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

[ManuelW]

final RC box

To the end it was really hard to find place for all the cables as the box was really narrow. It worked but it couldn't be a smaller one. He also used a small mesh guard on many cables to give them a nicer look. He told me it was like a surgery to do that.

Here some pictures, first a few overall then detail ones:

[ManuelW]

What was still to do was the wiring of receiver battery, receiver and servo but compared to the other part that was a margin. He also installed an emergency cut-off to be able to disconnect the receiver battery from the receiver. Also the servo arm got some little carbon fibre upgrades. The receiver battery is a 2S2P LiFe 1450mh, I desoldered it to two independent but still parallel connected parts. There was just not enough space for a single block of 4 cells. He installed also a little board to be able to check the receiver battery voltage.

[ManuelW]

Thats enough for today, the next work will have to do with the turbines themselves but that is a story I'll tell in a future not too far away.

For today I whish you a nice evening,
Manuel

[metalsak]

hi guys.....the way of christians glueing,and working on resin reminds me some of the finest TIC welders on stainless steel....SUPER!!!!! he always find the difficult way to build.... both,you are very lucky,that you are friends,as in my mind,the one gives to the other. keep this fantastic work,always. me ,from my side,for sure i will be more good on my projects,as we look a ton of quality work......stelios

[millzee]

It's nice to be able to start my day by seeing your progress, it get's my mind working instantly, love it. Your a modern day einstein

[graill]

Simply awesome. The work is of the highest calibre. To be truthful, i cant wait to see how Christian and Manuel will top this build.

[ecomisky]

Impressive Sir!

[ManuelW]

Okay, today a little more progress

turbine frame structure

The turbines come with a nice aluminium frame structure when you order these from JetCat. Its strong enough, light, cheap to produce and also has a nice optic. But as you maybe found out Christian has a little obsession with carbon fibre
I guess if he could afford, he would make almost everything including the furniture and the floors of his house in CF.

Here are two pictures how the stock frame structure looks:









So he came up with the question, if there's a chance to make a new frame structure out of CF. But there are two problems:
-heat: Most interesting is that not the turbine itself is the main problem with heat but the gearbox which is directly bolted to the ground plate and has a big contact surface. After a run it will have easily around 100°C so with standard CF sheets this can already be a problem. It could even be that the ground plate is already a kind of heat sink but we were not sure about that one
-brackets: On the side there are aluminium brackets to stiffen up the ground plate, so these are quite important. And its not easy at all to find suitable CF brackets, even more complicated if you need "good" ones which means good quality, heat resistant and stiff.

But already Obama said "Yes, we can!". So the first part was my task. I contacted Roman Kulossek from JetCat about the idea and he said if we find heat resistant CF material it is possible. Also the water and the cerosene cooling work well, the ground plate is not used as an additional heat sink. For the ground plates I ordered a suitable 3mm CF sheet, these are made of high-strength PrePreg material with aviation approval. They are pressed and tempered with 140°C so there should be no problems with that.
For the brackets I found a suitable supplier where I ordered 5 brackets, they feature a thickness of 2.5mm. Both, the sheet for the ground plates as well as the brackets, have a dull surface. This is due to the use of pressed PrePreg material. It might not have the glossy optic but it will be definitely stiffer and have more strength than a glossy CF sheet of the same thickness. I had all the material shipped to Christian and then he moved on with the work.

First he polished the bearing chair to a mirror-like finish:

[ManuelW]

The next task were the brackets in the rear of each frame structure. As you might see these are different but its not a mistake. This is due to the different turbines. One runs clockwise, the other one runs counterclockwise which needs an additional set of gears in the gearbox. Therefore the heigh of the mount as well as the output shaft is not the same for both turbines.







Afterwards he did the base plate and the side brackets. He was very surprised about the strength of the material compared to the glossy CF sheets he was used to. Especially the bores are not that easy as a usal drill gets blunt very fast. So he used a solid carbide drill, which worked very well. The side brackets are not only screwed to the ground plate with M4 screws but also glued with UHU Endfest 300 over the full surface. That means its like its a single unit which is almost impossile to break.



The last work were the plates for the bearing support on the front. To get the right thickness he glued several plates together, using also UHU Endfest 300. He also changed the shape to give it a nicer look, not that angular. So from now on just pictures!

[ManuelW]

[cuppa]

Amazing. The amount of skill, imagination and neat, clean design in this project is way beyond anything I could ever hope to achieve. It is nice to know that engineering skills of this magnitude are alive and well!

[Gimp]

Pure insanity, bravo!

What step is next?

[ManuelW]

And beside the nice optic the CF frame structure has two other advantages. First its much stiffer than the original aluminium one, second thing is weight. Didn't believe it first but the difference is nearly 200g for each side, makes almost 400g overall.

main fuel cells

What a surprise, Christian also wanted to replace the plastic main fuel cells which came with the boat. Sometimes I ask myself why he didn't build a completely new boat instead of replacing almost every part on this one. But the glossy CF interior, the Aquamania paint job and the custom hatch system with the three independent hatches make this hull really special - something Christian likes a lot.
Once I've seen a 72" skater with twin turbines online and I remembered it had cevlar cerosene fuel cells. I knew these are mostly used in jetpowered rc aircrafts. Cevlar is used due to its wear resistance, this is very important in cases of crashs. Carbon might be very stiff but it will break almost immediately in case of a crash. Sure you could make the fuel cell thicker and stronger but weight is a big problem. Therefore the use cevlar.
So I contacted one of the manufacturers and after exchanging several mails he decided to make me two custom produced fuel cells in glossy carbon fibre. These were also the first he did in CF, but the result was great. It took several weeks and also was not that cheap but definitely worth the effort.

Here a few pictures of the two "drivetrains":








So enough review for today. Thanks again for the response!!

Have a nice evening,
Manuel

[Boaterguy]

beautiful tanks, but they seem a little small?

[graill]

Well, i had a couple hours of free time to work on my rig.......as i worked on it i kept seeing Christians build in my head. I went and made a loaf of bread instead.