Douglas DC-3 (oz15529)

About this Plan

Douglas DC-3/R4-D. Free flight scale model twin, for electric power. Wingspan 39 in. Scale is 1/29.

Quote: "Douglas DC-3/R4D-5. 39 inch wingspan, electric-power model. Designed By P Wank and R Breckur for Scientext, Westport, CT.

Designer's Notes: Those of you with a life-long love affair with the 'Gooney Bird' (like me), or who may be ex C-47 or R4D drivers will doubtless find that the model you're about to build may differ a bit from the airframe that you're familiar with.

There is some disagreement about the total number of civilian and military DC-3's produced, both here, and abroad under license (Lisunov Li-2 in the USSR), but a figure of about 11,000 probably isn't too far off the mark. In this vast number of aircraft, of which about 500 are still flying, there are a large number of variants. Among these are window type, number, and placement (some were round), engine nacelle and cowling configurations, oil cooler shapes, cockpit layouts, vertical tail (the R4D-8 had a squarish one), engine installation (there were Rolls-Royce Dart turboprops), wing area and planform, landing gear (there were skis, and EDO floats) and so forth.

On a recent visit to the CR Smith American Airlines Museum at D/FW Airport in Dallas, I was informed by an ex-AA First Officer that all DC-3's manufactured for AA had the passenger entry door on the starboard side; apparently CR felt that passenger entry, and baggage loading should be separated.

My sources for planform and details were the following:

• A set of three-views from an old Aeromodeller magazine, from Pat March at The Skonk Works (RTP specialists).
• 'DC-3 and C-47 Gooney Birds', by Michael O'Leary, $19.95, Motorbooks Intl, publishers, loaned by Bob Breckur at Corsair Industries.
• Photographs of the DC-3 'Flagship Knox-ville', taken at D/FW Airport, October, 1993.
• Monogram Model kit #7590, U.S. Navy DC-3; a 1/72-scale plastic model, done in the R4D-5 configuration.

In order to be able to use the 5 inch, 3-bladed props supplied with this kit, the nacelles were moved outboard by 1/4 inch to accomodate the prop arc. Also, the stabilizer area was increased by about 20% (span increase), and the dihedral increased to provide needed free-flight stability. Any other deviations from scale result from inaccuracies in digitizing of the scale three-views into the computer, and, for these, I do apologize.

With a 39 in span, our DC-3 is at a scale of 1:29. Since the landing gear has no shock-absorbing ability, I suggest that you make the gear removable for flight. Since no decals (aside from the 1/72-scale) existed for this model, SIG Mfg. Co. agreed to silkscreen them from our artwork.

Materials Needed: The prototype used the following number of 3 in wide X 36 in long, medium grade, balsa sheets:

• 1/16": 3
• 3/32": 1
• 1/32": 2
• 1/8": 1

In addition, some small pieces of 1/32 ply, and a few foam or balsa blocks, for fairing-in the cockpit area, are needed. You should also have a balsa stripper, some CyA+ and Elmer's glue, and the usual other tooling needed for stick-and-tissue construction. The Nicad pack for the prototype was a 4X110 mAh unit. Nicads are available from TNR Technical (279 Douglas Ave, Altamonte, FL 32714, (800) 346-0601), as #N-110AA at $1.50 each.

Any other materials needed are specified at the appropriate sections in the following text.

Wing Construction: Since the center panel of the wing will be required in building up the fuselage, you might as well start here. Build the section of the box main spar needed for the center panel. Make it a little longer than needed, to allow for final sanding to correct length. Cut all R1 ribs (9 required) as shown on Sheet 7, and cut away the section represented by the spar from each rib with a razor saw. Build the center panel directly over the plans, and plank the area between the three center ribs, LE to TE, with 1/32" soft sheet. Plank also the area between LE and box spar (top only), out to the outboard ribs.

Lay out, with steel rule or straightedge, the box spars for the outer wing panels, and build the outer panels. Don't use the pattern on the plan since it may distort. Leave these a little longer to allow for sanding in the dihedral angle later on at assembly to the center panel. Install the inboard, R1 ribs only when assembling outer panels to the center panel. Wingtips are soft, 1/4" sheet.

Install the 1/32 sheet wire feed-thru panels as shown. The 1/4 in dia holes in these panels, and in the R1 ribs, are easily done with a one-hole paper punch - but don't forget them. (The panels protect the tissue covering from ripping when installing the wiring). Set aside all three completed wing panels (unassembled) till later.

Fuselage: Make photocopies of all pattern sheets; these sheets are all 11 x 17 in, and any Xerox machine should handle them. I prefer to glue-stick the patterns to the balsa, but you can try the hot iron or acetone swab techniques on the inverted photocopies, if you like. 3M dry bond spray adhesive is another possibility.

From medium 3/32 sheet, cut all keel parts as shown on Sheet 6, noting that 2 each of K8, K9, and K10 are needed. Assemble these keel parts over the plan, and carefully mark the position of each former, F1 thru F13, directly onto the keels. The former spacings are non-uniform, and they must be accurately spaced as shown. Mark also the notch for the tail wheel.

Note the dotted lines on formers F5 and F6; these should be cut partway through before assembly to allow for easy removal later on. Cut all formers from medium 1/16 sheet, with the grain as shown. Cut the small F7A pieces with grain horizontal, and glue them to F7 - they'll be used to help form the wing fillet. Add the 1/8 square pieces to F5 and F6 to provide some stiffness..."

Direct submission to Outerzone.

Supplementary file notes

Instructions.
Wiring diagram.

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