HEAVY-DUTY SCALE FLAPS

FUNCTIONAL CONTROL SURFACES WITH ADDED DETAIL

- JOHN GLEZELLIS

Building scale model aircraft takes a great amount of creativity, patience, and skill. With features like retractable landing gear, flaps and navigation lights, the detail possibilities are just about endless! My latest project is a CARF-Models Supermarine Spitfire, and to improve its overall scale appearance, I decided to re-hinge the flaps making them scale while adding detail to the interior surfaces. There’s nothing like the sight of an aircraft with its flaps down, exposing the added details. Let’s take a look at what’s involved.

HINGING BASICS

As a starting point, first examine the hinging used on the full-scale aircraft. Control surfaces are either center, top, or bottom-hinged, which refers to the pivot point location of the hinge. On the Spitfire, the flap hinge line is offset from the bottom surface with a deflection range from 0 to 85 degrees. Before hinging the model, remove the original flaps from the wing and study the surface and decide what type of hinge needs to be fabricated. Due to the surface length, I decided that three hinges and a Du-Bro 4-40 pushrod would be needed. A removable surface simplifies maintenance, allows the interior of the flap well to be fully detailed and improves access to the linkage.

To do the job I decided to use a Du-Bro 4-40 pushrod, 1/8-inch light ply, a 1/8-inch sheet of G-10 fiberglass, a Dave Brown fiberglass pushrod with included pushrod ends, Du-Bro 3/32-inch wheel collars, Zap medium CA, and Zap 30-minute epoxy mixed with Bob Violett Models milled fiberglass. The basic layout has the fiberglass pushrod tube placed at the front of the flap with the 4-40 wire pushrod wires inserted into the inboard and outboard 1/8-inch light-ply hinge/rib pivot points with the G-10 hinge in the center.