Mark Posted December 10, 2019 Share Posted December 10, 2019 I remember reading an article, probably late eighties, about fitting a swaged sheet metal panel between the boot and hood storage compartment on a Vitesse convertible in place of the fibre board. If it was securely attached to the edge of the rear deck, top of the spring tunnel and inner arches, I wonder how much rigitity it would add to the tub, if any? Link to comment Share on other sites More sharing options...
Nick Jones Posted December 10, 2019 Share Posted December 10, 2019 In the context of torsional stiffness of the tub at least, that is not the problem area. The (main) problem area is between the doors. Link to comment Share on other sites More sharing options...
JohnD Posted December 10, 2019 Share Posted December 10, 2019 (edited) John Thomason wrote an article for the Courier about testing chassis stiffness on the Spitfire, and deisgned a simple structure to improve it. The article appeared in Issue 273 (March 2003) from page 54. The structure looks like this: He also fitted a plate to the chassis rails, similar I think to the "T-shirt" plate often added to a TR6 chassis: The combined effect of these was found to significantly improve chassis stiffness: But I would suggest, with no evidence at all, that a full roll cage will do better than that, as well as providing the statutory protection if you wish to compete. No harm in belt and braces, though - the weight penalty of the Thomason stiffening cannot be great. John Edited December 10, 2019 by JohnD Link to comment Share on other sites More sharing options...
Mark Posted December 10, 2019 Share Posted December 10, 2019 I would like to fit a roll cage to the Vitesse just to stiffen everything up, but for a convertible, predominately road car, there's not a lot or room if you still want to use the soft top, frame and rear seat. The one's I saw fitted back in the day, probably 'Ally Bars,' I think just bolted to the floor, front and back, and rear wheel wells.That would protect the driver and add stiffness to the tub, not sure how much it would help with the chassis flex and twist unless it was connected in some way to the chassis also. I have seen a rear roll bar fitted to a Herald and Vitesse convertible, not sure who made them, two hoops welded together, think they mounted to the rear floor and wheel wells, no diagonal. Something like that may work if door bars were also fitted, sloping from the rear hoop down to the front tub chassis mounting along the side of the front seats. Something I've been contemplating. Link to comment Share on other sites More sharing options...
richy_rich Posted December 10, 2019 Share Posted December 10, 2019 1 hour ago, Mark said: not sure how much it would help with the chassis flex and twist unless it was connected in some way to the chassis also. It stiffens the tub, which is in-turn connected to the chassis. When I first started racing I only had a rear hoop, at some point after seeing a few cars upside down everyone pretty much decided that we needed a full cage and after fitting one the difference was huge and immediately noticeable (despite the weight penalty). A full cage (especially with door bars) would be completely unpractical for a road car however (and probably legally dubious, depending on your country/insurance etc.) Those 't-shirt' plates are probably a good idea and bolting them to the chassis would be fine IMO. It might be worth considering bolting the tub to the chassis in a few more places than it originally was as well, based on nothing but hand-wavey thinking but the tighter you can get it all the less likely it is to be able to twist. (Of course, you might just find that now your tub starts cracking... ) Link to comment Share on other sites More sharing options...
JohnD Posted December 10, 2019 Share Posted December 10, 2019 I thnink youare mistaken, Richy, about the legality of a roll cage or door bars for road use in the UK. Stage rally cars have to be equipped with FIA acceptable roall cages, that use triangulated boor bars, and as they drive from stage to to stage, have to be UK road legal, in every respect. Here's Malcolm Wilson showing off one of his Fords: Originally, the tub is fixed to the chassis by some large washers andrugger grommets. Leave out, or replace the grommets with solid aluminium discs and the connection is quite tight. Mark, A rear roll hoop without a diagonal is significantly inferior in protection! So much so as that the diagonal is essential for competion use. John Link to comment Share on other sites More sharing options...
