Discussion
race said:
does the kit car market require more radical designers to make the market more intresting?
I think yes. Most kits seem to be designed by engineers, not designers. They are pretty well executed in the oily department but far too many of them look like a pile of sh*t. In fact some seem to have been designed to be ugly. Engineers often design things to be easy to make . . . and that's perhaps why they look so seriously ugly.
How many well designed kits are there that don't look like a 7 or are a replica of another car ? I can think of the Shelsy T2 (sp ?) and the Vortex, both really good looking.
I don't think radical is the problem. There are plenty of kits out there which are certainly very radical-looking, if not attractive.
The problem is, as mentioned, a lack of response to the market and an unwillingness to take good styling seriously as a means of selling cars. If good engineering were all it took to sell kits, there would be several kit cars still being sold today. Instead there are several unattractive cars with great chassis that you can't buy any more.
I have tried to sell my skills, and the skills of my contractors, into this very market, and the above attitudes are overwhelmingly evident. Design is seen as an afterthought, a luxury to be considered only if funds allow. Many kit producers see it as so unimportant, they are only willing to go ahead if you produce the work for them 'on spec' and if they like it, they'll pay! Can you imagine if you said to them "Tell you what, design me a chassis, and if it handles well, I'll pay you for it"?
Am I dealing with any kit projects at the moment? As you may have guessed from the above, no. It's a shame, because we have specifically tried to sell some of the world's best design talent into this market (there's lots of it about, eager for work, if you know where to look), and all we have had in response is the above.
There needs to be a serious culture change in the kit industry if more are to break out into the mainstream. It doesn't need new designers, as they are readily available, it needs a willingness to engage with those designers properly.
The problem is, as mentioned, a lack of response to the market and an unwillingness to take good styling seriously as a means of selling cars. If good engineering were all it took to sell kits, there would be several kit cars still being sold today. Instead there are several unattractive cars with great chassis that you can't buy any more.
I have tried to sell my skills, and the skills of my contractors, into this very market, and the above attitudes are overwhelmingly evident. Design is seen as an afterthought, a luxury to be considered only if funds allow. Many kit producers see it as so unimportant, they are only willing to go ahead if you produce the work for them 'on spec' and if they like it, they'll pay! Can you imagine if you said to them "Tell you what, design me a chassis, and if it handles well, I'll pay you for it"?
Am I dealing with any kit projects at the moment? As you may have guessed from the above, no. It's a shame, because we have specifically tried to sell some of the world's best design talent into this market (there's lots of it about, eager for work, if you know where to look), and all we have had in response is the above.
There needs to be a serious culture change in the kit industry if more are to break out into the mainstream. It doesn't need new designers, as they are readily available, it needs a willingness to engage with those designers properly.
busa_rush said:
does the kit car market require more radical designers to make the market more intresting?
I think yes. Most kits seem to be designed by engineers, not designers. They are pretty well executed in the oily department but far too many of them look like a pile of sh*t. In fact some seem to have been designed to be ugly. Engineers often design things to be easy to make . . . and that's perhaps why they look so seriously ugly.
How many well designed kits are there that don't look like a 7 or are a replica of another car ? I can think of the Shelsy T2 (sp ?) and the Vortex, both really good looking.
Yes and no.
Radical doesn't have to mean ugly. The Countach was radical but back in the seventies it looked amazing. It really does mystify me why some companies spend so much time and effort on some seriously dodgy looks! Don't they ever stand back and take a reality check?
As for the "oily bits", in kit car terms this means the chassis, suspension and how the body work fits together.
Take the much vaunted kit car space frame, usually described as being race bred etc etc. A simple X braced ladder frame would be as stiff and lighter in most cases!
Why do most kits persist in adjusting doors by putting shims under the hinges? This method is very awkward as anyone who has ever tried it wil tell you. My solution would be to have a non adjustable hinge supporting a door framework. Mount the door on the frame work in an adjustable manner. Put the shims behind the door skin on bolts attaching to the door frame. It's much easier to adjust these than grovelling around under the dash while trying to work out which way the door will move when you fit or take out another shim.
Some suspension stuff is a bit suspect to. The positioning of spring and damper units on wishbones and chassis is often very suspect. I've seen linkages on live axles that can only work by trying to twist the entire axle over every bump! As for those that claim to reduce unsprung weight by using the upper wishbone as a rocker to an inboard spring-damper unit, please read a basic text book...
cymtriks said:
Take the much vaunted kit car space frame, usually described as being race bred etc etc. A simple X braced ladder frame would be as stiff and lighter in most cases!
Some suspension stuff is a bit suspect to. The positioning of spring and damper units on wishbones and chassis is often very suspect. I've seen linkages on live axles that can only work by trying to twist the entire axle over every bump!
Sorry, Cymntriks, but you wheel out this old chestnut without fail, every time the topic of chassis design arises, which wouldn't be so bad if your own figures didn't disprove it! IIRC, your 'simple X braced ladder frame' requires substantial 3-dimensional scuttle bracing before it starts to match the figures of even a badly designed spaceframe (the Locost). A ladder frame, by definition is a two dimensional, planar, structure. If you start fudging the figures by adding 3D bracing, or the stiffness added by a bolting it to a bodyshell, you are kidding no-one but yourself!
