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Smokey's JW4 Formula Four Rebuild Thread


Mark (smokey mow)

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Mark (smokey mow)

Many of the regular readers will know that one job I've been delaying for well over a year now has been the roll bar.  I've lost count of how many times I've drawn this, then made mock-ups in foam board and plastic pipe to try and find a solution that is both functional and aesthetic.

 

The problem is that the original roll hoop on the JW4 was 3/4" diameter tube with a couple of basic braces as a token gesture to add some stiffening.  Those of you who are active in sprinting on may read the uphillracers forum will also be aware that roll bars on single seaters have been receiving quite a lot of scrutiny recently from the MSA as there are several cars competing with roll bars that don't comply with the MSA's regulations which has been causing some embarrassment to manufacturers and issues for those who unwittingly bought their cars thinking they complied fully with MSA safety regulations.

 

To ensure I have a compliant roll bar the MSA blue book mandates that it should have a tube diameter of 42.4mm and no bends within the legs.  That though posed a big problem for me as I not only wanted to try and re-use as much as possible the original holes in the bodywork but also I wanted to use a tube diameter that was aesthetically within keeping of the cars diminutive size.

 

I looked at various designs and mounting points and options but none would allow me to end up with a design I was happy with. I wanted to try and end up with a design similar to this on Bob Dustan's old JW4;

 

walkerside2.jpg

 

But unfortunately for me the MSA Blue Book would only allow me something more like this on Mike Combrink's JW4.

 

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Mark (smokey mow)

Not being happy with the option that the MSA blue book presented me with I had one alternative and that was the complex and costly route of Homologation. This decision was not taken lightly; its complex, time consuming and very costly for a "one off" but it would however enable me to have a design that was unique and outside of the blue book limitations.

 

The following document outlines the MSA procedure for homologating the roll structure. 

MSA NATIONAL ROPS HOMOLOGATION GUIDELINES.PDF

 

The first stage was to formally submit an application to the MSA and obtain an agreement in principle for the proposal after which I would be issued a unique Homologation number. Because of the volume of car manufacturers that were applying for homologation the MSA had agreed to wave their £340 application fee for any applications made before Christmas so that was one bonus cost saving for myself.

 

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Mark (smokey mow)

The documents were duly submitted to start the process and once agreement in principle had been obtained the next hurdle would be to obtain a calculation report from MIRA for the proposed design.  Sadly MIRA were not being as generous as the MSA in waving their fees but luckily my past experience as a design engineer came in useful here as I was able to produce the 3D IGS Models they need to undertake the simulation as else I would have been charged extra for them to model it from drawings.

 

Verney.png

 

The 3D models are loaded into their stress analysis software and from this 3-loads are applied simultaneously in different directions to simulate the effects of a severe accident and impact on the crash structure.  For a car of less than 470kg the loads applied are13.2kN laterally, 49.5kN Longitudinally and 66kN Vertically The MSA technical guidelines allow for a maximum deformation of 50mm and thankfully my design passed with a maximum of 13.5mm.

 

HORIBA%20MIRA%20Report%201213616%20Johnn

HORIBA%20MIRA%20Report%201213616%20Johnn

HORIBA%20MIRA%20Report%201213616%20Johnn

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Mark (smokey mow)

Having successfully completed the simulation the next stage would be to have a roll bar made.  To save time I actually took a chance and ordered this before Christmas whist MIRA were still doing their simulation, it was a gamble to take but I had confidence in my design and it also allowed me to save several weeks in the process. In fact Martin at MJS Fabrication turned this around in only 1-week for me.

 

87C965C0-6A14-4D0D-808D-EE8529EEC432.jpg

 

The final step once all that is completed its time to submit the application formally to the MSA for certification. The application document itself that needs to be prepared consists of 6 pages of details and questions.  This includes various drawings of the roll bar structures from various angles, details of the attachment method, component weights, material specifications for the steel tube.  The last two pages are reserved for a series of photographs of a fully assembled roll bar showing the bar fitted to the car at various angles, the different connections and attachments and also the location and details of the unique ID plate.

