Sunday, 11 October 2009

Twas only a bird in a gilded 'Cage.


Many years ago now I was looking to find a suitable subject for an "on-spec" model and I found, quite locally, a company who had in at that time no less than three Tipo 61 Maseratis, otherwise known as Birdcages, because of their astonishingly complex multi-tubular spaceframe chassis.
I couldn't resist the challenge, so I photographed and measured the one that seemed to me most "unrestored", though I soon discovered there ain't no such thing as unrestored where old racing cars are concerned. This one was the ex-Moss and Gurney winner of the Nurburgring 500.

Measuring such a car, even when the bodywork is conveniently off it is no easy task. I decided to split the chassis up into imaginary "bays" and drew each one on the back of a business card (I had plenty!). Then I sketched all the difficult bits from different angles and, of course, photographed every little detail.

When I got home I started the drawings, but found that due to the number of diagonal members of the frame I had to resort to drawing them in colour to explain the different planes in which frame members went through space.

It was much later that I discovered such a system is used when computerised draughtsmen do complex drawings on CATIA, etc. for car body design and the associated engineering.
The model was to be made in my favourite for large models of 1/12th scale, or one inch to the foot, a splendid scale which is on everyone's steel rule.
Surprisingly, though a presumably metric car, I found it to have a great many dimensions that were spot-on Imperial including some of the many tube sizes.

I made the model from various scale sizes of nickel silver rod, because nickel is so much stronger than brass. All bracketry and platework that was part of the chassis was done in brass as I had some the right thickness. The removable panels were made in thin aluminium as are the real ones. These all fixed to tiny brackets soldered to the framework.

I had to make special jigs for the front suspension mountings as they sit in mid air at strange relationships to any pieces around them. The most difficult assembly of tiny bits was the front suspension tower, being many small pieces of thin sheet. The tiniest parts were the 1mm diameter steel ball joints in the throttle mechanism. I had intended having the model carburettors working as far as external mechanism was concerned, so turned the tiny ball joints in the lathe with a special tool and then "popped" them into undercut receptacles which then allowed a fully jointed mechanism all the way from accelerator pedal to engine.

Also the gear selector was made to work, so that you had to depress the gear lever to engage first and reverse and flip a little detent over to get reverse, too.

The jigs for the front suspension can be seen on the left of the above picture and the gear selector and gate on the lower right.

The steering worked with a real rack and pinion operation, which would have used correct steering arms, but the model was bought by an eager French gentleman before I got any further!
The steering wheel was made just as the real car, with 24 seperate pieces of wood, twelve either side of the aluminium rim, in four layers, with the grain running in the correct direction, like the rim of a cart wheel. The steering column had three fully working universal joints, a la Maserati, just 3mm in diameter.
I regret not fully finishing the model, but my unexpected French customer was insistent that he take it as it was, so who am I to have argued?

But I have some nice pictures of the work to remember it by.

8 comments:

  1. Stunning! Now we all have the ability to enjoy your work!
    Looks as though the only way I can post a comment is to use sodding MSIE. The horror! The horror!!

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  2. A stupendous model. I takes me hat off to you, sir!

    ReplyDelete
  3. Thanks, Rich and Iain. much appreciated.

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  6. Hi Anonymouses. Many thanks for your appreciation. Not sure I could do it these days!

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  7. The work on the birdcage is beautiful .
    I would like to build a replica but having trouble with chassis drawings .I have done some similar work over the years which can be viewed oat marqrest@iimetro.com.au
    Could you help please .
    All the best Gerard

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  8. Thanks Gerard. I'm afraid I loaned all my drawings to someone in the States and they were lost.I measured the chassis locally to me. It's a good few years ago now!

    ReplyDelete