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Fiat 806: research and scratchbuilds


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Dear Olivier , photo 3 seems to be the key for that question .On your improved photo we can see both bars . The frontal one seems to be longer than necessary but this could be an foresighting effect .

I think , Nick is the right person for solving this problem .

Many greetings !  Hannes

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Improved photo  3  is a new source for discoveries as well ! Now we can see some structures inside the cockpit . One interesting detail I found out : The frontal suspension for the crossed struts under the engine ( below the breast-shaped leaf spring suspension ) is slanted regarding it´s upper part but turns into a vertical direction at it´s lower end . Another new perspective after 163 pages full  of research !

Many greetings !  Hannes

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We know that the car had problems with LH wheel ......maybe the rear bar(steering drop-link area) got a bit bent after a sneaky "tank-slapper" wobble? It seems like a viable solution as to why this bar is bent imho!!

 

I love this sleek beast!!!!!!

 

Cheers, H

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If the kit´s  steering wheel gets turned .to the left , the drop link rotates into the rear direction and the rod gets closer to the chassis .. The horizontal  rod of the real car  is situated on the same vertical height as the rear suspension of the frontal leaf springs .

The rear bar was possibly constructed to avoid a contact between  the rod and the suspension .

If the kit´s steering wheel gets turned to the right ,the drop-link rotates into the  frontal direction and  the rod ´s distance to the suspension gets greater - no danger of a collision .

But the kit´s levers are constructed according drawing 1 and the levers on the right front wheel are different on  drawing 2

.

Many greetings !  Hannes

 

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It will be interesting to see how long it will take me to achieve the simple task of modelling that little bracket. I'll be at Atlanta tomorrow, not far from Roy at all, en route to Wyoming and a rendez vous with an eclipse.

 

Having spent some time on the engine bracket, and having thought that there was no more to know I can now bin my previous efforts.I realised yesterday that If you look at the plan version of drawing 2 the engine plate is shown as a flat plate that stands off from the chassis. The bolts have spacers to cope with the curve. so much simpler than my previous effort.


Unfortunately it scraps Harvey's lovely scratchbuilt mounts.

 

Regards

 

Nick

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sneaky

1 minute ago, Olivier de St Raph said:

sneaky "tank-slapper" wobble

Sneaky - really underhand, naughty, cheaky

wobble - to weave from side to side

"tank-slapper" - to very, very, very, very nearly completely lose control and stuff it in the wall. Comes from the sort of loss of control you get on a motor bike!

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Look closely to the front fasteners on our VHR photo 3: for the first time, we can see the coils of the front spring. This shows how better is this version vs the one we had before.. You will notice the springs goes up to the fastener, differently from the rear one. Definitely, the front and the rear are quite different.

UGYILB.png

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Dear Nick ,if these plates are not directly mounted to the chassis ( with spacers as you said ) why dont´t we see a gap ? It´s  quite confusing !

Another topic : Are you interested in astronomy ?  ( solar eclipse ) I am since I was a boy and built my own telescope together with my father , a Cassegrain reflector . Don´t get devoured by the Yellowstone volcano in Wyoming !   Hannes

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When I see the very high resolution of our photos 2 and 3 now, I can't help thinking that there must be somwhere the same VHR version of our photo 1 and especially 28 (this last one is pity LD), taken presumably the same day with the same excellent camera and by the same photograph. But we may consider that, with what we have now, it is possible to build a very convincing model. In the next days, I will do other enlargements of photos 2 and 3, so that when I will be back home, I will have time for my build. 

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22 hours ago, NickD said:

Having spent some time on the engine bracket, and having thought that there was no more to know I can now bin my previous efforts.I realised yesterday that If you look at the plan version of drawing 2 the engine plate is shown as a flat plate that stands off from the chassis. The bolts have spacers to cope with the curve. so much simpler than my previous effort.


Unfortunately it scraps Harvey's lovely scratchbuilt mounts.

Dear Nick, I can understand where you're coming from with that idea, but, I think that the bolts you are seeing are the 3 bolts on the triangular flange.....that's how I interpreted it anyway. 

 

Cheers, H

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On ‎17‎.‎08‎.‎2017 at 17:05, Olivier de St Raph said:

Interesting assumption indeed, dear Hannes. Pity, we will probably never know if you are right with it. If yes, you would be a very sharp investigator, what you are, anyway...

 

Thanks , dear Olivier ! But I´m convinced that my theory is more than an assumption , that´s why I was digging deeper . Some months ago Roy published side-view photo 28 .

You possibly remember my analysis regarding the separation line between bonnets and bodywork . It´s vertical . Below the exhaust it is slightly slanted .

What´s the reason ?  

It´s as I said : The bodywork was made according drawing 1 . A new , flatter and longer chassis was required for the 4-stroke engine .No new bodywork was built . The old bodywork had to get adapted not only to the new chassis 806 but to the new inclination of the bonnets as well .

The bodywork sits directly on the chassis only at it´s frontal beginning .  It sits on spacers over the chassis and the gaps were filled with putty as we can see on the new HRD version of photo 2 .