It is easy to become obsessive about things like chassis stiffness at the cost of everything else. You have to maintain a sense of perspective!
It's all very well having 20,000ft.lbs.degree stiffness, but does it really matter about constraining chassis twist to a fraction of a millimetre when you have un-damped tyres at 18psi and rubber suspension bushes squidging about all over the place!
It's also worth remembering that the live axle linkage design to which you refer has probably won more kit car races and championships than every other manufacturer put together!!
The lateral location linkage that is currently considered to be the ultimate for a live axle, the Mumford link, theroretically binds up completely in roll, but that doesn't seem to stop it winning races with monotonous regularity when bolted to a Mallock or a 750 Formula car.
Colin Chapman's method of location for the Seven's rear axle is similarly flawed (as was his design for longitudinal location of the front suspension, too, come to think of it...).
Design is all about compromises. The mark of a seriously talented design engineer is not knowing how to do things perfectly, but how to make the right compromises. You and I can easily sit back and pick fault with the designs of Colin Chapman, Lee Noble, Jeremy Phillips, Arthur Mallock and others, but their designs work and are buildable for a reasonable cost.
The kit car spaceframe is described as being race-bred because that's exactly what it is...it has been winning races since the 1950's and is still the chassis structure of choice for clubman level racing to this day, because it offers the best compromise.
If you think you can do better with a planar ladder frame, it's time to put up or shut up!
D-Angle said:
I have tried to sell my skills, and the skills of my contractors, into this very market, and the above attitudes are overwhelmingly evident. Design is seen as an afterthought, a luxury to be considered only if funds allow. Many kit producers see it as so unimportant, they are only willing to go ahead if you produce the work for them 'on spec' and if they like it, they'll pay! Can you imagine if you said to them "Tell you what, design me a chassis, and if it handles well, I'll pay you for it"?
I believe Justin said it all........I have met a few creative Kitcar manufacturers who are crazy enough to invest in a new design, but they are more of an exception than the rule. These are very creative people that understand the difference a good design makes, and have the courage to invest. I admire risk takers!
Very few manufacturers have had the courage to invest in new and original designs, maybe because the cost of failure in this business would be to high to bear financially for a small kit manufacturer .
I can think of a few, GTM, AEON and a few others.
The Seven replica market is big, but it's the easy and less expensive way to get in the Kit business. Financially it makes more sense if you want a fast return on your investment , with little risk.
If you do something a little more creative than a seven clone or a cobra, just think of the Sylva Mojo, it will take you at least 7 to 10 years before this new concept becomes succesful in the kit market and this new kit is basically a mid-engine Seven !!!!, and maybe by that time you would have failed a few times.
I believe that this market is still too small, and Kitcar manufacturers don't have the kind of development money that bigger sportscars manufacturers do.
As someone said in past threads, creative designs on kitcars will come more often from single enthusiast working in their shed, investing their own money, and creating their own car design.
Very few by kit manufacturers have used real designers, but the ones that have, have had successful products. Take any Richard Oakes design and you will see a success story.
Maybe things will change in the future, but it will take time..........let's hope for 2006!
I have tried to sell my skills, and the skills of my contractors, into this very market, and the above attitudes are overwhelmingly evident. Design is seen as an afterthought, a luxury to be considered only if funds allow. Many kit producers see it as so unimportant, they are only willing to go ahead if you produce the work for them 'on spec' and if they like it, they'll pay! Can you imagine if you said to them "Tell you what, design me a chassis, and if it handles well, I'll pay you for it"?
I believe Justin said it all........I have met a few creative Kitcar manufacturers who are crazy enough to invest in a new design, but they are more of an exception than the rule. These are very creative people that understand the difference a good design makes, and have the courage to invest. I admire risk takers!
Very few manufacturers have had the courage to invest in new and original designs, maybe because the cost of failure in this business would be to high to bear financially for a small kit manufacturer .
I can think of a few, GTM, AEON and a few others.
The Seven replica market is big, but it's the easy and less expensive way to get in the Kit business. Financially it makes more sense if you want a fast return on your investment , with little risk.
If you do something a little more creative than a seven clone or a cobra, just think of the Sylva Mojo, it will take you at least 7 to 10 years before this new concept becomes succesful in the kit market and this new kit is basically a mid-engine Seven !!!!, and maybe by that time you would have failed a few times.
I believe that this market is still too small, and Kitcar manufacturers don't have the kind of development money that bigger sportscars manufacturers do.
As someone said in past threads, creative designs on kitcars will come more often from single enthusiast working in their shed, investing their own money, and creating their own car design.
Very few by kit manufacturers have used real designers, but the ones that have, have had successful products. Take any Richard Oakes design and you will see a success story.
Maybe things will change in the future, but it will take time..........let's hope for 2006!
Out of curiosity D-Angle what services were you offering?
I think there is a very good point here about the extremely independent mindset of the kit car manufacturer. They sometimes seem to regard outside help as a threat!
One thing that would really help the introduction of new models would be the use of a different approach to mould making. The current labour intensive methods make the whole process difficult for a small company to undertake.
I'd be interested in thoughts on-
1)Making a one off alloy body and taking moulds off that. This was apparently done for the Caterham 21 as it was cheaper and faster than making a traditional buck.
