CH-47 Mechanics Notes
The following notes
and photos are intended to provide additional tips and guidance for
those building this project.
1. Main Truss: The truss is the backbone of the
helicopter. I machined mine from 1" square aluminum tube from the
hardware store, but you could just as easily build it up from plywood
or G10 fiberglass. The torsional loads are
actually pretty light, so my truss is certainly stronger than
necessary. Note the lightening holes and the slot in the middle
that allows me to route the wiring around the middle drive shaft
support block.
2. Drive Shaft and Bevel Gears:
Here's a closeup of the drive shaft, showing the bevel gear and
the journal block that supports the shaft housing. The bevel
gears mate with the crown gears on the rotor shafts to synchronize the
front and aft rotors. I used spare parts from the
widely-available Lite Machines Corona 120 for the drive shaft, but you
can use any suitable industrial bevel gears. Note that I used
5/64" (.078") music wire for the drive shaft, so the Corona bevel gears
and shaft bushings had to be reamed out to fit. I milled
the journal blocks from ABS barstock, but you could just as
easily cut them from plywood.
