DESIGN: UniCopter ~Special Tool - Rotor - Blade - Spar - Overview
This page is associated withOTHER: CNC - Workstation
This page is associated with the spar on pages1355.html and 1054.html.
Transverse along X-axis (linear).
Rotation of spar about X-axis. 180º after each transverse.
If the epoxy cures at room temperature, give the work table sidewalls and a refrigeration unit. This will stop the prepreg thread from curing while the spar is being 'wound'.
This might be a cold box with open top. The carriage might have a horizontal 'roller blind' on each side that covers the top of the refrigerated box, which is not directly below the carriage. This is so that work can be done slowly without having the cure process start.
If the epoxy (Towpreg) cures at high temperature, forget the refrigeration and consider an oven or OTHER: Composite - Special Tool - Hot Pressurized Oil Device.
Could the refrigerated workbox also serve as the curing oven since it is already insulated?
The device that pays out the thread maintains the tension on the thread.
The horizontal bar at the tip end is located approximately 2-4 inches beyond the end of the blade. This 2-4" is cut off after curing.
The horizontal bar at the tip end might have rubber backed thin Teflon strips located between the layers of tows. This is to adjust for any differences in tension on the individual tows.
The female mold is located against the outer surface of the spars. It probably will incorporate a hot oil cure.
The inside mold will be a foam core, which in turn, is backed by the tip to root tool used for winding.
Gloves or Hand Tool:
The thread must not warm up due to head transfer from the operators hands. This necessitates thin insulated gloves and/or a hand tool.
Wrapping Around the Pins at Each End:
The tension does not have to be excessively high when laying the thread. It only has to be constant. The tension of all thread can be, collectively, taken to the maximum just before curing; perhaps by the clamping of the tip.
Consider having the thread spring loaded under a light tension when laying the thread. When the carriage gets to an end, it stops two inches short of the pins.
The inside surface of the spar is machined down. From the NACA 0009 to the tip, it is greatly machined, so that when laid up against the outer spar they are to totally flush surfaces. From NACA 0009 on toward the root only the outer edges is machined, because the spar has a slight curvature.
A central groove should probably be machined out. This is for wires etc. The spars might also have to be machined for leading edge weight and/or trailing edge core.
The width of the spar will also be machined so that it is narrower at the tip end.
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Initially displayed: August 8, 2002 ~ Last Revised: September 25, 2010
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