Uploaded June 2026 | Updated September 2026, 2 weeks ago
Introduced by the Pioneer division of the Bendix Corporation in 1944, the AN5841 and the associated 12580-3-B Air Position Indicator System were used aboard late and post-war long-range military aircraft including the B-29 Superfortress. The system integrates air mileage data from a pressure pump system with heading data from a compass to continuously track the aircraft's latitude and longitude from its point of departure. The navigator could then add the wind vector to determine the true ground position.
Thank you to Tim from the channel Wistarmo Moore for providing the technical documentation that made this video possible! youtube.com/@UCsxIJ8GIz9jiDURR95Uw_UQ
Air Mileage Unit Mk.I video: youtu.be/HPVWMNp9EVE
E6B Flight Computer video: youtu.be/__0F6JAXj8U
Jeppesen CR-3 Flight Computer video: youtu.be/FDje5ASk_Nc
Coutinho Course Corrector video: youtu.be/01hIn1YRh8A
Vetrochet Course Corrector video: youtu.be/4I5hT6Y3f3g
Course Corrector, Pelorus, and Marine Computer video: youtu.be/Lsa_UrnO-e4
Drift Sights video: youtu.be/weT_cEWoCBQ
Sextant video: youtu.be/RnXauBYXPSE
Astrocompass video: youtu.be/xBScbuBYv0w
Astrograph video: youtu.be/2RJqo5oNbWk
Planimeter video: youtu.be/tfVHBVGdOsg
TIFO Fisher P-75 Eagle video: youtube.com/watch?v=c0hUlf6gius&pp=ygUidG9kYXkgaSBmb3VuZCBvdXQgZGVzaWduZWQgdG8gZmFpbA%3D%3D
0:00 Introduction
1:40 Basic Principles
2:24 Air Mileage System
5:21 Compass System
6:27 Computer Dial and Controls
7:52 Computer Inputs
8:30 Computer Mileage System
8:43 Ball and Disk Integrators
9:20 Latitude/Longitude System
10:45 Meridian Convergence Compensation
11:34 Heading System
12:20 Rocker/Ratchet Mechanism
13:07 Autosyn Repeater
14:09 Motorized Drive
14:34 Autosyn Adjustment Mechanism
15:12 Variation Mechanism
15:25 Outro
SOURCES
AN-05-35-36: Overhaul Instructions With Parts Catalog for Air Position Indicator System (Eclipse-Pioneer), United States Army Air Forces, May 17, 1946 [*can be supplied on request*]
aeroantique.com/products/air-position-indicator-system-computer-12580-1-b?variant=31261065347161
usautoindustryworldwartwo.com/Fisher Body/fisherbodyternstedt.htm
scribd.com/document/439811363/selsyn-desyn
Introduced by the Pioneer division of the Bendix Corporation in 1944, the AN5841 and the associated 12580-3-B Air Position Indicator System were used aboard late and post-war long-range military aircraft including the B-29 Superfortress. The system integrates air mileage data from a pressure pump system with heading data from a compass to continuously track the aircraft's latitude and longitude from its point of departure. The navigator could then add the wind vector to determine the true ground position.
Thank you to Tim from the channel Wistarmo Moore for providing the technical documentation that made this video possible! youtube.com/@UCsxIJ8GIz9jiDURR95Uw_UQ
Air Mileage Unit Mk.I video: youtu.be/HPVWMNp9EVE
E6B Flight Computer video: youtu.be/__0F6JAXj8U
Jeppesen CR-3 Flight Computer video: youtu.be/FDje5ASk_Nc
Coutinho Course Corrector video: youtu.be/01hIn1YRh8A
Vetrochet Course Corrector video: youtu.be/4I5hT6Y3f3g
Course Corrector, Pelorus, and Marine Computer video: youtu.be/Lsa_UrnO-e4
Drift Sights video: youtu.be/weT_cEWoCBQ
Sextant video: youtu.be/RnXauBYXPSE
Astrocompass video: youtu.be/xBScbuBYv0w
Astrograph video: youtu.be/2RJqo5oNbWk
Planimeter video: youtu.be/tfVHBVGdOsg
TIFO Fisher P-75 Eagle video: youtube.com/watch?v=c0hUlf6gius&pp=ygUidG9kYXkgaSBmb3VuZCBvdXQgZGVzaWduZWQgdG8gZmFpbA%3D%3D
0:00 Introduction
1:40 Basic Principles
2:24 Air Mileage System
5:21 Compass System
6:27 Computer Dial and Controls
7:52 Computer Inputs
8:30 Computer Mileage System
8:43 Ball and Disk Integrators
9:20 Latitude/Longitude System
10:45 Meridian Convergence Compensation
11:34 Heading System
12:20 Rocker/Ratchet Mechanism
13:07 Autosyn Repeater
14:09 Motorized Drive
14:34 Autosyn Adjustment Mechanism
15:12 Variation Mechanism
15:25 Outro
SOURCES
AN-05-35-36: Overhaul Instructions With Parts Catalog for Air Position Indicator System (Eclipse-Pioneer), United States Army Air Forces, May 17, 1946 [*can be supplied on request*]
aeroantique.com/products/air-position-indicator-system-computer-12580-1-b?variant=31261065347161
usautoindustryworldwartwo.com/Fisher Body/fisherbodyternstedt.htm
scribd.com/document/439811363/selsyn-desyn