2)Using the DP cars ( check their website - an amazing project) approach of milling the buck out of foam coated with a hard surface. Mill to a near finished state, do the last preparation by hand and take moulds. The machining costs a lot (I'd like to know how much!) but the process gets you very close to finished very quickly.
One enormous potential source for new bodies is other failed projects!
Does anyone remember the OSCA 2500 GT ? Google it. It would make a lovely kit car but it seems to have disappeared without trace, and it's certainly not the only nice shape to do that! There must be dozens of aborted designs and old concept cars stashed in warehouses or outbuildings. Perhaps it would pay to do some digging?
Now for my reply to Sam_68...
No. And if you noticed I devoted much more space to doors, which every builder complains about, and styling, which is very niche appeal in some cases.
My figures from one of my earlier posts:-
Lowcost chassis to the book has a stiffness of 1200ftlbs per degree of twist and 160lbs weight for the welded steel structure. Considering the variations in the book the stiffness and weights could vary a bit either way. An X braced ladder frame of 4x2x14gauge for the same size of car could have about 1350ftlbs per degree stiffness and weight of 130lbs. Even allowing for the extra structures needed to support the body work this is still likely to equal the Lowcost book chassis.
And two quotes from kitcaranalysis.doc which has more up to date results:-
“Locost chassis
Chassis by the book with 16 gauge sheet steel panels
Stiffness is 1180 ftlbs per degree of twist
The weight is 181 lbs.
With a welded on dashboard structure and considering some of the possible variations in the book the stiffness could be about 1400 ftlbs per degree of twist.”
And
“An X braced ladder frame for a Seven type car with side beams following a similar profile to a Ford model B chassis, as found under many hot rod cars, made of 100 x 50mm with 2mm wall box section tubes would weigh about 140lbs and have a torsional strength of about 1400ftlbs per degree of twist. Additional structures would be required to provide support for the body work, seat belt mounts, dashboard and other parts but these could be designed to add strength to the chassis. Overall the chassis would probably result in a car about 5 to 10 percent heavier than a typical Locost with a torsional strength between the original space frame chassis and my modified space frame chassis.
A panelled footwell and dashboard structure welded to the main side rails is good and bracing this to the front suspension region is also good. Some Cobra replica chassis make good use of this approach.”
Every chassis, as you point out, has its own set of compromises and deviations from a text book chassis type. Would you describe a Locost chassis as a monocoque because it had a welded on floor and footwell ends? Is any spaceframe fully triangulated? Does a rally car stop being a monocoque when you weld in a roll cage? I would suggest that in the real world a ladder frame can have some degree of 3D structures without failing my description.
Because of this design or inspite of it?
Very interesting. I have a suspicion that this suspension works on the following basis-
a) it provides a "sprung suspension" to comply with the rules.
b) it restricts roll to a very small value thus eliminating a suspension variable while giving much greater control of the underbody airflow....
c) allows you to make claims about roll centre location to hide (b) even though it hasn't got a roll centre... roll is locked out!
I never said a ladder frame was better, I was just pointing out that most spaceframes failed to surpass them due to their design. This shouldn't be the case. All that's needed is a bit of carefully thought out triangulation.
I was involved with some analysis of a real chassis earlier this year. I made a few suggestions that gave a big change in stiffness from less than book Locost to a fair bit more.
The result was in immediate improvement in handling, especially on S bends where the car was reported as noticeably more stable and faster.
I think there is a very good point here about the extremely independent mindset of the kit car manufacturer. They sometimes seem to regard outside help as a threat!
One thing that would really help the introduction of new models would be the use of a different approach to mould making. The current labour intensive methods make the whole process difficult for a small company to undertake.
I'd be interested in thoughts on-
1)Making a one off alloy body and taking moulds off that. This was apparently done for the Caterham 21 as it was cheaper and faster than making a traditional buck.
2)Using the DP cars ( check their website - an amazing project) approach of milling the buck out of foam coated with a hard surface. Mill to a near finished state, do the last preparation by hand and take moulds. The machining costs a lot (I'd like to know how much!) but the process gets you very close to finished very quickly.
One enormous potential source for new bodies is other failed projects!
Does anyone remember the OSCA 2500 GT ? Google it. It would make a lovely kit car but it seems to have disappeared without trace, and it's certainly not the only nice shape to do that! There must be dozens of aborted designs and old concept cars stashed in warehouses or outbuildings. Perhaps it would pay to do some digging?
Now for my reply to Sam_68...
Sam_68 said:
Sorry, Cymntriks, but you wheel out this old chestnut without fail, every time the topic of chassis design arises, which wouldn't be so bad if your own figures didn't disprove it! IIRC, your 'simple X braced ladder frame' requires substantial 3-dimensional scuttle bracing before it starts to match the figures of even a badly designed spaceframe (the Locost).
No. And if you noticed I devoted much more space to doors, which every builder complains about, and styling, which is very niche appeal in some cases.
My figures from one of my earlier posts:-
Lowcost chassis to the book has a stiffness of 1200ftlbs per degree of twist and 160lbs weight for the welded steel structure. Considering the variations in the book the stiffness and weights could vary a bit either way. An X braced ladder frame of 4x2x14gauge for the same size of car could have about 1350ftlbs per degree stiffness and weight of 130lbs. Even allowing for the extra structures needed to support the body work this is still likely to equal the Lowcost book chassis.
