Chocktaw Warrior (oz14704)

About this Plan

Chocktaw Warrior. Radio control sport aerobatic model, for .60 engines or larger.

Quote: "Designed for slow aerobatics, the Warrior is a natural for easy-going maneuvers. Power is a .60 or larger, and the weight should be kept to seven and a half pounds for best results.

Out of the mists the warrior appears, ready for battle! Sound like Louis L'Amour? Hardly. In this case the 'warrior' is special, wanting only to battle the pattern competition. Of course, CHOCTAW WARRIOR is the name of this new, slow-aerobatic job. With all the controversy over 'turn around' boiling around us, I elected to classify this design as 'slow pattern,' and boy is it terrific! To start, the design is based on all of the parameters developed for hot pattern, but this design flies on aerodynamics, not ballistics. Admittedly the airfoil is symmetrical and 'non-lifting' but the airframe set up converts it to full lifting surfaces right-side-tip or upside-down. With all this sweep-back, you can point the Choctaw where you want it to go and it'll stay that way.

In designing any new, or different version of model aircraft the basic reason must be addressed, that is, why? Choctaw gives us many different aerodynamic variations from the norm, but relies mostly on the simplest reasoning; light. That's all, simply light. With a .60+ engine the total airframe weight is only 7 lb 14 oz, and if your version comes out heavier, look over your building methods real hard, cause you're overbuilding somewhere.

I haven't used light materials, but being careful of grain and quality is very important. A lot of strength is gained by the covering and that will be covered completely later in the article. If you are a beginning builder now is the time to get an experienced modeler to help you with this model; it is not a project to learn on.

Let's get into the building now and cover more of the technical details later. Start with cutting out all of the parts. I agree with the idea of making a kit to work from, building just seems to go smoother with every thing cut and ready to fit.

WINGS: Starting with the wings, cutting the spars and leading edge material to the proper taper will require a simple jig to make them accurate, and easy to cut. Take a look at Figures 1 & 2. For this type of set up to work you will need to use a regular plane, as the razor planes normally used in model construction for balsa won't work too well. Be very sure when cutting the guides for the jig to make them as straight as possible! Wedge the spar blank in place very well, so no movement of any kind will occur. Be sure, in setting up the spar blanks, that the two blanks are mirror duplicates; in other words, the grain direction and density must be identical but opposite. One of the deviations from the plans is the spacing between ribs W-2. If you use one aileron servo and it does not fit the space shown, you will have to reduce the ribs slightly and move them outboard a little. Of course the biggest deviation from the plans will be the use of foam cores for the wing construction. Warrior II is built this way and it is actually a little lighter than the built-up version.

Install the servo lead paper tube in rib numbers 2 through 6 before aligning them for final assembly.

W-16 can be built-up from three pieces of 1/4-inch spruce. The drawing shows how I machined it out of a solid piece of 3/4-inch using a 1/2-inch rotary file in the drill press.

Start the wing by positioning the top main spars over the plans with 1/16 scrap spacers evenly spaced between the plans and the spars. Then with the rear spar building spacer in place, build the entire wing frame upside down in one piece.

Notice the airfoil patterns: the leading edge from W-8 to W-12 has a sharp entry, This, of course, is to allow the outboard airfoil to trip, or stall easier. With the extreme sweepback this design has, the sharper the airfoil on the tips, the quicker the reaction to rolls and turns. Be careful flying this design set up; it snap rolls easily on takeoff and landings, so you will have to experiment for the best set up for your flying expertise. By the way, don't add wash-out to the wing tips, it will negate the control symmetry..."

Direct submission to Outerzone.

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