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Old Oct 17, 2012, 12:27 PM
Ospreyman is offline
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Cheshunt, Hertfordshire
Joined Aug 2009
224 Posts
Nice to see you Joe, here goes,

One problem that needed sorting fairly early on was the TX I was going to use. I have 2 x Spektrum DX6i’s and they have a flap ‘switch’ rather than a rotary knob and I wanted to use the flap channel for rotor spin up.

The answer was to convert an old Futaba Skysport 6a to 2.4 Ghz using a FR sky 2.4 TX hack module. Now I have a 6 channel TX that I can proportionally control the spin up motor with.
Oh wait a minute the Skysport 6a is not a heli radio and I need to operate the swash plate, like a heli.

The solution was to have one servo for forward and back cyclic and one servo for left and right. I don’t need them to work together as collective is not going to be used, the swash plate is fixed on the shaft between two collets.

On the 4 blade heli head there are 3 ball links at 120 degs. The rear one was ok but I needed the left/right cyclic control to be a t 90 degrees to the fore /aft. To overcome this I fitted a steel band between the front ball links extending to a 90 degree position and put another ball link on it. Now it all works in the right sense. The picture should explain it.

I suppose before I go much further I should give some weights and measures

Rotor disc = 40”

Weight = 900g

Propulsion motor = 300w

Spin up motor = cheapo 450 size heli motor

Prop = 9X6 APC slowfly

Lipo = 1 X 1800mAh 3s

ESC = 2X 30A

Now, where was I, oh yes, as a result of making a longer main shaft the swashplate anti rotation fitting had to be lengthened (also in picture), but this wasn't much of a task.

As I mentioned the tail is pure minimum, the only difference being that the fin and rudder are built up balsa 6mm sq and tissue covered. There is on servo slung low on the U/C which has a CF pushrod going back to the rudder and forward to the nosewheel for better ground handling

The propulsion motor is offset to the right just as the motor on the minimum. you can see the amount of offset in the picture.To mount the motor i removed the heli boom holder and bent the side frames out 90 degs with a bit of a twist to give me 8 degs upthust compared to the shaft. This is in fact parallel with the tail plane .
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