I cannot explain why no new bodywork was constructed for the new chassis . Money ? Time pressure ?  We will probably never know . But-who knows ? :D

Many greetings !  Hannes

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I must say, dear Hannes, that your explanation is quite convincing. I will transmit it to Sebastien... They had few time, it is probable that if they wanted to take part to the 1927 GP, a quick solution, modifying the 1st bodywork instead of making a new one, may have been chosen.

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Another interesting discovery : It´s about the  Roots-blowers .These blowers are not considered as compressors because they don´t compress the air , they just accelerate the air flow and force the engine to higher RPM ´s . But : In 1923 a patent was given to Fiat regarding a blower- system that cools down the temperature of the air before it reaches the combustion chambers . Besides a protection against overheating there has been a compressor effect too !

This patent was stolen by other companies by slightly  altering this system .

There are two results : We could designate these kinds of Roots-blowers as compressors .

It´s intelligible that old Agnelli was not amused . Not only his best engineers were lured away by other companies , his patents were stolen too !

Many greetings Hannes

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Another topic that´s interesting for me is about the two oil tanks . Protar represented the big rear oil tank as a high-tech version with a lot of bolts . That´s nonsense imho .

Thanks to Harvey we do know now that the frontal oil tank has been much bigger compared with the kit´s version  . 

How  did these tanks look like ?

In my opinion these tanks were made out of welded sheets similar with the fuel tank . If there were bolts and screws they were most likely placed around the openings  but I doubt there were many of them .

For the successor the U-shaped tube was shifted from the front to the center of the tank , probably for ergonomical reasons .

There´s a case ( about 20/10 /10 cm size ) at the rear end of the  big oil tank . I don´t believe this to be a part of the oil tank system .

It looks like a simple box for me with a strenghtening sheet below .

The question is : What was inside this box ? Tools , spark plugs or a piece of pizza for Bordino ? I don´t know if there were prescriptions at that time if tools had to be aboard .Fred could possibly answer this question .

There´s a hanging tube system below the big tank . It hangs lower than the chassis rail and should get represented on the left side of the car imho . This construction was possibly multi-functional :

An easy replacement of the old oil by new one , possibly a filter function and a system for cooling down the oil temperature a bit .

Many greetings !  Hannes

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10 hours ago, Hannes said:

It sits on spacers over the chassis and the gaps were filled with putty as we can see on the new HRD version of photo 2 .

Hannes, when you talk about the gaps filled with putty, you mean this?

 

xbUZPQ.jpg

 

 

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Yes exactly , dear Olivier . We both altered the inclination of the chassis rails  , that´s why we were forced to alter the bodywork at the same  spots . Most likely the engineers could not simply lower the whole bodywork instead because other parts had to get altered too and it was easier to use spacers instead . The gap gets wider towards the rear imho , Instead of putty this possibly could be  welding works .

Many greetings !  Hannes

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I'll submit all that to Sebastien. I look forward to have his opinion about that. It makes sense, that is sure. One of the questions is to know if it is the change of engine (2 stroke/ 4 stroke) that made these important modifs necessary. Another reason to low the body could be efficiency and driving stability...

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As far as  I know both engines were developed simultaneous . I think it was Massimino who told Rogliatti that at this time it was consensus among the engineers that the two-stroke engine  in combination with Roots compressors  ( type 451 )is more efficient compared with an 4-stroke engine .In my opinion drawing 1 was considered as  version for the 451 engine . But - as we all know - this engine caused too much problems and the 406 engine was developed further instead .

Many greetings !  Hannes

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On ‎17‎.‎08‎.‎2017 at 21:59, Hannes said:

 .

On ‎17‎.‎08‎.‎2017 at 21:59, Hannes said:

 

If the kit´s steering wheel gets turned to the right ,the drop-link rotates into the  frontal direction and  the rod ´s distance to the suspension gets greater - no danger of a collision .

 

.

 

 

.I have to correct myself : The frontal bar was possibly necessary for avoiding  a contact between steering rod and right front tyre !

.

Many greetings !  Hannes

 

 

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I still can't believe the amazing neatness of this VHR photo 2. Look these details on the grille and radiator case. I will have to add little rivets on my bolts, that were totally invisible up to now... Even with such big enlargements, no pixels, and tiny details incredibly neat... I regret not having got such docs sooner. It should be anyway very useful for all the ones who are building this model, beginning with Hannes and Harvey, or the ones who intend to build it a bit later...

 

JdE7jh.png

 

qPUqMy.png

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In one of my earlier posts I mentioned that there´s been cut away too much  by the photographer . On your second photo we can see the upper part of the grille´s frame . On it´s right side seen from our point of view there´s  a falsification by not following the form of the frame . It´s not much in mm but it alters the real shape On top of the radiator case a part of the background can be seen  . You can check this out by using a ruler and elongating the hinges of the bonnets ..The impression of an U-shaped grille is wrong as we can see on other documents .

Such falsifications should not get underestimated imho  !  Hannes

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