Waco YQC-6 (oz16012)

About this Plan

Waco YQC-6. Free flight scale cabin biplane model for .09 - .15 engines. Scale is 1/9.

Direct submission to Outerzone.

Note this plan could do with a good cleanup. I just ran out of time on this one. Steve.

Update 8/5/2025: Added article, thanks to Pit.

Quote: "THIS WACO YQC-6 biplane is a most fortunate combination of good looks and flight performance with ample opportunity for scale detail work. Dick Meixell's prototype has been a great centre of attraction wherever it has appeared - especially at the 1962 USA National Championships.

It is a model of the 1936 Waco Custom Cabin biplane - a cleaned up and refined version of the first Waco cabin bipe with larger tail moment arm, a smaller cowling and no shoulder fillets on the landing gear. In the designation YQC-6, the 'Y' refers to the engine, 'Q' the wing design, 'C' denotes Custom Cabin and '6' is the model year, 1936. Five passengers could be carried at 140 mph cruising speed for 500 miles on 225 hp.

This model features padded seats, cloth upholstery, hardwood veneer trim, a dummy radial engine and scale structure. About 1/4 inch has been added to the tail outline and the dihedral increased by 1-1/2°. As modified, longitudinal stability is satisfactory, but lateral stability is somewhat borderline when flown in a wind. Consequently any amount the builder cares to increase the dihedral from scale will increase stability, but at the cost of scale fidelity. This is the choice always forced on a scale model builder. Heavy wheels also give a built in pendulum effect.

Take-offs are long, shallow and realistic at 27 oz weight. Climb with a moderate .09 engine is at a shallow angle with the model looking like the real plane climbing out of the aerodrome. The glide is not slow; but is safe.

All possible details are included on the model, and the plan. Large windows and skylight allow the interior to shown to the best advantage. Weight reduction can be accomplished by using tissue instead of silk, fewer coats of dope, eliminating wheel spats, plastic radial engine, fillets, moveable control surfaces, external details, hardwood veneer trim, etc.

The large size model (1-1/3 in = 1 ft for this Waco) always gives a more impressive appearance than a smaller plane, gives more latitude for scale detailing, has larger wheels for easier take-offs, is easier to build, and is more stable in a wind. The designer has never felt the need for detachable wings. One piece models arc lighter and better looking with no split lines, hooks, elastic bands, etc, to spoil the appearance. The model is shown as a one-piece job, though detachable wings could be devised.

Wing structure has proven to be light and amply strong. With firm struts one has a practically unbreakable and a warp-proof assembly. The type of strut bracing shown is lighter and stronger than the single heavy rib system and transfers stresses to where they belong. Dihedral braces are set up for 4-1/2°. Add dihedral before LE sheeting. Check the entire tip area for a smooth taper from the full depth ribs out to the tip, chordwise and spanwise. Carve the tips to conform to this taper. Leading edge sheeting should be quite soft with the close rib spacing used. At final sanding, round edges of every piece that will contact the covering, including both sides of every rib and front of TE and rear of sheeting. Then clear dope, sand smooth, and clear dope again. This applies to the framework of the entire model. Wings must be assembled to the fuselage before covering.

Use bond (stiff writing or cartridge) paper to simulate flaps and fuel tanks after covering has been clear doped. Add dummy ribs to tank and cover with tissue.

Tail surfaces are conventional except for the mounting and the laminated rudder outline. Build the tailplane in the usual manner but do not cover. Mount on the covered fuselage with the fairing in place and add 3/32 dowel through the faking opening. Dope all visible structure silver. Do not cover the gap between tailplane and fuselage. The laminated rudder outline is made of soaked strips of 1/16 by 3/16 saturated with glue. This system could be used on the elevator if desired. Incidentally, the C-6 was the first Waco to use an airfoil section on the tailplane.

The fuselage is the usual box frame with a fairing. 1/16 by 1/8 longeron fairings are a must on all scale models since it keeps the crosspieces from showing and blends in with the nose sheeting. Main consideration is the building sequence which should be as follows; basic box, centre bulkheads, engine mounts and landing gear struts, remaining bulkheads, sub cowl, bond cabin interior except for ceiling, hardwood veneer trim, side stringers, fuselage sheeting, hinge doors, add upper wing, cabin ceiling, mount lower wing, tail wheel, upper and lower stringers, sand and clear dope structure, shellac hardwood trim, finish interior, cover fuselage and wings, add wing and landing gear struts and fillets, add covered fin, fin fillet and tailplane fairings, and then uncovered tail..."

Supplementary file notes

Article.

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