Design Challenge 2010
Discussion
The Challenge
The challenge is to improve the safety of Kit cars, both active and passive. This is a brainstorming thread, wacky ideas are perfectly acceptable. I will add some heading, but feel free to add more.Side Impact Protection
- Side impact bar
- GRP/kevlar sill moulding (eg. Sylva Phoenix style) filled with rigid foam.
Rear Impact Protection
- Crumple zone
- Move fuel tank within 'cage' formed by roll bar back stays.
- Bumpers
Frontal Impact Protection
- Crumple zone
- Bumpers
Offset Impact Protection
- ?
Roll-over Protection
- Roll hoop
- Low CoG
Low Visibility/Road presence
- Paint in fluorescent yellow/orange
- Fit 'pylon' with flashing beacon on top
Material Failure
- Poor fatigue resistant materials - Avoid
Edited by DozyGit on Monday 19th July 18:26
Edited by DozyGit on Monday 19th July 18:26
Side Impact Protection
- GRP/kevlar sill moulding (eg. Sylva Phoenix style) filled with rigid foam.
Rear Impact Protection
- Move fuel tank within 'cage' formed by roll bar back stays.
- Bumpers
Frontal Impact Protection
- Crumple zone
- Bumpers
Low Visibility/Road presence
- Paint in flourescent yellow/orange
- Daytime running lights/headlamps wired 'on' whenever engine is running.
- Fit 'pylon' with flashing beacon on top (not an original idea - Frank Costin offered this as an optional extra on the Costin Amigo, back in the '70's)
Material Failure
- erm... design it right?
Edited by Sam_68 on Monday 19th July 18:25
O/P where are you coming from on this?
You have set out what appears to be an arbitrary set of criteria without any background. Are you looking help with a thesis, or is there a set of statistics that indicate a vulnerability of 'kit cars' in a particular area?
One could add all sorts of impact protection, and end up with a safety cell/ impact protection structure that by it's weight negates the point of the car itself.
I know that's going to absurd lengths, but you should indicate what other design parameters would still be important. Or are you just looking for the safest possible kit car?
You have set out what appears to be an arbitrary set of criteria without any background. Are you looking help with a thesis, or is there a set of statistics that indicate a vulnerability of 'kit cars' in a particular area?
One could add all sorts of impact protection, and end up with a safety cell/ impact protection structure that by it's weight negates the point of the car itself.
I know that's going to absurd lengths, but you should indicate what other design parameters would still be important. Or are you just looking for the safest possible kit car?
Thanks for the contribution.
I plan on designing and building my own kit, when funds permit of course.
One of the things that put people off kit cars is of course safety, and there are many approaches to it,good design or stick after thoughts. While safety may seem trivial in the future it would be critical if the industry were to survive.
My hope is that we build a resource where future builders/designers can tap off the knowledge, hopefully a sticky thread, and update the original post with ideas.
I believe safety to the home builder mustn't be an expensive knowledge, but shared amongst all builders for the betterment of the industry.
I am not asking this for a thesis, I am a qualified mechanical engineer for the past 12 years or so and this is just a hobby of mine. Obviously I would be happy for anyone to write a thesis on this if they wanted to as it would be free knowledge :-)
I plan on designing and building my own kit, when funds permit of course.
One of the things that put people off kit cars is of course safety, and there are many approaches to it,good design or stick after thoughts. While safety may seem trivial in the future it would be critical if the industry were to survive.
My hope is that we build a resource where future builders/designers can tap off the knowledge, hopefully a sticky thread, and update the original post with ideas.
I believe safety to the home builder mustn't be an expensive knowledge, but shared amongst all builders for the betterment of the industry.
I am not asking this for a thesis, I am a qualified mechanical engineer for the past 12 years or so and this is just a hobby of mine. Obviously I would be happy for anyone to write a thesis on this if they wanted to as it would be free knowledge :-)
Sam_68 said:
DozyGit said:
One of the things that put people off kit cars is of course safety
In that case, the first thing you need to do is to teach people the difference between primary safety and secondary safety.I have added your contributions, most appreciated :-)
The problem about current road safety is all of the electronic safety devices like OOPS ( occupant out of position sensors) and electronic advanced braking along with multi axis sensors and airbags. This means that you need a degree in electrical engineering before you can look at any of these systems. Therefore they are impossible to implement into the kit car Market. The only way of doing this would be to have a company fit these things for you. The only other alternative is adding collapsable structures and strengthening beams, but this adds a lot of weight and therefore makes the kit a "build your own pruduction car"
slomax said:
The problem about current road safety is all of the electronic safety devices like OOPS ( occupant out of position sensors) and electronic advanced braking along with multi axis sensors and airbags. This means that you need a degree in electrical engineering before you can look at any of these systems. Therefore they are impossible to implement into the kit car Market. The only way of doing this would be to have a company fit these things for you. The only other alternative is adding collapsable structures and strengthening beams, but this adds a lot of weight and therefore makes the kit a "build your own pruduction car"
I personally think the electronic safety devices can be added as a module, say the OOPS will probably available like a CAT 1 alarm or Tom Tom sat nav, so to me these are minor additions.The fundamental crash resistant structure need not be heavy, look at the smart car for instance, not bad for a production car of that size. The question is how ingenious can be Kit car manufacturers?
We can put in I beams and 120mm thick steel armour, but should we be doing that instead of using energy absorbing materials, composites etc, which can be worked at home, yet have superior overall performance? This is my challenge to all the PHers :-)
Paul Drawmer said:
DozyGit said:
....One of the things that put people off kit cars is of course safety, ...
Can you substantiate that?In my case, it didn't put me off. It was a considered risk which I accepted.
