McLaren M23 x 2 (CAD, 3D Print & Tamiya kit upgrade)

[Flying Badger]

Started a long road this week.

2 McLaren M23 F1 cars:

- Emerson Fittipaldi's WDC winning M23/8 from 1974

- James Hunt's WDC winning M23/8-2 from 1976 

 

Initially modelling everything digitally at 1:1 scale, then I will 3D resin print the parts to create a 1:20 kit for the 1974 car as the first prototype along with some DIY photoetch and I guess decals (thats a long way off yet).

 

At the same time I'll also be using select printed parts from the 3D modelling to update, correct and detail the Tamiya 1:20 kit of James Hunt's 1976 M23/8-2 (as the Tamiya kit is lacking in the level of obsessive detail I want!).

 

I'm currently following the same build process as the real thing modelling each part as I go - starting with sheet metalwork (16 Gauge Alu) on the monocoque tub, next is fiberglass sidepod internal skins and then on to modelling a full DFV engine and it's integration, suspension etc. and finally all the fiddly gubbins. 

 

Virtual sheet metal work is a lot easier than the real thing so it is starting to look like an M23 already! However there were also some smaller parts that were easy time fillers when I was limited to using only one hand this week.... the other arm had a poorly 1 yr old asleep on it!

 

First screen shots: 

And with some token colour added.

 

Can you tell what it is yet?

 

More later as things progress and I collect more reference material to help.

 

 

Edited February 14, 2022 by Flying Badger
Better thread title

[Flying Badger]

Also I know the discs themselves should be vented.... these modelled parts are templates to test the fit of the disc carriers which still need their castellations in the rear rim face.

 

The chromate green of the forward frame is a bit harsh - seen a rebuild using this treatment but not sure what the original chassis's were protected with yet. More research to do!

 

Flying Badger

[Jo NZ]

Regarding your 16swg tub - that's about 1.6mm full size. I've just printed a component that's 2mm full size in 1/8 scale, and it's a bit thin... Your skins will be 0.08mm in 1/20 scale - that's probably see through. You might want to overscale them a bit.

[Flying Badger]

16 Gauge Alu sheet is 1.29mm in real life so at 1:20 is around 64microns which, yes, is a bit thin.

As most resin printers have a layer height of 50microns I realise I'll be adapting the 3D model for printing by increasing the sheet metal thicknesses (and adding some bracing in hidden areas like the crush structure).

Knowing this I've modelled it all usung a solidify modifier that I will leave unapplied so I can just tell blender to make them thicker for the print files.

[Mpfiend]

by the colour of the front spoiler, a McLaren of some description? M23?

[Jo NZ]

39 minutes ago, Flying Badger said:

16 Gauge Alu sheet is 1.29mm in real life so at 1:20 is around 64microns which, yes, is a bit thin.

 

From working on aircraft structures  for 20 years  I think this is more like it.... 16 SWG = 0.064” / 1.626 mm. You are talking Imperial wire gauge?

[Flying Badger]

16 Gauge sheetmaterials is 0.064" (I.e. c.1.6mm) in Ferrous.... but not Alu as that's thinner (1.29mm).

 

Yeah makes no sense to me either 🙂

 

Although I suspect often quoted thicknesses refer to the ferrous measurements for everything rather than the technically correct different sizes for non-ferrous sheet materials like Alu. So I'm not 100% what McLaren mean exactly by "16 Gauge alu sheet" might be 1.626mm or 1.29mm Alu. I've gone with the technically correct  1.29mm for the moment.

Edited February 12, 2022 by Flying Badger

[Flying Badger]

3 hours ago, Mpfiend said:

by the colour of the front spoiler, a McLaren of some description? M23?

Spot on. As you might guess from the "Project 74/76" I'm doing both the 1974 Fittipaldi M23/8 and the 1976 Hunt M23/8-2. Fortunately the monoqocue for both is almost identical and the differences are in the other parts of the car. 

Edited February 12, 2022 by Flying Badger
Corrected typo

[Sabrejet]

16 SWG seems a bit thick: 18 or 20 SWG sounds more like the gauge you'd expect on a monococque of this age?

[Flying Badger]

Just now, Sabrejet said:

16 SWG seems a bit thick: 18 or 20 SWG sounds more like the gauge you'd expect on a monococque of this age?

That's what I'd expect. But 16 Gauge is what my McLaren reference material says.... but this is partly why I think McLaren are using the correct alu gauge measure as that's thinner and closer to 18 gauge ferrous. 

