Post by swanrail on Sept 20, 2007 23:30:20 GMT 1
While the scurvy crew have been fooling about with nothing in particular, and whilst the build is now in the doldrums, I have decided to make further investigations on the rotating/lifting guns.
My prototype is virtually to the same scale as the model, and is mounted on a seperate plinth. I have used hole cutters to produce the parts (the multi bladed type using a mandrel).
For the Barbette and the ramp I cut out two rings, each used two different size cutters in the mandrel at the same time. For the gun mounting plate, I used a single cutter.
The guns are made of 6mm dowel, with a hole drilled in one end to fit a wire as a hinge. These were then mounted in 4 trunnions on the gun mounting plate. The guns were also spaced apart by a piece of ply drilled to set the gap, this was also used to fit the lifting pin ( a 90 degree brass wire as used in the gun hinges).
See picture:
The underside of the gun mounting plate was fitted with 4 shaped pieces of wood to engage with the servo head:
The ramp ring had two ramps cut at about 40 degrees either sde of the centre, and then glued down around the servo head.
The barbette was loosely fixed in place and the gun mounting disk fitted over the servo head.
The lifting pin acts as follows:
At max turning, the pin runs up the ramp and lifts the gun spacer which has a hole drilled in it fore and aft.
The next picture shows the turret in its fore and aft position with the guns lowered.
In the next picture, the guns have rotated by about 40 degrees and lifted:
The next stage is to add refinements: the guns need a small spring to pull them back down to the level condition when centred.
The lifting pin needs a small curved plate soldering underneath so as to run smoothly over the wooden ramps and not wear in.
The servo needs modifying as per Markus remarks so that it can turn the full 90 degrees port and starboard. This latter will be difficult as the servo is very small, the cover has minute philips head screws much smaller than any watchmaker screwdrivers I have and I have never been inside a servo before!!!!
If anyone has any somments or suggestions for improvement I will welcome them.
Please not I am not concerned about the turret cover at present. When the time comes it will have to be fixed in place so that it is easy to remove for servicing, etc (velcro? or small magnets again!!!)
My prototype is virtually to the same scale as the model, and is mounted on a seperate plinth. I have used hole cutters to produce the parts (the multi bladed type using a mandrel).
For the Barbette and the ramp I cut out two rings, each used two different size cutters in the mandrel at the same time. For the gun mounting plate, I used a single cutter.
The guns are made of 6mm dowel, with a hole drilled in one end to fit a wire as a hinge. These were then mounted in 4 trunnions on the gun mounting plate. The guns were also spaced apart by a piece of ply drilled to set the gap, this was also used to fit the lifting pin ( a 90 degree brass wire as used in the gun hinges).
See picture:
The underside of the gun mounting plate was fitted with 4 shaped pieces of wood to engage with the servo head:
The ramp ring had two ramps cut at about 40 degrees either sde of the centre, and then glued down around the servo head.
The barbette was loosely fixed in place and the gun mounting disk fitted over the servo head.
The lifting pin acts as follows:
At max turning, the pin runs up the ramp and lifts the gun spacer which has a hole drilled in it fore and aft.
The next picture shows the turret in its fore and aft position with the guns lowered.
In the next picture, the guns have rotated by about 40 degrees and lifted:
The next stage is to add refinements: the guns need a small spring to pull them back down to the level condition when centred.
The lifting pin needs a small curved plate soldering underneath so as to run smoothly over the wooden ramps and not wear in.
The servo needs modifying as per Markus remarks so that it can turn the full 90 degrees port and starboard. This latter will be difficult as the servo is very small, the cover has minute philips head screws much smaller than any watchmaker screwdrivers I have and I have never been inside a servo before!!!!
If anyone has any somments or suggestions for improvement I will welcome them.
Please not I am not concerned about the turret cover at present. When the time comes it will have to be fixed in place so that it is easy to remove for servicing, etc (velcro? or small magnets again!!!)