Douglas DC-9-31

History
The Douglas DC-9 is a twin-engine, single-aisle jet airliner. It was first
manufactured in 1965 with its maiden flight later that year. The DC-9 was designed for
frequent, short flights. The final DC-9 was delivered in October 1982. The DC-9 was
followed in subsequent modified forms by the MD-80, MD-90 and Boeing 717. With the
final two deliveries of the 717 in 2006, production of the DC-9/MD-80/90/717 aircraft
family ceased after 41 years and nearly 2,500 units built.
The -30 was the definitive series, produced to counter Boeing's 737 twinjet, with
662 produced, accounting for about 60% of production. The -30 entered service with
Eastern Airlines on February 27, 1967 with a 14 ft 9 in fuselage stretch, wingspan
increased by just over 3 ft, and full-span leading edge slats, improving takeoff and
landing performance. Gross take-off weight was typically 110,000 lb. Engine options for
Models -31, -32, -33 and -34 included the P&W JT8D-7 and JT8D-9 rated at 14,000-
14,500 lbst of thrust, or JT8D-11 rated at 15,000 lbf of thrust.
The Series 30 was designed to incorporate extremely effective leading edge
devices in order to reduce the landing approach speeds exhibited by the Series 10, at
substantially higher maximum landing weights. The addition of full-span leading edge
slats reduced approach speeds by 6 knots, despite the gross weight being 5000 lbs
greater. The full span slats offered a significant weight advantage over slotted Krueger
flaps, since the wing leading edge structure associated with the slat is a more efficient
torque box than the structure associated with the slotted Krueger. The wing also had a 6%
increase in wing chord, all ahead of the front spar. This increase in wing chord allowed
the 15% chord slat to be incorporated.

Specifications

Length: 119' 3.5"

Wingspan: 93' 5"
Height: 27' 6"
Basic Empty Weight: 57,190 lbs
Max Takeoff Weight: 108,000 lbs
Fuel Capacity: 3,679 US Gallons
-24,833 lbs
Engines: (2) Pratt & Whitney JT8D-7
Low Bypass Turbofan
Engines, 14,000 lbst each
Max Cruise Speed: 565 MPH
Crew: (5) 2 Pilots & 3 Flight
Attendants
Max Passengers: 115 in one class
Max Range: 1,923 Miles
 General Building Instructions

Fuselage

G The fuselage will be built basically from nose to tail, with basic provisions provided
to add the landing gear and cargo bays.

G Start by constructing the nose section. Roll and assemble the very front, part F1.

G Next roll and assemble nose section, part F2. Connect F2 to F1 using mating strip
F2A.

G Next roll and assemble nose section, part F3. Connect F3 to F2 using mating strip
F3A.

G Next roll and assemble nose section, part F4. Connect F4 to F3 using mating strip
F4A.

G Next roll and assemble nose section, parts F5A, F5B, & F5C. F5A will be the
bottom section, F5B are the flight deck windshields, and F5C is the flight deck
roof. Connect the completed F5 section to F4 using mating strip F5D.

G Next roll and assemble nose section, part F6. Connect F6 to F5 using mating strip
F6A.

G Next roll and assemble nose section, part F7. Connect F7 to F6 using mating strip
F7A.

G (Gear Up Option) To depict a “gear-up” airplane, cut out part NG10. Use this
part to cover the lower fuselage opening on part F4. Cut out the rear nose gear
doors, NG11L, and NG11R. Use these to cover the rear nose gear well on part
F5A.

G (Gear Down Option) To depict a “gear-down” airplane, cut out and assemble the
nose gear bay, part NG1. Once assembled, align the nose gear bay to the floor of
the fuselage, aligned with the openings on the bottom of F5A and F4. Also note
that the roof of the nose gear bay should be parallel to the longitudinal axis of the
aircraft.

G Now to add the bulkhead sections to the nose of the aircraft. First cut out and
insert bulkhead W1* through the rear of the (so-far) assembled fuselage. Make
sure the arrow is carefully aligned to the bottom of the section. It should fit snugly
between sections F3 & F4.