[Flying Badger]

Some more minor progress - some more sheet metal work on the tub and the framework for the nose:

 

Framework for the nose was a bit fiddly to get the angles spot on but I'm getting there:

 

The framework isn't actually attached yet as I need to fabricate the brackets to allow it to be bolted to the forward monocoque frame via these shiny things:

 

Also as you can see I've been experimenting with material nodes to get more realistic materials... especially pleased with the cast alu of the disc brake carrier:

 

The disc itself is a bit too shiny at the moment but I've still got a lot more modelling to do on that anyway.

 

More as I get it done.

 

FB

Edited February 14, 2022 by Flying Badger
Typos

[Flying Badger]

That disc was annoying me... so I had some fun sorting it out:

Much better....

Looking at it now I think my vent spacing is bigger than it should be (it's 15 degrees on this and I think 12 or 10 degrees might be closer) so I may tweak that (I set it up as an array so altering the repeat is easy). The width is OK (it is a 1/2" gap with 1/4"of material either side).

 

Whilst I was at it I had a go at tweaking the material settings to get it to look more like polished steel of a new disc.

I still need to add the castellations to the carrier and to the disc itself but its a step closer

[Flying Badger]

Just to show I've not gone totally digitally demented, and there will be some actual modelling going on..... 

I have this:

 

The detail is not bad (It's Tamiya after all) but there are some rather obvious issues not the least of which is the lack of detachable nose,

 

or the total lack of detail in the floor of the car (with the exception of the randomly added AA battery compartment underneath!):

 

Hence the deep dive into all things digital for a while... well that and I wanted to make one kit into two cars 🤪

 

[Flying Badger]

Working on the wheels and associated stuff:

 

Added the four spokes to the front wheels and modelled the cuttouts to get some nice 13 x 11" magnesium front wheel rims:

 

 

Then used those to make the rear 13 x 18" ones...

 

Then they looked naked without some rubber hoops so I made those based on the Avon online tyre profile data (Avon are reported to strongly resemble the Goodyear tyres from the 70s) and they look close.

 

Those 18" x 26" rears are chunky!

 

I also added the wheelnuts and the safety clip pin on each hub.

The pin was an interesting challenge. Had to learn a new trick extruding a profile shape along a Bezier curve path. That technique is going to be hugely helpful when it comes time to model ducting, hoses and the exhaust systems.

 

Off now to do some real modelling and see if I can get the decals off the horror show that is the Williams FW11 kit (see other thread).

 

FB

[Malc2]

This is interesting. Looking forward to the printing!

Pretty sure the '76 car did not have the x brace under the battery tray.

 

M.

[Flying Badger]

Hi Malc

Thanks I'll dig a bit deeper as my research suggests it's chassis dependent rather than year. Some chassis had the cross brace and some did not.  The '74 car I'm doing did so I modelled it for that one of the two.

 

There are a number of other differences between the several years the M23 was actively used....The 76 and 74 cars have different wheelbases and rear wheel tracks as well but that is all due to a spacer at the gearbox so I'll deal with that when I get to that part. The wheeltrack is only 1inch different which at 1:20 and spread over the two rear wheels is 0.635mm per side! 

 

Lots of other minor differences. Building both years means I'm modelling everything but have a notes list of what to include in which model and what to omit.

 

 

[Malc2]

OK!  I assumed the 3d model was the '76 car because of the front suspension is not as the '73 cars.

3D modelling is for sure the future - I look forward to the results

 

M.

[Jo NZ]

11 hours ago, Flying Badger said:

The pin was an interesting challenge. Had to learn a new trick extruding a profile shape along a Bezier curve path. That technique is going to be hugely helpful when it comes time to model ducting, hoses and the exhaust systems.

 

Bezier curves!  What CAD program are you using?  Matra-Datavision Euclid used M. Bezier's curves in the 80s. At that time they were really difficult to manipulate to get the shape you wanted. Renault used the same software, we reckoned that's why all the late 70's Renaults were such strange shapes....

[Flying Badger]

I'm using Blender at the moment although I plan to try fusion 360 soon. 

 

Bezier curves in blender are easy to use and are essentially the same as the pen tool in Photoshop / Illustrator etc. 

 

Each vertex has a pair of handles that define how the line between it and the next vertex curves. Manipulating those is identical to the basic grab, rotate or scale operations on a vertex so super simple. Then when you are done you create the 2D shape of the profile and then tell blender to extrude that profile along the path of the bezier curve to give you a 3D shape. 