And two quotes from kitcaranalysis.doc which has more up to date results:-
“Locost chassis
Chassis by the book with 16 gauge sheet steel panels
Stiffness is 1180 ftlbs per degree of twist
The weight is 181 lbs.
With a welded on dashboard structure and considering some of the possible variations in the book the stiffness could be about 1400 ftlbs per degree of twist.”
And
“An X braced ladder frame for a Seven type car with side beams following a similar profile to a Ford model B chassis, as found under many hot rod cars, made of 100 x 50mm with 2mm wall box section tubes would weigh about 140lbs and have a torsional strength of about 1400ftlbs per degree of twist. Additional structures would be required to provide support for the body work, seat belt mounts, dashboard and other parts but these could be designed to add strength to the chassis. Overall the chassis would probably result in a car about 5 to 10 percent heavier than a typical Locost with a torsional strength between the original space frame chassis and my modified space frame chassis.
A panelled footwell and dashboard structure welded to the main side rails is good and bracing this to the front suspension region is also good. Some Cobra replica chassis make good use of this approach.”
Sam_68 said:
A ladder frame, by definition is a two dimensional, planar, structure. If you start fudging the figures by adding 3D bracing, or the stiffness added by a bolting it to a bodyshell, you are kidding no-one but yourself!
Every chassis, as you point out, has its own set of compromises and deviations from a text book chassis type. Would you describe a Locost chassis as a monocoque because it had a welded on floor and footwell ends? Is any spaceframe fully triangulated? Does a rally car stop being a monocoque when you weld in a roll cage? I would suggest that in the real world a ladder frame can have some degree of 3D structures without failing my description.
Sam_68 said:
It is easy to become obsessive about things like chassis stiffness at the cost of everything else. You have to maintain a sense of perspective!
It's all very well having 20,000ft.lbs.degree stiffness, but does it really matter about constraining chassis twist to a fraction of a millimetre when you have un-damped tyres at 18psi and rubber suspension bushes squidging about all over the place!
Sam_68 said:
It's also worth remembering that the live axle linkage design to which you refer has probably won more kit car races and championships than every other manufacturer put together!!
Because of this design or inspite of it?
Sam_68 said:
The lateral location linkage that is currently considered to be the ultimate for a live axle, the Mumford link, theroretically binds up completely in roll, but that doesn't seem to stop it winning races with monotonous regularity when bolted to a Mallock or a 750 Formula car.
Very interesting. I have a suspicion that this suspension works on the following basis-
a) it provides a "sprung suspension" to comply with the rules.
b) it restricts roll to a very small value thus eliminating a suspension variable while giving much greater control of the underbody airflow....
c) allows you to make claims about roll centre location to hide (b) even though it hasn't got a roll centre... roll is locked out!
Sam_68 said:
The kit car spaceframe is described as being race-bred because that's exactly what it is...it has been winning races since the 1950's and is still the chassis structure of choice for clubman level racing to this day, because it offers the best compromise.
If you think you can do better with a planar ladder frame, it's time to put up or shut up!
I never said a ladder frame was better, I was just pointing out that most spaceframes failed to surpass them due to their design. This shouldn't be the case. All that's needed is a bit of carefully thought out triangulation.
I was involved with some analysis of a real chassis earlier this year. I made a few suggestions that gave a big change in stiffness from less than book Locost to a fair bit more.
The result was in immediate improvement in handling, especially on S bends where the car was reported as noticeably more stable and faster.
In my experience most kit and some specilist cars tend to be 'designed' by company owners and dreamers. I meet at least one a month. People who own companies who earn enough cash and have the facilities to build a show car. Such people tend to have big egos and respond negativley to constructive critique. They also lack the sculptural awarness that a car design gradute has. Don't do it. The 30k or so required to get someone capable to do the job will be the difference between a show stopper and another GRP jellymoulded turd.
member8888 said:
In my experience most kit and some specilist cars tend to be 'designed' by company owners and dreamers. I meet at least one a month. People who own companies who earn enough cash and have the facilities to build a show car. Such people tend to have big egos and respond negativley to constructive critique. They also lack the sculptural awarness that a car design gradute has. Don't do it. The 30k or so required to get someone capable to do the job will be the difference between a show stopper and another GRP jellymoulded turd.
cymtriks said:
Lots of stuff
1) The Locost chassis is an abortion. Please stop using it as an example of spaceframe chassis design.
2) Spaceframes can be fully triangulated, certainly (possible if you take triangulated bays out around either side of the cockpit, and/or use the patented Costin design of triangulated transverse bays to form the seat structures), though you don't need full triangulation to justify the 'spaceframe' label. A spaceframe is simply a frame which encloses space...in other words a three dimensional structure of (usually) tubes. The description of it as a fully triangulated structure which is capable of remaining rigid even if all tube intersections are pin-jointed is merely a superimposed definition applied by the more anally retentive and perfectionist structures freaks.
Audi engineers call the 3D alloy frame structure underneath the A8 a 'spaceframe' and Lotus apply the same label to the alloy chassis of the Elise.
