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

[ManuelW]

Here how it looks inside the boat:

[ManuelW]

mount for the fuel filters

Christian decided to use two fuel filters instead of one. Normally one filter is used between the fuel pump and the Y-connector. His are before the 2 magnetic vents, one for the cerosene for the turbine and one for the start/ignition system. Beside each other there was not enough space in the box so he aligned them vertically. So he made a few drawings of the mount first, then filed out the single parts before he glued them together. The filters are clipped in from the side and fixed by the nut on each end.
A few pictures show it probably better than I could explain!

[ManuelW]

mounts for the magnetic vents

Each turbine has two magnetic vents which control and regulate the fuel supply during startup and running. As it was done for the filters he also aligned the vents vertically by a special mount. This time it was made from a turned aluminium part (T6 7075 aircraft aluminium, polished for sure). A big aim he had was not a single visible screw. So first he turned two pins with one rounded end, then cut them into pieces. One step before that he drilled two precise 3mm bores, these had to be absolute exact as they were given by the vents. On the bottom part he made a countersunk for an M3 screw, he even had to reduce the diameter of the head to the minium of 3.9mm. In the top part are some M3 threads so he can assemble each unit from the bottom invisible. After some little polishing also of the vents he assembled it as a unit with the fuel filters. I think it looks pretty nice.

[ManuelW]

on this picture you can see the M3 hex screws with countersunk in the bottom part:








and inside the box:

[ManuelW]

So for today it were mainly small parts, I hope you still enjoy these as these small parts take a lot of time.
As for sure feel free to add comments, questions, remarks and so on! We appreciate that!

Wish you a nice evening,
Manuel

[drwayne]

Fascinating.
Exquisite workmanship.
One asks what time taken to present this perfection ?
Wayne in Au.

[megalops]

Is Christian the lead fabricator at west coast customs in Berlin as a day job? LOL!

[CornelP]

Is Christian the lead fabricator at west coast customs in Berlin as a day job? LOL!

Maybe not, but in a previous life he was probably a Swiss watchmaker...

[galant2door]

Truly amazing the time and expertise it would take to create such a magnificent boat like this, my hat is off to you my good man

[JCAustralia]

Truly amazing!!!

He is a true perfectionist.

I am normally very careful with my builds but he is on another planet . I applaud his work.

Cheers

JC

[metalsak]

fantastic work.....and as i m also in the machining job,one think comes to my mind (like asterix and ovelix)...maby, when christian it was a small children,he eat a C.N.C controler.... very good for my eyes to see yours building...greetings from greece,manuel and cristian.....

[ManuelW]

Hello Guys,

today a bit more about the progress of the RC box.

@ drwayne: That would interest me as well - already told Christian a few times to document it. But for the build up to know I'd say already around 150-200 working hours.

@ metalsak: Thanks, especially as you also work a lot in the machining job. Kostas sends me nice pictures from your work from time to time over Facebook. Always a pleasure to see.

more lead-throughs in the RC box

Beside the lead-throughs for the main cables between ECU and turbine there have to be a few more. So thats another load of work to to. To be exat:
-2x fuel input through the bottom of the box
-2x 2x fuel output through side walls (1x fuel and 1x cerosene start per turbine)
-2x rpm sensor per turbine
-2x charging link (1x 2S LiPo for turbines, 1x 2S LiFe for receiver)

For the fuel lines he used special lead-throughs availabe by Vario Helicopter. The are made of soft rubber and the holes have to have the right diameter to be sealed. If the hole is too narrow you can't put the fuel line through, if it is too big it is not sealed. So he pre-drilled it with a small bore and then used sanding paper to get it to the right diameter. The charging plugs for the 2S batterys are Multiplex MPX-System. I ordered Christian several of them from Nessel Elektronik, they are the only ones who have these in black and not in the usual green. Again the rest should be clear from the pictures. For sealing he also used a black colored silicone, normally used to glue fish-tanks.

[ManuelW]

2S battery for turbine ECU's

The turbine itself needs a 2S Lipo battery as supply - standard is a 3300mAh lipo per turbine. But Christian perferred a single 2S Lipo for both turbines. So I ordered him a 2S 5800mAh 30C lipo from turnigy, it was also confirmed by JetCat that it is enough. When I received it I checked the batterys and then stripped it and removed the original cables and the balancer cable. On each pole I soldered three 2.5mm² cable (high flexible from Nessel Elektronik), for the balancer a single 1.5mm² cable between the two cells. So each ECU has now its supply over 2x 2.5mm² cable and charging is over 2x 2.5mm² wire with the additional 1.5mm² balancer wire. As you can't connect these MPX connectors wrong I used black wires on both poles as it looks better inside the box. Then I used black shrink tube. That was the work from my side.

For mounting the lipo in the RC box Christian created some kind of extra box or cover for the lipo out of 0.6mm CF sheet and some little mounts out of Aluminium.








On the last two pictures you can see my soldering job with the extra cables.

[ManuelW]

final wiring in the box

As for sure Christian wanted to align all cables and connectors as nice and possible. This also included nice soldering and the right shrinking on the connectors. There is very little space under the LED boards so he had to solder the cables in a 90° angle. Therefore normal shrinking was not possible but after a few tries he was satisfied with his work:

[ManuelW]

but still quite some work to do:

[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.