Bendix "polar path" directional gyro system

[judderbar]

Hi, I am just a hobbyist who has bought a polar path transmitter gyro off ebay and I have begun to investigate how the gyro I bought and the computer system it was connected to worked. This system is fairly famous for opening up the polar routes in the 1950's and proved so accurate it was fitted to the UK VC10's. The system used what appears to be a typical directional gyro arrangement with the gyro axis electrically maintained in a horizontal position, while the gyro was otherwise free to move as it wanted with a synchro connection to the computer. The gyro could be used as a free gyro with no magnetic correction because it had a very low error drift rate of 1 degree per hour, I have found some basic information about it but I am really struggling to understand how the directional gyro was corrected for earth rotation and transport drift when it appears there was no speed information of any kind being fed to the computer and all the computer had to work with was the latitude correction added by the crew and the position of the gyro. Meanwhile a VC10 cruises around 500mph which is a very significant speed compared to Earth rotation - more so near the poles.

Is there likely to be any RAF or airline documentation for a device like this?

Finally, am I right in believing as a stand alone device, the gyro be used to get Earth rotation and therefore calculate latitude?

Thanks

Andrew

[plhought]

I'm actually pretty sure those early gyros (indeed most physical gyros still today) were used only to figure out heading.

Sounds a lot like the good ol' C14 Latitude Compensating gyro still used in a lot of stuff today.

Latitude and positioning would have been a combination of Sextant and perhaps the occasional Astro-Compass look to double check heading.