Personally, I'd say that the Audi chassis is closer to your ladder frame with 3D bracing (it even has diagonal floor pan members approximating to your X-bracing), and the Elise frame is closer to a deep section twin-tube/ladder frame or a monocoque 'tub' clad in non-structural body panels, but then who am I to argue with the engineers from two such eminent companies?
3)You would suggest that in the real world a ladder frame can have some degree of 3D structures? I'm sorry, I disagree. By that definition, all current 750 Club chassis are ladder frames...they all retain the vestigial bottom rails of an Austin 7 ladder chassis. Is the majority of their stiffness derived from the ladder frame? I think not...
If a substantial part of the stiffness is derived from 3-dimensional additions, then it ceases to be a ladder frame, in my book.
4) Are you saying that
, a fraction of a millimetre of torsional chassis deflection is relevant, when the bushes and tyres are causing undamped deflections of tens of millimetres at the contact patch? If so, then there is little point in even continuing the discussion - you're clearly so deeply entrenched in structural theory that you have no comprehension of real-world vehicle dynamics. 5) Like I said, all designs are compromises, so no one feature can be said to be responsible for the success or otherwise of a competion car, but..
a) Relative roll stiffness front to rear is critical to a car's handling.
b)The Sylva rear suspension (which effectively uses the suspension bushes and axle tube to act as a large anti-roll bar) has a large influence on the weight transfer characteristics of the Sylva. I've spoken to Jeremy Phillips on this subject, so I know that this was a calculated aspect of the car's suspension design and not an accident.
Therefore...
c) I think it's fair to say that, yes, to some extent it's because of the rear suspension design, rather than in spite of it, that the car is successful.
6) The Mumford link gives a very high level of rear roll stiffness - though this is not quite the same as saying that it prevents roll.
a) Yes, it provides a sprung suspension in compliance with the rules...an interesting comment, in that it tacitly acknowleges the fact that karts are capable of very high performances with no 'suspension' at all and absolutely diabolical frame stiffness (from a true ladder frame!). Which rather neatly blows your theories about both the stiffness of the ladder fame and the importance of chassis stiffness to handling clean out of the water!
b) Airflow does not seem to be a major factor in its success. I've known narrow-bodied cars with no diffusers use Mumford links to great advantage. Most drivers report that the major advantage it offers over a Watts Link or Panhard Rod is better traction out of slow corners. This is a function of its influence on diagonal weight transfer, not aerodynamics.
b) I'm confused...why would making 'claims' about roll centre location (or making claims about anything?!) make a car go faster or slower? This again demonstrates that you are too entrenched in theory. 'Claiming' that a car has a low roll centre will have no more effect on its lap time than 'claiming' that it has more horsepower than it really has.
There is a point at which theory has to give way to demonstrable reality...
6) You repeatedly use the example of one very poor spaceframe design to justify the comment that most spaceframes are incapable of surpassing the stiffness of a x-braced ladder frame.
I'm sorry, but to me and presumably many other people reading your posts, it sounds exactly like you are saying that a ladder frame is better than a spaceframe.
This is misleading and incorrect.
I could apply the same logic to demonstrate that in comparison to the original Austin Seven chassis, it is clearly obvious that damp spaghetti stuck together with blu-tack is the way forward in cutting-edge chassis design.
Seriously...forget the Locost chassis. Don't waste your time trying to improve it - it has critical flaws with suspension geometry, even if you manage to improve the stiffness to an acceptable level.
I would genuinely love to see what you could come up with as a chassis design using a clean sheet of paper instead of plagiarising and fudging a badly executed copy of a 50 year old design concept.
It's difficult to say this on an internet forum without sounding antagonistic, but really, if you think you are capable of pushing forward the state-of-the-art, then for heaven's sake stop talking about it and put the theory into practice! I'm not being sarcastic in saying that I really would like to see what you could come up with!
>> Edited by Sam_68 on Monday 10th October 22:39
An excellent thread this one - I can only agree with the comments so far about the very real lack of design talent being applied to kit car bodywork.
Now what I want to know is this - The automotive design school in Coventry ( + RCA etc..)must have numerous students and graduates who have sculptural design flair by the bucketload. Many of them are hunting for their big break and must be aiming to be involved with creating a real car.
These designers have a UK car industry on their doorstep badly in need of aesthetic design to compliment some outstanding chassis engineering.
Why on earth are the two camps not making more of each other?
Now what I want to know is this - The automotive design school in Coventry ( + RCA etc..)must have numerous students and graduates who have sculptural design flair by the bucketload. Many of them are hunting for their big break and must be aiming to be involved with creating a real car.
These designers have a UK car industry on their doorstep badly in need of aesthetic design to compliment some outstanding chassis engineering.
Why on earth are the two camps not making more of each other?
cymtriks said:Styling and prototyping for low-volume vehicles. All offered from a lets-get-you-more-sales point of view, but very little interest, unless done for free.
Out of curiosity D-Angle what services were you offering?
