Sagitta 600 (oz5970)

About this Plan

Sagitta 600. RC sailplane. Wingspan 78-3/4 in, wing area 600 sq in, for 3 channels.

Quote: "Derived from the Sagitta 900 which has already proven itself, the Sagitta 600 is intended to be a fully competitive 2-Meter sailplane in both duration & multi-task contests. Sagitta 600, by Lee Renaud.

Up until the last two or three years, the majority of sailplane development in the United States has been concentrated on standard and open class sailplanes. Theoretically, larger sailplanes fly better, and therefore they should be more competitive in a straight thermal duration contest, But with the advent of shorter launch lines, precision duration, and FAI F-3B events, the easier handling and better maneuverability of the smaller airplanes outweighed the theoretical advantage of the open class ships. It has also become apparent that flying ability has a great deal more to do with a person reaching the winner's circle than the size of his airplane. The 1979 World Champion, Anton Wackerle, flew a 2-Meter airplane, as did John Brown, the winner of the 1981 AMA Nationals.

The majority of 2-Meter kits available on the market today are intended as trainers for newcomers to our sport, and so they are designed with simple construction and forgiving flying characteristics. These same airplanes can be flown by more experienced pilots and be quite competitive in AMA duration type contests. But under adverse conditions or in multi-task events the average 2-Meter airplane begins to struggle. In order to improve performance, the same type of design refinements that have developed in the larger classes must be applied to the 2-Meter ships. A semi-symmetrical airfoil for a wider speed range and improved L/D, a clean overall configuration, and careful attention to drag reduction are all musts on a fully competitive 2-Meter sailplane.

The Sagitta 600 is intended to be a fully competitive sailplane in both duration and multi-task contests. The Sagitta 600 is derived from the standard class Sagitta 900 (oz5950), which has already proved its contest winning potential. The 600 retains most of the 900's design features, with the construction slightly simplifed. The Sagitta 600 also has all of its big brother's flying characteristics; it tows well, handles easily, covers large areas of sky impressively and moves right out when a bit of down elevator is fed in. If you are looking for a high performance 2-Meter sailplane, then the Sagitta 600 is the one for you.

CONSTRUCTION: Stabilator: The stabilator assembly is constructed in one piece, and then cut apart on its centerline after construction and sanding are completed.

1.) Pin the 1/4 in balsa stab leading edge blanks in place over the plans. Be sure that they fit tightly against each other at the center.

2.) Plug each end of the two 1/8 OD x 1-7/8 brass joiner tubes with scrap balsa to prevent epoxy from getting inside the tubes. Sand the outside of the tubes with coarse sandpaper and then clean the tubes with thinner or acetone to ensure a good bond.

3.) Epoxy the joiner tubes into the forward and aft tube carriers, and then epoxy the carriers in place against the stab leading edge blanks.

4.) Cut the stab root ribs from 1/4 x 1/4 balsa stock and pin in place. Cut the trailing edges and tips from 1/8 x 3/8 spruce and the stab leading edges from 1/8 x 114 spruce. Fit all joints tightly, then glue the stab outline pieces in place, making sure to shim the LE, TE, and tip pieces 1/16 off the work surface.

5.) Cut the stab ribs from 3/32 x 1/4 balsa, starting from the center and working toward the tip. Be sure all end cuts are angled to fit tightly against the LE sheet and trailing edge. When all the ribs are fitted, glue them in place. Add the 1/4 sheet gussets and allow the stab to dry completely before removing from the plan.

6.) Remove the stabilator from the plan and sand to shape. The stab should taper spanwise in thickness from 114 at the tube carriers to 1/8 at the tip. The LE sheet and ribs should be sanded to an airfoil shape that matches the 1/8 thick LE and TE. Round the leading edge and tips, and taper the trailing edge slightly. When shaping is complete, separate the two stab halves by carefully cutting through the tube carriers and brass tubes with a razor saw.

Rudder:

1.) Pin the 1/4 in rudder leading edge sheet in place over the plan, then cut the 1/4 x 1/4 balsa rudder post and glue it in place against the rear edge of the LE sheet.

2.) Cut the rudder base from 1/4 x 3/8 balsa, then cut the trailing edge and tip from 1/8 x 3/8 spruce. Fit all joints tightly, then install the outline pieces, shimming them up 1116. Add the 114 balsa gussets.

3.) Cut the rudder ribs from 3/32 x LA balsa. Make sure the ribs butt tightly against the rudder post and trailing edge and glue in place. Let the entire assembly dry thoroughly.

4.) Remove the rudder from the board. Taper the rudder from 1/4 thick at the bottom of the LE sheet to 1/8 thick at the tip. Cut the base and tip to the outline shown on the plan, then use a sanding block to taper the ribs and trailing edge. Round the rudder LE, tip, and base, blending all joints smoothly.

5.) Slot the rudder post for the hinges and bevel the leading edge to a Vee-shape from the bottom of the LE sheet to the lower end. Work carefully and finish up with a sanding block. Mark and drill the holes for the rudder horn. This completes the rudder assembly.

Wing: The wing construction sequence outlined assumes that you have no special jigs and a limited working area. If you have enough space, building both panels at the same time will reduce building time. If you have a hinged building board, the tip panels can be built directly onto the center panels, which is the fastest way to build the wing. We suggest that you install the tubing for the spoilers and the spoiler frame even if you don't intend to use the spoilers initially. If you decide to go with the spoilers at a later date it's a great deal easier just to cut out the covering than to try and install... "

Direct submission to Outerzone.

Update: Added instructions from Airtronics for their Sagitta 600 kit, thanks to IanTammen.

Supplementary file notes

Article.
Instructions (Airtronics).

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