Herr Engineering P-51 Mustang

Model Airplane News, Jul 2000 by Randolph, Randy

I am always amazed at the fit of Herr's laser-cut parts. The leading-edge sheeting is perfectly cut to shape and, installed according to the instructions, it fits every rib and matches the leading edges on the top and bottom perfectly!

Having completed both wing halves, sand the inboard trailing edges, the spars and the leading edges flush with the center ribs, which are canted at the proper dihedral angle. Then epoxy the wing halves together at the center and reinforce the joint with a strip of nylon tape.

After you've installed the aileron hardware, the ailerons themselves require a little work: their inboard ends must be grooved and drilled to match the hardware. Temporarily mount them with masking tape so that you can sand the balsa blocks that form the wingtips to the proper shape. I first traced the pattern of the tip rib on each block and then used a band saw to rough-shape them. I used a razor knife to cut out the servo well in the wing center section and a razor saw to provide clearance for the servos in the two center ribs.

FINISHING UP

At this point, I usually assemble the airplane to see what the bare bones look like. When they look good, as in this case, I am eager to move on to covering. I covered this airplane with light gray and dark blue MonoKote*.

Because it seems to go more easily, I always cover the stab and fin and hinge the rudder and elevators before joining them to the fuselage. Also, mounting the control horns onto these surfaces is easier to do before the fuselage gets in the way! Of course, before you glue them together, you'll need to trim all of the covering material away from the areas that will contact the fuselage. Before I attached the canopy to the fuselage, I painted the cockpit area and engine compartment black.

The gear-leg torque anchors must be bent zo that the legs are angled forward properly. Do this before you attach the gear fairings. I covered the fairings and then trimmed away the covering from the area where the gear legs are attached. I used a few right triangles as jigs to be sure the legs and fairings were positioned properly as the epoxy set. I ironed strips of MonoKote over the gear legs to complete the job. After I had installed the gear on the wing, I ironed strips of Mono-Kote over the mounts to improve the appearance of the installation.

There is plenty of room in the fuselage for standard servos, and the area under the tank will easily hold a 500mAh battery pack. I mounted the servos in a plywood servo tray and, after I had mounted the Big Mig .061 in the Slick Mount, I moved the servos to achieve the proper balance and then attached them. I used florist wire through Nyrod for the throttle line and 0.047-inch-diameter music wire to make the pushrods that go to the rudder and elevator. A guide aft of the cockpit area eliminates any chance of the pushrods bending when they are under compression.

The addition of light wheels completes the airplane, which weighed in at 27 ounces-heavier than the stated weight on the box (22 ounces).