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Fiat 806: research and scratchbuilds


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On 09/05/2018 at 13:31, Hannes said:

Cut out overlapping pieces of paper , apply 2c epoxy glue ( 12 hours till firm ) soak the paper with epoxy and flatten the surface

What a great, simple idea.

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Dear Hannes,  

 

RE: the 451 engine.....what height do you reckon it is from the drawing? The measurements are somewhat blurry and difficult to define, but I get approx. 62mm in scale.

 

Cheers, H

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Dear Harvey , this engine reminds me of an upright boxer .There are measures on the frontal view´s drawing  .I guess the height was about73 cm .In Sebastien´s book there´s a chapter regarding this engine ( 6 pages) .Unfortunately my french is not good enough for understanding each sentence . If you are interested , I will post these 6 pages tomorrow . As I said before I believe the sandwiching of the engine was provided  for the451 engine and the 406 and the rest of the car  profited by this decision .  Hannes

PS :The numbers on the outer measure line are 110 , 390 ,50 mm

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Thank you dear Hannes,  that is approx. similar to what I calculated (744mm).

I would be very interested to see those 6 pages please. Although I don't read French, I'm sure Google translator will be able to lol!

 

Cheers, H

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Dear Harvey , if you want to build the car around this 451 engine , the drawing 1 / kit / master model version seems to be the right choice .

In my opinion something happened like this : At the end of 1926 the test runs of the 451 failed and Massimino was forced to show the  design of a car with the 4-stroke 406 engine .

He took a plan of the older version, drew  additional cam fairings and a single seat and forgot the  branches of the manifolds .Drawing 1 was born imho. As it seems it was not yet clear if the engine should get shifted towards the left side . It was a pre-design drawing and a lot of alterings were following like a different chassis " 806 " , different frontal axle and alterings regarding bodywork , bonnets and radiator case .

Because of the different dimensions of the two engines including their compressors  many new detail constructions were required .

Seen from Agnelli´s point of view a lot of manpower was wasted for that imho and I guess he was not amused .

Many greetings !   Hannes

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Dear Hannes,

 

Many thanks for those pages. Tonights project will be translating them and having a damn-good read:lol:

 

I have believed for a long time that D1 was a blueprint for the 451/2 "Head-knocker"!  There had to be. If you design a new engine, then surely, a chassis/coachwork had to be designed and constructed to fit the beast.

 

I agree, there will need to be a few modifications to the kit...there always is, but, I'm prepared to do it in order for this "never-seen-before outside of the Fiat test-crew" engine to come to life again after a 90yr hibernation in cryo-stasis!:D

 

I think they'll make a very sexy tribute to history in my living-room!!

 

Cheers, H

 

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Dear Harvey , regarding drawing 1 again . I believe that this was a " political " drawing . Projects like inserting another engine needed to be allowed by higher instances . I can imagine that Massimino showed this drawing to his directors and said : See, that´s almost the same car and we can use the parts we already made .

Some cam fairings and some minor alterings - that´s all !

In my opinion Massimino was a too good engineer not to know the real consequences .I think he was a cunning guy who loved motor racing.

Many greetings !   Hannes

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Dear Hannes,

 

The drawings on page 6 certainly make a lot more sense than the blueprint drawings, in regard to the compressor/inlet/carb set-up. I'm starting to get very excited at the prospect of recreating this " problematic baby brother" to the 406 beast. It will be a welcome distraction from the main build.

Thanks again my friend.

 

Cheers, H

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Dear Harvey , at that time most of the engineers believed  that the 2-stroke engine is the future especially if there´s a limited cubic capacity. Let´s be glad that this was not the case ore else the air would be even more polluted today by this gasoline-oil mixture .

I´m really enthusiastic for your plans to realize this engineer´s dream and of course you have my full support .

Many greetings !   Hannes

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I can understand it . It´s an enigma inside an enigma and we are the ones who are about to unravel these codes .It´s interesting to see a suspension structure above the compressor on the side- view . In my opinion there was a similar construction for the 406 compressor . The second cross-member ( inside the radiator case ) most likely was provided for bearing  the engine at it´s front .  Hannes

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Hi all,

 

Here's one for insomniacs and those lacking motivation to find something more interesting to do.

 

In the interests of completeness and for the record, this and probably a couple of other subsequent posts will capture the match between my Blender lines and the well known pictures of the 806. Much of this is well trodden ground but forms the basis for finally developing Some of you might rightly wonder about the lack of progress and question my motivation. In my defence I did get distracted by something else.

 

I will show the match for a number of the key pictures. Starting with Photo 28

 

 

9-7 Photo 28

 

 

Notes:

• Used this picture for along and vertical

• Lines captured as a “Sparktrace” in 3D

• Edges of all the pictures are probably suspect

• This picture seems to be the least worst

• Front and rear wheels are similar sizes - which is not as obvious as it seems. In one of the photos they appear to be different sizes. 

• Radiator fairing probably needs works

• Need to reconfirm louvres lines

 

Now Photo 3

 

 

9-7 Photo 3

 

 

• Used this for width

• Left rear is distorted unfortunately

• Tail is wrong due to the distortion - as noted previously

• Cockpit Cowl is slightly too low – confirmed on other photos too.

• Wheels are same size front to rear – helpfully

• Filler is a bit low

 

Now I submitted it photos are missing. Any ideas? thought I had done what I always done. 

Edited by NickD
Picture links now work - who knows why
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Many thanks , dear Nick ! Your elaborations will be very useful for us in the future .  In the last days I built a new radiator case from scratch by using  brass sheets and I will post some photos tomorrow .It was easier than altering the existing  case  and now I´m content because I finally got my thin walls .

One thought  regarding the frontal wheels . In my opinion the "bad" jumping left front wheel was more chambered than the right one .This could be the source of some geometrical confusions .

Many greetings and many thanks again !   Hannes

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Thank you , dear Roy ! It´s a fascinating journey and a lesson for me as well .These overwhelming  forms and proportions most likely  never would have been  achieved  with an inserted 451 engine  .It´s an interesting thought that the progenitor of modern racing cars  was created by chance and unpredictable circumstances .

Let´s revive it !   Hannes

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After the adaption works some walls of the bonnets and the radiator case became too thick. I replaced some sheets of the bonnets  but regarding the radiator case I decided to build a new one out of brass .

It was an advantage that a realistic case already existed and I could use it as a pattern.

For stability reasons I built the case  with two layers of thin brass sheets instead out of one thicker sheet . They are connected by epoxi and secured by 6 dowels . The bonnets support and a thin steel plate under the bottom sheet ( made out of a piece of a metal spatula ) were additional reinforcements .

Some small filler works will follow and a primer will protect the surface soon.

I´m glad that these works are done now and I´ll be able to focus on my bonnets again. Thank you , my dear Olivier !

Many greetings !   Hannes

 

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