Roll over bar

[PeteH]

1 hour ago, Bfg said:

In my opinion, the roll bar doesn't detract from either car's style.

I agree, but both where designed/made (I assume) with the roll bar in the mind. The Vittesse / Herald range where not so specified at conception by the designer. Which IMV makes fitting one retrospectivly like, The "Boil on the face of an old Friend".

Pete

[Colin Lindsay]

18 hours ago, PeteH said:

I agree, but both where designed/made (I assume) with the roll bar in the mind. The Vittesse / Herald range where not so specified at conception by the designer. Which IMV makes fitting one retrospectivly like, The "Boil on the face of an old Friend".

Pete

I almost bought a S/H one at Stoneleigh a few years back (I think £45 so I was sorely tempted); it would have had the backwards-facing braces that go on either sides of the rear sear, with possible mods required. Then I looked at the side profile of the Herald and decided against it. I just didn't think it would suit the car.

[thescrapman]

[mark powell]

I've got a leather cloth covered Aero bar for the Herald / Vitesse convertible available...

[Bob Horner]

I’m thinking of prepping my mk3 spitfire for a bit of light regularity rallying and I think a roll bar is essential.  I’d be keen to keep the hood rather than use a permanent hard top.  What are the options for a mk3?  I read that you need a “hinged” bar but that sounds a bit flimsy. Happy to pay for a bespoke job to do it proper if anyone has any recommendations.  To do it properly will I need to lose the hood?   I’m based in N Yorks.  Also, if any one has info re strengthening the chassis/ skid plates etc I’d be vey grateful.  I’ve prepped a TR4 before and there is loads of info and products for them but I can find very little for a spitfire. 
 

Thanks in anticipation. 

[thescrapman]

If you are thinking of just regularity stuff, you don't need to do anything I would have thought as it is all at such low speeds. well it is whe you aren't off route.

If you are thinking of te HRCR type stuff where the regularity is mixed in with tests then maybe a roll bar is an option.

Mike Banks who posts here occasionally has a role bar in his MK3

He has a Mk2 type removabke hood now to fit over it. Or he puts the hard top on.

[Bob Horner]

Thanks Scrapman.  What are the issues with swapping hoods?  Do the sockets that accept the mk2 hood frame bolt on to the body where the captives are for the mk3 hood or is it a welding job? Are the parts generally available?

Bob

[thescrapman]

It is a re-engineered Mk3 frame I think.

I will see if I can ask him to put a few photos up.

[Bfg]

Just out of interest ..on a wet day in February, I've been playing around with ideas on structure to land a roll bar on.  My own thoughts, for some time now, have been along the lines of the Triumph Stag, Lancia Beta and Porsche Taga, with a removable lid and a fold down rear window.  I think Mark Powell's post suggests he's half way to doing something similar and/or equally as interesting . .

On 30/12/2020 at 17:51, mark powell said:

 

So, in consideration of fitting a roll bar into a TR4A, I've been looking into the available off-the-shelf designs, the intrusion of large diameter tubing into a very tight space (I'm 6'5" tall and broad shouldered so I'll need the seat all the way back ..if not even further ! and also max shoulder width),  and then also the issues of landing a roll-over bar anywhere near a body chassis mounting or through to the chassis itself.   The IRS chassis of the TR4A is particularly useless in this latter respect.  The TR6 however made a slight improvement in-so-much as the interior's body step-over-the-rear-axle-structure was at least bolted to it.

    < tubby TR4A seats illustrate how little space there is along side them for a a roll over bar to squeeze in.

As an aside, until today I hadn't realised the amount of work there was in fitting a Surrey back-light frame to a TR4 - 6.   Don't quote me because I've never done it, but as it seems as though the folding hood frame has to be removed completely from the car, as do the press-stud or lift-a-dots around the back.  I had envisaged it was more like a bolt-on hardtop which sat over the top of everything original.  Certainly if this is the case - then swapping back to the folding hood arrangement is not a 2-minute, un-clip from car and hang it from the garage rafters, job. 

I would personally prefer a lift off (hard) surrey top lid, and a very quick to open rear window like the aforementioned cars ..rather than a rag top.  And given the choice I would also like some degree of side intrusion & roll-over protection, particularly if that can be pushed out to the extremities of width  (for the sake of interior airiness, as well as the lesser likelihood of my head fouling that roll-bar) then I simply have to accept that the conversion is likewise not going to be "quickly" reversible. 

Anyway., if like the aforementioned and Mark's design, a roll-over bar's load is spread onto the B-post structure and along the body ..rather than on four relatively small feet, then that may be more stable in the fore and aft (important in a sliding forward or backwards roll).  And if those parts of the body tube were specifically reinforced then all the better still.  Naturally with full-width roll bar designs like these - the original folding-hood frame cannot get passed the structure.  Conversely the structure can be pushed out as far as the doors side glass, so interior intrusion might  be much less.

Today I played around in Adobe Photoshop with an image borrowed off the internet of a TR6's rear body step, inner wing and inside of the B-post structure . . 