Mark Posted December 10, 2019 Share Posted December 10, 2019 Hi john Yes I know a roll bar with diagonal is definitely the way to go, and a hoop on its own is a compromise if i still want occassional use of the back seat. Not sure what i am going to do yet. I have a new full roll cage with door bars to fit to my mk3 Spitfire when I've restored it. I intend to use it on the road and the odd track day, so will check with the insurance before I fit it. Link to comment Share on other sites More sharing options...
richy_rich Posted December 10, 2019 Share Posted December 10, 2019 33 minutes ago, JohnD said: I thnink youare mistaken, Richy, about the legality of a roll cage or door bars for road use in the UK. Probably, I haven't been in the UK for a loooong time now But I did say depending on your country - the police here in Luxembourg bought some of new Teslas and they couldn't get them road legal for nearly a year because they were never homologated with flashing lights.. https://delano.lu/d/detail/news/tesla-electric-cars-now-lux-highway-patrol/187192 Link to comment Share on other sites More sharing options...
JohnD Posted December 11, 2019 Share Posted December 11, 2019 (edited) Mark, Roll bars with removeable diagonal bars are available. This is for a Mini: https://www.plminishop.com/Classic_Mini_Performance_and_Rally/7103/SAFETY_DEVICES_REAR_ROLL_CAGE_(REMOVABLE_DIAGONAL).html Tlak to Safety Devices: http://www.safetydevices.com/ OR, if you are in the North, to Protection& Performance: http://www.ppcages.com/ who have done bespoke work for me at very reasonable prices. You may find that insurers have strange 'rules'! I rang a well-known company to insure my road legal racer. Bigger engine (2.5L), Pi, disc brakes all round, roll cage, only one seat, stripped out trim - all fine, Sir! No rear seat (in a Vitesse)? Oh, no, Sir! We couldn't possibly insure that! Richy, Continental rules on build and roadworthyness are very different to those in the UK. But you will know better than I! I believe that Triumph mods such as the popular CV jointed rear transmission, or fuel injection would be forbidden, and that everything must be as Historic. John Edited December 11, 2019 by JohnD Link to comment Share on other sites More sharing options...
Nick Jones Posted December 11, 2019 Share Posted December 11, 2019 CV jointed rear not a problem judging by the number of kits I sold to Germany. EFI, yes, that’s a problem - unless heavily disguised as Webers ....... Link to comment Share on other sites More sharing options...
ahebron Posted January 4, 2020 Share Posted January 4, 2020 Cooking tea and thinking about the Vitesse. Would an 'H' similar to the ones on the GT6 and Spitfire between the floor and bulkhead be of any use, apart from somewhere to put a radio and speaker. Adrian Link to comment Share on other sites More sharing options...
Nick Jones Posted January 4, 2020 Share Posted January 4, 2020 Maybe...... but the Vitesse bulkhead doesn't have the metal dashboard structure so you'd have to go all the way back to the screen surround...... Also, our recent tests suggest that 2/3 of the problem lies behind this. Link to comment Share on other sites More sharing options...
NeilR Posted March 19, 2023 Author Share Posted March 19, 2023 It's been a long time between updates on the Herald Special we call 'Tempest' We had planned this adaption to add stiffness: But we have simplified the design a little in the tunnel. The engine is now 6" further back and 1.5: lower. More has been done, but will provide a better set of pics later if anyone is interested. Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted March 19, 2023 Share Posted March 19, 2023 1 hour ago, NeilR said: More has been done, but will provide a better set of pics later if anyone is interested. Oh yes please 1 Link to comment Share on other sites More sharing options...
Nick Jones Posted March 19, 2023 Share Posted March 19, 2023 5 hours ago, Escadrille Ecosse said: Oh yes please +1 1 Link to comment Share on other sites More sharing options...
