Herald/Vitesse Bulkhead Supportt

[Peaks]

The bulkhead on my Vitesse convertible is mounted on the correct mounts, but has always moved around too much for my liking (have you ever placed your fingers over the gap between the windscreen frame and quarter light whilst driving down the road? 😳).

 Spitfires had an H frame between the lower dash support and chassis main rails, and I've wondered for a while if firstly this is possible on a Vitesse, and secondly if this would stiffen things up a bit.

Has anyone fitted such a thing to their Herald or Vitesse? 

[Peter Truman]

Try driving around 100 on the auto barns (early1979’s) don’t put your shoulder near top at the back of the door and B post it’ll give you a nip and that was when my car was only 2 years old!!!

[ahebron]

I am wondering if the horizontal dash support for the Herald/Vitesse dash is strong enough to give an effective fixing point or would something aditional have to be added behind the dash.

[Peaks]

44 minutes ago, ahebron said:

I am wondering if the horizontal dash support for the Herald/Vitesse dash is strong enough to give an effective fixing point or would something aditional have to be added behind the dash.

I agree, that would need to be beefed up as well. 

[Eric Smith]

Quote from Wikipedia: Scuttle shake (sometimes called cowl shake in the US) is the term used for the phenomenon experienced in many convertible or open top automobiles where, due to lower structural rigidity caused by the lack of a roof, the middle section of the chassis flexes, causing the bulkhead in front of the passenger compartment to move and vibrate when the vehicle is subject to uneven road surfaces.^[1][2] Passengers feel it as a noticeable vibration and shudder.

 

When I owned a Spitfire I never noticed scuttle shake because the car was permanently fitted hard top, which must have put the strength back to the car - if the vibration and movement is getting more noticeable or worse, is it worth talking to the motor sport guys to see what they can suggest, they may have an easy diy solution?

Eric

 

[ahebron]

Didnt someones son look into this for a university thesis.
I recall a triangulation somehow being the best solution.

[Colin Lindsay]

That movement can be caused by the bulkhead on the chassis, so replacing the chassis mounting rubbers with something more solid can help but I've noticed that when I put the hood up in mine, the gaps close up too! 

Even with a fixed roof body flex can be alarming; my estate for example goes on the lift which lifts on the main chassis rails at the front outriggers, and just before the diff at the rear, and the door gaps open alarmingly. 

[GFL]

I've experienced this on all the Heralds/Vitesse's I've owned.

I took the roof off a saloon once and drove it briefly before starting a rebuild and that was bad, the passenger door flew open too!

I currently have mine on Axle Stands ready for some work to change the wheels/studs (when I finally get round to sorting some new tyres!) and the gaps have opened up at the rear and front of the doors significantly, and thats with a rebuilt chassis with all new Outriggers.

I'm afraid the Herald/Vitesse Chassis and Bodywork is not the most structurally sound piece of engineering and you may well have to live with it.

With regards to fitting a 'H' frame as per the Spitfire/GT6's, the existing lower 'U' section support for the dash is far to flimsy to provide any support.

Gary  

[trigolf]

Did'nt someone in the Club try boxing in the side rails and outriggers on a Vit ,as an experiment, to see if it increased rigidity significantly years ago? I can't remember the verdict.

[JohnD]

11 hours ago, ahebron said:

Didnt someones son look into this for a university thesis.
I recall a triangulation somehow being the best solution.

That would have been the son of  Nick Jones, of this parish, but more frequently on Sideways.   The triangular frame was to stiffen the chassis, not the bulkhead, and appeared in Courier in an article on Stiffness in the late '90s, possibly by John Thomason.  A search of the Technical Index would find it.

The frame was effective, but impractical, as it occupied the passenger seat and gear shift area.  A full roll cage is practical, if it is anchored to the windscreen.

John

[daverclasper]

21 hours ago, JohnD said:

John

Hi john. I PM'd you about something, though not aware of a reply?.  Wondering if you have seen it?

Thanks, Dave

[JohnD]

No PMs notified  to me from you, dave.  Try again?

[steveo]

When rebuilding mine I did seam weld the outriggers to the outer chassis rail as it looked like it was only spot welded from the factory, also did a inch long weld on the sills where the  two half's meet (covered by stainless sill tread plates) base of A & B posts plated & seam welded. 

As my car was so rotten anyway keeping it original was no longer important, sold it recently & the buyer was impressed how well it drove for a old convertible car.

