Matt Stein Models
Curtis SB2C / SBC
Helldivers

Conversion/Construction/Completion Tips



Click on Image to Enlarge
The SB2C/SBC Helldivers casting, shown here, includes excess volume and details for conversion to either aircraft type solely by removing mass (and in the case of the SBC using additional biplane parts provided).


=> IMPROVED VERSIONS (with wing ordnance racks): As required or desired for the specific conversion (e.g., to an SBC), remove wing racks now, beginning with grinding them down (using a sanding stick recommended) and restoring approximate surface finish by scraping sideways with a straight-edged blade (razor chisel recommended), being careful not to obliterate scribed-in guide lines for the SBC lower wing, or SB2C wing-fold, if either are to be needed later (see below). <=


I: SB2C (monoplane) Helldiver Conversion
(for completion as SBC [biplane] variant, skip to Conversion II, below)


Click on Image to Enlarge
Remove mass from the blacked-out (inverted) areas shown, in steps (below) proceeding from those most stressful on the casting through those which (as a general rule) are progressively more delicate/intricate. The majority of this is best done using a sanding stick - especially on wings and control surfaces - and then fine-tuned/finished by scraping sideways with a straight-edged blade (razor chisel recommended).

1- Grind the chin away to eliminate the slight keel (of the SBC oil cooler), leaving the cowling cylindrical as for an SB2C, and grind the fuselage underside into a straight-line profile from nose to wing, taking care to preserve the exhaust stack fairings.

2- Flush with the front of the cowling, chop off the spinner, being careful to save it (for propeller installation see below), and then hollow out the engine inlet, concentric in the cowling.

3- It is recommended at this point to PAINT and DECAL the aircraft, considering decal visibility on any wings to be folded (see next).

4- To fold one- or both wings as desired, on their undersides locate the molded-in guide lines, and continue the scoring in each groove until cut completely through. Reposition each wing flipped vertically, its tip over the fuselage (rotated approximately 135º, or until wing tips are almost touching), and secure its base with strong adhesive (e.g., gap-filling CA) at the wing-fold joint.

5- Add landing gear (using the "Glue Drop" method recommended), with struts of the following specifications:

Main Gear: 0.015" diameter x 0.08" long; mounted 0º (vertical)
Tail Gear: (Already provided in tooth-like skid - can add tiny droplet of glue to simulate tire)


6- To the hub of a pre-painted, 4-bladed propeller (with rounded blade tips, provided by builder), attach spinner retained from Step 2 and use a tiny spindle of plastic dowel, stretched sprue or wire (also provided by builder) to mount in engine inlet.

Touchup-paint any spot(s) as needed, to complete the aircraft.


II: SBC (biplane) Helldiver Conversion

Click on Image to Enlarge
Remove mass from the blacked-out (inverted) areas shown, in steps (below) proceeding from those most stressful on the casting through those which (as a general rule) are progressively more delicate/intricate. The majority of this is best done using a sanding stick - especially on wings and control surfaces - and then fine-tuned/finished by scraping sideways with a straight-edged blade (razor chisel recommended).

1- Chop and remove canopy mass (using a razor chisel recommended) of the entire forward grouping of canopy framing and, from the first frame of the rear canopy (compare above with original casting, at top) chop a new windshield face plate for the SBC at about a 60º angle, as indicated. Once established, chop- and/or scrape away corners around the faceplate symmetrically to complete the SBC windshield.

2- Flush with the front of the cowling, chop off the spinner and hollow out the engine inlet, concentric within the upper (about 2/3 of the) cowling.

3- Drill- and hollow out circular wheel wells in the lower fuselage ahead of lower wing, as indicated above, and in the center of each drill a small but distinct dimple, angled downward, to accept a (~0.02" diameter) landing gear strut.

4- Optionally reinforce the (SBC lower) wing at the beginning of this step by plugging the wing-fold grooves (SB2C) with strong filler (gap-filling CA recommended). To convert the wing, file down the TIPS FIRST (while the rest of the wing retains maximum strength) and then, following the underwing scribed-in guide-lines, file down the leading- and trailing edges to remove the excess mass indicated above.

5- Thin the lower wing, if needed, by sanding from underneath

6- Access additional parts included for the SBC conversion:


Click on Image to Enlarge
Conversion parts provided are an upper wing and two wing "I"-struts (plus one spare), as indicated. Remove all casting wafer (or wafer remnants) from these parts. Free the "I"-struts using a straight-edged kife, with the struts laid flat on a hard surface, to chop them free and then scrape to clean up their edges.

7- Prepare struts for attachment by dragging their ends across a flat, medium-rough file or sandpaper at an angle of about 75º; level the ends appropriate to this mounting geometry:


Click on Image to Enlarge
The struts are deliberately made a little long; find the locator sockets in the underside of the upper wing and file strut ends down (as above) until they seat optimally.

8- Secure struts into the top wing underside locators using strong adhesive (e.g., gap-filling CA), setting their angles approximately as shown - it is more important that both be angled symmetrically than precisely to the angle specified (there are no locators on the lower wing) - allow glue to cure fully.

9- When struts are firmly secured into the upper wing, gently sand down their feet until producing approximately the wing (vertical) separation indicated. For yet more detail, fit 0.01"-diameter plastic rod or PE (either one to be provided by the builder) to make fine fuselage struts to the upper wing, as indicated. The underside of the upper wing contains additional locator sockets for these as well. Attach the upper wing.

10- Add landing gear (using the "Glue Drop" method recommended), with struts of the following specifications:

Main Gear: 0.015" diameter x 0.05" long; mounted pitched 30º outward.
Tail Gear: (Already provided in tooth-like skid - can add tiny droplet of glue to simulate tire)

11- Pre-paint a 3-bladed propeller (with rounded blade tips, provided by builder) and mount it in the engine inlet using a tiny spindle of plastic dowel, stretched sprue or wire (also provided by builder), clipped just ahead of the prop to form a tiny hub, as well.

Touchup-paint any spot(s) as needed, to complete the aircraft.


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