Douglas DC-3 / C-47

About The Aircraft

The DC-3 was developed from the DC-2, to meet the need for a larger aircraft that could fit bunks in a sleeper configuration for American transcontinental overnight routes. The airframe was adapted as a military transport for WW II, and over 16,000 were produced. After the war, the abundant supply of surplus military aircraft made it the single most popular airliner of the early post-war period, and it has made a lasting impression as one of the most iconic aircraft in history. The type remains in limited service today, over 80 years after its maiden flight.

Specifications:

Propulsion: Pratt & Whitney 1830 Twin Wasp (2x), 14-cylinder air-cooled two-row radial engines, 1,200 HP each
Flight Crew: 2 (captain + first officer)
Capacity: 21-32 passengers
Empty Weight (OEW): 16865 lbs / 7650 kg
Typical Takeoff Weight: 25200 lbs / 11431 kg
Range: 1370 nmi
Service Ceiling: 23,200 ft

Configuration Options

The aircraft comes in 2 basic versions: a landplane (dc-3), and a seaplane version with floats (dc-3A). Both versions can be configured with 3 different interiors: civilian red, civilian grey, and military.

For the flightdeck, two options are currently available: an original ca. 1940 panel, with the instruments installed in typical nonstandard locations, and equipped with a Sperry autopilot; and a later, ca. mid-1980's panel as used by airlines such as Piedmont, with more modern instruments in a standard T-shaped arrangement, and a Century 41 autopilot system.

Flying the DC-3

The main thing to remember with this aircraft is that, being a taildragger, it is quite different from your typical modern airliner.

Startup

Running light: ON (left overhead panel)
Tail light: ON (left overhead panel)
Turn on master battery (left overhead panel)
Turn on both fuel boost pumps (right overhead panel)
Mixture levers in "AUTO RICH" position
Prop levers in "feather" position (full back)
Both magnetos in "BOTH" position (center overhead panel)
Left fuel selector: MAIN LH
Right fuel selector: MAIN RH
Throttles: ~1/2 inch forward.
Parking brake: set.
Left engine starter: ON (right overhead panel)
Wait for left RPM to rise to about 500 rpm
Left starter: OFF.
Right engine starter: ON (right overhead panel)
Wait for right RPM to rise to about 500 rpm
Right starter: OFF.
Throttles: IDLE.

Taxiing

Landing lights: AS NEEDED (the DC-3 has no taxi lights; standard procedure is to taxi with one landing light on and the other off)
Throttles: IDLE
Props: FULL FORWARD
Tail wheel: UNLOCK ("l" key)
Parking brake: RELEASE
Use differential brakes and differential thrust to steer; lock tail wheel for longer straight sections.

Takeoff

Flaps: UP
Cowl flaps: OPEN
Landing lights: ON
Tail wheel: LOCKED
Props: FULL FORWARD
Throttle: advance to manifold pressure (MP) 48
Pull slightly on the elevator to keep tail down
Use differential braking to steer while tail is down
Allow tail to come up at 50 knots
Maintain level pitch, use brakes and rudder to steer
At positive climb: gear up
Accelerate to 105 knots
~300 ft AGL: reduce MP to 40, maintain 105 knots
~800 ft AGL: accelerate to 115-120 knots
Reduce MP to 35
Props: pull back to maintain 2500 RPM
Cowl flaps: TRAIL

Cruise

Landing lights: OFF
Throttles: MP 20-25
Props: 1800-2200 RPM
Cowl flaps: CLOSE
Airspeed: 150-155 knots

Descent

Landing lights: ON
Cowl flaps: TRAIL
Airspeed: 150-160 knots
Throttles: MP 18-20
Props: 1800-2200 RPM

Approach

Airspeed: 105 knots
Throttles: as needed
Props: FULL FORWARD
Flaps: 7 deg
Gear: down

Final approach

Flaps: 30 deg (set gradually; keep at 22 deg for crosswind landing)
Cowl flaps: TRAIL
Airspeed: 80 knots (85 for crosswind landing)
Gear: confirm down & locked
Tailwheel: LOCKED

Landing

Make sure you're aligned with the centerline
Maintain 80 knots into flare
Perform a slight flare to bleed off speed
Use rudder to maintain centerline, help with diff braking
Use elevator to avoid nosing over while applying gentle braking to slow down; keep the tail up to maintain rudder authority.
At 50 knots, land the tail; use elevator to keep tail down for better directional stability. Remember that the rudder becomes ineffective once the tail is down.
At 30 knots, release elevator, unlock tailwheel as needed for runway turnoff.
Clean up aircraft while taxiing.