Cheers, Steve 

[Steve P]

On my 1968 13/60 Herald, the front outriggers are gusseted where they meet the chassis. I wondered if that was factory as the car was off the road from 1979 to 2010 when I took it on.

Must be stronger?.

Steve

Edited November 14 by Steve P

[68vitesse]

My Vitesse convertible currently up on four axle stands, using the recommend jacking points, while I try to fit a tubular manifold and door gaps have opened even with the extra catches. Not an expert but if you fit reinforcement to the chassis couldn't it concentrate the stress leading to failure?.

Regards

Paul.

[daverclasper]

On 13/11/2024 at 17:28, JohnD said:

No PMs notified  to me from you, dave.  Try again?

Thanks John. My original PM is recorded, though showing as "unread"?.

Have just sent another?

[ahebron]

12 hours ago, 68vitesse said:

My Vitesse convertible currently up on four axle stands, using the recommend jacking points, while I try to fit a tubular manifold and door gaps have opened even with the extra catches. Not an expert but if you fit reinforcement to the chassis couldn't it concentrate the stress leading to failure?.

Regards

Paul.

I have been looking into this recently and it what I have found is lifting the car then sitting it on its wheels will solve the issue of door gaps opening up when the car is raised. I have seen this on car restorer programs on TV and Youtube.

Youtube wheel cribs or wooden wheel stands.

[JohnD]

4 hours ago, daverclasper said:

Thanks John. My original PM is recorded, though showing as "unread"?.

Have just sent another?

Just checked, Dave, no PMs from you and I've not sent you anything.  Some board problem?

I'll try to send you my email, try that.

John

[PeteH]

On 16/11/2024 at 07:17, 68vitesse said:

Not an expert but if you fit reinforcement to the chassis couldn't it concentrate the stress leading to failure?.

Lots of years since I had much to do with structural fabrication, but as I recall, in adding stifeners you must ensure the stiffener tapers off?

For instance in Naval Architecture, virtually all stiffeners are fully radiused not just "square". This reduces the stress concentration at the change of angle or section. Part of the reason why openings in industrial/Marine, Steam Boiler`s are 1) Oval, and 2) have reinforcement adjacent. Thereby reducing stress concentration. The mathematics involved are very complex, If your doing it manually one calculation can cover several pages. All done by computer program`s now as I understand?

An interesting aside, It is also the reason why most Aircraft Windows are either Oval or seriously radisued in the corners, It was found to be the combination of a high stress concentration, and poor finishing that led to the 1950`s "Comet" disasters.

Pete

[Peter Truman]

I travelled by Comet from Aus to UK a couple of times early 60’s must have been lucky. I believe besides square corners for aperture's the holes for the holding rivets  were punched not drilled cresting more stress areas.

[Pete Lewis]

next time you fly Comet take some pop rivets and gaffer tape 

Pete

[Peter Truman]

I remember watching what I now assume were Turn & Lock fasteners bouncing around on a wing panel presumably removable panels over the in wing jets? but at around 14 yrs old didn't appreciate the danger!

[Eric Smith]

The thing about aircraft structures is - for a very long time they used solid rivets to be the main joining components and pop rivets to attach skin panels where it was safe to do so - the British Comet was different as they glued it together with a product called Redux which was then akin to modern epoxy resins. The Comet saw service from the early 1950’s till 1997 as a air liner and transport aircraft - if you count the RAF Nimrod as a Comet well they retired in 2011 so not a bad construction method for nearly 60 years of aviation history.

As to turn and lock fasteners - the panels which have them are only access panels and their fasteners are not structural.

Useless facts -

Fact 1. The RAF always called pop rivets - Tucker Pops, they were made by “Tucker Eyelets” in Perry Bar Birmingham the Eyelets were the metal rings put into shoes to protect boots and shoes from boot and shoelace damage.

Fact 2. The Supermarine Spitfire was originally built using countersunk solid rivets, they soon realised countersinking thousands of holes on the fuselage would slow down production so using British logic the design team went out and got packets of dried split peas and glued half a pea over each countersunk rivet on the fuselage - I believe they then sent the aircraft up for a quick trip up into the sky. When it came back they assessed the fuselage and discovered the airflow had not stripped off all the split peas off the skin - they made notes and if you go look at a Spitfire the rear of the fuselage are dome head the rest are countersunk.

Eric

 

[Colin Lindsay]

A little flex isn't a bad thing; none at all and the Herald might snap in two going over a bump...

If you've ever sat in an aeroplane and watched the wings flex up and down, it can be interesting... once you realise they're meant to do that.