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VSKYLABS DC-3 C-47 Flying Lab Manual

VSKYLABS DC-3/C-47 Flying Lab Project

User Manual and Instructions
(under construction)

NEED TO KNOW:
DC-3/C-47 AIRCRAFT MANUAL AND POH

DC-3/C-47 Manuals:
OK...as I've said up in this page...there is too much of practical information to learn...what I'm going to do is first to set here some really practical links to useful website and resources. Take your time and get to know the DC-3/C-47...I can recommend reading information regarding the aircraft "general" systems/systems operations and deeper into flying techniques and performance/limitations.

Here is an AMAZING resource for Flight Operating Instructions and Manuals for the DC-3/C-47. It called "www.avialogs.com" and it is a "treasure" for Aviation enthusiasts. You will find these, among other useful materials:

You don't have to subscribe to read these documentation online. There is a reading window  with comfortable pages view settings (screenshot attached below):

NEED TO KNOW:
Transatlantic crossing with the DC-3/C-47

The VSKYLABS DC-3/C-47 Flying Lab mission-range performance was tested, evaluated and tuned by flying authentic routes in real-time simulation (some times with time compression, of course). It is not enough to set the engine's Specific Fuel Consumption to be "by the book", and actually create an aircraft which is using it, so it will deliver the expected outcome (range and "practical" fuel management). 

Having the engines defined "by the book" will not define the practical operational radius of a simulated aircraft. Only the "whole" aircraft, as an aerodynamic, powered flying machine will do so. A lot of variables are to be added to the "calculated" SFC of an engine, in order to get the aircraft to demonstrate the actual performance....

We need to taxi, burn fuel in engines run-up (even if it is done with an estimation), take off with the authentic weight and fuel, climb, cruise, fight the winds, descent, approach, land....all of these were tested as a whole "mission" during the development phase of the flight dynamics model of the VSKYLABS DC-3/C-47 Flying Lab Project.

Tuning the various variables, such as wings performance, drag, propellers performance and drag, angle of attack during each phase of flight...even the position of the trims...is a complex "act of balance", since everything is tied up together and affecting the overall performance. Since there are limitations in (every) PC-based flight dynamics simulation engine (including X-Plane), sometimes, the "blanket" for covering the various flight envelope regimes, may be too "short", and a decision is to be made: "which part do I cover, and which I don't"...

Because of that, and in order to get a DC-3/C-47 which will perform good in all flight phases, the final flight dynamics model might "host" some compromises, in some of its aspects. Good news is that the VSKYLABS DC-3/C-47 Flying Lab model is now demonstrating a very accurate performance, within the acceptable margins of realism.

To make it short, and right until I'll gather the information into a useful guide, I highly recommend reading this amazing story: http://airfactsjournal.com/2017/01/flying-beyond-doubt-epic-dc-3-journey/

NEED TO KNOW: SYSTEMS AND SYSTEMS OPERATIONS

NEED TO KNOW:
SYSTEMS AND SYSTEMS OPERATIONS

Although defined with the various systems that are needed to operate the aircraft, the VSKYLABS DC-3/C-47 is not a "Study Level" model, in terms of advanced systems algorithm simulation. For example, in order to fire up the Pratt & Whitney R-1830 Twin Wasp engines, there is no need for the complex procedure involved in the start-up procedure of the real aircraft.

This section is a short briefing that explains how to use the main systems of the VSKYLABS DC-3/C-47 aircraft. 

This briefing is not covering *all* of the VSKYLABS DC-3/C-47 systems, but only some of them. 

NEED TO KNOW: SYSTEMS AND SYSTEMS OPERATIONS

AIRCRAFT MAIN SYSTEMS

COCKPIT CONFIGURATION:
The VSKYLABS DC-3 / C-47 aircraft is featuring the cockpit configuration similar to the one that is described in the AAF Manual Pilot Training Manual for C-47 Skytrain. (Few changes existing).  




