VOLUME 1
May 1, 1948
NUMBER 8
MODEL 18 SERVICE NOTES AND CHANGES
Elevator Tab Rheostat Modification
An improved elevator tab rheostat drive has been incorporated in Model D18 airplanes in production. This change was effective on D18S Serial A-402 and D18C Serial AA-27. Model D18 airplanes delivered prior to A-402 and AA-27 may be modified in accordance with the following instructions at the option of the customer.
Remove the rheostat from the elevator and cut off the shaft to 17/32-inch from the threaded section of the rheostat.
File a flat spot on the shaft 7/16-inch from the end of the shaft.
Install the new pinion, part No. 404-186112, on the rheostat shaft and reinstall the rheostat in the elevator.
Install the bracket, rack, and spring assembly on the elevator tab actuator.
NOTE: It may be necessary to make a cutout in the fabric to make this installation.
Calibrate the rheostat to the elevator tab indicator.
The following parts are required to perform this modification:
bullet 1 each 404-186112 pinion assembly
bullet 1 each AN500-A6-3 screw
bullet 3 each AN960-A616 washer
bullet 1 each AN392-19 pin
bullet 1 each AN960-4 washer
bullet 1 each 404-186113 rack assembly
bullet 1 each 404-186114 spring
bullet 2 each AN515-10-4 screw
bullet 2 each AN365-1032 nut
bullet 2 each AN960-10 washer
bullet 1 each 404-186111 bracket assembly