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HomeScale✈️AircraftScale HeliScale Helicopter Main Discussion › Vario benzine Bell 47 tail drive
09-07-2006 09:45 AM  14 years ago
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rha

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North Yorkshire, United Kingdom

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Vario benzine Bell 47 tail drive
I have just started to build up a benzine version Vario Bell 47G11 and the instructions are not very clear as to how the tail drive is configured.

The instructions show a single one piece drive tube from the tail rotor gear box down the mechanics, this isn't possible because as the tail rotor is angled upwards from the main boom the drive shaft needs to enter the mechanics where the exhaust muffler is.

It looks to me like there should be a second universal joint just down from the tail rotor gear box, is this correct? There are various tube connections, bearings and supports in the kit but I'm not sure if these are for other configurations or not.

Can anyone help?

Rich
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09-07-2006 11:52 PM  14 years ago
cfranks

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Adelaide South Australia

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Mine has a short shaft in the end tube, dogbone-coupler socket on each end. The drive shaft mates with this and is supported by those two bearing thingies. I don't have the proper parts diagrams to give you the required part numbers, sorry.

Charles
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09-08-2006 12:23 PM  14 years ago
rha

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Thanks for that Charles,

Looks like you have to fit the claw type couplings on the tail gear box end to a short length of shaft supported by 2 bearings within the short tube. Then fit the dog bone couplings on the long shaft going down to the mechanics supported by 2 bearings fastened to the lattice frame.

The next thing that confused me is that the tail rotor spins in the opposite direction to "normal".

Rich
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09-08-2006 02:48 PM  14 years ago
cfranks

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Only if the nylon gear (on the 8mm shaft) is below the tail drive nylon gear.

Charles
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09-08-2006 03:08 PM  14 years ago
rha

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Now you have got me confused

The instructions say to put the tail drive shaft gear above the vertical gear, this makes the tail rotor turn opposite to normal, yet yours is below which presumably makes the tail rotor turn in the correct direction (if there is a "correct/normal direction"?).

So which is the correct tail rotor direction for a Bell 47?

Think I'll go back to building my Chinook, its much easier.!

Rich
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09-09-2006 12:12 AM  14 years ago
cfranks

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Adelaide South Australia

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I got mine s/h , already built. Checking a real 47 tail suggests your instructions are correct. The tail blades rotate down into the downdraft. Obviously works for them. I won't bother to change mine though as tail rotor direction in our models has little or no effect.

Charles
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HomeScale✈️AircraftScale HeliScale Helicopter Main Discussion › Vario benzine Bell 47 tail drive
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