Modern GNS:
Version v2.5 is introducing dual folding GNS-530 terminals. This arrangement is letting the cockpit to stay authentic and old school, but to include a modern GNS environment for pilots who want to use it.

While folded, the terminals are set to 'off'. In addition, they offer full control over nav1,nav2,com1,com2 and separated dual display for maximum usability. Volume control knobs for com/nav on the GNS terminal are working also, so pilots who are using the GNS configuration are not required to use the upper old-school radio panel.

When folded up, they are turned off and thanks to their slim design they are blended perfectly into the upper windshield line and practically not causing any distractions. 


MIXTURE CONTROL:
The VSKYLABS DC-3/C-47 is featuring an auto-lean/auto-rich mixture settings, as it is in the real DC-3's. It eliminates the need to install a (non-authentic) EGT in the panel, and also, while in auto-lean mode, the mixture will be automatically adjusted to the peak EGT for cruising. To incorporate this feature into the mixture handles, I had to setup the operation method of the mixture handle so it will be effective also for shutting down the engines. It is very simple, as described in the instructions and the screenshot below:
  • Clicking at the "Auto Rich" zone:
    • Both engines set to "Manual Leaning".
    • Mixture control is "Normal": From 100% rich to 0% (shut off).
    • Mixture levers can be operated with the mouse (click and drag).
  • Clicking at the "Auto Lean" zone:
    • Both engines set to "Auto Lean".
    • Mixture is automatically set to peak EGT at all flight conditions.
    • Mixture levers can be operated only to "Auto Lean" or the "Shut off" positions.
    • Mixture levers can be operated with the mouse (click and drag), but only between the Auto Lean and Shutoff zones.
  • Switching between modes of operation:
    •  Simply click on the desired mode of operation zone.

AUTOPILOT:
Version 001 is incorporating A Sperry type Autopilot with the basic DC-3 configuration of Elevator (nose attitude for pitch) and Ailerons (bank angle). Maintaining heading ("Rudder") could not be setup and changed during flight (as it was in the real aircraft). Future versions will probably include the heading mode and other experimental aspects with the autopilot.

Autopilot Operation:
  1. Trimming the aircraft.
  2. Engaging the autopilot.
  3. Corrections for pitch and bank (thus heading) are made with the 'elv', 'ail' knobs.
  4. Heading ("Rudder") mode is not available in version v001 (one can using the setting knob of the upper scale as an independent heading bug). 
  5. In this workflow, it is quite easy to fly with the autopilot, even in a rapid navigation route. The aircraft is responding nicely and unless you tried to engage the autopilot while flight situation wasn't stable, it is very comfortable. Every once in a while a minor heading correction (using the bank knob) is needed. Not an annoying workload.

Autopilot Further Information:
The Sperry Autopilot which was used in the C-47 in the late 40's and 50's featured 3 knobs: ailerons "hold", rudder "hold" and pitch "hold". I wrote "hold" because the autopilot was in fact a gyro-pilot, and the axes were coupled to the relevant gyro axis (the "cage" was used for setting the gimbals).

Maintaining a desired pitch angle or bank angle using a gyro-pilot is easy to understand. I would like to put some light about the "rudder" knob, and the compass/setting scales that are related to it in the autopilot panel:

In the autopilot panel there is a compass scale window (lower scale is actual aircraft heading, and upper scale is a setting scale, biased to the "rudder" knob in the autopilot panel). The human pilot maintained a certain heading with his trimmed aircraft before engaging the autopilot. Then he used the rudder-knob to set up the upper scale to match with lower scale which presented the current aircraft heading (stable heading as the aircraft is trimmed). Then, he engaged the autopilot and the autopilot could maintain this heading with rudder control (gyroscopic attitude of the heading and not magnetic heading). So, in fact, while the autopilot could maintain a certain "heading", it could not turn into a new heading and then to maintain it.

So, heading corrections and resetting could not be achieved while flying in the real DC-3 C-47, with the use of the "scale-heading bug" in the autopilot panel...

