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  #11  
Old 07-09-2017, 04:42 AM
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Mirco Mirco is offline
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Beam Catcher:



The fuselage with all its folds and cutouts looks pretty scary, but it went together quite well. Be sure to laminate sides and ceiling where the wings attach. It's good to attach rear landing skid after the wings because you can punch holes in the white rectangle under it and push against the wings from within.

Wedge-shaped cutouts in the "prong" on the vertical wing need to get rid of tabs and be cut wider because the leading edge bloated by two layers of real paper and one tab since leaving virtual space:



This is how I did the antenna dish:



Worked well, recommendable. Those cardboard-laminated circles weigh something and my model tends to topple to the right, but a connecting magnet (which I didn't install) should be enough to keep it upright.
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  #12  
Old 07-09-2017, 04:43 AM
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And finally, the shots we were all waiting for:



BC and the refinery will need to find their exact positions between bows of SE and NL, Orca's side winglets and RL's wings (easy with magnets alone, but I'll need shape locks and electric connectors too). Opalia doesn't fit very well: the two cargo pods are too far apart to fit within the recess in its stern while the engines are too close together to fit around the wingtips easily - looks like paper thickness was ignored during construction. But I don't mind, that connection node is going to be HUBAR (hacked up beyond all recognition) anyway :-).
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  #13  
Old 07-17-2017, 01:53 PM
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Now it would be handy to know how big the "real" ships are. It determines the size of decks, hatches and other things I might need to build. I tried 1/1000 and voila, it looks perfectly plausible:



So 1 mm on the model corresponds to 1 m in real - great, I love simple math. Numbers of people on board also seem to match. The Jumbo jet and the bus can carry lots of passengers while being small and light, but you can't live in there for long. Marine ships offer more living space, but they're just hollow shells with some little machinery below the waterline, while a nuclear spaceship is full of machinery and fuel. So 602 people plus some recreational facilities, gardens, hydroponics etc. (as mentioned in the official backstory) look pretty realistic. My guess at Neucom's mass is in the order of tens of thousand metric tons. For comparison: Boeing 747 weighs cca 400 t, Titanic 52310 and Bismarck 50300 (Neucom doesn't look very big on the picture, but she's wider than the two sea ships combined).

Scale comparison says that shuttle number 8, which docks at Neucom's back, is so big that a whole family could comfortably live in it. Given how crowded the Robinson is, they certainly would be living there, so the windows would be lit up during the flight. There is no choice but to light up the tiny model too:



Given the window placement, I'll use three miniature SMD LEDs. The windows are "glazed" by cigarette paper (with an interesting square grid texture) and the inside of the hull is covered with aluminium tape to prevent light leaks. The LEDs will be wired in parallel with one limiting resistor (more of those wouldn't fit inside), supply voltage will be probably 5 V, landing gear will double as power connector. Nice theory, I hope it's going to work.

I'm not going to build the wreck of shuttle 8 (I aim for the middle of acceleration phase when it has already been recycled for parts), so its wings will make vertical rudders for shuttle 7. They were not included in the kit, but a rudderless plane is sort of... incomplete .

To be continued next week when I get my bag of cables home and measure how hungry the LEDs are (they are salvaged from an old phone, so I don't have their datasheet).
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  #14  
Old Today, 12:15 PM
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Let there be light!

An example of a LED testing circuit:




Exact values don't matter; I used 12V power source and 10kiloohm variable resistor just because they were at hand.

We're building a cozy living room, not a lighthouse. Therefore we don't need much light. These diodes produce sufficient amount at 2.78 V and 0.96 mA each (plus or minus manufacturing tolerances, multimeter inaccuracy, contact resistances etc.). The lighting circuit will look like this:



These LEDs can't go in series because their combined voltages would exceed the 5 V supply I'm going to use. So the only remaining question is how big the limiting resistor needs to be:
Voltage across the resistor = supply voltage - LED voltage = 5 V - 2.78 V = 2.22 V.
We want current of 3*0.96 mA = 2.88 mA running through the resistor at this voltage.
Ohm's law: I=U/R or R = U/I = 2.22 V / 2.88 mA = 2.22 V / 0.00288 A = 770.8 ohms (careful with the units: only use plain volts, ampers and ohms, no mili or kilo).
The closest available resistor values are 750R and 820R. I found one 750 in my electronic scrapbox, so it was easy. An ohmmeter says it is only 736 ohms, so the resulting current will be 2.22 V / 736 ohms = 3.0 mA which means 1 mA for each LED. Perfect, let's go soldering:



The scale of the picture deceives a little. The gray-insluated wires come from computer IDE ribbon cable and the two thick rods are stripped wires from an ethernet cable. Black smudges mark negative pole of the LEDs because they were originally unmarked (detection procedure: connect the diode over a resistor to harmless 3 V and see which polarity lights it up). The shiny stuff in the hull is aluminium sticky tape, the black one is electric insulation tape which prevents short circuits on the aluminium.

After some fixing and insulating:



White glue would take too long to cure and would dissolve the surrounding paper. Solvent-based glue wouldn't be much faster and would make bubbles with poor insulating properties. Hot glue gun is clumsy for miniatures like this, but still usable.

Coming next: hull final assembly.
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  #15  
Old Today, 05:41 PM
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Very interesting. Thanks for walking us through the process
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