Even worse is when you talk to someone's OH, and it goes, my husband wanted to buy this Kit car, but I didn't let him as it is unsafe or my husband has xyz it's lovely but I won't get in or let the kids get in as it's a death trap.
The only way we can get increased buy is by making it fundamentally safe by design and advertising the fact why it is safer. Safety need not mean weight. How much does an F1 car weigh, but how safe is it?
DozyGit said:
slomax said:
The problem about current road safety is all of the electronic safety devices like OOPS ( occupant out of position sensors) and electronic advanced braking along with multi axis sensors and airbags. This means that you need a degree in electrical engineering before you can look at any of these systems. Therefore they are impossible to implement into the kit car Market. The only way of doing this would be to have a company fit these things for you. The only other alternative is adding collapsable structures and strengthening beams, but this adds a lot of weight and therefore makes the kit a "build your own pruduction car"
I personally think the electronic safety devices can be added as a module, say the OOPS will probably available like a CAT 1 alarm or Tom Tom sat nav, so to me these are minor additions.The fundamental crash resistant structure need not be heavy, look at the smart car for instance, not bad for a production car of that size. The question is how ingenious can be Kit car manufacturers?
We can put in I beams and 120mm thick steel armour, but should we be doing that instead of using energy absorbing materials, composites etc, which can be worked at home, yet have superior overall performance? This is my challenge to all the PHers :-)
You are right about the collapsable structures. The thing you have to bear in mind when designing is if you get damage on a production car, the garage remove the panel and replace it with a new one. the attraction with kit cars is that they are small, agile and light and if you make lots of room for intrusion they tend to get bigger. A lot of kit cars are very safe because they are very strong and very rigid. if you roll a production car, the roof support pillars will bend a lot, whereas a lot of kit car chassis will stay the same shape. There is more exposure to cockpit intrusion like logs and bits, but the rigidity is likely to be better. higher performance kit cars also tend to have 4 or 5 point harnesses too which offer the occupants better protection.
Pretty much all road cars that are tracked have roll cages fitted, improving crash safety. but what is a kit car chassis? most of them are already roll cages with bits attached, not the other way around.
I think it is a misconception by the general public that Kit cars are unsafe. People do not realise that they have to go through very stringent tests like the IVA and checked by VOSA before they are allowed on the road. The General public need educating. If they look safe, then they must be. but because kit cars are open and are very light they do not look safe, and therefore are deathtraps.
If you park up a GTM Libra (for example) next to a Caterham (for example) and ask an ignorant member of the public which they thought was safer, I bet they would say the Libra, because it has a "proper" body, even though there is probably not much in it between the two.
This is of course, my opinion and can not substantiate any of this with hard facts.
A composite bodyshell is very energy absoding to start with. A molded in foam filled sill at the top of the door (yes, at the top, a sill running along the top of the door!) would help soak up some impact energy.
Crumple zones could be added to the front by using a radiator and air ducting as a collapsable structure. This wouldn't add much weight, some cars might actually save weight by requiring a smalled sized radiator with ducting.
A basic steering wheel air bag might be possible to fit.
Note
Making the chassis stronger (i.e. more rigid) might actually be the wrong thing to do for safety. A structure that gives a little will help absorb some of the impact energy and reduce the shock to the occupants.
Crumple zones could be added to the front by using a radiator and air ducting as a collapsable structure. This wouldn't add much weight, some cars might actually save weight by requiring a smalled sized radiator with ducting.
A basic steering wheel air bag might be possible to fit.
Note
Making the chassis stronger (i.e. more rigid) might actually be the wrong thing to do for safety. A structure that gives a little will help absorb some of the impact energy and reduce the shock to the occupants.
Interesting topic. I would have thought that bearing in mind the popularity of full harnesses in kits, a HANS device would be money well spent, but who is going to want to wear one? Side air-bags would surely be better use than a steering wheel one? And probably easier for the home builder to fit as a kit?
Since buying my seven I have been amazed at the structural integrity of the sevens and kits I have seen crashed.
Being shunted in the rear worries me more than crashing into something (apart from the back of a lorry god forbid) as the back arrangement of most sevens just looks less robust - I know it isn't - but it just doesn't look like it will take the beating the front does? Maybe a trick on the eye/mind of the distance between end of rear and driving position?
Since buying my seven I have been amazed at the structural integrity of the sevens and kits I have seen crashed.
Being shunted in the rear worries me more than crashing into something (apart from the back of a lorry god forbid) as the back arrangement of most sevens just looks less robust - I know it isn't - but it just doesn't look like it will take the beating the front does? Maybe a trick on the eye/mind of the distance between end of rear and driving position?
I'd stick my neck out and say a GTM Libra is FAR safer than a Caterham! Judging by some photos of the intact safety cell of a Libra after at least 3 wheels and the engine itself have departed company with the tub, I'd sat you'd need and Apache gunship to kill a Libra's occupents! But a Caterham with a full cage and 5 point harnesses is also quite a safe place to be.
A kit car with steel chassis, FULL substantial rollcage, crash structure around the FiA fuel cell, painted flourescent yellow with 5 point harnesses and agility to lessen the likelyhood of crashing in the first place. Pretty much everything you can't do with a production car! Could you imagine how safe the worlds roads would be if every vehicle incorporated a steel rollcage, ALL seatbelt front and back were 4 point harnesses and car would not move unless all were being used, and occupents wore Helmets! That's why I feel quite safe in my kitcar.
slomax said:
If you park up a GTM Libra (for example) next to a Caterham (for example) and ask an ignorant member of the public which they thought was safer, I bet they would say the Libra, because it has a "proper" body, even though there is probably not much in it between the two.
The Caterham would need a substantial cage to be in the same league, I reckon.Gassing Station | Kit Cars | Top of Page | What's New | My Stuff