Graupner/Mugen Mercury CAD model...

[silvertriple]

There is an amount of adjustment in the locking of the centre differential, similar to a slipper clutch. The different output gear sizes in the main gear means if the nut is loose you get 2/3 of the torque to the rear wheels under power, with 1/3 to the front wheels. This will give you more steering under power and under braking, as you will also have a rear bias in braking from the motor. Combined with the gear diffs the downside of running it loose is that if one wheel starts slipping all the power will go to that wheel. If the nut is tightened down so the centre diff is locked up you have both front and rear wheels locked together so the torque and braking is evenly split between front and rear and you get less steering. By adjusting the nut you can change how much slip you have, just like you can vary how much slip a slipper gives, which changes how the buggy drives through corners. Mine was adjusted so it is a little stiff but still works as I had a lot of steering on the grass surface we were racing on.


I also first thought the wing end plates were bent from storage as well, as you can see on my original wing here


But it shows the bends in the sides in the manual

I guess I'll have to change the wing, or to make a second one, with the angles. The fact is that car was sold under Mugen, Academy, Ryuz and Graupner. I've not seen much of Academy and Ryuz pictures, but it seems that the Ryuz one had a different body, a metal undertray (and no lateral decks), and potentially a different wing from what I saw. And I'm affirmative I saw some Mercury with no angled sides.
The fact is as well, manual don't necessarily gets updated when change in production occurs for a reason or another (I have seen some examples of that in some other cars, where there is clealy at least 2 different versions within the same brand and there was no update of the manual between V1 and V2 - although the changes were there and clearly visible although not impacting the build). And here, while there was four versions of this car, I always only saw the Graupner manual online... Not that important anyway, as change wise this is quite easy to deal with in CAD...

[GoMachV]

Not sure if this helps. Very hard to photograph and get that line. Mine is the World Engines version (Academy)

[silvertriple]

Not sure if this helps. Very hard to photograph and get that line. Mine is the World Engines version (Academy)

Jeff, but why oh why did I model this while you have a plain brand new one ? I suppose you have a body as well... I would be great if there was a way to do a mould in an non destructive manner (And unfortunately, I guess this is not necessarily something the lie of TBG or others are doing...).

[GoMachV]

Boki is close to me, a couple hours drive, and can do it non destructively however it's not a body he would usually take on with other more popular bodies ahead of it in line. If I could prove it would be a value for him, I'd be happy to try.

I'm not sure why tbg claims the body is destroyed, I suspect he has a container full of the bodies that have been backpoured that are perfectly fine still

Sorry I didn't mention it earlier, happy to get you any dimensions you need or pics.

[silvertriple]

I'm not sure as well, because I can't see how taking a mould can be destructive, specially considering that some are saying clearly it's not. But they are not necessarily following the same process...

My friend at Loisirs Creations RC told me he already made some mold from damaged body. He don't actually care if it a new body or a damaged/used body, which is also another difference with others. I guess some care more about rentability and being able to pour another mould in case there is an issue with the first mold (so easy to claim it's destructive, just to keep the body?)...

[silvertriple]

Following @terry.sc and @GoMachV indications, I modified the wing...
Also added a white stripe on the body... It doesn't change much the car...


And here is some new renderings...

[terry.sc]

I'm not sure why tbg claims the body is destroyed, I suspect he has a container full of the bodies that have been backpoured that are perfectly fine still

The technology of the time when Bluegroove started meant that to get the best finish and sizing you backpoured resin straight into the body, meaning you end up cutting the body off the tooling to release it. Plus most original vintage bodies are fairly brittle compared to new bodies, and there is a chance they would break anyway. You can treat it with mould release to stand a chance of getting the body off the mould, but of course that makes the mould slightly smaller again, which is not something we want.

If you have modelmaking skills you can take a damaged or cut out body, use filler or similar to get the shape, then modify and fill in the missing bits to get the complete body shape that you can then take a mould from. This takes some time, and therefore cost, as well as needing the skills to produce something usable, and if you are Bluegroove and don't have the skills to do this you just backpour new, complete bodies as financially that's the most cost effective.

I have been looking into producing my own patterns from the body and broken wing that I have so Penguin could make bodies from them. As there is a limited market of about 5 people in the world who would want one, there is no way Penguin are going to create a mould for me.

[Dadio]

Back when I was as school I did try making a mould and there is more to it even if you use plaster , we tried to do a Ford RS200 body and what we didn't expect was that the weight of the plaster bowed out the sides of the body and distorted it so you need to put a support frame around the outside as well , i was able the use the body afterward and we made a few copies , school had a vacuum former , my best mate's dad was the caretaker and we both worked after school as cleaners so we had the run of the place , unfortunately the only plastic for the vacuum former was orange flocked stuff for making jewellery box interiors , very brittle but we had fun smashing them .
I think if I were doing it regularly then setting the body upside down on expanding plumbers foam as the support as the easiest way and that would ruin the body .

[GoMachV]

TBG had that problem with a TOJ body I sent them. When I got the repop from them, it looked like a balloon. Of course they couldnt do anything because the original was destroyed, so I sent them my 2nd and last new TOJ and they were able to successfully backpour it.

[silvertriple]

My friend Johann who has both a printer and vacforming machine proposed to run a test... I sent him the STL for the bodyshell mould... He printed it and he advised that the areas that I patched at the rear need revision.


I modified the body accordingly and reapplied the mould elements. It should be better now. Lesson learned for surface mode here : Patch as smallest areas as possible when using patch, and used small faceted areas (triangles) to address the big angle changes. This definily helps. Second thing is that I could have spot the issue earlier if I had done a section analysis before sending the stl to Johann.


Anyway, he reprinted the rear with the new version, and it is much better now. Angles are still a bit rough, but that should be workable...

[silvertriple]

I also reviewed the mould for the wing following the design change.


The bodyshell mould print is in progress... (adaptative layers are used in order to reach the best possible quality, which is the reason the slicer preview looks this way)


Results tomorrow...

[silvertriple]

This morning the bodyshell mold was waiting on the printer bed


It's almost perfect except an issue on the rear part which look like a layer shift but is not a layer shift as frront did not have any issue. I guess this is probably a filament issue rather than anything else (ABS, transluscent (the only one I had at home currently), print with generic profile, adaptative layer set to max quality).


The issue only affect the very rear of the body, and mostly support rather than the body itself (i'm not going to do a reprint for this). The change of tone is due to adaptative layers.


The pictures were taken this morning before taking my breakfast. I launched the wing and went to the office.

Back home, I was quite impatient to look at the result... And the bodyshell mold is quite close. I can't push the bodyshell further on the rear, because the body top parts are narrower... But the line and the dims are there...


At least it is in the original spirit...


I can't say the same for the wing... Maybe there was still some leftovers of the previous day when I started to key in the wing dimensions ... I will need to redo it...


But at least, the body is good enough

[silvertriple]

A friend send me pics of two bodyshells for the Mugen Mercury

The one that I modeled, first, unpainted :



And another one which appears to be the same as the Mugen Mercury proto bodyshell.

[silvertriple]

Few hours later... A few sketch reviewed, and the wing is now much better. (I suspected the issue in the first sketch when I saw the difference and I was right). I also increased tha angle on the sides.


And few minutes later, I had the mould as well. It is actually easy to do, using surface and patchs to close the model to have a solid body...


The print is launched and in progress...

[terry.sc]

That's looking really good. If you do get some bodies off it I would be interested in one as I want to keep racing mine.

The bigger body does look like the prototype body, the prototype had a flat alloy plate to mount the electrics instead of the plastic covers and needed the extra sides to cover it.