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The swash plate This little device is freaky. In a nutshell, the pitch of the blades varies through their rotation, according to the motions of the aileron/elevator servos (called cyclic on a helicopter) and the collective pitch. It's all a bit mad and I onyl slightly understand it so far.
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The engine OS 32 helicopter engine. Here it is with the Raptor cooling fan attached, basically a centrifugal fan.
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Side view
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Engine, other side
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Digital servo The Gyro came with this servo. Because the tail rotor pitch is being computer controlled, and you want it to react fast, you have to use a fast servo. Better yet, you use a digital servo, which mostly means the servo PWM's the motor inside much much faster. This is a reasonably speedy digital servo. When it's going, it whines a bit, but I am pretty sure that's normal.
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Assembling the rotor head These bits will eventually sit atop the swash plate.
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Look at the mess!
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Engine, closeup
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Getting started When I remembered I wanted to take pictures of the construction, this is far as I was already.
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The engine The slot-shaped hole you can see is where the exhaust (muffler) pipe will attach, when it arrives.
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Gyro This is described by many as the "most cost effective" stabilisation gyro on the market at present. It's job: keep the machine pointing in the direction you want it to. In the old days, you would program a "revolution mix" into your radio which altered the tail rotor blade pitch according to what you were doing with the throttle/collective, the idea being that you could match the rotational energy being put out by the main rotors to make the tail rotor counteract it, and keep the machine steady. Technology these days simply measures the rotation and does what it needs to counteract it. Funky. This is what makes the difference between whirly-top-with-dangerous-bits and simply "dangerous".
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Clutch The silver drum in the centre of the picture is the clutch bell. Inside this is a clutch disc, which runs directly from the engine below it. It's designed to be fully diengaged below about 7000rpm and fully engaged above 10000rpm. The rotor blades operate at a fraction of this speed, not normalyl going faster than about 1700 rpm.
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Rotor head bearings At this point, I only assembled one end of this piece. The bearing set in the bag fit onto the shaft with a collection of washers, spacers, bolts, loctite and so on. It's all a bit busy. Particularly sicne I forgot to put in a supporting piece rigth in the centre to had to disassemble the thing.
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Flybar again
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Tail rotor assembly This was a fiddly piece to put together.
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Engine in the frame, other side
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Engine in the frame
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Rotor head and flybar The fly bar, I think, ,ostly balances the main blades. They are on a single bar whose pitch alters with the cyclic, but not the collective (I think, lots of "I think"'s here!). The bar is supposed to be near-perfectly balanced otherwise it causes really nasty vibrations in the rest of the machine. Rememeber, this thing is a huge spinning top, really.
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Engine in the frame, closeup
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Tail rotor The orange material you can see through the hole is the belt. The blades twist together, in opposite directions. This is how you point the helicopter.
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Main drive wheel The belt goes back to the tail rotor. The grey spindle meshes with a drive wheel on the engine drive shaft. There is a shaft going up through these two wheels directly to the rotor hub.
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Beastie so far
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Tail rotor assembly The red coloured pulley is a two-piece item, a flange fits on one end, and it can go two ways round. The correct way si with the shorter end into the pulley, longer end outwards. Otherwise, as I discovered, there is about 2 to 3mm play in the tail rotor shaft. Not good.
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Coming together nicely now Tail piece is in, various tail-plane bits and bobs. The tail rotor blades are on the wrong way round here (and remained so for a while) until I realised I had the belt on the wrong way. I noticied this long before firing up the engine, thankfully.