Douglas DC-7DT (oz16849)

About this Plan

Douglas DC-7DT. Free flight scale model for rubber power. Wingspan 40 in.

Direct submission to Outerzone.

Quote: "DOUGLAS DC-7DT
40” SPAN FOUR ENGINE PROPOSED PROTOTYPE
DRAWN 7 JUN 2024

You gotta love this fore runner of the DC-8 with the swept tail surfaces and the turbo-prop engines. It looks good in the proposed Douglas markings for the airliner. I loved the looks of this bird and you can’t beat early airliners for looks and livery. TWA or Eastern Airlines would be good as well.

CONSTRUCTION:

WING: Use the Dave Rees’ sliced rib wing construction. Laminated tips 3 lams 1/32”x3/32”. This will build a very strong and light wing. The nacelles are primarily over the wing structure so there should be minimal interference with the rubber motor. Don’t forget the dihedral (2”) under each tip.

NACELLES: There are two basic nacelle structures. The outer nacelle and the inner nacelle. The inner nacelle is larger and longer to allow for the landing gear. They are both constructed using the box style construction. I do show an alternative using a 1/32” balsa tube with the shape filled out with foam. The type you use is up to you. I plan on leaving the rear of the nacelle, open for the motor to be attached to a hook on the T.E. for a bit more length. But this is an option that you can choose for yourself . Choose your preferred style of nose block/prop block.

FUSELAGE: I would build the fuselage using the ladder jig construction. The formers are made of 3 laminations of 1/32”x1/16” strips wrapped around the former templates. You can use 1/16” sheet balsa or foam board to make these formers. Be sure to use wax or Teflon tap to keep the templates from sticking to the laminations. Be sure to mark the demarcations lines on the formers so proper alignment can be made on the ladder jig. I usually start applying stringers first dorsal, then ventral and then both lateral stringers. This will firm up the formers and stabilize them for the addition of the other stringers. Just be sure to leave yourself room to remove the rungs from the ladder and formers before you completely close off the fuselage. Now add the wing saddles between the 9th and 12th formers to allow the wing to slide through the fuselage before adding the nacelles.

EMPENNAGE: The horizontal stab is built of 3/32” sq and sheet balsa. I was considering adding an additional ribs over the completed stab and sanding this to an airfoil shape. This will stiffen up the stab and help in avoiding warps. The vertical stab is what I call “Building in the Air”. Build the outline flat on the building board and when dry add the vertical spar from 1/16” sheet balsa in a triangular shape from the cap to the base of the vertical stab. 3/32” wide at the top and 5/16” at the base. Then add the 1/32”x1/8” strip ribs over the spar from L.E. to T.E."

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