Hello, Gian.
This is MAAM-SIM manual -
SPERRY AUTOPILOT OPERATION
DEVELOPMENT HISTORY Shortly after the original R4D panel was uploaded I received a very complimentary e-mail from Arne Bartels, the designer of the original Sperrypilot gauge used in virtually every FS DC-3 panel, and many other aircraft. When I did my second panel for the R4D, Arne offered to do a new version of the venerable autopilot to exactly match the one aboard R4D #508819. I jumped at the offer and made a special trip back to Reading to get the close-up digital photos I would need to produce the graphics for Arne. In short order, he had programmed the new gauge which has some terrific new features and which is now familiar to thousands who use the R4D and its many repaints, as well as a number of other panels, since we offered it as freeware for developers to use. Now, in this latest version, I have redone the graphics yet again, since the quality of my camera has improved quite a bit from v1 of the R4D panel.
HOW THE SPERRY CONTROLS FLIGHT The Mark III is very different in operation from modern autopilots that hold set altitudes, headings, rates of climb and descent, and so on. The Sperry tends to control ATTITUDES, namely BANK, and PITCH angles. I say tends to control, because what the Sperry is really controlling are the angles held by the elevators and ailerons. So it really isn't accurate to claim it will hold attitudes, since these can be affected by changes in aerodynamic forces. For instance, as every pilot knows, wind will affect the angle of bank for a given aileron angle as the aircraft turns through the direction of the wind. Even Trixie, your slightly overweight stewardess, bringing you a cup of java from the aft galley will cause a change in pitch trim, even though you have the Sperry set to hold a specific elevator angle. The YAW axis is handled differently. The Sperry will hold a gyro compass heading (by use of the rudder alone). So, to summarize, the Sperry does not hold a set altitude, nor a rate of climb or descent, as the modern AP does, but it will hold a given gyro-compass heading.
OPERATING THE MARK III The Sperry takes a bit of practice to master. But once familiar with its capabilities and quirks, many FS pilots love it. It's part of the old time charm of this plane. OK, here we go...
There are three gauges and a number of control knobs and wheels which make up the U.S. Navy Mark III Automatic Pilot mounted in the panel of R4D #50819. The first gauge is the Heading Indicator (HI), on the left side of the unit, which has two moving scales or cards. The upper one is controlled by the first of three control knobs at the top of the AP. The knob is marked RUD. The lower card is the AP's Directional Gyro (DG), adjusted by clicking on the left and right of the caging and adjustment knob just below it. Note: This knob will also adjust the main DG's on both panels. Pressing the D key will calibrate all three DG's with the magnetic heading of the aircraft. If you have set up your options to include gyro drift, you should periodically calibrate your DG's by hitting the D key. When turned On (see later section on master switch), lining up these two cards will cause the Sperry AP to hold the present heading using the rudder.
IMPORTANT: There is a bug in FS2004 that causes its DG and the main DG to adjust only in 10-degree increments when the Sperry is switched ON. When it is OFF, the card will adjust in one-degree increments. There is no known fix for this problem, however, as a work-around, using the wheel on a wheel mouse will allow single-degree adjustment.
The center gauge is the Artificial Horizon (AH). There are two fixed alignment index marks and corresponding moveable pointers, called follow-up indexes. The pair at the top are set by the center control knob, marked AIL. When the marks are aligned, and the unit is On, the ailerons will hold the present roll attitude. Moving the follow-up index to the right of the alignment index will cause the ailerons to hold a banked attitude in that direction. The pair of marks on the right side of the AH are controlled by the right hand knob marked ELE and are used to maintain a set pitch attitude, using the elevators.
The third gauge is the Vacuum Gauge and registers the suction of the instrument vacuum system required to operate the gyros. The correct reading should be between 3.75 and 5 hg, shown by the heavy white arc on the gauge.
Below and to the right of the artificial horizon is the autopilot's Master ON/OFF Knob. Note that ON is on the left, a counter-clockwise twist. It's a rather atypical arrangement these days, so it will take some getting used to. Mouse click on the desired side to move the white pointer. This knob can also be operated remotely by the key command Z.
ADJUSTING CONTROL FORCE SENSITIVITY The three SPEED VALVE control wheels at the bottom edge of the unit are used to vary the sensitivity of the Sperry's hydraulic controls. Since it was designed specifically for this plane and panel, Arne has made the center setting of the Mark III's wheels normal for the R4D. Just click on the center of a wheel to set it to normal. When loading the R4D into FS, the wheels will be centered by default. Each wheel controls one axis and is situated below the corresponding gauge and control knob. Rotating the wheels toward a higher number, by clicking repeatedly on their right sides make the controls more sensitive, while clicking on the left makes them less so. You may hold the mouse button down for continuous movement.
Don't be thrown by that arrow and the "sensitivity increase" label in relation to the mouse points. Think of the mouse points as where you would initially place your finger to rotate the wheel in the desired direction. Practice using the wheels in conjunction with the "RUD", "AIL", and "ELE" knobs to fine tune your control. Anyone can set digital readouts and push lighted buttons on a modern AP -- but it takes a virtuoso to master the Sperry's wheels and knobs to make the Douglas do your bidding!
