Sunday, October 22, 2017
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China Model Production Tiger Moth DH-82

A 35-Size EP

Scale RAF

Primary Trainer

 

Photographers

Walter Sidas & Jim Onorato

NEED TO KNOW

MANUFACTURER: China Model Productions (CMP)

DISTRIBUTOR: Nitro Models

TYPE: Electric scale military trainer ARF

FOR: Intermediate sport pilots

PRICE: $249.00

NEEDED TO COMPLETE:

Motor, propeller, spinner, ESC, flight battery, 4-channel radio with two standard servos and two micro servos, two 12-inch servo extensions, adhesives, and building tools

ASSEMBLY

The 12-page Tiger Moth assembly manual contains a minimum amount of written instructions but includes numerous photos and drawings to guide you through assembly. Since all of the fasteners are metric, you will need several small metric hex wrenches, nut drivers and metric drill bits of the sizes spelled out in the instructions. #1 and #2 Phillips screw drivers, a crimping tool and blue thread lock will also be required before you begin assembly.

Assembly begins with attachment of the tail feathers. The stab gets glued to the fuse after the covering in the area of the stab that contacts the fuse is removed (This may or may not have already been done). The fin is then glued to the stab and also secured with two long bolts that thread up through the bottom of the fuse and into pre-installed blind nuts in the fin. Next, you assemble the tail wheel and epoxy it to the rudder. The elevator halves and the rudder utilize CA-type hinges. The hinges and their slots are already installed but have to be glued in place. Insert a pin in the center of each hinge before inserting the hinge to make sure it stays centered while gluing. (Just be sure to remove the pins before applying the CA). Both the elevator and rudder are driven via pull- pull systems so two control horns are required on each surface. Holes for all of the control horns are already drilled. The rudder and elevator servos are both installed in the wing saddle area of the fuselage.

At this point, I found it advantageous to skip ahead and install the landing gear and wheels so the plane could sit upright on my workbench. The landing gear is already assembled and gets attached with four nylon straps and eight sheet metal screws. I attached the scale fairings to the landing gear with PFM adhesive.

A long straight control horn for the rudder cables gets installed inside the fuse near the rudder servo with its ends protruding from the sides of the fuse. This control horn gets connected to the ruder servo with a short pushrod and ball link. The ball should be attached to the control horn before the horn is installed in the fuse. The pull-pull system uses 0.4mm braided cable with 1.3mm rigging couplers and tiny nylon clevises. I found that the rigging couplers would not thread into the clevises so I ran a #56 drill through the clevises to make threading less difficult. Once I adjusted the tension on the cables and got the rudder centered, I placed a drop of thin CA on the threads of each coupler at the clevis so they would not pull out. I also did this on the couplers used on the elevator cables.

Installation of the pull-pull cables for the elevator can be tricky and the instructions are not too clear on how they get installed. One cable runs from the upper control horn on one side of the elevator, through a hole in the side of the fuse through a rigging coupler on the elevator servo then back out through a hole on the other side of the fuse to the upper control horn on the other elevator half. The tricky part comes when you have to thread the cable back out through the fuse from the inside. I accomplished this by inserting a length of fine piano wire through the hole in the side of the fuse than gluing the cable to the piano wire with a single drop of medium CA and pulling it back through the hole to the elevator. You have to use very little CA or the wire will not fit through the tiny hole in the fuse. The cable for the lower control horns gets installed in the same way.

The Tiger Moth has ailerons in the lower wing only and these are driven with separate servos that get mounted on servo hatch covers. Narrow servos are required to fit in the limited space and 9 inch extensions are required to bring the servo leads to the center of the wing. Alloy parts are provided for attachment of the cabane struts, interplane struts and the wing rigging. These are best installed in the slots and pre-drilled holes in the wing panels before the wings are glued together. The lower wing panels get joined with an anti-rotation pin and spar and get glued together with 30 minute epoxy. The lower wing attaches to the fuse with tabs in the front and two screws in the rear. However, I suggest you install the motor, ESC and receiver before the wing is installed so you can get everything checked out before things get inaccessible. A motor box is provided that you attach to the firewall with four 3x12mm cap screws into pre-installed blind nuts. The firewall is correctly positioned to provide the desired right and down thrust for the motor. I installed the ESC to the inside of the fuse just behind the firewall and held it in place with double-sided tape.

The upper wing consists of three pieces including the center section which is actually a dummy fuel tank. Be sure to epoxy the six alloy cabane attachment fittings between the center section and the wing panels when the pieces of the upper wing are joined. The cabanes and interplane struts are installed using hex head bolts, washers and lock nuts. The wing rigging is made up of 0.4mm braided cable with 2mm couplers and nylon clevises. You can save some time by assembling all eight of the couplers and clevises before attaching the cables. I made a spreader bar out of 3/16 inch dowel and installed it in the rigging where the cables cross.

I made two additional modifications to my Tiger Moth: first, instead of using two screws to attach the battery cover plate to the bottom of the fuse, I glued two tabs to the rear of the cover to secure the rear and used a single screw in front, second, I glued the three small wood cowl mounting blocks to the fuse instead of in the cowl as shown in the instruction manual. The first mod lets me secure the battery cover more quickly once the battery is connected and the second mod provides hard points for the cowl mounting screws.

Images

Tiger Moth’s hardware sorted and ready

Typical alloy fittings for struts and cable attachment

Rudder and Elevator servos and battery compartment

Hacker motor mounted on motor box included in kit

Rudder and elevator both use pull-pull cables

Wing rigging with spreader bar

Cowl mounting block added to fuselage

Thunder Power 3-cell LiPo installed in battery compartment

Tabs added to rear of battery cover

Short pushrod used on ailerons