         

This is where I started from (left image)         .  .  .  . and (to the right) is work in progress.

The proposed reinforcing starts off with a thicker plate fitted (welded) inside the rather lightweight B-post (which I've illustrated in light green. It's orientated 90-deg to the car's CL.  And then inside the car ; the first reinforcing plate is a wide saddle strap over the wheel-arch (seen as a red border line with light-grey tint)  This goes quite a way over the top in readiness to land the diagonal-rear bracing of a roll bar.  A forward plate extends along the floor alongside the sill (quite a way forward with the IRS chassis) to the standard body-mount.  The inside of the inner wing panel, the B-post and the sill then have vertical plates, which makes a near 90 degree angle along the reinforcement's welded join. Additional boxing in is seen below where a roll bar may sit, it purpose is again to transfer vertical (rolled over bar) loads. The resultant box structure is stiff in vertical compression, when the attachment to the body shell minimises the potential to twist or splay (common failings with angle-iron like structures). 

The rear deck is reinforced with deep vertical web(s), brown coloured in my illustration, which when attached to the original bodywork would add enormously to the strength and rigidity of the transverse deck beam.  I'm looking into moving my car's fuel tank from under here, and so am envisaging the web plates being both under the front and the back of this deck, and then closing under those webs as a large box section beam, full width of the car's body tube. This being similar to an Xk150 I once owned. In any case the additional stiffness of the body shell, after pop-rivetting an aluminium firewall across / in front of the fuel tank is well known. 

Presently tentative sketched in (..in light blue) is a reinforcing angle beam across the rear axle deck, which ties in to the TR6's body mounts.  I've shown this locally scalloped for the seat backs to sit into.

All in all these reinforcement plates could be prefabricated and welded to the body tub, or else be bolted-in as Left and Right handed structures, plus the rear deck deep web.  In any case the whole would be hidden under carpet & trim. The most obvious outward sign of any additional structure in there would be the doubling plate of the sill, in the rear corner of the open door frame.  I envisage the top if those webs to be closed off and finished in body colour. 

Together these, easily home cut and fabricated from flat plate, reinforcing structures would contribute to side-impact protection, would stiffen the rear deck and rear half of the door sills, and of course would be a load-distributing foundation to land the upper roll-over bar on., without the legs of that roll-bar needing to squeeze passed the seat back to get to the floor..  

Added weight yes, but lightening holes could be cut if the time and trouble warranted it. Conversely, the shorter the length of tube (roll-over bar in this instance) the smaller the diameter needed to withstand the same bending force ..and that in turn relates to less intrusion within the interior. 

Anyway, I'm just playing around with ideas to see where, if anywhere, they lead.

 Wrap up warm and I bid you a very good evening.

Pete.   

       

 

[Dick Twitchen]

12 hours ago, Bfg said:

it seems as though the folding hood frame has to be removed completely from the car, as do the press-stud or lift-a-dots around the back.  I had envisaged it was more like a bolt-on hardtop which sat over the top of everything original.  Certainly if this is the case - then swapping back to the folding hood arrangement is not a 2-minute,

Pete, 

Cannot help on the roll bar issue but from memories of my TR4 43 years ago you are correct on the Surrey top fitting; it is a serious piece of kit and not just a clip on hard top.  I had fabric rather than solid panel and never had an issue rain or shine.

Dick  

[Bfg]

Thanks Dick, 

Yesterday I spoke to a chap who got rid of his fabric Surrey top and back-light to buy a hood and the bows to convert back to a soft top.  He was saying that the Surrey top was OK but he and his wife preferred a proper open top car, and that fitting his fabric surrey-top and its bows was always a hassle.  The later type (4a - 6) soft top just folds down and quickly n' easily tucked away under the cover ..and more importantly to them - it, almost as quickly, is put back up again should there be more than a light shower of rain. 

I'm hoping to just have a hard lid panel, but then modifying a boot rack for its en-route conveyance.  The aforementioned chap didn't have a hard lid so couldn't say how quick it would be to re-fit just that.  But if it proves to be a hassle - I guess I'll use one of those half car covers that drops over just the roof and windows ..for when parked. That'll also provide an all round curtain to annoy nosy-parkers and would-be opportunist thieves.

Pete.

[mark powell]

Hi Pete

 The roll over bars in the Herald pick up serve a few purposes.  A degree of safety, a mount for the targa top (cut down saloon roof), A rigid anchor to tie the sides of the tub together (no more tub spread). I've also fitted the saloon 'B' post uprights to the vertical bar to allow fitment of the side window / door seal .

 I haven't  successfully come up with a rear window design yet.  There's a sheet of clear acrylic keeping the weather out at the moment.

[thescrapman]

2 hours ago, Bfg said:

Thanks Dick, 

Yesterday I spoke to a chap who got rid of his fabric Surrey top and back-light to buy a hood and the bows to convert back to a soft top.  He was saying that the Surrey top was OK but he and his wife preferred a proper open top car, and that fitting his fabric surrey-top and its bows was always a hassle.  The later type (4a - 6) soft top just folds down and quickly n' easily tucked away under the cover ..and more importantly to them - it, almost as quickly, is put back up again should there be more than a light shower of rain. 

