CB model designs CBMD-002 Construction Manual - Page 5

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After shaping the stab structure, seal with nitrate dope at structure boundaries and the edges of the

S-2 ribs and closeout common to the notch area. Before covering prefit the stabilizer to the stab

platform on the fuselage and adjust the fit of the notch to the platform edges.

There should be very little lateral movement of the stab in the flight position, but still enough

clearance to allow minimal friction when the D/T release occurs for stab pop-up. If there is a tight fit

to the stab platform, sand the edges of the platform lightly until a good sliding fit is obtained with the

stabilizer. Finish profile the stab platform filler to match the upper contour of the stab airfoil in flying

position.

Cover the stab with tissue but do not shrink yet. Lightly sand the exposed side of the S-6 ribs to

level any tissue overlap from the covering step. It is suggested that the vertical fins be covered with

tissue prior to installation. It is not a requirement to cover these with tissue, but they should be

sealed with several coats of thinned dope or wipe on polyurethane and then sanded lightly prior to

installation if not. The fins have laser etched reference lines that denote the bottom edge of rib S-6

to guide positioning during installation. If you covered the fins with tissue, pin prick the tissue on

the bonding surface that will contact the S-6 rib. Rub cellulose cement (Duco, etc.) over this area

with your finger to force the glue into the pin holes and also to saturate the tissue grain and improve

adhesion of the tissue to the fin in this area. Use cellulose glue to install the fins; position according

to the reference lines and with the fin held at 90 degrees to the bottom of the horizontal stabilizer.

Once the fin installation is completed, shrink the tissue covering and apply one coat of thinned non-

tautening nitrate dope to seal. At the stab center section, apply two additional layers of tissue over

the bay that will be in contact with the stab platform on the fuselage, to improve mounting stability

and allow a strong surface for stab tilt shims applied during flight trimming steps.

Install the two D/T band hooks by pushing the ends into the top of the doubled S-2 ribs and apply a

small fillet of medium CA dusted with microballoon filler to improve the glue fillet strength. Install

S-7 and the wire D/T connector eye on the aft end of the stab. Cover this with a patch of tissue and

dope to improve strength.

On the bottom of the T.E., on the centerline of rib S-1, bond the 1/64" x 1/4" x 3/8" ply to act as a

strike plate for the incidence adjustment screw. Construct the fuselage before adding the scrap

balsa keys on the strike plate.

Fuselage Assembly

Cover the plan with wax paper prior to assembling the two side frames. These assemblies are

shown with the inboard side up for construction, to allow flush outside fit of the filler parts which are

not 3/32 thick.

As done for the wing, it is suggested that balsa strip be positioned at the edge of the fuselage

longerons for boundary control in the areas that are straight-the area under the wing covered by

F-5, and along the fuselage bottom under the wing. As the fuselage box will be assembled sitting

upright, the straight bottom section is used as a control surface from which to maintain squareness

of the fuselage box. Also provide a boundary control strip for the short longeron in the stab

platform area. Similarly, provide a boundary control strip for the forward edge of F-1.

Assemble left and right hand motor peg filler F-8 with the F-9 doubler; make the grain of the F-9