage of being (in theory) a uniform thickness all over the whole component whereas GRP or any other composite can easily be varied in thickness, have other materials (and their specific properties) added into small or large areas, so its GRP again is more versatile. That said before Atom came along withj some scaffold tube and an engine, the exo-skeleton wasnt exactly in vogue either lol
As this guys proposed cars quite dinky in proportions, will barely have 6sq" of truly flat panel especially if it looks that Mac F1 inspired white car pictured above, then its not as daft as it would first seem. Certainly from what ive read of interviews with Tony Shute and his Expose (which i often bump into in hillclimb paddocks) the vac formed body is incredibly light and tough even when compared with the Expose's relative the 340R's, GRP body work
Like most of these things, it only needs someone like Lotus to perfect the process and it will become more commonplace. They did it with injection moulding resin GRP panels (actually Reliant pioneered the process, but Lotus made it work!) and again its now a good way of volume production of light consistent GRP laminate panels.
i think in terms of it being the right material for production cars then its a definite no. Also for large unsupported largely flat panels, again no. It also has the disadvantage of being (in theory) a uniform thickness all over the whole component whereas GRP or any other composite can easily be varied in thickness, have other materials (and their specific properties) added into small or large areas, so its GRP again is more versatile. That said before Atom came along withj some scaffold tube and an engine, the exo-skeleton wasnt exactly in vogue either lol
As this guys proposed cars quite dinky in proportions, will barely have 6sq" of truly flat panel especially if it looks that Mac F1 inspired white car pictured above, then its not as daft as it would first seem. Certainly from what ive read of interviews with Tony Shute and his Expose (which i often bump into in hillclimb paddocks) the vac formed body is incredibly light and tough even when compared with the Expose's relative the 340R's, GRP body work
Like most of these things, it only needs someone like Lotus to perfect the process and it will become more commonplace. They did it with injection moulding resin GRP panels (actually Reliant pioneered the process, but Lotus made it work!) and again its now a good way of volume production of light consistent GRP laminate panels.
Edited by CNHSS1 on Thursday 22 April 22:35
not sure if its feasible with your average vac form machine to be honest, although im sure some of the aerospace vac formers (aero canopies etc ) may well have machines that have enough adjustment range of temperature across the platten to compensate for the pull and its effects on the thickness.
I suspect if you were say using the process to produce a low volume car (kit car/race car) it would be best to make or modify your own vac form machine.
I mentioned Tony Shute before. He was the guy in charge of the Elise project for lotus btw.
I suspect if you were say using the process to produce a low volume car (kit car/race car) it would be best to make or modify your own vac form machine.
I mentioned Tony Shute before. He was the guy in charge of the Elise project for lotus btw.
Edited by CNHSS1 on Friday 23 April 13:29
Gassing Station | Kit Cars | Top of Page | What's New | My Stuff