G Next cut out and insert bulkhead W2* through the rear of the (so-far) assembled
 fuselage. Make sure the arrow is carefully aligned to the bottom of the section. It
should fit snugly between sections F4 & F5. Also note that NG1, the nose gear bay
will sit snugly on the bottom of this bulkhead. You may need to slightly trim the
bulkhead to ensure a decent fit.

G Next cut out and insert bulkhead W3* through the rear of the (so-far) assembled
fuselage. Make sure the arrow is carefully aligned to the bottom of the section. It
should fit snugly in the center of F6.

G First cut out and insert bulkhead W4* through the rear of the (so-far) assembled
fuselage. Make sure the arrow is carefully aligned to the bottom of the section. It
should fit snugly at the rear of section F7.

G Next we’ll construct the center fuselage, part F8. This section will bridge the nose
and tail sections of the aircraft, be a foundation for the wings, and house the
optional forward cargo bay.

G Start here by rolling and assembling the center fuse section, part F8. Cut out the
opening on each side for the wing box, to be added later.

G (Open Cargo Option) To create an open cargo bay in the forward compartment,
be sure to cut out the cargo bay door before rolling and assembling the main fuse
section F8. You can discard the door. Next cut out and assemble the forward
cargo bay, part H1. Once complete, insert and glue it into place into F8. Be sure
to carefully align the bay door opening with the external door opening.

G Next add the center fuselage bulkheads. Bulkhead W5* should be placed
approximately in the center of segment F8. Carefully align the arrow to the bottom
seam of the section, and also be careful not to block the wing box openings.

G Next add the center fuselage bulkheads. Bulkhead W6* should be placed
approximately 1" from the rear of segment F8.

G Now attach the center fuselage segment to the completed nose section. The rear
of part F7 should mate cleanly with the center fuselage, section F8. Use part F8A
as a mating strip to connect them.

G Now to build the rear fuselage. We’ll start with section W9.

G (Open Cargo Option) To create an open cargo bay in the rear compartment, be
sure to cut out the cargo bay door before rolling and assembling the rear fuse
section F9. You can discard the door. Next cut out and assemble the forward
cargo bay, part H2. Once complete, insert and glue it into place into F9. Be sure
to carefully align the bay door opening with the external door opening.
G Next roll and assemble rear section, part F10. Connect F9 to F10 using mating
strip F9A.

G Next roll and assemble rear section, part F11. Connect F11 to F10 using mating
strip F10A.

G Next roll and assemble rear section, part F12. Connect F12 to F11 using mating
strip F11A.

G Next roll and assemble rear section, part F13. Connect F12 to F11 using mating
strip F12A.

G Last add the fuselage antennas. Part A1 to the top of the fuselage, and A2 & A3 to
the bottom of the fuselage. Use the diagrams to help, and all should mount to
section F8.

Wings

This procedure is to build the left wing only. To construct the right wing, just repeat the
steps using the R designated parts.

G Let’s start by building the wing box. Fold and assemble parts V1L and V1R.

G Once dry, glue or tape together V1L and V1R at their open centers.

G Take the completed wing box (V1L & V1R) and push them through the opening at
the center of the fuselage, segment F8. Be VERY CAREFUL of alignment of this
part. It will provide strength, shape and alignment for the wings. If this part is not
aligned well, then the wings will not take correct shape when added to the
fuselage.

G Add & align bulkhead V2L* to the end of the wing box, part V1L.

G Next add the alignment parts to the fuselage. Parts Y1L and Y2L should be added
to the marked areas on the left side of segment F8. These will later help the wing
mate to the fuselage.

G Now construct the outer main wing structure. Part LW1 makes almost all of the
outer wing structure.

G (Gear-Down Option) For a “gear-down” version of the aircraft, be sure to cut out
and discard the main gear door, toward the under root of the wing. Next
assemble the main gear well, part LG2. Once dry, carefully align and glue into
place into the interior of the wing, part LW1.
G Now mount the wing onto the fuselage. Part LW1 should mount cleanly to the
fuselage on part F8. Use the wing box part V1L, and the mounting guides, Y1L &
Y2L to help.

