Piper PA-18 (oz15885)

About this Plan

Piper PA-18 Super Cub. Radio control scale model. Wingspan 47.67 in, for electric power with geared GWS 350C-B motor.

Quote: "Free pullout Plan. Piper PA-18 Super Cub. Scale park flyer.

Ask most people what one design they would turn to for an easy flying scale model, and they will likely answer a Cub. An American classic since the first versions rolled off the line in the early 1930s, the Piper Cub continues as the iconic light aircraft for our country. Dave Patrick offers us perhaps the most utilitarian version, the PA-18 Super Cub. The Super Cub is as functional as a Jeep, proving invaluable for those needing an honest flying, load hauling economical aircraft that will get the goods in and out of the shortest and most inhospitable landing strips imaginable. Whether fitted with oversized balloon tires, skis or floats, the Piper Super Cub is one of the all-time great bush planes.

A big fan of model Super Cubs, Dave has flow them successfully at Top Gun, and offers a IA scale ARF version through Dave Patrick Models. Spanning just shy of 4S inches, this Cub should have tremendous appeal for those who prefer smaller models.

There is a reason everyone loves a Cub. They are naturally great flyers, and this version is no different. Despite its small size, this Cub flies exceptionally well. It will easily take off from a reasonably smooth surface, including dirt or even short grass. The base paths at your local ball field will be perfect. Pick a calm day for your first flights. The model can handle a surprising amount of breeze, but still air will help you quickly become familiar with your new friend.

Line up into the wind and slowly advance the throttle as you keep the nose straight with the rudder. The tail comes up almost immediately and within just a few more feet, the Cub will become light on its wheels and smoothly lift into the air. Full power takeoffs happen quite quickly. I usually let it float off at partial throttle for a more realistic effect. Once in the air, hold the Cub level For just a moment to build speed, and then pull back to clear any obstacles at the end of the runway. It is easy to imagine flying this model off a gravel bar alongside a river in Alaska, while shuttling supplies into a prospecting party.

Since this model likes rudder in the turns, limber up your left thumb. You actually get plenty of time to think about what you are doing, so flying with coordinated rudder inputs is easy. The Super Cub flies so smoothly and slowly that patrolling the field at 6-10 feet is as relaxing as flying up high.

If you do venture to altitude, don't hesitate to try a loop or two. With just a little dive, the Cub will be going fast enough to pull up and around. A perfect circle would be out of place here, so back off the throttle as you get inverted, and let the nose fall through to give an egg-shaped figure.

Lazy barrel rolls are also possible, and can be smoothed out a bit with the rudder and elevator. Don't expect a smooth axial roll however, as it just wouldn't be Cub-like. The Super Cub also does lovely spins. Slow it down at altitude, and add full left rudder and up elevator just before stalling. The Cub should pirouette over and quickly stabilize in spin with the nose well down. Simply neutralize the controls, level the wings and pull back to recover.

The flight characteristics of the Super Cub continue to shine when it comes time to land. I like to come in a bit high, and then put it into a hard slip with opposite rudder and aileron to dump off any extra altitude. As it gets within a few feet of the ground, relax the ailerons and rudder to straighten its flight path. Tease the stick back a bit and it should settle right in on its mains. Hold it off a bit longer and you will be rewarded with a fully stalled, three-point landing. Because of its low weight, the Cub will slow quickly on the ground, with rarely a threat of a ground loop.

The prototype was set up with the following control throws: V2 inch of both up and down for the elevator and as much throw as possible for the rudder. The Super Cub needs a lot of aileron differential to minimize adverse yaw. I use 5/8 inch up and I/4 down, and still add rudder in the turns.

Construction: Building the Super Cub is quite straightforward. The structure is a traditional balsa affair, and goes together quickly. Building this design will be very familiar to anyone who has completed a balsa kit or two.

Start by cutting out all the parts. Once you have this done, you are ready to build your own Cub 'kit.' One way to save a lot of time is to only rough-cut the pieces that make up the outlines of the tail surfaces. As you can see in the photos, it is easier and more efficient to assemble a rough piece first, then trim and shape the final part from this assembly. I only spent 10-15 minutes building the parts shown.

I started the wing ribs by stacking a series of rough-cut rib blanks. To hold them together, reached for a bottle of Dave Patrick thick CA and lightly rubbed a fine bead into the ends. If you are spare with the glue, you can easily separate the parts once you are done shaping them. Don't think, even for a minute, about using thin CA. It will instantly wick between the pieces, providing you with a single, very thick rib blank.

I glued a copy of the rib pattern to the stack, and sanded the ribs to the desired shape using a disk sander. Be careful not to taper your stack of ribs. I cut the spar notches and lightening holes with my scroll saw. With a fine tooth blade, you will not need to finish sand the ribs after cutting the holes. The lightening holes remove about 1/3 of the weight of the ribs and make it easy to thread the aileron servo leads..."

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