User Manual

Finish the engine compartment ❏
1. Use a high-speed rotary tool with a carbide
cutting bit to cut the hole in the cowl for the carburetor. For the U.S. Engines 41, this procedure is made easier if the muffler and venturi are removed. Slip the cowl into position, then, carefully viewing the cowl and the carburetor inside and out, mark the approximate location of the cutout. Remove the cowl. Cut inside the lines starting with a small hole. Fit the cowl, redraw the lines, then remove and cut the cowl again. Continue to “zero-in” on the correct size and shape of the cutout by fitting, marking and enlarging the cutout in small increments. Mount the venturi after the cowl has been fit over the carb. Note: The
venturi must be removed whenever the cowl requires removal or installation. During initial engine tuning and break-in it will be best to leave the cowl off the model until all adjustments have been made. When satisfied with the performance and reliability of the engine, the cowl can be installed.
❏ 2. Cut the fuel line that goes to the carburetor to
the correct length, then hook up the fuel line. Drill two holes through one of the remaining 1/2" x 13/16" x 13/16" [12 x 20 x 20mm] hardwood blocks to accommodate the fuel lines. Trim the block to a smaller, finished shape, then use epoxy to glue the block to the bottom of the firewall. Guide the fueling line and the vent through the holes in the block.
❏ 3. Cut any other necessary holes in the cowl for
the ignition switch, engine exhaust, fuel lines, etc.
❏ 4. If you haven’t already done so, remove the
engine and coat all bare wood parts (such as the engine mount, engine mount spacers, cowl mount blocks, etc.) with 30-minute epoxy or fuelproof paint. Allow to dry, then remount the engine.
MOUNT THE SCALE DETAILS
Radiator air scoop ❏
1. Mount the wing to the fuselage with the wing
bolts. Place the fiberglass radiator air scoop on the wing. Place a piece of thin cardstock between the back of the air scoop and the fuselage. Use a fine- point felt-tip pen to mark the outline of the air scoop onto the bottom of the wing.
❏ 2. Carefully cut the covering 1/32" [1mm] inside
the line. Be careful not to cut into the balsa. Peel the covering from the wing.
❏ 3. Glue the plywood wing bolt plates to the
bottom of the wing with 30-minute epoxy using the wing bolts to hold them down. (Although the covering is still on the wing in this photo, the covering should be removed from your wing under the air scoop.)
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