Here is a quick link to the C-47 Sperry Autopilot control panel taken from the Skytrain manual: https://drive.google.com/open?id=0B18IAG6g43Y_a1dHeWpLNUJkdm8

TAIL WHEEL LOCK AND CONTROL:

There are TWO modes of operation:
  1. Novice (default): "Locked" is actually an "augmented lock" state. While "locked" the aircraft can be operated as a conventional tail-dragger with additional tail-wheel steering ability (not realistic, but will make taxi more easy for the novice pilots).
  2. Expert (toggle mode): "Locked" is totally locked. To enable this feature simply click on the Lock-Light-Indicator, and the letters "EX" will appear on the light itself, indicating that it is now in "Expert mode".
  3. In both modes...Tail Wheel Lock operation should be made only by using the Tail-Lock handle at the lower pedestal.

AIRSPEED INDICATOR ADJUSTABLE TAB:



WINDSHIELD WIPERS:

Use the Windshield Wipers handle to operate:


NAVIGATION AND COMMUNICATION:
Aircraft is including: 2*COMM, 2*NAV, 2*ADF, 2*DME in the overhead panel. All radios are equipped with working volume control knobs.

Aircraft is including: Radio Compass with fixed card (biased to ADF1), RMI with rotating card and NAV1/2 ADF 1/2 needles and switches, CDI+OBS, OMI markers.

FUEL SYSTEM OPERATION AND READINGS:
Fuel system is including Main L, Aux L, Main R, Aux R tanks with a cross-feed. Fuel consumption selection is only between the Left and the Right Main tanks, while the Aux tanks will start to feed in the engines when the Main tanks are empty (on each side). So, effectively and physically we have 4 tanks, all 4 can feed the engines but the selector can select Main L or Main R only (X-Plane default fuel system limitation...stretched to its its limits...). EDIT: Fuel system may be setup in the future so it will manage automatically the fuel level on each side, between the Aux and the Main...



FLAPS AND GEARS:
  1. Could be operated also by their handles (point and click).
  2. Flaps are set to be infinitely-adjustable between up/down when using keyboard or assigning a button/hardware switch.
  3. FLAPS operation by the handle itself (with the mouse) it is setup with a 3 click zones - for "up", "half" and "down" modes.
  4. GEARS operation by the handle is setup with 2 click zones - for "up" and "down".

HIDE THE YOKES:
When a full view of the instrument panel is needed, click on the aluminum plate underneath the left pilot seat, in front for the Rudder pedals:



TRIM-TABS OPERATION:
The real C-47/DC-3 Surface Control System consists of elevators, ailerons and rudder, which are made of metal frames covered with fabric. There are all-metal Trim-Tabs on the elevators, the right aileron and on the rudder.
  • Operate Trim-Tabs for elevators by using the wheel on the left side of the pedestal.
  • Operate Trim-Tabs for ailerons and rudder by using the hand cranks on the lower part of the pedestal.

Landing Gears Skis:
The VSKYLABS DC-3/C-47 Flying Lab is equipped with landing gear skis. In real life, the skis are installed for operation on snow and ice covered terrain. The skis system is an integral part of the aircraft, but can be switched on and off (default state is "off"), simply by using the ski selector handle which is installed below the side window to the left of the pilot's seat (left seat).


Activating the skis will affect the flight model physics with additional drag forces that will be induced around the skis, and as a result of the location of the skis below the CG, will induce a slight nose-down moments that will require re-trimming of the aircraft. The main wheels tires extend approximately 8 inches below the bottom surface of the skis.