 

So in my pin above I used the bezier curve to draw the shape of the pin (took only 8 vertices!). Then created a 2D circle with radius of 1mm. Blender extruded that circle along the bezier curve shape to give me the pin in 3D. 

 

Works great and is really easy. No more spending hours doing this manually to get a rough outcome!

 

[Flying Badger]

Got some more of the main coachwork done over the weekend and last night. She is starting look like a McLaren M23 at last:

 

 

A quick trip to the virtual paintshop for a basecoat of white to cover all that shiny aluminium:

 

Also got the roll bars and their supporting struts done (again using a profile applied to bezier curves):

You can see the rear frame as well in this that was the end of last week as well as the rear of the fibre glass side pod internal skin (I assume they went with fibre glass as the curves added complexity that was easier in fibreglass than in alu sheet metal work)

A few more bits of sheet metal work to finish off on the rear frame area then I'll start on miriad of different airboxes.

 

This is still the 1976 specification setup. I've done a fair amount of number crunching to work out how implement the 1974 (and possibly 1973 & 1975) cars as well. Mostly it's wheelbase differences that are all down to spacers at the gearbox to engine block junction.... but there are some subtle extras (like a 1 inch extension to the nose length from 1974 to 1975).

 

The front wing is different in 1974 with an angled leading edge rather than the straight one in '76.

That big rear wing is currently modelled on the USA grand prix for 1976 but it varied a bit over just that season let alone the several seasons.

[Jo NZ]

On 18/02/2022 at 21:02, Flying Badger said:

I'm using Blender at the moment although I plan to try fusion 360 soon. 

 

The bezier curve descriptors were so difficult to manipulate (computer power? It was only a VAX 760 (?)) that we often gave up... Good to hear that they work nowadays.

 

If you're going to learn Fusion 360, it's free for students and hobbyists (a bit difficult to find the free site though). I can recommend the tutorials on YouTube by Arnold Rowntree https://www.youtube.com/watch?v=LSRKJgTSS4c&list=PLFCTgdiT5-kLBNvrkUNy63Gu1tWdRuKkr. I tried several others and got confused until I found these.

 

[Flying Badger]

Thanks Jo... had a look at those video tutorials to refresh my memory (I've done some basic design in fusion360 a few years back but I'm rusty). Nice simple and informative videos.

 

Not much free time this weekend time to get very far. Concentrating on the Ford Cosworth DFV now the main shape of the monocoque looks ok. Over the weekend I've managed to get the gearbox flange, the timing cover and valve covers pretty much finished, as well as the initial rough outs of the two parts of the head and the sump. 

 

Spent a lot of time reverse engineering dimensions by extrapolating from the few engineering drawings I can source which have a known dimension on them. Fusion 360 is really useful for that and I've been exporting my sketches and their dimensions as a useful future reference. 

 

I'll export the models from sketchfab to blender to refine their appearance a bit as fusion360 doesnt render materials anywhere near as well.

 

Hopefully a picture of some of these parts imminently!

[Flying Badger]

Got the Valve covers done in Fusion360 then imported into Blender for a bit of prettying:

 

 

 

I know there are thru-holes for the bolts missing but the bolt/cap heads themselves will cover that and ultimately this will end up being 3D printed (so I don't want the holes anyway)

 

These are Ford badged valve covers as almost all the cars that ran the DFV had the Ford version. Cosworth badged covers do occasionally appear in photos of some cars (e.g. Jochen Mass's Arrows A3) although I'm not sure how many of those are original or recent replacement parts.... Needless to say I know all the McLaren M23 engines had Ford badged valve covers.

 

One omission on this part is the embossed part number. I'm not convinced it will come out in 1:20 scale and the number appears to have varied a fair bit (the main reference I have is DA0088 but I have seen others such as DA745 etc.) Anyone cast any light on that?

Whilst thinking of badges etc. I've started a decal list of extras I need to create including the Nicholson McLaren Engineering badge that at some races is present on both covers, others on only one and at Watkins Glen in 1974 was on neither. Fortunately being mostly orange it contrasts rather well with the black of the valve covers so is easy to spot in photos.

 

More as it happens.

FB

[Malc2]

Looking good!

From the work you have done, do you know if the 1/20 Tamiya DFV is slightly undersize or not?

 

M.

[Flying Badger]

Hi Malc2, 

 

I've not looked yet... the engine sprues are still in their bags for both the McLaren and the Lotus 79 I have sitting on the shelf waiting building.

 

I can take a look over them with my micrometre / Vernier gauges etc. and see how they compare to the dimensions if I get a chance in the next day or so. I'll let you know what I find out.