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

[ManuelW]

hopper tanks

As like in the original build, the fuel pumps are not fed directly from the main fuel cells but there is a hopper tank in between. This is mainly due to better/more reliable fuel supply of the turbines, as it is smaller and always full. The included one was made of GFK but as Christian works a lot on turning machines he decided to make a pair of hopper tanks out of high strength T6 aluminium.
Each tank is made of two seperate parts, they can be screwed together over a M75x1 fine pitch thread. I think this alone took quite some time to produce. On the bottom is a M5 thread for the Festo 90° angle which goes to the fuel pumps. On the top are three M5 threads, one for the intake from the main, fuel cells, one for filling the fuel tanks and the third one for a display tube which goes to the bottom. Otherwise you can't check the fuel stand inside the hopper tank as it is made out of Aluminium. For all threads Loctite 648 was used to seal them.
To make it even nicer he did some marquetry work with 3D optic CF sheets.

Here some pictures of the progress:

[ManuelW]

After that was done he polished the aluminium parts to a superior finish.

[ManuelW]

As I mentioned he needed some kind of display tube to show the fuel stand. You could just do it by using a clear tube which goes from the top to the bottom. But it would not be Christian if he did it the easy way. So he invested quite some time to do it as perfect as possible. It would be difficult to explain but I think its easy to see when you check the pictures.

[ManuelW]

For the final touch he found someone on the forum who does laser engraving. So he sent the hopper tanks away to had the skull from the paint job engraved on the top surface. Here some pictures of the final result.

[ManuelW]

Comparison Old vs. New: On the right you can see the combined hopper tank for both turbines and on the left one of the new ones. Also the new ones are together slightly bigger than the old one.







Another little job was to cover the turbine cowls with some heat protection foil, as usual it had to be done absolutely precise and symmetric:

[millzee]

WOW, I always love to read these threads although they sure remind me where I'm at with my building skills (lack of).

[cuppa]

That is a work of art. Many thanks for sharing it with us.

[Drax21]

This is great!

[Derrick Davis]

Dear Santa.....
Another thread where I'll be anxiously watching the progress. Good stuff and thanks for sharing!

[graill]

Why the hopper tanks Manuel? They are not needed and in my opinion simply clutter up a beyond fantastic engine bay. I fully baffled my tanks, there is no problem with fuel starvation or not wondering if the pumps will get fuel as i have replaced the orings with the proper material, something next to no one does but should with these turbines. Methinks Chris loves to make things, BiggGrin. Glad to see someone finally putting aluminized fibeglass cloth/ceramics inside their hulls too. I had talked to a couple gentlemen a couple years ago and they used the word gaudy and unneeded, i disagreed. I am glad to see Chris knows the deal. Let him know i have a line on some small vented steel if he is interested, to cover the first stage, better than the solid slab of stainless they have wrapped around it stock, if anything i am sure he can improve or take that to the next level.

[Boaterguy]

I can't tell whether i hate or love this guy.
he does amazing work that far outstands anything i have seen before, especially his gold digger.
then again, he makes me feel poor and unattentive.

[Drax21]

I can't tell whether i hate or love this guy.
he does amazing work that far outstands anything i have seen before, especially his gold digger.
then again, he makes me feel poor and unattentive.

Same, still there are a few tips and tricks in his builds that can be applied to all boaters.

[ManuelW]

@ grail: You've got a long PM :D

@ the others: BIG thanks for the credits

And now let's continue with the build...

RC Box Mystic TwinTurbine

Welcome to the review about the build of the RC box. Its one of the parts were we worked really close together. Normally a rc box is not a very complicated part but everybody who knows Christian also knows, that off-the-shelf parts are not what he is looking for. So I think this could probably be the most advanced/complex RC box ever built. Also it was very nice to see how state of the art CAD software and Christians manual dexterity can work together.

the idea

Christian visited me at home and came with 2-3 sketches and a DXF file (a vector graphic format) on an USB-stick. The main idea was easy: The box should have the shape of the skull (same one which is laser engraved in the hopper tanks), at the end of the tooth it should be extended (see pict. 1). So overall this was the available data:







Picture 2 also shows, that the box should be seperated. The extended part is seperated and contains the servo with receiver and receiver battery. In the main box is enough space for the power supply (2S Lipo) as well as the electronics and the fuel system for both turbines. The box consists of several frames and a base plate. Each seperated part should have its own plexiglas cover. Then there should be another final cover for the complete box. It should have the same shape as the box and made of glossy CF sheet with the skull cut out of texalium sheet on it. Maybe difficult to understand from what I write, when you see the pictures it should be clear.

As a CAD program allows complicated designs it didn't took much time to decide that we'd need another frame. This would enable concealed plexiglas covers and give a nicer look.
Picture 3 shows the skull from the original file, for Christian it looked like vertically compressed. As my CAD program doesn't allow stretching of vector graphics, I used a picture to show how it should look like:



The skull was stretched to 117%, that gave the desired look. As the design was clear I could start with the CAD draft. Meanwhile I sent the vector graphic file to a friend who stretched it to me and sent the new version back to me. The draft of the RC box did take about one day work overall, then it looked like on the pictures below. As I wanted it as realistic as possible I also needed the CF look, but there was just no suitable material implemented in the program. So first I created photo textures of glossy CF and texalium, then I created new materials and imported them in the program. In the draft the bottom of the box as well as the inner walls had a texalium optic, but when building it Christian decided only to have the bottom of the box with texalium, everything else has glossy CF optic.

the CAD draft

[ManuelW]

on the following pictures I added the transparent plexi glass covers





And the highlight of the box, the final cover with the skull in texalium optic:

[ManuelW]

As a few might have noticed the skull still has the same shape of the compressed one. This was as I started my work immediately and received the stretched one at the end of the draft. Here the comparison, I think the stretched one on the right looks definitely better



The I showed my final draft to Christian and he fell in love with it immediately. Without the smallest thing he wanted to change I could continue. First enough material had to be ordered, one HUGE 3mm CF sheet with enough area for three complete frames, a thicker texalium sheet for the bottom, a thin texalium sheet for the skull and enough glossy CF sheet for the side walls and the final cover. As we couldn't get any thin texalium sheet in Germany/Austria we had to import it from Switzerland.

production planning

My CAD draft was already built together digitally from several independent parts. Therefore it was easy to make technical drawings and create vector graphics from the individual frames. So I put three of these frames as close together as possible so save the needed amount of CF sheet. As it should be CNC milled I added little "bars" to make it as easy to cut them out and there is no danger of distortion.
Also created another drawing with the shapes of the plexiglass covers, to have these cut out from another friend. He did a great job on these, instead of real plexiglass he recommended and used 3mm lexan sheets. It's the same material as used for auto bodys of rc cars at it is very strong and not as breakable as plexiglass.





CNC cutting

This job was done by a good friend of Christian, they used a 2.1mm solid carbide miller with special cut for CF I recommended. On the right you can see the huge 3mm CF sheet with the three frames. Each of the frames has a different "width" (10mm for the floor, 12mm for the bottom and 5mm for the top), on the left the bottom sheet and the glossy CF sheet for the final cover. There you can also see the little bars, Christian only had to remove these and do a little bit of grinding and trimming to get the final parts.