G Now to construct the wing fairings. They come in four parts, and have guides to
help alignment.

G Start by adding the supporting bulkheads. Parts Q1L* & Q3L* are small parts and
should be handled carefully. These parts are really optional and should be
mounted on top of the wing.

G Next add the bottom supporting bulkheads, parts Q2L* & Q4L*. These are larger
and will sit at the bottom of the wing.

G Next add the top wing fairing, part LW8. It should align to the upper supporting
bulkheads.

G Now add the lower fairing, part LW7. It is fairly large and sits at the bottom of the
wing. Also not that it bends a full 90 degrees from the wing to the fuselage. Take
your time and properly for this part before gluing into place.

G Now add the front wing fairing, part LW6. It should connect to part LW8 at the
top, and LW7 at the bottom. If there is a fit issue, take time to trim the part so it
wraps around the wing properly.

G Now add the rear wing fairing, part LW9. It should connect to part LW8 at the
top, and LW7 at the bottom. If there is a fit issue, take time to trim the part so it
wraps around the wing properly.

G Next we’ll add the under wing fairings. Start by adding the inner flap canoe, part
LW2.

G Next add the main wing aerodynamic strake, part LW3 to the forward underside
of the wing.

G Last add the outer wing canoes, parts LW4 and LW5.

G This complete the wing structure. Repeat the steps for the right wing.

Engines

This procedure is to build the left engine only. To construct the right engine, just repeat
the steps using the R designated parts.

G Start by rolling and assembling the front segment, part E1L.

G Next roll and assemble the next segment, part E2L. Connect E2L and E1L with
mating strip E2LA.

G Next roll and assemble the next segment, part E3L. Connect E3L and E2L with
mating strip E3LA.

G Next roll and assemble the next segment, part E4L. Connect E4L and E3L with
mating strip E4LA.

G Now build the engine inlet. Start by rolling and assembling the inlet, E6L. Once
dry, add the engine compressor face, part E9L*.

G Next add the inlet bullet. Start by carefully aligning and adding E10L* to the front
of E9L*.

G Now add the front bullet segments. First roll and assemble E8L to the face of both
E10L* and E9L*.

G Cap off the segment E8L with E7L.

G Once dry, add the completed inlet to the rear of the mostly completed front engine
nacelle. Be sure to align the bottom inlet seam to the bottom seam of E1L.

G Now construct the exhaust & turbine section. Start with the outlet face, part E23L*.
Add the turbine outlet face, part E19L*. Be sure to check alignment.

G Next add the bypass duct, part E24L. Roll and wrap this part around E19L*.

G Now to add the exhaust plug. It comes in two parts, E21L and E22L. E21L should
be rolled and added to the rear of the exhaust face, part E19L. Cap off E21L with
E22L.

G Next add the exhaust duct. Roll and assemble part E20L. Take the completed
Exhaust face and insert and glue into place into the front of the exhaust duct, part
E20L. Make sure the white outlet guide vanes on the exhaust turbine align with the
seam on the exhaust duct.

G Next roll and assemble the next segment, part E5L.

G Now insert the completed exhaust assembly into the front of segment E5L. Before
gluing, be sure to make sure the seam of the exhaust duct aligns with the seam at
the bottom of E5L.

G Connect E5L and E4L with mating strip E4LA.

G Now we’ll add the thrust reverser fairings. The have two halves, a left and a right,
and have four parts each.

G Start with the left (outer) reverser housing. From front to rear, add sections E11L,
E12L, & E13L to the blank area on the left of the engine. Last add the inner
section, part E14L to the inside of E13L.

G Next the right (inner) reverser housing. From front to rear, add sections E15L,
E16L, & E17L to the blank area on the right of the engine. Last add the inner
section, part E18L to the inside of E17L.

G Now construct the engine pylon, part E26L. Once folded and assembled, carefully
align and glue the pylon onto the blank area of the left engine.