Ski Take-Off:
  • The ski takeoff is similar to the normal wheel takeoff. The run may be longer depending upon surface condition. It is recommended to lower the wing flaps to 1/4 DOWN.
  • To avoid nose-over, the entire ground run should be made in a 3-point or tail low attitude. Excessive back pressure on the yoke will cause the tail wheels to dig-in and increase friction. To get the aircraft as soon as possible to the air, normally 45 inches MP is used.
  • After becoming airborne, relax back pressure immediately and continue accelerating until a safe airspeed is attained. The flaps should be retracted slowly (with short pauses) between 80 and 110 mph.
  • Note: X-Plane is not simulating true snow/ice when the aircraft is 'off-runway', and takeoff run is much longer when trying to takeoff from a point which is located off-runway (not on an X-Plane 'snow air strip').
  • Real life tip (currently not practicable in X-Plane...): Depending upon snow conditions, it may be advisable to prepare several tracks along the planned takeoff path by taxiing over the length of the run several times prior to takeoff. This procedure is assisting in shortening the takeoff run. 
Ski Landing:
  • Expect a much shorted landing slide than a normal landing. A reference point should be picked up to aid in maintaining direction.
  • It is recommended that half flaps be used.
  • All skis landing should be made tail low, and slightly above stalling speed. Immediately upon touchdown, reduce power, hold the control column full back and raise the flaps as soon as possible. 
  • When landing with low visibility and no horizon, depth perception is difficult when no visual reference points are available. Under these conditions, it is necessary to establish a constant rate of descent and attitude with the use of power and "fly on" at a slow sinking rate until contact with the surface is made in the tail low (3-point) landing attitude).
  • Under average load conditions with gear and skis down and half flaps, a descent of approximately 300 feet per minute at an airspeed of 90 to 95 mph is recommended.

XC-47C - A DC-3/C-47 with floats (only for upcoming version 2.7):

The VSKYLABS DC-3/C-47 Flying Lab project is including a second variant of the DC-3/C-47. It is the XC-47C variant, which was intended to be used in the Pacific, with its amphibious capabilities for use around islands without airfields.



The Edo Corporation, of College Point, N.Y. designed twin, 1-ton floats, (the largest floats ever built). Each float was 42 feet long. Each float also had a 325 gallon fuel tank. The floats had fully retractable, hydraulic wheels, and could land on water, snow or land. The float rudders were connected to the air rudder.

The XC-47C weighed 34,162 pounds and it was difficult to launch in rough water. It had a high tire failure on land, and was difficult to handle in a crosswind landing. The XC-47C was slow on take-off and it was also about 30 mph slower than the conventional DC-3/C-47.

Development note: The VSKYLABS XC-47C will be implemented in the VSKYLABS DC-3/C-47 Project is steps. The initial step (v2.7) will not include the additional ~300 gallon fuel tanks. Maximum weight limitations are the same as in the conventional variant. Additional, extensive flight testings are planned down the road to set the XC-47C with these as well.

The XC-47C floats are featuring retractable landing gears. The two front wheels are free-castors wheels. Steering is made by the use of differential braking and power. Ground taxi should be carried out nice and easy, and there is no need to use the tail-wheel lock handle upon takeoff.

Water rudders are effective in water. They are set up to retract automatically when the landing gears are deployed, to avoid water-rudder ground strike on land operations.



Ground operations notes for the EDO-78:

  • Ground operations with the EDO-78 floats is straight forward. 
  • The front wheels are not connected to a steering system. Use differential braking and power to execute a turn or to fine-tune it.
  • To make a tight turns, come to a full stop, then execute the turn while taxiing slowly, with the use of differential power and braking.
  • During the takeoff run, pay attention to rotation speed. The aircraft/floats landing gears configuration will allow an early nose-up attitude while running, especially with full power. On shorts runways, make sure to ease up the nose attitude right after liftoff, to prevent a non-climbing aircraft situation, or stalls.
  • Landings should be carried out normally.

Water operation notes for the EDO-78:
  • The EDO-78 floats are equipped with operational water rudders. Steering the aircraft on water with rudder, water rudder and differential power. At low speed, controlled high power "boosts" will help the aircraft in tight turns.
  • Takeoff should be carried on calm water with a headwind component.
  • For take off - use approximately 25% flaps down configuration.
  • Make sure that X-Plane's anchor is not deployed (it is deployed like parking brakes in X-Plane, with an on-screen notification).
  • Apply takeoff power and let the aircraft to build up airspeed.
  • Rotation should be carried out firmly, not below 70-75mph.
  • Nose attitude should be fixed in a shallow climb-out attitude until airspeed has reached 90mph. At low airspeed/high power takeoff a tendency for a slight pitch up moment should be anticipated.
  • Landings should be carried out normally.