I'm hoping to just have a hard lid panel, but then modifying a boot rack for its en-route conveyance.  The aforementioned chap didn't have a hard lid so couldn't say how quick it would be to re-fit just that.  But if it proves to be a hassle - I guess I'll use one of those half car covers that drops over just the roof and windows ..for when parked. That'll also provide an all round curtain to annoy nosy-parkers and would-be opportunist thieves.

Pete.

I thought the panel for the Surrey top fitted in the boot?

solution for parking with a Surrey top is a golf umbrella with a couple of poppers on it. Some of the TRR North London chapter have done it.

[Bfg]

I have another photo of your car Mark, which I'm guessing I admired on the Autoshite forum.  It looks a great Fun little runabout, nice and airy inside and a useful around-town or boat-yard utility, which if I remember from my days with a Herald would turn on a sixpence.   I could certainly imagine myself driving around in something very similar indeed.

Regarding the rear window, as I said in my own post I'm looking to use a fabric / folding back rear window ..and I think that would work really well with your Herald too, taking the fabric around your roll-over bar to lift-a-dot fasten just behind your door window shut (..the front edge of which would then be sheltered from the driving rain / air-stream).  At first glance it would look like a convertible fitted with a hard top lid, with press studs along the bottom edge but a hidden rope-bead to attach the top under the roof overhang.

Pete.

[Bfg]

On 06/02/2021 at 21:32, Bfg said:

on a wet  Snowy  day in February, I've been playing around with ideas on a structure to land an upper  roll-over bar on., without the legs of that roll-bar needing to squeeze passed the seat back to get to the floor..  

furthermore. . .

        a little more sketching today, including using an on-line calculator to assess the bending deflection of different tubular sections under a 1/2 long-ton load. 

I used 50mm dia with 3mm wall thickness round-tubing as a yardstick to compare its deflection with wider but less deep rectangular box section ..with the primary objective being to replace the usual single, 45 or 50mm diameter, tube with two smaller-diameter ones and plating those inside and out.  To match or better a 50mm x 3mm round tube's bending deflection over a 48" span, under the that load - I'm proposing to use two 30mm dia round tubes of 2mm wall thickness with flat plates welded flush to the tube's inside and out extremities. The two plates are to be 4.5" (114mm) wide x 3mm thick, and so the overall oval cross-section would be 30mm x 160mm.  This is how things are presently looking . . .

Of course having been drawn in Adobe Photoshop ..it is not to scale ..only to a visual approximation derived from this and other photos. 

Pete. 

[Clive]

Are you not using a hoodframe at all? That design looks like it would make it impossible. 

[Bfg]

No hood frame at all. Like the Lancia or Porsche I want to use the roll-over bar to support a Surrey hard-top lid, and then to use it as the rear-most hood stay for a fold down or lift off fabric / plastic rear window. Of course window seal flanges have yet to be added.   I'll probably sell this car's hood & bows, but if not then this roll bar (..not the additional B-post structure) would have to come out to re-fit and use the standard hood bows.

[cliff.b]

On 30/12/2020 at 12:41, Colin Lindsay said:

Again, I don't want to feel like I'm 'getting away with anything' but it can always be argued that our cars, being less safe than moderns, are dangerous. Brakes are less efficient. There are no airbags or crumple zones. If I decide to stick with an original car in original spec, no matter how well maintained, no matter how well I drive or how carefully, someone somewhere will be able to come up with a well-reasoned argument about how much I'm risking my life and how many more times I'm likely to be killed or seriously injured than in a modern or an armoured / uprated / heavily strengthened and protected equivalent of a 1960s Triumph. Someone, somewhere, will always nod their head sagely and tell me: 'Well, it's your life.'

It's an argument that I simply cannot win. If I try to argue: 'someday it may happen, someday it may not', I'll be made to feel that's an irresponsible attitude. No, I can't guarantee that I won't be in accident, and I can't vouch for all the idiots out there in oncoming cars. All I can do is try to be responsible, try to be careful, and try to finish every journey that I start in one piece. I'll keep good tyres, good uprated brakes, improved lighting and well fitted seatbelts, and trust that these are adequate. But: I don't want to fit a roll bar.

Colin, I have been aquainting myself with some of the older threads and read this one with interest.

Understand you not wanting to fit a roll bar and thought you might consider one of these as a period correct solution.

[Colin Lindsay]

That's just how I see myself.... 

Fill 'er up and give me twenty Woodbine, would you? Stuck in traffic for hours, Fred, all these cars rolled over these days...

 

 

[cliff.b]

1 hour ago, Colin Lindsay said:

That's just how I see myself.... 

Fill 'er up and give me twenty Woodbine, would you? Stuck in traffic for hours, Fred, all these cars rolled over these days...

 

 

And the bloke fillin 'er up would have been smoking a woodbine while he was doing it lol