Mercedes-Benz W165 Grand Prix engine in 1:3 scale

[Vixen]

Put my name down for one of your action man models with the crash hats and steering wheel for when you market them too!!!    
Chris   

Hello Chris,

Before you finally decide, did you know there will also a range of accessories in the "made by Vixen" series?



But unfortunately, you will not be able to order one of these either.  

They only exist in the memory of the AI bot, ChatGPT.  All you need to do is upload a photo and four or five lines to describe what you want to see or what changes you may want it to make; then less than five minutes latter, it sends you your requested image of a bubble packed action figure. The power of ChatGPT is frightening, I have only played with some simple image creation, but already I have learned never to trust any images as being real, ever again.      So this is a glimpse of the future.   

Well that's a whole day wasted, just playing about with AI, when I could have started work on the next mini-project; which is the flywheel and clutch at the rear of the engine. Maybe tomorrow?   

Cheers   

Mike

[crueby]

Hi Chris,

The Halloween edition was considered far too scary for the general public, so it was removed from the virtual shelves 



Mike

Aaaaaahhhhhh!!  Run away!!

[Roger B]

Excellent work on the magneto and good family shots     

That's some fun Chat GPT work   

[Vixen]

Part 39       Flywheel + Clutch

Thank you Roger,

Yes, playing this ChatGPT to generate the action figures was good fun, a fun way to waste a complete afternoon. But the images were just that; images within the memory bank of the AI machine. Nothing tangible, nothing you could actually touch, was produced. For a tangible result, you need to get out into the workshop and make chips.

So, to return to the engine. The top, the sides and underneath of the engine are now becoming well detailed. However, the rear of the engine, aft of the cam box covers, is completely bare. So the next step (mini project) is to make the flywheel/ clutch assemblies for the two engines.

I have good references for the flywheel/ clutch. I have a copy of the original Mercedes works drawing for the flywheel/ clutch assembly, obtained from the British Intelligence BIOS Report No 1755. I also allowed to take a set of photos (courtesy of Crosthwaite and Gardner) of the component parts of the almost identical W125 engine. The W165 flywheel/ clutch is a lot smaller than the one for the W125 (260HP as opposed to 600HP for the W125) but almost identical in design.



You can see the flywheel is an extremely light racing flywheel. In fact, the clutch driven plate and the clutch pressure plate together, comprise the majority of the flywheel's rotating mass. Clutch pressure is applied by a ring of 12 coil springs. This engine design predates the diaphragm clutch by a couple of decades. A ring of 6 withdraw levers, pressed by a central thrust bearing, engage and disengage the clutch. I intend only to make the flywheel clutch assembly but not the bell-housing.

As ever the first task, was to generate a set of 1/3 scale working drawings from the Mercedes blueprint and collect together enough stock.

More to follow, so stay tuned.

Cheers     

Mike

[Laurentic]

Gosh Mike, but at first glance that looks complex, but of course it is but a small scale reproduction.  I guess full size it would look clearer, and broken down into component parts clearer still.   

What size is your works drawing?

Chris

[Vixen]

Gosh Mike, but at first glance that looks complex, but of course it is but a small scale reproduction.  I guess full size it would look clearer, and broken down into component parts clearer still.   

What size is your works drawing?

Chris

Hello Chris,

M-B were not well known for making things simple. 

The drawings in the BIOS Report were a double page, so quite large. But once they have been scanned, you can scale them to any size you want, larger or smaller. The clutch disc on the model works out at about 76mm diameter. I am sure you could zoom in on your phone or PC for a bigger image.

The end view is interesting.     It contains cut-away views at several different depths to show different features. That takes a bit of effort to understand, but I had access to a dismantled full size W125 clutch (for a few minutes) which helped me work things out. When M-B were happy with a particular design they would carry it forward to the next engines, with little change, other than scaling the size to mach the power level.

Cheers   

Mike

[Laurentic]

Thanks for the explanation Mike

M-B were not well known for making things simple.  I think that is a standard German characteristic. During WW2 their tanks were brilliant but anything but simple, especially compared to the very simplistic American tanks, and even today there are reports from Ukraine that the Leopard 2 tanks are proving too complex, so the so called simple maintenance is too highly specialist to be done on the battlefield.  But brilliant engineers.  Reading the life of Sir Roy Fedden and have reached where he goes to Germany at the end of WW2 and is blown away by how advanced they were.  Not for the first time it made me think how lucky we were to have the likes of Fedden on our side and Hitler in charge on theirs!