G Once dry, add the pylon bulkhead, part E25L* into the opening on part E26L. The
printed side should face the opening. This part is not depicted in the diagrams,
and is optional.

G Last add the completed engine to the left side of the fuselage. Be sure to check
alignment before allowing to dry.

G Repeat all steps to complete the right engine.

Nose Gear

G Start by rolling and assembling the main nose gear strut, part NG2.

G Glue the strut into the roof off the nose wheel well, part NG1. Frame the nose
gear brace with pivots NG3 (x2) to the roof of NG1.

G Next add the drag brace, part NG8. It connects NG2 to NG1. Frame the well
connection (NG1) with parts NG5 (x2) and the nose gear strut portion (NG2) with
parts NG6 (x2).

G Now add the sway braces. These are parts NG4. There are two and they attach to
the main strut NG2, and form a 45 degree connection to the left & right walls of
the well part NG1.

G Now add the nose gear mount, part NG7. Roll and assemble NG7 and add it the
end of NG2.

G Next add the torque link, part NG9. It connects NG2 to NG7. Note that this part
faces the rear of the aircraft.
G Next add the nose lights. Roll and assemble parts NG14, and add them to the
sway braces, NG4. Be sure to have the lens portion facing the front of the aircraft.

G Now take your wheels (wooden, foam, or otherwise) and glue the hubs in place.
Note that NG13 will lace the inside of the wheels, and NG12 faces the outside.

G Once ready, align and glue your nose wheels in place, onto NG7.

G Next fold and assemble the rear nose gear doors. NG11L will be on the left, and
NG11R on the right. These should be facing parallel the vertical axis of the
aircraft.

G Last add the front fuselage doors. This is part NG10 and should cover the opening
remaining on F4.

Main Gear

This procedure is to build the left main gear only. To construct the right main gear, just
repeat the steps using the R designated parts.

G Start by rolling and assembling the main gear strut, part LG6.

G Glue the strut into the roof off the main wheel well, part LG2. Frame the left gear
brace with pivots LG4 &LG5 to the roof of LG2.

G Next add the drag brace, part LG7. It connects LG6 to LG2. Frame the main strut
portion (LG6) with parts LG9 (x2).

G Now add the sway braces. These are parts LG10. There are two and they attach to
the main strut LG6, and form a 45 degree connection to the left & right walls of
the well part LG2.

G Now add the main gear mount, part LG8. Roll and assemble LG8 and add it the
end of LG6.

G Now add the retraction actuator, part LG3. It sits parallel to the main strut, LG6,
on the side facing the fuselage. It is framed at the bottom by parts LG9 (x2), on the
side attaching to LG6.

G Now take your wheels (wooden, foam, or otherwise) and glue the hubs in place.
Note that LG11 will lace the inside of the wheels, and LG12 faces the outside.

G Once ready, align and glue your nose wheels in place, onto LG6.

G Last add the main gear doors. This is part LG1 and should swing outward from
 the wing approximately 60 degrees.

G Repeat all steps to complete the right main gear.

Empennage

G Start by building the rudder. Add the alignment guide, part Y3 to the designated
area atop the fuselage.

G R1L and R1R should be glued gently together to avoid connecting the inner
portions of the rudder. Care should be taken to ensure only the outer seams are
glued together. Also, be sure that the bottom opening is not glued together.

G Once dry, align and glue into place the rudder atop the alignment guide, part Y3.
Make sure the rudder is perpendicular to both wings.

G Once dry add the elevator mounts to the top of the rudder. These are laminated
parts R2L* and R2R*.

G Next add the elevator alignment guides to the elevator mounts. These are parts
R3L* and R3R*, which align and mount directly to R2L* and R2R*.

G Next construct the elevator sections. Care should be taken to ensure only the
outer seams are glued together. Also, be sure that the inner opening is not glued
together.

G Now add the left elevator part S1L, to its rudder mount, R3L*. The section should
slope downward about 2 degrees.

G Now add the right elevator part S1R, to its rudder mount, R3R*. The section should
slope downward about 2 degrees.

DIAGRAMS