Using the Sperry ... FSX

FSX Sperry Autopilot

  1. On-Off indicator
  2. Heading Adjustment
  3. Pitch Adjustment
  4. Autopilot heading
  5. Aircraft Heading … same as DG heading
  6. AP On-Off switch
  7. Correction Control to synchronize DG with compass reading
  8. AP Pitch Reference Window
  9. Actual Aircraft Pitch
  10. Horizon Reference
  11. Attitude reference knob … adjust to show level flight
  12. AP Caging knob 12 … this knob locks the AP gyros so they won’t be damaged in heavy turbulence. Notice that there is also a caging knob on the Artificial Horizon on the main panel, for the same reason.

The "Sperry Gyropilot for Aeroplanes" was a remarkable invention. It was superior to other designs since there was no direct mechanical linkage to the gyroscope, thus preventing the possibility of the sensitive gyro element being disturbed.

There is a natural tendency for a pilot to distrust any mechanical device which its designers claim will do a job that formerly depended on his own skill and experience. It is almost an aggravation to find one's aeroplane is being flown as accurately under automatic control as when it is receiving all the concentrated attention on the part of a human pilot to maintain course and altitude.

In time, airline pilots overcame these prejudices, if not quite ready to admit that the "Gyropilot" might even fly the aeroplane more accurately than they.

The Sperry Autopilot is a fun instrument to fly. It requires much more attention than the more modern autopilots, but all of this adds enjoyment to flying the DC-3. Once you have gone through the explanations below, you'll enjoyably engage the Sperry for many of your flights.

You will find that the Sperry Autopilot is very easy to understand, and a very straight-forward instrument, once you have read these operation procedures,. It's a lot of fun piloting an aircraft with the Sperry engaged because you are actively in control at all times. You won't be dozing at the controls at all.

The Sperry Autopilot Controls

1) The Heading Control.

Sperry Heading ControlThe real Sperry Autopilot, and those modelled by third-parties in versions earlier than FS2004, maintained heading by rudder control, not by aileron control. For reasons known only to Microsoft they have inaccurately modelled the FS2004 Sperry to perform like a modern Autopilot for heading control. That is a disappointment, but we’re stuck with it.

The operation of the Heading Control unit is very simple. Control #1 in the upper right corner adjusts the autopilot heading hold. You may set the autopilot heading either by left-clicking on knob #1 or by moving the heading bug on your Directional Gyro, if one exists on your panel.

As you adjust knob #1 to change the AP heading hold, the upper scale in the AP window, #2, will rotate to indicate the selected heading.

The lower scale portion of the heading indicator (4) is a directional gyro similar to the primary directional gyro on the aircraft panel.

In the real Sperry, with the AP disengaged, the pilot manually turned the aircraft to the desired heading, then rotated the heading knob, #1, so that scales 2 and 3 in the window were exactly aligned, then engaged the autopilot. The real Sperry maintained a heading, did not turn an aircraft top a heading.

With the FS2004 Sperry one can select the desired heading with knob 1 and the aircraft will bank and turn to the desired heading.

Each mouse-click of the heading knob, plus or minus, will change the selected heading by one degree. That is the procedure, for example, to keep the localizer needle centered while flying the ILS.

2) The Pitch Control.

Sperry pitch controlHappily, the FSX Sperry Pitch Control nicely models the real Sperry Autopilot in performance. Controlling aircraft pitch with the Sperry autopilot is easy. “Rotate” the “Pitch” knob, #4, by clicking on it. The plus sign that appears when the mouse is on the knob indicates a positive climb, while the negative sign indicates reducing the climb or an actual descent.

Adjusting the Sperry for a climb moves the AP Attitude Reference window, #3, in a downward direction. The horizon bar, #2, will move down into the reference window. This increases the distance between the aircraft wings, #1, and the horizon indicating a climb.



Here are three examples of the Sperry AP Pitch unit for various flight situations.

Level flight


Level Flight




Sperry pich control - climb 



Aircraft is above the horizon.  



Sperry pitch control - descend 



Aircraft is below the horizon 


1) Using the Sperry when climbing … Adjust power settings for climb configuration, 36 in MP and 2350 RPM. Adjust the Sperry pitch control to set the airspeed at 105 kts, the Best Rate of Climb airspeed.

2) Using the Sperry when descending from cruise altitude … Adjust the power settings for descent configuration, about 18 in MP and 2050 RPM. Adjust the Sperry pitch control for desired descent speed, usually about cruise speed, then adjust power to maintain 500 fpm descent.