Mystic 185 Twin Turbine Build by Chris "Sir File-a-Lot" Fischer

[brooks93]

holly crap what amazing craftsmanship.

[rearwheelin]

I agree with everyone...... Awesome !

[RCKong]

GOOD SHEET ! We can all take lessons off this from the inventive craftsmanship, and attention to appearance and detail.

RCK

[ManuelW]

Hello Guys,

tomorrow will be an update for the new drives, so just a little more patience....

Best regards,
Manuel

[ManuelW]

Hello Guys,

so now it is officially time for:

The Monster-Drives

Already last year Christian machined me a set of custom drives for my SAW HPR 135. These were intended for maximum stability and control at very high speeds so they were designed by form follows function. And the function was great, they performed excellent on the hull right as expected. Also Christian liked them, especially the look.

So as for his new hull, this Mystic C5000, he also wanted a kind of similar set of drives. Overall it took me about 15 hours of work just in the CAD program to design the drives and make the technical drawings. Did think a lot about how to make the dimensions and proportions right as these should also work on this hull which is not self-evident. Therefore I couldn't just scale-up the drives from my HPR 135 but had to make some changes and tricks to get it right. But I think it should be fine and they should work very well on that hull but the first test runs will prove.
The optic is definitely a sharp contrast compared to the rest of the boat but they have just the desired look. They are quite huge (overall length from transom to the DogDrive is 240mm or almost 10" ) and look massive but without looking clumsy or unshaped.

So I gave Christian the drawings and he was very very satiesfied and started immediately to order suitable raw material. He used very high quality T6 7075 aluminium which has a very high strength. The round stock for the drive tubes had a diameter of 60mm so it produced quite a lot of chips to machine the drive tube out of it.

Here the comparison of the round stock with the hull and the technical drawing, I think it shows the dimensions in the right proportion:




At first he turned the side with the ball joint, followed by the other side with a 12mm + 0.01mm bore for the bearings:

[ManuelW]

Here the result after the turning process completed, and seriously, the drives have already the final length!!!

[ManuelW]

Now the really hard work started, the milling. The turning was done on a CNC machine, as especially the ball joint is almost impossible to do on a normal turning machine. But for the complete milling process, he did everything by hand on his little Proxxon machine shown in one of the previous posts. And he did also take quite some pictures as documentation.

First step was to clear the two side surfaces and the bottom as these were just flat surfaces:










Next step was the upper surface which was much more complicated. But I think it is not necessary to explain, just take a look at the pictures:

[ManuelW]

[ManuelW]

Then they were sanded with 800 grit to remove any marks from milling or the vise:


Another project were the gearboxes, as you might already know Christian likes to use vast amount of nice little screws. So thats how I designed the drive. As it really was a complicated part he finally decided to had it CNC machined by a good friend of him who also cycles with road bikes. I think this was the right decision, it might have been possible to do it on his little Proxxon milling machine but the necessary time and effort would be in no proportion to the result, furthermore we already know his skills so another demonstration is not necessary... ;-)

These are the gearboxes after he received them:




The rest of the parts including some special plastic washers he also did on his CNC turning machine:

[ManuelW]

When all the parts where basically "finished" he started the assembly and polishing work:

[ManuelW]

A still missing part is the upper support of the drive which is screwed to the hull. The first step was turning, the second one milling. As he has a dividing head this was not a big deal - as for sure also done on his little Proxxon machine:

[ManuelW]

Next work was to drill twenty 1.6mm holes in the two cap nuts for the drive. Sadly this time he had bad luck, after 19 of 20 bores the 1.6mm drill gave up and broke. So he had to make this part again but then everything went okay for the second try. Here some pictures to see the work and the dimensions:

[ManuelW]

After drilling the holes and cutting the threads he grinded the parts like the drives with 800 grit and polished them to a mirror-like finish:

[ManuelW]

As you might have seen on the gearboxes there is a little circle with a diameter of 10mm. So he took some effort to cover it nicely with glossy CF to give the gearbox a nicer look - I think this can be called a win. To get a precise circle with 10mm diameter he turned himself a kind of stamp and used his vice. The CF sheet has only 0.3mm so it was not a big deal.

[ManuelW]

Some of you might remember, Christian had a skull lasered on his aluminium hopper tanks by his friend Hannes in the German Forum. Their work was beautiful so it was an easy decision to send them the gearboxes and the drives for a little "update".

Here you can see the result, definitely worth the effort: