Sunday 26 June 2011

Nieuport Build Part 11 - Fitting Control Horns and Aileron Bell-cranks

Now that all the control horns and bell-cranks have been made from paxolin they can now be 'dry fit' into each appropriate slot.

The revised elevator horns are located in the same position as that shown on the plan. All that needs to be done it to saw a slot into the leading edge of each elevator.

This slot has to be deep enough to allow the semicircular cut-out in the horn to sit behind the carbon fibre tube when fitted.



Slot cut into elevator leading edge.






Paxolin horn 'dry fit' into elevator.
These horns will be permanently glued in place after covering.



The tube and horn both 'dry fit' into elevator.


The carbon fibre tube should fit tight up against the back of the rebate. If the tube rocks on the horn it's just a simple task of making the slot for the horn a little deeper, until  the tube stops rocking.


Stabilizer and elevator temporarily assembled.

 


Close-up of starboard elevator.



Close-up of elevator control horn and hinge detail.
   
The above picture also shows a mounting hole in the gusset for the stabilizer bracing tube to bolt to. A tube is inserted into this hole to act as a 'compression tube' to prevent the wood being crushed when you tighten up the nut and bolt.


Next came the rudder horn. This was fitted in place in the same manner as that use for the elevator horns. Again making sure that the carbon fibre tube fits into the rebate correctly.


The slot for the horn is cut out ready
for the horn and tube to be 'dry fit'



 Horn in place, 'dry fit', and the hinge strap cut-out.



Horn and tube in place, 'dry fit'.


 

And finally I 'dry fit' the aileron bell-cranks. Each torque tube was pushed through the wing ribs and into the bell-crank box. The bell-crank was then pushed onto the end of the tube and the tube and bell-crank pushed into the plywood wing rib (this plywood rib acts as the bearing for the tube) and the 'scale' rear spar was also pushed into place.


  Torque tube being pushed into position.
Also seen, the bell-crank and 'scale' rear spar.



Bell-crank components in place, 'dry-fit'.



Plan view of Bell-crank components, 'dry-fit'.


To prevent the aileron bell-crank from rotating on the torque tube it will be necessary to key the two items together with a metal dowel. Slots will be cut in the hole of the aileron bell-crank that the torque tube passes through. A hole is then drilled through the torque tube and a short metal dowel is inserted into this hole. On final assembly the torque tube and pin will be glued into the bell-crank hole and once the glue has cured the bell-crank will be unable to rotate around the tube.


Sketch showing metal dowel detail.


In the next post I'll be fitting the rigging brackets to the top and lower wing panels.




To be continued...

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