AH-56 Cheyenne - Main Mechanics Assembly and
Because of the Cheyenne's unusually slender body, I opted to install
a smaller 132T main gear rather than have the stock 150T gear
protruding through the fuselage sides. This has worked out
very well, but it did make for some added challenges during the
build. This chapter describes the necessary mods to the main
mechanics to fit inside the molded fiberglass body.
The 0.7 modulus 132T main gear is carefully machined out to fit
the stock Trex 450 autorotation hub.
Gears of this size are used on a number of 400 class helis like
the Shogun and Revo-CP and are readily available on eBay.
This photo shows the modified left side frame required to have the
pitch servo fit inside the narrow "doghouse". This
frame mod is detailed in the plans which are available from the
AMA Plans Service.
This shows the motor mount mods required to use the smaller 132T
main gear. The slots are extended, and the screw bossed are
partially milled away to give the motor greater travel.
Here are the assembled main mechanics. Note that the servos
are installed with their mounting lugs inside the frame to make a
little more room - this is a very close fit. The aluminum
bearers are cut from 1/2" extruded aluminum angle from the
hardware store. I recommend swapping to longer screws for
mounting the bearers (M2 X 16mm). The lower frames are cut
off flush with the bottom of the bearers.
Here's the final arrangement of the mechanics. The battery
mount has been modified to a horizontal orientation in order to
provide a mount for the 9-channel receiver and gyro above and the
Phoenix 35 ESC and CC-BEC below. That's a lot of hardware in
a tight space, but it all fits, and the accessible gyro is a real