 

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UK0098-6.jpg

 

As one can also never have enough stickers I had to get a stack of 80 metal stickers printed up for the ID plates (that being their minimum order :d ) That should leave me with a few spares since Johnny Walker only ever made 56 cars in total :d

 

DSC_0782.jpg

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Mark (smokey mow)

Bringing this thread up to date the whole lot was completed and emailed off to the MSA 2-weeks ago for their final approval and now I'm pleased to say that todays post brought me a pack containing the signed Homologation Documents.

 

It hasn't been the easiest journey to get to here, and the process in total took about 3-months to complete.  I'm sure a car manufacturer with experience in making applications could have done it in half the time, but I'm glad I did it as I now have a roll bar which to me is much more in keeping with the diminutive scale of the car than that which the MSA blue book would have required from me. Also and equally as important I have a bolt-on solution which other owners of JW4's can adopt for their own cars if required.

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Nic (NICO) - Shropshire and Mid-Wales AO

Blimey Mark no one could accuse you of half measures!!

Keep up the good work. Looking forward to seeing the finished article. 

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Cleggy the Spyder Man

top stuff m8

 

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Mark (smokey mow)
11 minutes ago, Nic (NICO) - Shropshire and Mid-Wales AO said:

Blimey Mark no one could accuse you of half measures!!

Keep up the good work. Looking forward to seeing the finished article. 

Thanks Nic, I just figured that for something which would affect the look of the car so dramatically it was worth spending the money to have it the way I wanted.

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Stirling work as always Mark :t-up:

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Kit Car Electronics

No wonder we haven't seen you out and about for ages - top effort!

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Dave Eastwood (Gadgetman) - Club Secretary

Wow. Congratulations for sticking with it and getting what you wanted.

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Well done Mark - that shows it can be done but what an effort (and would any individual without the contacts or your background be able to do it - I doubt it)

Having raced (Monoposto) and sprinted my old Jedi I'm still interested in how they're getting on as I often think of returning to the sport - but the MSA appear to be killing off cars such as the Jedi. If ROPS wasn't enough, it looks like they have now banned any car where the heel of the foot is in front of the front wheel axis. As far as I can see that's all Sprints and Hillclimbs, Monoposto and any other "open" single seater classes (Formula Jedi itself seems to have been exempted though ???)

I know we always have to consider safety but I don't believe anyone has even been mildly hurt in a Jedi since their inception 1984 !!

You would have thought that the MSA would have exempted vehicles manufactured (or even designed) prior to 2016/2017 from these new regulations - but no, something else seems to be at work with the MSA (some say it's down to circuit insurance / possible litigation). It's certainly put me off thinking of competing with a Jedi again and tbh even the Westfield :down:

Sorry to hijack the thread for a moan :oops:

Colin

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Mark (smokey mow)
2 hours ago, tisme said:

You would have thought that the MSA would have exempted vehicles manufactured (or even designed) prior to 2016/2017 from these new regulations

Why should they? These regulations have been inplace and haven't been changed for over 30 years now. 

I also doubt the MSA's insurers would be to willing to provide event cover for them allowing vehicles to run than do not meet the established and minimum safety regulations.

the MSA are not blameless but they certainly are not wholely resonsible either, their new vehicle passport system has simply highlighted that there is a lot of cars that they have allowed to compete up to now that do not meet the safety regulations.

there are also the car manufactuers that have known the ROPS regulations for years but have chose for different reasons to ignore and overlook these when releasing new models.

And finally there is the owners who are the one that carry the legal responsibility for ensuring their cars when presented at an event comply with the rules and regs.

 

Regarding feet forward of the front axle centreline this is nothing new and has been in the Blue Book since 2000.  cars constructed prior to 1999 or that have taken part in a FIA championship before that date are exempted from that requirment.

 

 

 

 

 

 

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alexander72

superb - interesting you can have a bolt at the top but a rose joint is banned still? 

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