Someone else mentioned the amount of car design graduates available - part of our service is sourcing and managing these guys, as a trained designer myself I can sort between pretty drawings and good design(there's a BIG difference - don't forget graduates came up with the FBS Census!) and match suitable designers to a project, eg if you like Renault's stuff, we'll get a guy who did his placement there etc. They're part of a big network we manage, and also includes prototypers etc. A lot more difficult to sell to kit builders than you would think! cymtriks said:Still quite a skilled job, and labour-intensive. Also, if there's something you don't like when you see it in the flesh, it's a right royal pain to change. This is where clay modelling(another part of the network we have been trying to market) comes into its own - just melt it, scrape it back and start again.
I'd be interested in thoughts on-
1)Making a one off alloy body and taking moulds off that. This was apparently done for the Caterham 21 as it was cheaper and faster than making a traditional buck.
cymtriks said:Obviously the milling is expensive as you've said, also there's the cost of the CAD work. However, since it needs finishing by hand anyway, I've always thought it would be more practical to just hack the basic shape out of foam and put clay over it, and go from there.
2)Using the DP cars ( check their website - an amazing project) approach of milling the buck out of foam coated with a hard surface. Mill to a near finished state, do the last preparation by hand and take moulds. The machining costs a lot (I'd like to know how much!) but the process gets you very close to finished very quickly.
Some people have had some good results producing bodywork by using sheet metal from exisiting cars. By cutting out parts with the desired lines and hammering and welding it together, you can do reasonably well.
This is really interesting
I've designed a chassis that I will be building next year, I'll be tracking it with very rough body work before even thinking about final bodywork, just in case it's a complete duffer
I'm interested in this thread becasue I fear I may fall into your description of a bloke that may make a "difference between a show stopper and another GRP jellymoulded turd."
However, the only reason I'd want to employ a designer is if they could make something more aerodynamically efficient, not necesarily more appealing. If you shoe me a design, the first thing I'll ask will be "how much does it weigh"
Do you design types have wind tunnels etc, do you (could you) work from a desigin in quite an advanced stage. Does "sculptural awareness" lead to a light fast body (the only 2 criteria I'm interested in (IMHO if you design something to excell in a specific area it almost always has an inbuilt beauty anyway))
And the bottom line
How much would it cost, bearing in mind, I can (and would like to) do all the tedious things like doing the aero calculations, do all the filler work laying up glass etc (I used to work in car refinishing so no point in paying someone to do that, I've never made wooden bucks but with a load of sections that should be well within my capabilities)
I've designed a chassis that I will be building next year, I'll be tracking it with very rough body work before even thinking about final bodywork, just in case it's a complete duffer
I'm interested in this thread becasue I fear I may fall into your description of a bloke that may make a "difference between a show stopper and another GRP jellymoulded turd."
However, the only reason I'd want to employ a designer is if they could make something more aerodynamically efficient, not necesarily more appealing. If you shoe me a design, the first thing I'll ask will be "how much does it weigh"
Do you design types have wind tunnels etc, do you (could you) work from a desigin in quite an advanced stage. Does "sculptural awareness" lead to a light fast body (the only 2 criteria I'm interested in (IMHO if you design something to excell in a specific area it almost always has an inbuilt beauty anyway))
And the bottom line
How much would it cost, bearing in mind, I can (and would like to) do all the tedious things like doing the aero calculations, do all the filler work laying up glass etc (I used to work in car refinishing so no point in paying someone to do that, I've never made wooden bucks but with a load of sections that should be well within my capabilities)
Sam_68 said:
1) The Locost chassis is an abortion. Please stop using it as an example of spaceframe chassis design.
I only use this as an example because it is so well known. Anyone can get the chassis plans from a book shop or library. This means that if I describe how this chassis can be improved everyone has a fair chance of understanding what I'm saying. I make it quite clear that this chassis can be greatly improved in most of my posts on lowcostbuilders.co.uk which is the whole point of most of my posts there. See my kitcaranalysis.doc! Most kit car spaceframes aren't much better, remember that the kit market isn't dominated by Radical etc, it's dominated by Locost/Westfield copies and Cobra replicas.
Sam_68 said:
2) Spaceframes can be fully triangulated, certainly (possible if you take triangulated bays out around either side of the cockpit, and/or use the patented Costin design of triangulated transverse bays to form the seat structures), though you don't need full triangulation to justify the 'spaceframe' label. A spaceframe is simply a frame which encloses space...in other words a three dimensional structure of (usually) tubes. The description of it as a fully triangulated structure which is capable of remaining rigid even if all tube intersections are pin-jointed is merely a superimposed definition applied by the more anally retentive and perfectionist structures freaks.
True, but somehow you seem to be very rigid (no pun intended!) about the definition of a ladder frame but somewhat more, erm, flexible about the definition of a spaceframe.
Sam_68 said:
Audi engineers call the 3D alloy frame structure underneath the A8 a 'spaceframe' and Lotus apply the same label to the alloy chassis of the Elise.
Personally, I'd say that the Audi chassis is closer to your ladder frame with 3D bracing (it even has diagonal floor pan members approximating to your X-bracing), and the Elise frame is closer to a deep section twin-tube/ladder frame or a monocoque 'tub' clad in non-structural body panels, but then who am I to argue with the engineers from two such eminent companies?