COCKPIT SIDE WINDOWS OPERATION :
The VSKYLABS DC-3/C-47 Flying Lab is featuring sliding cockpit side-windows. To slide open or close, simply point and click on either one of the side windows handles (XP11) or the whole window area (XP10.51). In X-Plane 11 version, opening the window will let the external sounds to get into the cockpit.




RAIN EFFECT:
The VSKYLABS DC-3/C-47 Flying Lab Project is featuring rain-effect. The rain effect is applied automatically every time the aircraft is sensing rainy conditions. Note that when setting rainy weather, but flying out of the rain areas, the rain effect will not have any effect.

The rain effect is visible on both sides of the windshields, and can be seen in external view.

Here are a few screenshots, demonstrating the phases of the effect, depending on flying conditions and wipers operations:



ICING VISUALIZATION (only for upcoming version v2.7):
The VSKYLABS DC-3/C-47 Flying Lab Project is featuring icing visualization. The visualization has four (4) steps of icing status representations, and it is working side be side with X-Plane's flight dynamics model and icing conditions simulation.



Icing will form around the aircraft surfaces (mostly wings and other high-velocity air inlets/flows), when the atmospheric conditions will allow. Icing condition exist when the surrounding air contains droplets of supercooled water, which are forming into ice around "ice grains", which is the initial infrastructure for wide-spread ice forming.

Ice forming on aircraft surfaces may result in adding excessive weight, degraded aerodynamics and performance (stall speed is higher with ice load). Flying in ice conditions may get dangerous, and throughout aviation history, it is one of the reasons for aircraft accident and fatalities.

When flying in a suspected icing condition situation, it is important to monitor outside are temperature gauge, and to visually inspect the wings for ice existence.

There are several types of structural ice, here are the major ones:
  • Clear ice - it is clear and smooth, very difficult to identify inflight.
  • Rime ice - rough and opaque, formed by rapid freeze of drops upon impact with the surface. It will form mostly along the aircraft's stagnation points (direct impact). It will start to form around the leading edges of the wings, and will gradually spread along the airfoil, usually up to the thick area.
  • Frost ice - water freezing on unprotected surfaces while the aircraft is standing still (parking etc..). This type of icing may be fatal as it will disrupt the airfoil boundary layer airflow, dramatically increase drag and in many cases, will make takeoff impossible within the limits (runway/aircraft).  

Effect of ice:
The wings will stall sooner, at lower angel of attack (higher airspeed). Stall characteristics with ice may be degraded, resulting in more severe/violent outcome. Ice forming my be asymmetric between the two wings, resulting in roll moments and different stall speed of each one of the wings. If ice remains on wings it is recommended to increase approach speeds.



The VSKYLABS DC-3/C-47 Flying Lab Project ice visualization is working side by side with X-Plane's icing simulation. If the atmospheric conditions are right, ice will start to form on the aircraft. The ice visualization will give you a visual representation of the icing, with a 4-progressive steps. In real life, wing inspection during flight is one of the crucial actions for the aircrew to carry when icing conditions are existing. Now, you will be able to do so too!

When icing is forming around the wings/windows, activate the Deicing equipment for the wings/windows by using the the Deice wing boots and window switches.




CARGO/PASSENGER MODES OPERATION:
The VSKYLABS DC-3/C-47 Flying Lab Project will feature a detailed cargo configuration in future updates. The mechanism for switching the aircraft interior from Passenger mode to Cargo mode is simple and intuitive.

All you need to do is to turn your head back (when sitting in cockpit view), point and click on the first two seats to the left (right hand side seats when looking to the nose section).

This is a Toggle-Switch mechanism, so clicking in the same area again will bring back the seats:


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