Dymond Modelsports Tiger Moth ARF: Classic '30s biplane with performance

Model Airplane News, May 2002 by Yarrish, Gerry

With its swept-back wings and distinctively shaped fin and rudder, the de Havilland DH-82a Tiger Moth is one of the most popular antique biplanes around. Used in both military and civilian aviation, the Tiger Moth was designed as a primary training aircraft. Countless models of this aircraft have been designed and built, and, now, Dymond Modelsports gives us a very easy to assemble, almost-ready-to-fly (ARF) version. Intended for .60 to .90 2-stroke and .90 to 1.20 4-stroke engines, the Dymond Tiger Moth is also very easy to fly. Let's take a closer look.

The Dymond Tiger Moth is available uncovered; covered in yellow and black or green and black plastic film; and with a paintable fabric finish. The cockpit area is a separate part and forms a slide-out hatch cover; it slides into place from the side and two screws within the cockpit openings hold the structure in place. It's very easy and convenient to check the radio and fuel tank while leaving the bottom wing in place.

The wings come in halves and two aluminum joiner/dihedral braces provide strength. The model has four ailerons; the full-size aircraft had only two. You can fly the model with either two or four ailerons, but to use only two, you must tape the top ones into a fixed position. I used all four ailerons and made slave pushrods to connect the top and bottom control surfaces.

The tail surfaces are completely built and covered, and the fin has a tab that fits into a slot in the horizontal stabilizer. All the control surfaces, including the ailerons, come hinged and sealed with film covering, Also included in the kit are instructions; a fiberglass engine cowl; aluminum cabane and interplane struts; a formed and painted landing gear; a tailwheel assembly; wheels; fuel tank and basic nuts and bolts.

ASSEMBLY

Start by joining the wing panels. Slide the aluminum dihedral braces into the root ribs, and slide the wing panels together. For the top wing, two black aluminum crossbars hold the panels together and join the wing to the cabane struts Make sure to place the shorter crossbar aft when you screw them into place. For added strength, I "hardened" the attachment screw holes by applying a few drops of thin CA. The bottom wing also uses aluminum dihedral braces, but its panels are held together with alignment dowels and the nylon winghold-down bolts.

FUSELAGE

The fuselage is a simple, strong and light box structure. The forward and aft turtle decks are foam covered with balsa. [he removable fuselage hatch makes installing the fuel tank and radio gear a snap. The firewall and wooden engine-mount rails are already in place and have been fuelproofed with resin; side- and downthrust have already been incorporated into the structure.

It's easy to attach the tail feathers to the fuselage; simply remove the covering material on the underside of the stab and glue the control surfaces into place. I used CyberBond 30-minute epoxy to allow time for the minor adjustments needed to keep the surfaces straight. Attach the tailwheel assembly to the rudder before you glue the fill into place. Dowel pushrods come assembled and already installed. Install the servos and center the output arms before you attach the pushrods to the elevator and rudder. After the pushrods are attached to the servos, adjust the devises to center the control surfaces,

The aluminum cabane struts must be screwed into place on the sides of the fuselager the attachment screw holes have been drilled for you. Instead of using locknuts to secure the attachment screws, I installed 440 blindnuts with flat washers under the cap-head screws. The washers prevent the screw heads from pulling into the long slots in the cabanes; those slots allow you to adjust the top wing's incidence.

The landing gear comes formed and so]dered together. Four metal straps hold the front and rear struts in slots that have been cut into the fuselage and lower wing. In my kit these slots were too narrow, so I enlarged them with a Moto-Tool and a small, grinding hit. The landing gear was finished with a thick coating that made the axles too big for the wheels to slide on. I enlarged the holes in the wheels so they would slip over the axles, and then I ground down the ends of the axles so that the wheel collars would fit over them. The landing gear looks scale, but you must remove it to take off the bottom wing.

The lower wing panels come with the aileron-servo-wire extension leads already in place, and this makes the servo installation very easy. Simply attach your servo's lead to the extension, pull the wires through the wing and install the servo. A tight-fitting servo well is built into the bottom of each wing panel, and I was able to glue my servos into place with PFM adhesive. Plastic hatch covers come with the kit, but for simplicity, I left them off.

The kit has eight interplane strut attachment fittings that you must install in slots cut into the wing panels. Once these

T-shaped fittings are screwed into place, you can attach the interplane struts to the fittings and join the wings. Twelve 4-40 screws and locknuts are used to secure the wings.