You've come to the same conclusions that I've come to on these examples! Or perhaps you've just read kitcaranalysis where I say almost exactly what you've just said. I reckon Lotus and Audi know perfectly well that there is a significant aspect of ladder frame in their designs, they just don't want to say so! (Marketing I suppose)
Sam_68 said:
3)You would suggest that in the real world a ladder frame can have some degree of 3D structures? I'm sorry, I disagree. By that definition, all current 750 Club chassis are ladder frames...they all retain the vestigial bottom rails of an Austin 7 ladder chassis. Is the majority of their stiffness derived from the ladder frame? I think not...If a substantial part of the stiffness is derived from 3-dimensional additions, then it ceases to be a ladder frame, in my book.
My comment about rigid and flexible opinions again! I think you sum it up very well, The ladder frame bit is vestigial in a 750 club car.
As I said earlier very few structures conform exactly to one type. I base my descriptions on how most of structure behaves and how most of structure gains its stiffness.
Sam_68 said:
4) Are you saying that
Ah, how difficult it is to convey a meaning sometimes over the internet. I actually ment
the other way... which would be no to the above! I suppose that once the chassis stiffness has exceeded the suspension stiffness by an order of magnitude then it's time to stop. Sam_68 said:
5) Like I said, all designs are compromises, so no one feature can be said to be responsible for the success or otherwise of a competion car, but..
a) Relative roll stiffness front to rear is critical to a car's handling.
b)The Sylva rear suspension (which effectively uses the suspension bushes and axle tube to act as a large anti-roll bar) has a large influence on the weight transfer characteristics of the Sylva. I've spoken to Jeremy Phillips on this subject, so I know that this was a calculated aspect of the car's suspension design and not an accident.
Therefore...
c) I think it's fair to say that, yes, to some extent it's because of the rear suspension design, rather than in spite of it, that the car is successful.
I never thought it was deliberate! Hard to tune though. You're stuck with the rubber bushes acting as an anti roll bar. Also as the bushes wear you'll have to keep twiddling the front roll bar to compensate, in theory, in practice you may not notice.
Sam_68 said:
6) The Mumford link gives a very high level of rear roll stiffness - though this is not quite the same as saying that it prevents roll.
a) Yes, it provides a sprung suspension in compliance with the rules...an interesting comment, in that it tacitly acknowleges the fact that karts are capable of very high performances with no 'suspension' at all and absolutely diabolical frame stiffness (from a true ladder frame!). Which rather neatly blows your theories about both the stiffness of the ladder fame and the importance of chassis stiffness to handling clean out of the water!
b) Airflow does not seem to be a major factor in its success. I've known narrow-bodied cars with no diffusers use Mumford links to great advantage. Most drivers report that the major advantage it offers over a Watts Link or Panhard Rod is better traction out of slow corners. This is a function of its influence on diagonal weight transfer, not aerodynamics.
b) I'm confused...why would making 'claims' about roll centre location (or making claims about anything?!) make a car go faster or slower? This again demonstrates that you are too entrenched in theory. 'Claiming' that a car has a low roll centre will have no more effect on its lap time than 'claiming' that it has more horsepower than it really has.
I thought that the roll centre bit of the story was a smoke screen for the real improvement, i.e. that it permitted a level and closely conroled underbody surface for airflow under the car while stil permitting a sprung suspension.
Your comment about narrow bodied cars casts doubt on this, though it may still have been the original intent.
Yout comment that it makes a flexible car behave more like a cart is interesting...
Sam_68 said:
6) You repeatedly use the example of one very poor spaceframe design to justify the comment that most spaceframes are incapable of surpassing the stiffness of a x-braced ladder frame.
I'm sorry, but to me and presumably many other people reading your posts, it sounds exactly like you are saying that a ladder frame is better than a spaceframe.
This is misleading and incorrect.
That's not what I'm saying, I'm pointing out that many spaceframes are much less than they could be to the extent that ladder frames are actually better, which is a shame, while at the same time, using Locost as an example, indicating how they could be improved.
Sam_68 said:
Seriously...forget the Locost chassis. Don't waste your time trying to improve it - it has critical flaws with suspension geometry, even if you manage to improve the stiffness to an acceptable level.
Out of curiosity what stiffness do you think a Seven style of car should have? And how would you improve the suspension geometry, I've never looked at this aspect of the book design other than to do enough to decide that I didn't want to copy it!
Sam_68 said:
I would genuinely love to see what you could come up with as a chassis design using a clean sheet of paper instead of plagiarising and fudging a badly executed copy of a 50 year old design concept.
It's difficult to say this on an internet forum without sounding antagonistic, but really, if you think you are capable of pushing forward the state-of-the-art, then for heaven's sake stop talking about it and put the theory into practice! I'm not being sarcastic in saying that I really would like to see what you could come up with!
I'd love to see it too! Space and funds are somewhat limiting at the moment.
If I do get round to building my own design it would probably be fairly standard in some respects, i.e. spaceframe, double wishbone suspension, traditional styling, etc. For a long time I schemed away at a hybrid chassis with ladder, monocoque and spaceframe aspects which had some atractive plus points.
Regarding a race car I schemed away at something very similar to the dp cars project for a while. Check out the dp cars website, a superb build diary.
Have you got any ideas for your own cars? I have put the styling concepts for mine on the styling/design thread a while back.
I have only one comment about kit car aesthetics & "design" (stylist) graduates:-
Compare a GTM Libra / Spyder, with any current BMW.
