A-5 Autopilot Control Unit: Documentation

2banaviator · **Posted:** Wed Jan 25, 2017 3:21 pm

I was thrilled to find an exceptional specimen of the Sperry A-5 Autopilot control unit to add to the menagerie (which includes the A-5 PDI and the typically-mated Sperry T-1 Bomb Sight). An Acceptance tag shows that it transferred from the Ford (B-24?) plant and has a yellow tag dated 1944. I've been looking for some A-5 technical manuals, and any leads would be appreciated.

Also, I've located references citing its use in B-24's, but none yet citing its use in B-17's or any bomber-trainer aircraft. Any info on use in B-24's and any aircraft would be appreciated.

More info/photos on it can be found here https://aeroantique.com/products/autopilot-control-panel-a-5-sperry as well.

Its not for sale, but perhaps for donation some day to an aviation museum or a B-24 restoration project.

Thanks in advance.

ALOHADAVE · **Posted:** Thu Jan 26, 2017 12:22 am

Sperry A-5 Autopilot system see picture below
Trim tab
Control Unit
Gyro
Amplifier
Follow up and Comp Mech. (type 9)

Sperry A-5 autopilot was the first all-electric autopilot. The autopilot used three dual-element vacuum tube amplifiers and high-speed gyros. Each amplifier was associated with a different axis: Yaw, pitch, and roll. The high-speed gyros were more sensitive and established a base reference level of the aircraft’s level flight path. Whenever the aircraft deviated from the base reference level, the autopilot adjusted for the amount of time that occurred between the changes in reference levels. This allowed the autopilot to detect the velocity and acceleration of the change. The calculated change was then communicated quickly to the control surfaces by independent electro-hydraulic servos. This led to faster, more stable corrections of the aircraft.
The faster stabilization of the aircraft by the A-5 autopilot made it possible for new bombsights to be used on military aircraft. The Norden Bombsight and Sperry Bombsight were both used onboard Army and Navy bombers during the war. Both bombsights used gyroscopes, telescopes and analog computers to calculate the release point for bombers to drop their payloads accurately onto ground targets. The A-5 had the ability to be integrated with these bombsights. Once the bombardier found the target and adjusted the bombsight, the autopilot would be engaged to fly the aircraft straight and level to the target, where the bombsight would automatically calculate the release point of the bombs.

I sold my stuff to Taigh Ramey for use on his PV-2 Harpoon

Taigh Ramey · **Posted:** Fri Jan 27, 2017 2:36 pm

I bought these items for the museum's collection specifically for the Sperry S-1 sight. We will use it for the bombsight display and the newly built A-2 bombsight trainer. The S-1 sight and A-5 autopilot were not used on the Harpoon, or other Navy aircraft that I am aware of, but the system was used for training in the Beech AT-11 and in combat in the B-24 and possibly the B-17 but I am not certain of this.

I have met bombardiers who said that they trained on the Norden only to get to the theatre of operations and find the Sperry in use. Those that I have talked to have said that the Sperry was not only as good as the Norden but that it was easier to use and they liked it better. It seems that the military wanted one system so they chose the Norden over the Sperry and cancelled further contracts. I believe this was in 1944 but again I am not certain of the specific date.

I have most of the components to put the Sperry system together and I intend to fly it some time in the AT-11 or maybe in the B-24 for Bomber Camp.

Warbird Information Exchange

A-5 Autopilot Control Unit: Documentation

Who is online