Some general tips

Diff braking and diff thrust are fairly critical to keep this bird controllable; rudder pedals with toe brakes and split thrust levers are absolute game changers.
For crosswind landings, neither the usual "de-crab" technique (approaching the runway in a crab, then using rudder to align while flaring) nor the "slip" technique (use cross-controlled rudder and ailerons to keep the aircraft aligned through the final approach, and touch down with the upwind wheel first) work particularly well; I have found that the best technique is to fly most of the approach in a crab, then transition into a bit of a slip, but keeping the wings level, and finally kicking out the remaining crab shortly before touchdown. The aircraft can take a bit of side loading, but you have to be quick on the rudder and brakes to prevent a ground loop. Don't forget to use ailerons to counter the tendency to tip over when doing this.

The Autopilots

Sperry Autopilot

The Sperry unit isn't an autopilot in the modern sense; it has only very limited capabilities, but nonetheless it is surprisingly useful. It controls 3 axes: rudder, ailerons, and elevator; and they are controlled completely independently. The rudder axis is coupled to a pair of gyros, and will deflect the rudder in an attempt to achieve and maintain a selected heading; the aileron axis holds a selected bank angle, and the elevator axis holds a selected pitch.

To execute a turn, first synchronize the two gyros using the rudder knob, and synchronize the attitude bar on the attitude indicator on the Sperry unit with the current attitude using the ; then enable the autopilot, use the rudder knob to select the target heading, and the aileron knob to bank in the desired direction. You will have to manually select level attitude again as the aircraft approaches the target heading; the autopilot will not do this for you. Once established on the target heading, the rudder control is usually enough to keep the aircraft on course.

The elevator axis is fairly straightforward: turn the knob to select a target pitch.

Century 41 Autopilot system

The full operation manual for the Century 41 can be found here:

https://www.centuryflight.com/images/operating-manuals/CENT41.pdf

A short summary is provided here.

Configuration

The AP can be enabled and disabled with the "ON/OFF" rocker switch on the autopilot control unit. You can also bind a joystick button to the property controls/autoflight/autopilot[0]/engage property. When the autopilot is disconnected, the "AP" light on the FMA panel will flash for 5 seconds.
The unit faithfully models "CWS" ("Control Wheel Steering"), a button that temporarily disconnects the autopilot, and synchronizes the flight director with the current attitude and/or altitude. The autopilot will revert to its previous lateral and vertical modes and maintains the new attitude / altitude when the CWS button is released. CWS is not bound to anything by default, but you can bind a joystick button to controls/autoflight/cws.
The unit also supports a "go-around" mode ("GA"), accessible through the controls/autoflight/toga property.
The "UP/DOWN" rocker on the right of the control unit can be used to adjust the selected altitude / pitch to make fine adjustments. It can be mapped to joystick buttons or an axis using the autopilot/inputs/pitch-button property.

Lateral modes

ROLL (no annunciation): this mode is the default when the autopilot is first engaged, a basic wing leveler.
HDG: capture and hold the heading indicated by the heading bug on the HSI.
NAV: fly a 45° intercept course, capture and track the VOR radial selected on NAV1.
NAV ARM (both HDG and NAV light up): fly the selected heading as per HSI until intercepting the VOR radial on NAV1, then switch to NAV mode.

Vertical modes

ATT: hold current pitch attitude. UP/DOWN rocker switch increases or reduces pitch up to +/- 500 fpm while pressed, and maintains the resulting pitch upon release.
ALT: hold current pressure altitude. UP/DOWN rocker switch initiates a climb/descent up to +/- 500 fpm while pressed, and maintains the resulting pressure altitude upon release.
GA: pitch for best single-engine climb speed (105 knots). Lateral mode is unaffected.
GS: maintain ILS glideslope. This mode cannot be selected directly, but engages when capturing the glideslope with APR armed (see below).

Combined modes

APR: approach mode. Lateral mode is set to NAV, vertical mode remains unaffected until an ILS glideslope is captured, at which point it transitions to GS.
APR ARM (both HDG and APR light up): same as NAV ARM, but transitions to APR after capturing the localizer.

tdammers / Douglas-Dc3