Compare a Sylva Phoenix / Fury / Stylus, with any current Fiat.
The Kit Car industry has produced more than it's fair share of ugly cars, but spending money-by-the-bucketful on stylists is certainly no guarantee of visual appeal either.
But then I guess that you'll know from the account name where I'm coming from.
I've got two kit cars, one space frame, the other ladder - both good fun - something seriously lacking in the mainstream.
Compare a GTM Libra / Spyder, with any current BMW.
Compare a Sylva Phoenix / Fury / Stylus, with any current Fiat.
The Kit Car industry has produced more than it's fair share of ugly cars, but spending money-by-the-bucketful on stylists is certainly no guarantee of visual appeal either.
But then I guess that you'll know from the account name where I'm coming from.
I've got two kit cars, one space frame, the other ladder - both good fun - something seriously lacking in the mainstream.
Fury 1630
I'm sure that you are aware that the GTM Libra, was designed by a real designer/stylist (Richard Oakes), and that most production cars are approved by management more than the designer themselves.
The designer creates a new model, using as a brief parameters coming from Marketing, Engineering, and others.
Sometimes things get messed up and you do get cars designed that look like s..t !, but sometimes you get gorgeous looking cars like Aston Martin DB9.
I'm sure that you are aware that the GTM Libra, was designed by a real designer/stylist (Richard Oakes), and that most production cars are approved by management more than the designer themselves.
The designer creates a new model, using as a brief parameters coming from Marketing, Engineering, and others.
Sometimes things get messed up and you do get cars designed that look like s..t !, but sometimes you get gorgeous looking cars like Aston Martin DB9.
Incorrigible said:www.mira.co.uk , there are some software packages you could try as well. Us design types tend to be given a chassis and asked to clothe it, so if that's what you mean by an advanced stage, yes.
Do you design types have wind tunnels etc, do you (could you) work from a design in quite an advanced stage.
Incorrigible said:To be honest, this is more or less exactly what I'm talking about in my previous post. While you may ask "How much does it weigh", are you going to buy 100 cars a year? Please, please don't take this offensively, but if you just want to make one body for your chassis and have it as your personal car, then you wouldn't need a designer. However, if you want to sell your car to other people, please bear in mind that you are currently talking about engineering and aerodynamics in the same way many failed kit producers do. If you just intend to market it as a track car that's fine, if you want people to buy it for other purposes, it isn't. Read this thread for a very good example of some great engineers on a hiding to nothing:
However, the only reason I'd want to employ a designer is if they could make something more aerodynamically efficient, not necesarily more appealing. If you show me a design, the first thing I'll ask will be "how much does it weigh"
Do you design types have wind tunnels etc, do you (could you) work from a design in quite an advanced stage. Does "sculptural awareness" lead to a light fast body (the only 2 criteria I'm interested in (IMHO if you design something to excell in a specific area it almost always has an inbuilt beauty anyway)
www.pistonheads.com/gassing/topic.asp?f=57&t=148551
Incorrigible said:We have quoted £12,500 for design and styling work, materials and a clay model ready to take moulds from - that was a 7-shape sports car, so there were less materials involved. Cars with more bodywork would cost more.
How much would it cost, bearing in mind, I can (and would like to) do all the tedious things like doing the aero calculations, do all the filler work laying up glass etc (I used to work in car refinishing so no point in paying someone to do that, I've never made wooden bucks but with a load of sections that should be well within my capabilities)
D-angle said:
To be honest, this is more or less exactly what I'm talking about in my previous post. While you may ask "How much does it weigh", are you going to buy 100 cars a year? Please, please don't take this offensively, but if you just want to make one body for your chassis and have it as your personal car, then you wouldn't need a designer. However, if you want to sell your car to other people, please bear in mind that you are currently talking about engineering and aerodynamics in the same way many failed kit producers do. If you just intend to market it as a track car that's fine, if you want people to buy it for other purposes, it isn't.
By "design" what exactly do you mean? This word covers a multitude of sins!
To most people I suspect design means styling.
To some it means specialist knowledge technical stuff like aerodynamics and suspension design, or my own speciality, FEA.
To others it means thinking about the implications of making something to the right spec, including complying to any regulations, at the right price.
I suspect that by failed kit car companies you mean that they never paid much attention to the latter!
cymtriks said:Sorry, that wasn't very clear. By design I mean styling and ergonomics. I tend to use 'engineering' for alost everything else.
By "design" what exactly do you mean? This word covers a multitude of sins!
To most people I suspect design means styling.
To some it means specialist knowledge technical stuff like aerodynamics and suspension design, or my own speciality, FEA.
To others it means thinking about the implications of making something to the right spec, including complying to any regulations, at the right price.
I suspect that by failed kit car companies you mean that they never paid much attention to the latter!
By failed kit car companies I mean they never paid much attention to Joe Public. I remember the threads involving the builder of the FBS Census - "It's ugly." Yes but its got great engineering." "But no-one's buying them." "But they should, it's got a class-leading chassis." "Please change the car, some of us would buy it if you did what we recommend." "It doesn't need to change, the engineering is first class. I would buy one in a second."
I've always wondered how many kit car manufacturers read these threads, and more importantly, how many act on what they read. Let's face it, these forums are some of the best free market research for the motor industry you could find!
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