Thought you would have excellent details to work from - plus you were very fortunate to have the access you did.  No point in having excellent contacts if you don't make full use of them, I always think!!

Loooking forward to seeing what follows.........

Chris

[Vixen]

It's clutch time.

The first item to make is the Lever Plate. As it's name implies, this plate fits at the rear of the rotating clutch assembly and carries the six levers used to disengage the clutch.  The Lever Plate was going to require a session on the lathe, followed by at least three milling set-ups, and will involve work on three different machines. Therefore, some forethought was required regarding how to hold the stock and accurately position it for the different machining operations.

I started with 100mm x 100mm x 8mm thick aluminium plate. I always prefer to use 6082 T6 (HE30) for it's machine ability and corrosion resistance. I could hold the square plate in a four-jaw for the lathe work. Then bolt the plate to a sacrificial jig plate by four accurately placed bolt holes drilled near the corners.

The Lever Plate centre hole and outside profile were machined on the big lathe using a four-jaw chuck. The transferred to the mill for further machine work.





The first mill opp was to machine the 12 stepped pockets for the pressure spring holder on the front face of the Lever Plate. The embryo plate was bolted to a sacrificial jig plate by the four corner screws. The work was centred using the big central hole.




The work was flipped over to enable machine work on the rear face of the Lever Plate. I used a 2R x 6 OD, corner radius, bull mill to cut away the six pockets. The bull mill creates nicely radiused corners for authenticity and added corner strength. The 12 spring pockets, machined in the previous set-up, are now exposed.




Next. a 4mm ball mill was used to form the space in which the six clutch operating levers will reside. Note the wider lands where the clutch operating lever hinge pins reside. The mounting holes were then drilled around the outside, before the part finished Lever Plate was parted off from the square stock using a 3mm end mill.






The part finished Lever Plate was then transferred to the rotary table on my 4 axis machine for the six hinge pin holes to be drilled. The embryo plate was held in the three jaw chuck by it's outer diameter. An extra long centre drill was needed to reach in and spot the six holes, which were drilled and reamed to final size before the plate was indexed to the next position. Somehow, I have no photos of this set-up.

Finally, the whole Lever Plate was given a good clean up with wet-n-dry and Scotchbrite to remove the machine marks.

Much more to follow, so stay tuned

Mike   

[crueby]

More very complex parts!  Still following along...   

[steamer]

Looking really good Mike!    I might have some time myself this week for some whittling...

Dave

[Vixen]

Thanks guys,
Dave, a little metal theropy always does a power of good.

Mike

[scc]

Wonderful       Terry

[Vixen]

Thank you Terry,

The Lever Plates are made, so here come the clutch disengagement levers.

The levers started life as roughly cut blocks of 5mm brass stock. Two holes were accurately drilled in each block to secure them to a jig plate and machine the outside profile. One side was then thinned, before the lever was flipped over to allow the second side to be similarly thinned.




Each lever was mounted, in turn, on the side of the jig, to machine the tiny fork on the outer end of each arm. It was simpler to use the same drill, used to drill the mounting hole, to locate the end of the lever for this operation.




Here you can see the lever arms nearing completion. The finished levers on the left with a few still awaiting the fork machining are on the right.




Here are the levers, complete with hinge pins assembled onto the Lever Plate.




Next, the top-hat shaped pressure spring holders were turned and parted off from aluminium bar stock. The holders were each transferred to an upward facing three jaw chuck on the mill, to machine the inside pocket. There are rather a lot of spring holders required; twelve per clutch plus a couple of spares.




Here are the spring holders in place, viewed from the front.




And again, together with the levers, viewed from the rear. It's starting to look busy at the rear of the clutch.

Mmmm,      Looks like the top and bottom mounting holes in the Lever Plate, need to be spot faced.




Stay tuned, plenty more to follow

Cheers   

Mike

[Laurentic]

Following along .......  and closely observing some very nice stuff 

Chris. 

[Kim]

Very nice, Mike! 
That is elaborate, and beautiful work you've done on those levers, spring holders, and clutch plates. Just amazing!

Kim