Nick Jones Posted March 19, 2023 Share Posted March 19, 2023 In case you haven't seen this already..... https://sideways-technologies.co.uk/forums/applications/core/interface/file/attachment.php?id=11927 It's a mk 2 chassis and our scope was a little different from yours so not totally relevant - but maybe still interesting. I did discuss your wooden mockup pic with the reports author earlier. That'll work, he said. In fact the backbone section doesn't need to be anything like that big and beefy to be useful. His other observation was that you really want to look at some way of bracing the area between from outriggers and the suspension turrets as by bracing the rest, that will be the area of maximum flex. Dunno about the export mK1 chassi used in Oz but the original UK versions were notoriously feeble just there as only single skinned unlike the double skin of the Mk2. Link to comment Share on other sites More sharing options...
NeilR Posted March 20, 2023 Author Share Posted March 20, 2023 This is the big reason for this project, my son William. At 6' 4" and a solid 100kg, he's not what you'd call the ideal size for a Spitfire ... luckily the Herald is a bit longer. Even so we're replacing the last outrigger to get an extra 80mm behind the driver. This created more challenges in how to mount the trailing links, until we realised the Spitfire links were shorter, but if we used them as planned we'd lose the rear toe adjustment: If this looks a little unfinished at the sill tube (which is 75 x 50 x 2), let me explain that the rearward protruding sill tube gets boxed in to the outrigger and becomes the roll hoop mounting point - we need it a long way back because of the tall driver. However this suspension mount meant no toe adjustment, so a search through a breaker's yard and we got these, which we laid next to the Triumph part. : The longer one is our choice due to three things: 1. the adjustment is at the chassis end (top of pic) and seems a structurally better solution. 2. the wheel end is a sealed spherical bearing with lovely dust cover. 3. The wheel end is crimped, not welded. Splitting the tube had the end falling out and the tube was thus easy to shorten. It will be tig welded back together when we decide on the length of the link. Link to comment Share on other sites More sharing options...
NeilR Posted March 20, 2023 Author Share Posted March 20, 2023 It strikes me that the longer rear link of the Herald is slightly better for reducing the amount of toe change ... correct me if I am wrong. Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted March 20, 2023 Share Posted March 20, 2023 55 minutes ago, NeilR said: It strikes me that the longer rear link of the Herald is slightly better for reducing the amount of toe change ... correct me if I am wrong. It will, yes. 1 Link to comment Share on other sites More sharing options...
NeilR Posted March 20, 2023 Author Share Posted March 20, 2023 Well we could go all the way through and use the std Herald length. Link to comment Share on other sites More sharing options...
ahebron Posted March 20, 2023 Share Posted March 20, 2023 Just a thought but with all the chassis work going on could you have changed the rear suspension design. BTW I am 6ft5 110kgs(when I owned it) and happily drove my Mk4 Spitfire with Mk2 Vitesse running gear. Link to comment Share on other sites More sharing options...
NeilR Posted March 21, 2023 Author Share Posted March 21, 2023 Good to know that you fitted! As for suspension, yes we could have changed it. I could not find a Rotoflex suspension and we could have made our own ... but then we run into problems. As it is I can get the car on the road as a 'rebodied' Herald ... if I changed the suspension the car becomes an individually constructed vehicle and has to pass far more challenging rules including emissions. Link to comment Share on other sites More sharing options...
NeilR Posted April 9, 2023 Author Share Posted April 9, 2023 Recent work complicated by my own ineptitude - I assumed both side of the chassis were the same, when I know they are not. Current state of chassis: Below working out steering column angles, having a straight shaft would be rather uncomfortable - you can see part of front bracing added too. Also note legroom for 6'4" driver. New steering arrangement will involve two universal joints and a short intermediate shaft. Link to comment Share on other sites More sharing options...
Escadrille Ecosse Posted April 9, 2023 Share Posted April 9, 2023 The straight column on the Spitfire and Herald/Vitesse seems perfectly natural to me. Maybe my arm have evolvedto be diferent lengths because I've been driving them for so long 1 Link to comment Share on other sites More sharing options...
NeilR Posted April 10, 2023 Author Share Posted April 10, 2023 We do tend to get used to things that initially seem odd (note to self - no comments about marriage!), however we have a chance to correct this and hopefully the angular displacement may make the car a little safer in a frontal impact. Link to comment Share on other sites More sharing options...
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