|
|
|
|
|
Hirobo Bell UH-1B |
|
|
||
|
Tail drive |
|
|
|
|
|
|
|
Instead of using an intermediate gearbox a flexible cable is used to drive the tail gearbox. The flexible cable runs inside a steel tube with a gentle curve. The steel tube must be supported in the fuselage so that it exits the main mechanics level and goes into the tail gearbox housing straight. |
|
|
|
|
|
|
|
|
A template is made out of card to ensure that the bolt holes are in the correct position to hold the tail gear box housing. The template is also used to fabricate a thin plastic brace that when secured to the fuselage with epoxy will help spread the load. |
|
|
|
|
|
|
|
|
It helps to work on a flat workbench. The height of the tail drive support is measured first (short pencil line) followed by an adjustment for the height of the fuselage mount (longer blue line). The fuselage is then supported so that the belly of the fuselage is lying flat. It is then possible to determine the height of the steel tube before the gentle upward bend. |
|
|
|
|
|
|
|
|
It is then just a matter of scuffing the fuselage and steel tube so that the epoxy will have something to key into. A small amount of balsa wood is cut to shape to support the steel tube and provide a base for the epoxy to stick to. A cut is made to accommodate the tail pitch rod passing through the fibreglass. |
|
|
|
|
|
|
|
|
Care is taken to ensure that the flexible cable is centred in the tail drive coupling. A light weight aluminium tube is bent to support the tail pitch rod. A flexible pushrod sleeve is also supported by a thin carbon rod down the length of the tail boom. |
|
|
|
|
|
|
|
|
Slow curing epoxy is used again to hold the tail pushrod. |
|
|
|
|
|
||
|
Webmaster: John Neasham |
|
|