Hand Formed Aluminium Body

[Hamish]

38 minutes ago, RedRooster said:

Nice intake scoop on that bonnet is what you need to give it a bit of attitude. 

A discrete DB5 style ? 

[RedRooster]

Exactly, you could mock it up in cardboard. 

[John Bonnett]

It's not too late to consider a scoop rather than a bulge so I'll think on.

Thank you for your suggestions.

 

 

[JohnD]

John,

 May I suggest a NACA duct?     Other forms of intake look plebeian or just gross, but the sculpted lines of a NACA are just beautiful, and grace the greatest cars ever made.  This Ferrari seems to have an excess of them!

There are many websites that describe the design of a NACA duct, eg https://cozyserenity.weebly.com/uploads/2/1/8/0/21804934/__naca_duct_design.pdf  which is for aircraft, but none the worse for that!

But what goes in must come out.   Extra air under the bonnet will escape under the car, and at speed may add to lift.   An intake should  be matched to an extractor duct.   The type chosen  by many classic car owners and self builders is the louvre, which as a single slot is efficient.  But that slot mucks up the airflow for the one behind it, reducing it's efficiency by about a third, and then  the one behind that, a third of a third.  A bank of louvres is only as effective as the size of the first slot, and a third!

NACAs do not work in  reverse.   Instead a wide duct, with a floor that slopes up to join  the rear edge at no more than 15 degrees will work.  Better is one with a small lip on the front edge, like a Gurney Flap .  This causes a vortex behind in the throat of the duct, energising the air there, so that it moves into the outside airstream and is replaced by air from within.   The shallow slope of the rear wall prevents the duct 'choking'.

These show extractors like that on m y SofS:

Good luck!

John

Edited February 7, 2024 by JohnD

[RedRooster]

A subtle version of this perhaps. 

[Escadrille Ecosse]

That would suit the style of the car.

Is that a Mini bonnet?

[Nick Jones]

Alpine?

(the stripey version)

[RedRooster]

That one is a LAT 79 period option (Las Angeles Tuning). 

[Gt64fun]

23 hours ago, John Bonnett said:

It's not too late to consider a scoop rather than a bulge

Why not have both....no, I never understood why either!

Ian

[Escadrille Ecosse]

36 minutes ago, Gt64fun said:

Why not have both....no, I never understood why either!

Ian

Because nothing exceeds like excess 

[RogerH]

Nothing Succeeds like a toothless Budgie.

 

Roger

[John Bonnett]

Thank you all for your considered replies. What none of you have taken into account is the fact that I am a novice and my skills are extremely limited which severely impacts on my choices. I am also keen to keep the project moving and not go back which is what would need to be done if a new design of bulge or scoop were decided upon. My personal preference is the scoop on the Aston but having at the outset decided to remain faithful to the artist's impression I'm going to stick with it and rework it. If that fails then we are looking at starting again with new material and then would be an opportunity to take stock and decide what options are available to me given my limitations. Believe me, it isn't easy. I had done no metal shaping until I turned 60 so it really isn't realistic to expect to be able to reproduce the shapes and quality achieved by time served apprentices with 40 years experience.

Currently, I'm having problems with TIG welds cracking and I have made the decision to go back to gas welding. My thanks to Ian for making this possible given the price of acetylene. Gas welding aluminium is one of those skills that when you start learning you  keep burning holes and think I'm never going to be able to master this but when eventually the penny drops and all of a sudden you can weld, you wonder why it took you so long and why everyone cannot do it. It's just a technique like any other. But, and it's a big but, the last time I did any gas welding of aluminium was 9 years ago so I am under no delusions about how hard it's going to be to relearn the skill. These two photos are practice welds, top and bottom done by me in 2009. If I can achieve that standard I won't be cross.

[John Bonnett]

It took longer than I was expecting and to be honest, I anticipated a couple of practice pieces to get back to the above level of welding and then straight onto the panels. Sadly, not the case and in the event it took two days to become proficient again. Gas welding aluminium isn't difficult, it's just different, a knack, really, getting the neutral flame to the exact heat required, nearness of the flame to the aluminium and recognising when the aluminium is melting and the time to get moving. But I'm pleased to say that it did all come back and such a relief to be able to be rid of the hard TIG weld beads and not worry about cracking either in the weld or the adjacent areas. The fully annealed strip either side of the gas welded joint is an absolute pleasure to planish and work. The first pieces that I gas welded together were sections of the front valence and they came out really nicely.

[Escadrille Ecosse]

Nice. If you're not doing this sort of thing every day then it takes time to remember the 'knack'.

[Nick Jones]

Well done John 

[Gt64fun]

Looking good John

Nice to see the skills be rekindled and the acetylene being put to good use.

Ian

 

[John Bonnett]

5 hours ago, Gt64fun said:

Looking good John

Nice to see the skills be rekindled and the acetylene being put to good use.

Ian

 

Definitely Ian and thank you so much for your generosity.

There was a time during those two days when all I could do was burn holes that I thought old age had taken its toll and that I'd not be able to get back into it but fortunately that wasn't the case and although I'm not quite at the standard I achieved on the Lightweight I'm getting there.

[John Bonnett]

Since the change to gas welding, the project has moved into overdrive and some good progress has been made. I've been working on the front valance which has quite lot going on in terms of changing shapes in the same panel. By dividing each piece into several sub-panels the job was made very much easier. The centre section is largely single curvature with a little bit of shrinking on each end to lead into the curvature of the adjoining panels. The outer ones on the other hand are a different matter. Anyway here are a few photos bring things up to date.

[John Bonnett]

Two outer valence panels in place.

[Mark]

Really coming together. I can appreciate the amount of work you've  put into this, but definitely paying off. 

[RedRooster]

Looking good John. 

 

[Hamish]

Wow That’s looking great John

really coming together nicely. 
 

[Nick Jones]

Complicated shapes there. Have come out very well 

[Escadrille Ecosse]

Excellent progress there.

[RogerH]

A  thing of beauty.

 

Roger